/* * mpegtspacketizer.c - * Copyright (C) 2007, 2008 Alessandro Decina, Zaheer Merali * * Authors: * Zaheer Merali * Alessandro Decina * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Library General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Library General Public License for more details. * * You should have received a copy of the GNU Library General Public * License along with this library; if not, write to the * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, * Boston, MA 02110-1301, USA. */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include #include /* Skew calculation pameters */ #define MAX_TIME (2 * GST_SECOND) /* maximal PCR time */ #define PCR_MAX_VALUE (((((guint64)1)<<33) * 300) + 298) #define PCR_GST_MAX_VALUE (PCR_MAX_VALUE * GST_MSECOND / (PCR_MSECOND)) #define PTS_DTS_MAX_VALUE (((guint64)1) << 33) #include "mpegtspacketizer.h" #include "gstmpegdesc.h" GST_DEBUG_CATEGORY_STATIC (mpegts_packetizer_debug); #define GST_CAT_DEFAULT mpegts_packetizer_debug static void _init_local (void); G_DEFINE_TYPE_EXTENDED (MpegTSPacketizer2, mpegts_packetizer, G_TYPE_OBJECT, 0, _init_local ()); #define ABSDIFF(a,b) ((a) < (b) ? (b) - (a) : (a) - (b)) #define PACKETIZER_GROUP_LOCK(p) g_mutex_lock(&((p)->group_lock)) #define PACKETIZER_GROUP_UNLOCK(p) g_mutex_unlock(&((p)->group_lock)) static void mpegts_packetizer_dispose (GObject * object); static void mpegts_packetizer_finalize (GObject * object); static GstClockTime calculate_skew (MpegTSPacketizer2 * packetizer, MpegTSPCR * pcr, guint64 pcrtime, GstClockTime time); static void _close_current_group (MpegTSPCR * pcrtable); static void record_pcr (MpegTSPacketizer2 * packetizer, MpegTSPCR * pcrtable, guint64 pcr, guint64 offset); #define CONTINUITY_UNSET 255 #define VERSION_NUMBER_UNSET 255 #define TABLE_ID_UNSET 0xFF #define PACKET_SYNC_BYTE 0x47 static inline MpegTSPCR * get_pcr_table (MpegTSPacketizer2 * packetizer, guint16 pid) { MpegTSPCR *res; res = packetizer->observations[packetizer->pcrtablelut[pid]]; if (G_UNLIKELY (res == NULL)) { /* If we don't have a PCR table for the requested PID, create one .. */ res = g_new0 (MpegTSPCR, 1); /* Add it to the last table position */ packetizer->observations[packetizer->lastobsid] = res; /* Update the pcrtablelut */ packetizer->pcrtablelut[pid] = packetizer->lastobsid; /* And increment the last know slot */ packetizer->lastobsid++; /* Finally set the default values */ res->pid = pid; res->base_time = GST_CLOCK_TIME_NONE; res->base_pcrtime = GST_CLOCK_TIME_NONE; res->last_pcrtime = GST_CLOCK_TIME_NONE; res->window_pos = 0; res->window_filling = TRUE; res->window_min = 0; res->skew = 0; res->prev_send_diff = GST_CLOCK_TIME_NONE; res->prev_out_time = GST_CLOCK_TIME_NONE; res->pcroffset = 0; res->current = g_slice_new0 (PCROffsetCurrent); } return res; } static void pcr_offset_group_free (PCROffsetGroup * group) { g_free (group->values); g_slice_free (PCROffsetGroup, group); } static void flush_observations (MpegTSPacketizer2 * packetizer) { gint i; for (i = 0; i < packetizer->lastobsid; i++) { g_list_free_full (packetizer->observations[i]->groups, (GDestroyNotify) pcr_offset_group_free); if (packetizer->observations[i]->current) g_slice_free (PCROffsetCurrent, packetizer->observations[i]->current); g_free (packetizer->observations[i]); packetizer->observations[i] = NULL; } memset (packetizer->pcrtablelut, 0xff, 0x2000); packetizer->lastobsid = 0; } GstClockTime mpegts_packetizer_get_current_time (MpegTSPacketizer2 * packetizer, guint16 pcr_pid) { MpegTSPCR *pcrtable = get_pcr_table (packetizer, pcr_pid); if (pcrtable == NULL) return GST_CLOCK_TIME_NONE; return mpegts_packetizer_pts_to_ts (packetizer, pcrtable->last_pcrtime, pcr_pid); } static inline MpegTSPacketizerStreamSubtable * find_subtable (GSList * subtables, guint8 table_id, guint16 subtable_extension) { GSList *tmp; /* FIXME: Make this an array ! */ for (tmp = subtables; tmp; tmp = tmp->next) { MpegTSPacketizerStreamSubtable *sub = (MpegTSPacketizerStreamSubtable *) tmp->data; if (sub->table_id == table_id && sub->subtable_extension == subtable_extension) return sub; } return NULL; } static gboolean seen_section_before (MpegTSPacketizerStream * stream, guint8 table_id, guint16 subtable_extension, guint8 version_number, guint8 section_number, guint8 last_section_number) { MpegTSPacketizerStreamSubtable *subtable; /* Check if we've seen this table_id/subtable_extension first */ subtable = find_subtable (stream->subtables, table_id, subtable_extension); if (!subtable) { GST_DEBUG ("Haven't seen subtable"); return FALSE; } /* If we have, check it has the same version_number */ if (subtable->version_number != version_number) { GST_DEBUG ("Different version number"); return FALSE; } /* Did the number of sections change ? */ if (subtable->last_section_number != last_section_number) { GST_DEBUG ("Different last_section_number"); return FALSE; } /* Finally return whether we saw that section or not */ return MPEGTS_BIT_IS_SET (subtable->seen_section, section_number); } static MpegTSPacketizerStreamSubtable * mpegts_packetizer_stream_subtable_new (guint8 table_id, guint16 subtable_extension, guint8 last_section_number) { MpegTSPacketizerStreamSubtable *subtable; subtable = g_new0 (MpegTSPacketizerStreamSubtable, 1); subtable->version_number = VERSION_NUMBER_UNSET; subtable->table_id = table_id; subtable->subtable_extension = subtable_extension; subtable->last_section_number = last_section_number; return subtable; } static MpegTSPacketizerStream * mpegts_packetizer_stream_new (guint16 pid) { MpegTSPacketizerStream *stream; stream = (MpegTSPacketizerStream *) g_new0 (MpegTSPacketizerStream, 1); stream->continuity_counter = CONTINUITY_UNSET; stream->subtables = NULL; stream->table_id = TABLE_ID_UNSET; stream->pid = pid; return stream; } static void mpegts_packetizer_clear_section (MpegTSPacketizerStream * stream) { stream->continuity_counter = CONTINUITY_UNSET; stream->section_length = 0; stream->section_offset = 0; stream->table_id = TABLE_ID_UNSET; g_free (stream->section_data); stream->section_data = NULL; } static void mpegts_packetizer_stream_subtable_free (MpegTSPacketizerStreamSubtable * subtable) { g_free (subtable); } static void mpegts_packetizer_stream_free (MpegTSPacketizerStream * stream) { mpegts_packetizer_clear_section (stream); g_slist_foreach (stream->subtables, (GFunc) mpegts_packetizer_stream_subtable_free, NULL); g_slist_free (stream->subtables); g_free (stream); } static void mpegts_packetizer_class_init (MpegTSPacketizer2Class * klass) { GObjectClass *gobject_class; gobject_class = G_OBJECT_CLASS (klass); gobject_class->dispose = mpegts_packetizer_dispose; gobject_class->finalize = mpegts_packetizer_finalize; } static void mpegts_packetizer_init (MpegTSPacketizer2 * packetizer) { g_mutex_init (&packetizer->group_lock); packetizer->adapter = gst_adapter_new (); packetizer->offset = 0; packetizer->empty = TRUE; packetizer->streams = g_new0 (MpegTSPacketizerStream *, 8192); packetizer->packet_size = 0; packetizer->calculate_skew = FALSE; packetizer->calculate_offset = FALSE; packetizer->map_data = NULL; packetizer->map_size = 0; packetizer->map_offset = 0; packetizer->need_sync = FALSE; memset (packetizer->pcrtablelut, 0xff, 0x2000); memset (packetizer->observations, 0x0, sizeof (packetizer->observations)); packetizer->lastobsid = 0; packetizer->nb_seen_offsets = 0; packetizer->refoffset = -1; packetizer->last_in_time = GST_CLOCK_TIME_NONE; packetizer->pcr_discont_threshold = GST_SECOND; packetizer->last_pts = GST_CLOCK_TIME_NONE; packetizer->last_dts = GST_CLOCK_TIME_NONE; packetizer->extra_shift = 0; } static void mpegts_packetizer_dispose (GObject * object) { MpegTSPacketizer2 *packetizer = GST_MPEGTS_PACKETIZER (object); if (!packetizer->disposed) { if (packetizer->packet_size) packetizer->packet_size = 0; if (packetizer->streams) { int i; for (i = 0; i < 8192; i++) { if (packetizer->streams[i]) mpegts_packetizer_stream_free (packetizer->streams[i]); } g_free (packetizer->streams); } gst_adapter_clear (packetizer->adapter); g_object_unref (packetizer->adapter); g_mutex_clear (&packetizer->group_lock); packetizer->disposed = TRUE; packetizer->offset = 0; packetizer->empty = TRUE; flush_observations (packetizer); } if (G_OBJECT_CLASS (mpegts_packetizer_parent_class)->dispose) G_OBJECT_CLASS (mpegts_packetizer_parent_class)->dispose (object); } static void mpegts_packetizer_finalize (GObject * object) { if (G_OBJECT_CLASS (mpegts_packetizer_parent_class)->finalize) G_OBJECT_CLASS (mpegts_packetizer_parent_class)->finalize (object); } static inline guint64 mpegts_packetizer_compute_pcr (const guint8 * data) { guint32 pcr1; guint16 pcr2; guint64 pcr, pcr_ext; pcr1 = GST_READ_UINT32_BE (data); pcr2 = GST_READ_UINT16_BE (data + 4); pcr = ((guint64) pcr1) << 1; pcr |= (pcr2 & 0x8000) >> 15; pcr_ext = (pcr2 & 0x01ff); return pcr * 300 + pcr_ext % 300; } static gboolean mpegts_packetizer_parse_adaptation_field_control (MpegTSPacketizer2 * packetizer, MpegTSPacketizerPacket * packet) { guint8 length, afcflags; guint8 *data; length = *packet->data++; /* an adaptation field with length 0 is valid and * can be used to insert a single stuffing byte */ if (!length) { packet->afc_flags = 0; return TRUE; } if ((packet->scram_afc_cc & 0x30) == 0x20) { /* no payload, adaptation field of 183 bytes */ if (length > 183) { GST_WARNING ("PID 0x%04x afc == 0x%02x and length %d > 183", packet->pid, packet->scram_afc_cc & 0x30, length); return FALSE; } if (length != 183) { GST_WARNING ("PID 0x%04x afc == 0x%02x and length %d != 183", packet->pid, packet->scram_afc_cc & 0x30, length); GST_MEMDUMP ("Unknown payload", packet->data + length, packet->data_end - packet->data - length); } } else if (length == 183) { /* Note: According to the specification, the adaptation field length * must be 183 if there is no payload data and < 183 if the packet * contains an adaptation field and payload data. * Some payloaders always set the flag for payload data, even if the * adaptation field length is 183. This just means a zero length * payload so we clear the payload flag here and continue. */ GST_DEBUG ("PID 0x%04x afc == 0x%02x and length %d == 183 (ignored)", packet->pid, packet->scram_afc_cc & 0x30, length); packet->scram_afc_cc &= ~0x10; } else if (length > 182) { GST_WARNING ("PID 0x%04x afc == 0x%02x and length %d > 182", packet->pid, packet->scram_afc_cc & 0x30, length); return FALSE; } if (packet->data + length > packet->data_end) { GST_DEBUG ("PID 0x%04x afc length %d overflows the buffer current %d max %d", packet->pid, length, (gint) (packet->data - packet->data_start), (gint) (packet->data_end - packet->data_start)); return FALSE; } data = packet->data; packet->data += length; afcflags = packet->afc_flags = *data++; GST_DEBUG ("flags: %s%s%s%s%s%s%s%s%s", afcflags & 0x80 ? "discontinuity " : "", afcflags & 0x40 ? "random_access " : "", afcflags & 0x20 ? "elementary_stream_priority " : "", afcflags & 0x10 ? "PCR " : "", afcflags & 0x08 ? "OPCR " : "", afcflags & 0x04 ? "splicing_point " : "", afcflags & 0x02 ? "transport_private_data " : "", afcflags & 0x01 ? "extension " : "", afcflags == 0x00 ? "" : ""); /* PCR */ if (afcflags & MPEGTS_AFC_PCR_FLAG) { MpegTSPCR *pcrtable = NULL; packet->pcr = mpegts_packetizer_compute_pcr (data); data += 6; GST_DEBUG ("pcr 0x%04x %" G_GUINT64_FORMAT " (%" GST_TIME_FORMAT ") offset:%" G_GUINT64_FORMAT, packet->pid, packet->pcr, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (packet->pcr)), packet->offset); PACKETIZER_GROUP_LOCK (packetizer); if (packetizer->calculate_skew && GST_CLOCK_TIME_IS_VALID (packetizer->last_in_time)) { pcrtable = get_pcr_table (packetizer, packet->pid); calculate_skew (packetizer, pcrtable, packet->pcr, packetizer->last_in_time); } if (packetizer->calculate_offset) { if (!pcrtable) pcrtable = get_pcr_table (packetizer, packet->pid); record_pcr (packetizer, pcrtable, packet->pcr, packet->offset); } PACKETIZER_GROUP_UNLOCK (packetizer); } #ifndef GST_DISABLE_GST_DEBUG /* OPCR */ if (afcflags & MPEGTS_AFC_OPCR_FLAG) { /* Note: We don't use/need opcr for the time being */ guint64 opcr = mpegts_packetizer_compute_pcr (data); data += 6; GST_DEBUG ("opcr %" G_GUINT64_FORMAT " (%" GST_TIME_FORMAT ")", opcr, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (opcr))); } if (afcflags & MPEGTS_AFC_SPLICING_POINT_FLAG) { GST_DEBUG ("splice_countdown: %u", *data++); } if (afcflags & MPEGTS_AFC_TRANSPORT_PRIVATE_DATA_FLAG) { guint8 len = *data++; GST_MEMDUMP ("private data", data, len); data += len; } if (afcflags & MPEGTS_AFC_EXTENSION_FLAG) { guint8 extlen = *data++; guint8 flags = *data++; GST_DEBUG ("extension size:%d flags : %s%s%s", extlen, flags & 0x80 ? "ltw " : "", flags & 0x40 ? "piecewise_rate " : "", flags & 0x20 ? "seamless_splice " : ""); if (flags & 0x80) { GST_DEBUG ("legal time window: valid_flag:%d offset:%d", *data >> 7, GST_READ_UINT16_BE (data) & 0x7fff); data += 2; } } #endif return TRUE; } static MpegTSPacketizerPacketReturn mpegts_packetizer_parse_packet (MpegTSPacketizer2 * packetizer, MpegTSPacketizerPacket * packet) { guint8 *data; guint8 tmp; data = packet->data_start; data += 1; tmp = *data; /* transport_error_indicator 1 */ if (G_UNLIKELY (tmp & 0x80)) return PACKET_BAD; /* payload_unit_start_indicator 1 */ packet->payload_unit_start_indicator = tmp & 0x40; /* transport_priority 1 */ /* PID 13 */ packet->pid = GST_READ_UINT16_BE (data) & 0x1FFF; data += 2; packet->scram_afc_cc = tmp = *data++; /* transport_scrambling_control 2 */ if (G_UNLIKELY (tmp & 0xc0)) return PACKET_BAD; packet->data = data; packet->afc_flags = 0; packet->pcr = G_MAXUINT64; if (FLAGS_HAS_AFC (tmp)) { if (!mpegts_packetizer_parse_adaptation_field_control (packetizer, packet)) return FALSE; } if (FLAGS_HAS_PAYLOAD (packet->scram_afc_cc)) packet->payload = packet->data; else packet->payload = NULL; return PACKET_OK; } static GstMpegtsSection * mpegts_packetizer_parse_section_header (MpegTSPacketizer2 * packetizer, MpegTSPacketizerStream * stream) { MpegTSPacketizerStreamSubtable *subtable; GstMpegtsSection *res; subtable = find_subtable (stream->subtables, stream->table_id, stream->subtable_extension); if (subtable) { GST_DEBUG ("Found previous subtable_extension:0x%04x", stream->subtable_extension); if (G_UNLIKELY (stream->version_number != subtable->version_number)) { /* If the version number changed, reset the subtable */ subtable->version_number = stream->version_number; subtable->last_section_number = stream->last_section_number; memset (subtable->seen_section, 0, 32); } } else { GST_DEBUG ("Appending new subtable_extension: 0x%04x", stream->subtable_extension); subtable = mpegts_packetizer_stream_subtable_new (stream->table_id, stream->subtable_extension, stream->last_section_number); subtable->version_number = stream->version_number; stream->subtables = g_slist_prepend (stream->subtables, subtable); } GST_MEMDUMP ("Full section data", stream->section_data, stream->section_length); /* TODO ? : Replace this by an efficient version (where we provide all * pre-parsed header data) */ res = gst_mpegts_section_new (stream->pid, stream->section_data, stream->section_length); stream->section_data = NULL; mpegts_packetizer_clear_section (stream); if (res) { /* NOTE : Due to the new mpegts-si system, There is a insanely low probability * that we might have gotten a section that was corrupted (i.e. wrong crc) * and that we consider it as seen. * * The reason why we consider this as acceptable is because all the previous * checks were already done: * * transport layer checks (DVB) * * 0x47 validation * * continuity counter validation * * subtable validation * * section_number validation * * section_length validation * * The probability of this happening vs the overhead of doing CRC checks * on all sections (including those we would not use) is just not worth it. * */ MPEGTS_BIT_SET (subtable->seen_section, stream->section_number); res->offset = stream->offset; } return res; } void mpegts_packetizer_clear (MpegTSPacketizer2 * packetizer) { guint i; MpegTSPCR *pcrtable; packetizer->packet_size = 0; if (packetizer->streams) { int i; for (i = 0; i < 8192; i++) { if (packetizer->streams[i]) { mpegts_packetizer_stream_free (packetizer->streams[i]); } } memset (packetizer->streams, 0, 8192 * sizeof (MpegTSPacketizerStream *)); } gst_adapter_clear (packetizer->adapter); packetizer->offset = 0; packetizer->empty = TRUE; packetizer->need_sync = FALSE; packetizer->map_data = NULL; packetizer->map_size = 0; packetizer->map_offset = 0; packetizer->last_in_time = GST_CLOCK_TIME_NONE; packetizer->last_pts = GST_CLOCK_TIME_NONE; packetizer->last_dts = GST_CLOCK_TIME_NONE; pcrtable = packetizer->observations[packetizer->pcrtablelut[0x1fff]]; if (pcrtable) pcrtable->base_time = GST_CLOCK_TIME_NONE; /* Close current PCR group */ PACKETIZER_GROUP_LOCK (packetizer); for (i = 0; i < MAX_PCR_OBS_CHANNELS; i++) { if (packetizer->observations[i]) _close_current_group (packetizer->observations[i]); else break; } PACKETIZER_GROUP_UNLOCK (packetizer); } void mpegts_packetizer_flush (MpegTSPacketizer2 * packetizer, gboolean hard) { guint i; MpegTSPCR *pcrtable; GST_DEBUG ("Flushing"); if (packetizer->streams) { for (i = 0; i < 8192; i++) { if (packetizer->streams[i]) { mpegts_packetizer_clear_section (packetizer->streams[i]); } } } gst_adapter_clear (packetizer->adapter); packetizer->offset = 0; packetizer->empty = TRUE; packetizer->need_sync = FALSE; packetizer->map_data = NULL; packetizer->map_size = 0; packetizer->map_offset = 0; packetizer->last_in_time = GST_CLOCK_TIME_NONE; packetizer->last_pts = GST_CLOCK_TIME_NONE; packetizer->last_dts = GST_CLOCK_TIME_NONE; pcrtable = packetizer->observations[packetizer->pcrtablelut[0x1fff]]; if (pcrtable) pcrtable->base_time = GST_CLOCK_TIME_NONE; /* Close current PCR group */ PACKETIZER_GROUP_LOCK (packetizer); for (i = 0; i < MAX_PCR_OBS_CHANNELS; i++) { if (packetizer->observations[i]) _close_current_group (packetizer->observations[i]); else break; } PACKETIZER_GROUP_UNLOCK (packetizer); if (hard) { /* For pull mode seeks in tsdemux the observation must be preserved */ flush_observations (packetizer); } } void mpegts_packetizer_remove_stream (MpegTSPacketizer2 * packetizer, gint16 pid) { MpegTSPacketizerStream *stream = packetizer->streams[pid]; if (stream) { GST_INFO ("Removing stream for PID 0x%04x", pid); mpegts_packetizer_stream_free (stream); packetizer->streams[pid] = NULL; } } MpegTSPacketizer2 * mpegts_packetizer_new (void) { MpegTSPacketizer2 *packetizer; packetizer = GST_MPEGTS_PACKETIZER (g_object_new (GST_TYPE_MPEGTS_PACKETIZER, NULL)); return packetizer; } void mpegts_packetizer_push (MpegTSPacketizer2 * packetizer, GstBuffer * buffer) { GstClockTime ts; if (G_UNLIKELY (packetizer->empty)) { packetizer->empty = FALSE; packetizer->offset = GST_BUFFER_OFFSET (buffer); } GST_DEBUG ("Pushing %" G_GSIZE_FORMAT " byte from offset %" G_GUINT64_FORMAT, gst_buffer_get_size (buffer), GST_BUFFER_OFFSET (buffer)); gst_adapter_push (packetizer->adapter, buffer); /* If the buffer has a valid timestamp, store it - preferring DTS, * which is where upstream arrival times should be stored */ ts = GST_BUFFER_DTS_OR_PTS (buffer); if (GST_CLOCK_TIME_IS_VALID (ts)) packetizer->last_in_time = ts; packetizer->last_pts = GST_BUFFER_PTS (buffer); packetizer->last_dts = GST_BUFFER_DTS (buffer); } static void mpegts_packetizer_flush_bytes (MpegTSPacketizer2 * packetizer, gsize size) { if (size > 0) { GST_LOG ("flushing %" G_GSIZE_FORMAT " bytes from adapter", size); gst_adapter_flush (packetizer->adapter, size); } packetizer->map_data = NULL; packetizer->map_size = 0; packetizer->map_offset = 0; } static gboolean mpegts_packetizer_map (MpegTSPacketizer2 * packetizer, gsize size) { gsize available; if (packetizer->map_size - packetizer->map_offset >= size) return TRUE; mpegts_packetizer_flush_bytes (packetizer, packetizer->map_offset); available = gst_adapter_available (packetizer->adapter); if (available < size) return FALSE; packetizer->map_data = (guint8 *) gst_adapter_map (packetizer->adapter, available); if (!packetizer->map_data) return FALSE; packetizer->map_size = available; packetizer->map_offset = 0; GST_LOG ("mapped %" G_GSIZE_FORMAT " bytes from adapter", available); return TRUE; } static gboolean mpegts_try_discover_packet_size (MpegTSPacketizer2 * packetizer) { guint8 *data; gsize size, i, j; static const guint psizes[] = { MPEGTS_NORMAL_PACKETSIZE, MPEGTS_M2TS_PACKETSIZE, MPEGTS_DVB_ASI_PACKETSIZE, MPEGTS_ATSC_PACKETSIZE }; if (!mpegts_packetizer_map (packetizer, 4 * MPEGTS_MAX_PACKETSIZE)) return FALSE; size = packetizer->map_size - packetizer->map_offset; data = packetizer->map_data + packetizer->map_offset; for (i = 0; i + 3 * MPEGTS_MAX_PACKETSIZE < size; i++) { /* find a sync byte */ if (data[i] != PACKET_SYNC_BYTE) continue; /* check for 4 consecutive sync bytes with each possible packet size */ for (j = 0; j < G_N_ELEMENTS (psizes); j++) { guint packet_size = psizes[j]; if (data[i + packet_size] == PACKET_SYNC_BYTE && data[i + 2 * packet_size] == PACKET_SYNC_BYTE && data[i + 3 * packet_size] == PACKET_SYNC_BYTE) { packetizer->packet_size = packet_size; goto out; } } } out: packetizer->map_offset += i; if (packetizer->packet_size == 0) { GST_DEBUG ("Could not determine packet size in %" G_GSIZE_FORMAT " bytes buffer, flush %" G_GSIZE_FORMAT " bytes", size, i); mpegts_packetizer_flush_bytes (packetizer, packetizer->map_offset); return FALSE; } GST_INFO ("have packetsize detected: %u bytes", packetizer->packet_size); if (packetizer->packet_size == MPEGTS_M2TS_PACKETSIZE && packetizer->map_offset >= 4) packetizer->map_offset -= 4; return TRUE; } static gboolean mpegts_packetizer_sync (MpegTSPacketizer2 * packetizer) { gboolean found = FALSE; guint8 *data; guint packet_size; gsize size, sync_offset, i; packet_size = packetizer->packet_size; if (!mpegts_packetizer_map (packetizer, 3 * packet_size)) return FALSE; size = packetizer->map_size - packetizer->map_offset; data = packetizer->map_data + packetizer->map_offset; if (packet_size == MPEGTS_M2TS_PACKETSIZE) sync_offset = 4; else sync_offset = 0; for (i = sync_offset; i + 2 * packet_size < size; i++) { if (data[i] == PACKET_SYNC_BYTE && data[i + packet_size] == PACKET_SYNC_BYTE && data[i + 2 * packet_size] == PACKET_SYNC_BYTE) { found = TRUE; break; } } packetizer->map_offset += i - sync_offset; if (!found) mpegts_packetizer_flush_bytes (packetizer, packetizer->map_offset); return found; } MpegTSPacketizerPacketReturn mpegts_packetizer_next_packet (MpegTSPacketizer2 * packetizer, MpegTSPacketizerPacket * packet) { guint8 *packet_data; guint packet_size; gsize sync_offset; packet_size = packetizer->packet_size; if (G_UNLIKELY (!packet_size)) { if (!mpegts_try_discover_packet_size (packetizer)) return PACKET_NEED_MORE; packet_size = packetizer->packet_size; } /* M2TS packets don't start with the sync byte, all other variants do */ if (packet_size == MPEGTS_M2TS_PACKETSIZE) sync_offset = 4; else sync_offset = 0; while (1) { if (packetizer->need_sync) { if (!mpegts_packetizer_sync (packetizer)) return PACKET_NEED_MORE; packetizer->need_sync = FALSE; } if (!mpegts_packetizer_map (packetizer, packet_size)) return PACKET_NEED_MORE; packet_data = &packetizer->map_data[packetizer->map_offset + sync_offset]; /* Check sync byte */ if (G_UNLIKELY (*packet_data != PACKET_SYNC_BYTE)) { GST_DEBUG ("lost sync"); packetizer->need_sync = TRUE; } else { /* ALL mpeg-ts variants contain 188 bytes of data. Those with bigger * packet sizes contain either extra data (timesync, FEC, ..) either * before or after the data */ packet->data_start = packet_data; packet->data_end = packet->data_start + 188; packet->offset = packetizer->offset; GST_LOG ("offset %" G_GUINT64_FORMAT, packet->offset); packetizer->offset += packet_size; GST_MEMDUMP ("data_start", packet->data_start, 16); return mpegts_packetizer_parse_packet (packetizer, packet); } } } MpegTSPacketizerPacketReturn mpegts_packetizer_process_next_packet (MpegTSPacketizer2 * packetizer) { MpegTSPacketizerPacket packet; MpegTSPacketizerPacketReturn ret; ret = mpegts_packetizer_next_packet (packetizer, &packet); if (ret != PACKET_NEED_MORE) mpegts_packetizer_clear_packet (packetizer, &packet); return ret; } void mpegts_packetizer_clear_packet (MpegTSPacketizer2 * packetizer, MpegTSPacketizerPacket * packet) { guint8 packet_size = packetizer->packet_size; if (packetizer->map_data) { packetizer->map_offset += packet_size; if (packetizer->map_size - packetizer->map_offset < packet_size) mpegts_packetizer_flush_bytes (packetizer, packetizer->map_offset); } } gboolean mpegts_packetizer_has_packets (MpegTSPacketizer2 * packetizer) { if (G_UNLIKELY (!packetizer->packet_size)) { if (!mpegts_try_discover_packet_size (packetizer)) return FALSE; } return gst_adapter_available (packetizer->adapter) >= packetizer->packet_size; } /* * Ideally it should just return a section if: * * The section is complete * * The section is valid (sanity checks for length for example) * * The section applies now (current_next_indicator) * * The section is an update or was never seen * * The section should be a new GstMpegtsSection: * * properly initialized * * With pid, table_id AND section_type set (move logic from mpegtsbase) * * With data copied into it (yes, minor overhead) * * In all other cases it should just return NULL * * If more than one section is available, the 'remaining' field will * be set to the beginning of a valid GList containing other sections. * */ GstMpegtsSection * mpegts_packetizer_push_section (MpegTSPacketizer2 * packetizer, MpegTSPacketizerPacket * packet, GList ** remaining) { GstMpegtsSection *section; GstMpegtsSection *res = NULL; MpegTSPacketizerStream *stream; gboolean long_packet; guint8 pointer = 0, table_id; guint16 subtable_extension; gsize to_read; guint section_length; /* data points to the current read location * data_start points to the beginning of the data to accumulate */ guint8 *data, *data_start; guint8 packet_cc; GList *others = NULL; guint8 version_number, section_number, last_section_number; data = packet->data; packet_cc = FLAGS_CONTINUITY_COUNTER (packet->scram_afc_cc); /* Get our filter */ stream = packetizer->streams[packet->pid]; if (G_UNLIKELY (stream == NULL)) { if (!packet->payload_unit_start_indicator) { /* Early exit (we need to start with a section start) */ GST_DEBUG ("PID 0x%04x waiting for section start", packet->pid); goto out; } stream = mpegts_packetizer_stream_new (packet->pid); packetizer->streams[packet->pid] = stream; } GST_MEMDUMP ("Full packet data", packet->data, packet->data_end - packet->data); /* This function is split into several parts: * * Pre checks (packet-wide). Determines where we go next * accumulate_data: store data and check if section is complete * section_start: handle beginning of a section, if needed loop back to * accumulate_data * * The trigger that makes the loop stop and return is if: * 1) We do not have enough data for the current packet * 2) There is remaining data after a packet which is only made * of stuffing bytes (0xff). * * Pre-loop checks, related to the whole incoming packet: * * If there is a CC-discont: * If it is a PUSI, skip the pointer and handle section_start * If not a PUSI, reset and return nothing * If there is not a CC-discont: * If it is a PUSI * If pointer, accumulate that data and check for complete section * (loop) * If it is not a PUSI * Accumulate the expected data and check for complete section * (loop) * **/ if (packet->payload_unit_start_indicator) { pointer = *data++; /* If the pointer is zero, we're guaranteed to be able to handle it */ if (pointer == 0) { GST_LOG ("PID 0x%04x PUSI and pointer == 0, skipping straight to section_start parsing", packet->pid); mpegts_packetizer_clear_section (stream); goto section_start; } } if (stream->continuity_counter == CONTINUITY_UNSET || (stream->continuity_counter + 1) % 16 != packet_cc) { if (stream->continuity_counter != CONTINUITY_UNSET) GST_WARNING ("PID 0x%04x section discontinuity (%d vs %d)", packet->pid, stream->continuity_counter, packet_cc); mpegts_packetizer_clear_section (stream); /* If not a PUSI, not much we can do */ if (!packet->payload_unit_start_indicator) { GST_LOG ("PID 0x%04x continuity discont/unset and not PUSI, bailing out", packet->pid); goto out; } /* If PUSI, skip pointer data and carry on to section start */ data += pointer; pointer = 0; GST_LOG ("discont, but PUSI, skipped %d bytes and doing section start", pointer); goto section_start; } GST_LOG ("Accumulating data from beginning of packet"); data_start = data; accumulate_data: /* If not the beginning of a new section, accumulate what we have */ stream->continuity_counter = packet_cc; to_read = MIN (stream->section_length - stream->section_offset, packet->data_end - data_start); memcpy (stream->section_data + stream->section_offset, data_start, to_read); stream->section_offset += to_read; /* Point data to after the data we accumulated */ data = data_start + to_read; GST_DEBUG ("Appending data (need %d, have %d)", stream->section_length, stream->section_offset); /* Check if we have enough */ if (stream->section_offset < stream->section_length) { GST_DEBUG ("PID 0x%04x, section not complete (Got %d, need %d)", stream->pid, stream->section_offset, stream->section_length); goto out; } /* Small sanity check. We should have collected *exactly* the right amount */ if (G_UNLIKELY (stream->section_offset != stream->section_length)) GST_WARNING ("PID 0x%04x Accumulated too much data (%d vs %d) !", stream->pid, stream->section_offset, stream->section_length); GST_DEBUG ("PID 0x%04x Section complete", stream->pid); if ((section = mpegts_packetizer_parse_section_header (packetizer, stream))) { if (res) others = g_list_append (others, section); else res = section; } section_start: subtable_extension = 0; version_number = 0; last_section_number = 0; section_number = 0; table_id = 0; /* FIXME : We need at least 3 bytes (or 8 for long packets) with current algorithm :( * We might end up losing sections that start across two packets (srsl...) */ if (data > packet->data_end - 3 || *data == 0xff) { /* flush stuffing bytes and leave */ mpegts_packetizer_clear_section (stream); goto out; } /* We have more data to process ... */ GST_DEBUG ("PID 0x%04x, More section present in packet (remaining bytes:%" G_GSIZE_FORMAT ")", stream->pid, (gsize) (packet->data_end - data)); GST_MEMDUMP ("section_start", data, packet->data_end - data); data_start = data; /* Beginning of a new section */ /* * section_syntax_indicator means that the header is of the following format: * * table_id (8bit) * * section_syntax_indicator (1bit) == 0 * * reserved/private fields (3bit) * * section_length (12bit) * * data (of size section_length) * * NO CRC ! */ long_packet = data[1] & 0x80; /* Fast path for short packets */ if (!long_packet) { /* We can create the section now (function will check for size) */ GST_DEBUG ("Short packet"); section_length = (GST_READ_UINT16_BE (data + 1) & 0xfff) + 3; /* Only do fast-path if we have enough byte */ if (data + section_length <= packet->data_end) { if ((section = gst_mpegts_section_new (packet->pid, g_memdup2 (data, section_length), section_length))) { GST_DEBUG ("PID 0x%04x Short section complete !", packet->pid); section->offset = packet->offset; if (res) others = g_list_append (others, section); else res = section; } /* Advance reader and potentially read another section */ data += section_length; if (data < packet->data_end && *data != 0xff) goto section_start; /* If not, exit */ goto out; } /* We don't have enough bytes to do short section shortcut */ } /* Beginning of a new section, do as much pre-parsing as possible */ /* table_id : 8 bit */ table_id = *data++; /* section_syntax_indicator : 1 bit * other_fields (reserved) : 3 bit * section_length : 12 bit */ section_length = (GST_READ_UINT16_BE (data) & 0x0FFF) + 3; data += 2; if (long_packet) { /* Do we have enough data for a long packet? */ if (data > packet->data_end - 5) goto out; /* subtable_extension (always present, we are in a long section) */ /* subtable extension : 16 bit */ subtable_extension = GST_READ_UINT16_BE (data); data += 2; /* reserved : 2 bit * version_number : 5 bit * current_next_indicator : 1 bit */ /* Bail out now if current_next_indicator == 0 */ if (G_UNLIKELY (!(*data & 0x01))) { GST_DEBUG ("PID 0x%04x table_id 0x%02x section does not apply (current_next_indicator == 0)", packet->pid, table_id); goto out; } version_number = *data++ >> 1 & 0x1f; /* section_number : 8 bit */ section_number = *data++; /* last_section_number : 8 bit */ last_section_number = *data++; } else { subtable_extension = 0; version_number = 0; section_number = 0; last_section_number = 0; } GST_DEBUG ("PID 0x%04x length:%d table_id:0x%02x subtable_extension:0x%04x version_number:%d section_number:%d(last:%d)", packet->pid, section_length, table_id, subtable_extension, version_number, section_number, last_section_number); to_read = MIN (section_length, packet->data_end - data_start); /* Check as early as possible whether we already saw this section * i.e. that we saw a subtable with: * * same subtable_extension (might be zero) * * same version_number * * same last_section_number * * same section_number was seen */ if (seen_section_before (stream, table_id, subtable_extension, version_number, section_number, last_section_number)) { GST_DEBUG ("PID 0x%04x Already processed table_id:0x%02x subtable_extension:0x%04x, version_number:%d, section_number:%d", packet->pid, table_id, subtable_extension, version_number, section_number); /* skip data and see if we have more sections after */ data = data_start + to_read; if (data == packet->data_end || *data == 0xff) goto out; goto section_start; } if (G_UNLIKELY (section_number > last_section_number)) { GST_WARNING ("PID 0x%04x corrupted packet (section_number:%d > last_section_number:%d)", packet->pid, section_number, last_section_number); goto out; } /* Copy over already parsed values */ stream->table_id = table_id; stream->section_length = section_length; stream->version_number = version_number; stream->subtable_extension = subtable_extension; stream->section_number = section_number; stream->last_section_number = last_section_number; stream->offset = packet->offset; /* Create enough room to store chunks of sections */ stream->section_data = g_malloc (stream->section_length); stream->section_offset = 0; /* Finally, accumulate and check if we parsed enough */ goto accumulate_data; out: packet->data = data; *remaining = others; GST_DEBUG ("result: %p", res); return res; } static void _init_local (void) { GST_DEBUG_CATEGORY_INIT (mpegts_packetizer_debug, "mpegtspacketizer", 0, "MPEG transport stream parser"); } static void mpegts_packetizer_resync (MpegTSPCR * pcr, GstClockTime time, GstClockTime gstpcrtime, gboolean reset_skew) { pcr->base_time = time; pcr->base_pcrtime = gstpcrtime; pcr->prev_out_time = GST_CLOCK_TIME_NONE; pcr->prev_send_diff = GST_CLOCK_TIME_NONE; if (reset_skew) { pcr->window_filling = TRUE; pcr->window_pos = 0; pcr->window_min = 0; pcr->window_size = 0; pcr->skew = 0; } } /* Code mostly copied from -good/gst/rtpmanager/rtpjitterbuffer.c */ /* For the clock skew we use a windowed low point averaging algorithm as can be * found in Fober, Orlarey and Letz, 2005, "Real Time Clock Skew Estimation * over Network Delays": * http://www.grame.fr/Ressources/pub/TR-050601.pdf * http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.102.1546 * * The idea is that the jitter is composed of: * * J = N + n * * D : a constant network delay. * n : random added noise. The noise is concentrated around 0 * * In the receiver we can track the elapsed time at the sender with: * * send_diff(i) = (Tsi - Ts0); * * Tsi : The time at the sender at packet i * Ts0 : The time at the sender at the first packet * * This is the difference between the RTP timestamp in the first received packet * and the current packet. * * At the receiver we have to deal with the jitter introduced by the network. * * recv_diff(i) = (Tri - Tr0) * * Tri : The time at the receiver at packet i * Tr0 : The time at the receiver at the first packet * * Both of these values contain a jitter Ji, a jitter for packet i, so we can * write: * * recv_diff(i) = (Cri + D + ni) - (Cr0 + D + n0)) * * Cri : The time of the clock at the receiver for packet i * D + ni : The jitter when receiving packet i * * We see that the network delay is irrelevant here as we can eliminate D: * * recv_diff(i) = (Cri + ni) - (Cr0 + n0)) * * The drift is now expressed as: * * Drift(i) = recv_diff(i) - send_diff(i); * * We now keep the W latest values of Drift and find the minimum (this is the * one with the lowest network jitter and thus the one which is least affected * by it). We average this lowest value to smooth out the resulting network skew. * * Both the window and the weighting used for averaging influence the accuracy * of the drift estimation. Finding the correct parameters turns out to be a * compromise between accuracy and inertia. * * We use a 2 second window or up to 512 data points, which is statistically big * enough to catch spikes (FIXME, detect spikes). * We also use a rather large weighting factor (125) to smoothly adapt. During * startup, when filling the window, we use a parabolic weighting factor, the * more the window is filled, the faster we move to the detected possible skew. * * Returns: @time adjusted with the clock skew. */ static GstClockTime calculate_skew (MpegTSPacketizer2 * packetizer, MpegTSPCR * pcr, guint64 pcrtime, GstClockTime time) { guint64 send_diff, recv_diff; gint64 delta; gint64 old; gint pos, i; GstClockTime gstpcrtime, out_time; #ifndef GST_DISABLE_GST_DEBUG guint64 slope; #endif gstpcrtime = PCRTIME_TO_GSTTIME (pcrtime) + pcr->pcroffset; /* first time, lock on to time and gstpcrtime */ if (G_UNLIKELY (!GST_CLOCK_TIME_IS_VALID (pcr->base_time))) { pcr->base_time = time; pcr->prev_out_time = GST_CLOCK_TIME_NONE; GST_DEBUG ("Taking new base time %" GST_TIME_FORMAT, GST_TIME_ARGS (time)); } if (G_UNLIKELY (!GST_CLOCK_TIME_IS_VALID (pcr->base_pcrtime))) { pcr->base_pcrtime = gstpcrtime; pcr->prev_send_diff = -1; GST_DEBUG ("Taking new base pcrtime %" GST_TIME_FORMAT, GST_TIME_ARGS (gstpcrtime)); } /* Handle PCR wraparound and resets */ if (GST_CLOCK_TIME_IS_VALID (pcr->last_pcrtime) && gstpcrtime < pcr->last_pcrtime) { if (pcr->last_pcrtime - gstpcrtime > PCR_GST_MAX_VALUE / 2) { /* PCR wraparound */ GST_DEBUG ("PCR wrap"); pcr->pcroffset += PCR_GST_MAX_VALUE; gstpcrtime = PCRTIME_TO_GSTTIME (pcrtime) + pcr->pcroffset; send_diff = gstpcrtime - pcr->base_pcrtime; } else if (GST_CLOCK_TIME_IS_VALID (time) && pcr->last_pcrtime - gstpcrtime > 15 * GST_SECOND) { /* Time jumped backward by > 15 seconds, and we have a timestamp * to use to close the discont. Assume a reset */ GST_DEBUG ("PCR reset"); /* Calculate PCR we would have expected for the given input time, * essentially applying the reverse correction process * * We want to find the PCR offset to apply * pcroffset = (corrected) gstpcrtime - (received) gstpcrtime * * send_diff = (corrected) gstpcrtime - pcr->base_pcrtime * recv_diff = time - pcr->base_time * out_time = pcr->base_time + send_diff * * We are assuming that send_diff == recv_diff * (corrected) gstpcrtime - pcr->base_pcrtime = time - pcr->base_time * Giving us: * (corrected) gstpcrtime = time - pcr->base_time + pcr->base_pcrtime * * And therefore: * pcroffset = time - pcr->base_time + pcr->base_pcrtime - (received) gstpcrtime **/ pcr->pcroffset += time - pcr->base_time + pcr->base_pcrtime - gstpcrtime; gstpcrtime = PCRTIME_TO_GSTTIME (pcrtime) + pcr->pcroffset; send_diff = gstpcrtime - pcr->base_pcrtime; GST_DEBUG ("Introduced offset is now %" GST_TIME_FORMAT " corrected pcr time %" GST_TIME_FORMAT, GST_TIME_ARGS (pcr->pcroffset), GST_TIME_ARGS (gstpcrtime)); } else { /* Small jumps backward, assume some arrival jitter and skip it */ send_diff = 0; /* The following code are the different ways we deal with small-ish * jitter, ranging in severity from "can be ignored" to "this needs a full * resync" */ if (time == pcr->base_time) { /* If this comes from a non-fully-timestamped source (i.e. adaptive * streams), then cope with the fact that some producers generate utter * PCR garbage on fragment ends. * * We detect this comes from a non-fully-timestamped source by the fact * that the buffer time never changes */ GST_DEBUG ("Ignoring PCR resets on non-fully timestamped stream"); } else if (pcr->last_pcrtime - gstpcrtime < GST_SECOND) { GST_WARNING ("(small) backward timestamps at server or no buffer timestamps. Ignoring."); /* This will trigger the no_skew logic before but leave other state * intact */ time = GST_CLOCK_TIME_NONE; } else { /* A bigger backward step than packet out-of-order can account for. Reset base PCR time * to be resynched the next time we see a PCR */ GST_WARNING ("backward timestamps at server or no buffer timestamps. Resync base PCR"); pcr->base_pcrtime = GST_CLOCK_TIME_NONE; } } } else send_diff = gstpcrtime - pcr->base_pcrtime; GST_DEBUG ("gstpcr %" GST_TIME_FORMAT ", buftime %" GST_TIME_FORMAT ", base %" GST_TIME_FORMAT ", send_diff %" GST_TIME_FORMAT, GST_TIME_ARGS (gstpcrtime), GST_TIME_ARGS (time), GST_TIME_ARGS (pcr->base_pcrtime), GST_TIME_ARGS (send_diff)); /* keep track of the last extended pcrtime */ pcr->last_pcrtime = gstpcrtime; /* we don't have an arrival timestamp so we can't do skew detection. we * should still apply a timestamp based on RTP timestamp and base_time */ if (!GST_CLOCK_TIME_IS_VALID (time) || !GST_CLOCK_TIME_IS_VALID (pcr->base_time)) goto no_skew; /* elapsed time at receiver, includes the jitter */ recv_diff = time - pcr->base_time; /* Ignore packets received at 100% the same time (i.e. from the same input buffer) */ if (G_UNLIKELY (time == pcr->prev_in_time && GST_CLOCK_TIME_IS_VALID (pcr->prev_in_time))) goto no_skew; /* measure the diff */ delta = ((gint64) recv_diff) - ((gint64) send_diff); #ifndef GST_DISABLE_GST_DEBUG /* measure the slope, this gives a rought estimate between the sender speed * and the receiver speed. This should be approximately 8, higher values * indicate a burst (especially when the connection starts) */ slope = recv_diff > 0 ? (send_diff * 8) / recv_diff : 8; #endif GST_DEBUG ("time %" GST_TIME_FORMAT ", base %" GST_TIME_FORMAT ", recv_diff %" GST_TIME_FORMAT ", slope %" G_GUINT64_FORMAT, GST_TIME_ARGS (time), GST_TIME_ARGS (pcr->base_time), GST_TIME_ARGS (recv_diff), slope); /* if the difference between the sender timeline and the receiver timeline * changed too quickly we have to resync because the server likely restarted * its timestamps. */ if (ABS (delta - pcr->skew) > packetizer->pcr_discont_threshold) { GST_WARNING ("delta - skew: %" GST_STIME_FORMAT " too big, reset skew", GST_STIME_ARGS (delta - pcr->skew)); mpegts_packetizer_resync (pcr, time, gstpcrtime, TRUE); send_diff = 0; delta = 0; } pos = pcr->window_pos; if (G_UNLIKELY (pcr->window_filling)) { /* we are filling the window */ GST_DEBUG ("filling %d, delta %" G_GINT64_FORMAT, pos, delta); pcr->window[pos++] = delta; /* calc the min delta we observed */ if (G_UNLIKELY (pos == 1 || delta < pcr->window_min)) pcr->window_min = delta; if (G_UNLIKELY (send_diff >= MAX_TIME || pos >= MAX_WINDOW)) { pcr->window_size = pos; /* window filled */ GST_DEBUG ("min %" G_GINT64_FORMAT, pcr->window_min); /* the skew is now the min */ pcr->skew = pcr->window_min; pcr->window_filling = FALSE; } else { gint perc_time, perc_window, perc; /* figure out how much we filled the window, this depends on the amount of * time we have or the max number of points we keep. */ perc_time = send_diff * 100 / MAX_TIME; perc_window = pos * 100 / MAX_WINDOW; perc = MAX (perc_time, perc_window); /* make a parabolic function, the closer we get to the MAX, the more value * we give to the scaling factor of the new value */ perc = perc * perc; /* quickly go to the min value when we are filling up, slowly when we are * just starting because we're not sure it's a good value yet. */ pcr->skew = (perc * pcr->window_min + ((10000 - perc) * pcr->skew)) / 10000; pcr->window_size = pos + 1; } } else { /* pick old value and store new value. We keep the previous value in order * to quickly check if the min of the window changed */ old = pcr->window[pos]; pcr->window[pos++] = delta; if (G_UNLIKELY (delta <= pcr->window_min)) { /* if the new value we inserted is smaller or equal to the current min, * it becomes the new min */ pcr->window_min = delta; } else if (G_UNLIKELY (old == pcr->window_min)) { gint64 min = G_MAXINT64; /* if we removed the old min, we have to find a new min */ for (i = 0; i < pcr->window_size; i++) { /* we found another value equal to the old min, we can stop searching now */ if (pcr->window[i] == old) { min = old; break; } if (pcr->window[i] < min) min = pcr->window[i]; } pcr->window_min = min; } /* average the min values */ pcr->skew = (pcr->window_min + (124 * pcr->skew)) / 125; GST_DEBUG ("delta %" G_GINT64_FORMAT ", new min: %" G_GINT64_FORMAT, delta, pcr->window_min); } /* wrap around in the window */ if (G_UNLIKELY (pos >= pcr->window_size)) pos = 0; pcr->window_pos = pos; no_skew: /* the output time is defined as the base timestamp plus the PCR time * adjusted for the clock skew .*/ if (pcr->base_time != -1) { out_time = pcr->base_time + send_diff; /* skew can be negative and we don't want to make invalid timestamps */ if (pcr->skew < 0 && out_time < -pcr->skew) { out_time = 0; } else { out_time += pcr->skew; } /* check if timestamps are not going backwards, we can only check this if we * have a previous out time and a previous send_diff */ if (G_LIKELY (pcr->prev_out_time != -1 && pcr->prev_send_diff != -1)) { /* now check for backwards timestamps */ if (G_UNLIKELY ( /* if the server timestamps went up and the out_time backwards */ (send_diff > pcr->prev_send_diff && out_time < pcr->prev_out_time) || /* if the server timestamps went backwards and the out_time forwards */ (send_diff < pcr->prev_send_diff && out_time > pcr->prev_out_time) || /* if the server timestamps did not change */ send_diff == pcr->prev_send_diff)) { GST_DEBUG ("backwards timestamps, using previous time"); out_time = GSTTIME_TO_MPEGTIME (out_time); } } } else { /* We simply use the pcrtime without applying any skew compensation */ out_time = time; } pcr->prev_out_time = out_time; pcr->prev_in_time = time; pcr->prev_send_diff = send_diff; GST_DEBUG ("skew %" G_GINT64_FORMAT ", out %" GST_TIME_FORMAT, pcr->skew, GST_TIME_ARGS (out_time)); return out_time; } static void _reevaluate_group_pcr_offset (MpegTSPCR * pcrtable, PCROffsetGroup * group) { PCROffsetGroup *prev = NULL; #ifndef GST_DISABLE_GST_DEBUG PCROffsetGroup *first = pcrtable->groups->data; #endif PCROffsetCurrent *current = pcrtable->current; GList *tmp; /* Go over all ESTIMATED groups until the target group */ for (tmp = pcrtable->groups; tmp; tmp = tmp->next) { PCROffsetGroup *cur = (PCROffsetGroup *) tmp->data; /* Skip groups that don't need re-evaluation */ if (!(cur->flags & PCR_GROUP_FLAG_ESTIMATED)) { GST_DEBUG ("Skipping group %p pcr_offset (currently %" GST_TIME_FORMAT ")", cur, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (cur->pcr_offset))); prev = cur; continue; } /* This should not happen ! The first group is *always* correct (zero) */ if (G_UNLIKELY (prev == NULL)) { GST_ERROR ("First PCR Group was not estimated (bug). Setting to zero"); cur->pcr_offset = 0; cur->flags &= ~PCR_GROUP_FLAG_ESTIMATED; return; } /* Finally do the estimation of this group's PCR offset based on the * previous group information */ GST_DEBUG ("Re-evaluating group %p pcr_offset (currently %" GST_TIME_FORMAT ")", group, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (cur->pcr_offset))); GST_DEBUG ("cur->first_pcr:%" GST_TIME_FORMAT " prev->first_pcr:%" GST_TIME_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (cur->first_pcr)), GST_TIME_ARGS (PCRTIME_TO_GSTTIME (prev->first_pcr))); if (G_UNLIKELY (cur->first_pcr < prev->first_pcr)) { guint64 prevbr, lastbr; guint64 prevpcr; guint64 prevoffset, lastoffset; /* Take the previous group pcr_offset and figure out how much to add * to it for the current group */ /* Right now we do a dumb bitrate estimation * estimate bitrate (prev - first) : bitrate from the start * estimate bitrate (prev) : bitrate of previous group * estimate bitrate (last - first) : bitrate from previous group * * We will use raw (non-corrected/non-absolute) PCR values in a first time * to detect wraparound/resets/gaps... * * We will use the corrected/absolute PCR values to calculate * bitrate and estimate the target group pcr_offset. * */ /* If the current window estimator is over the previous group, used those * values as the latest (since they are more recent) */ if (current->group == prev && current->pending[current->last].offset) { prevoffset = current->pending[current->last].offset + prev->first_offset; prevpcr = current->pending[current->last].pcr + prev->first_pcr; /* prevbr: bitrate(prev) */ prevbr = gst_util_uint64_scale (PCR_SECOND, current->pending[current->last].offset, current->pending[current->last].pcr); GST_DEBUG ("Previous group bitrate (%" G_GUINT64_FORMAT " / %" GST_TIME_FORMAT ") : %" G_GUINT64_FORMAT, current->pending[current->last].offset, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (current->pending[current->last]. pcr)), prevbr); } else if (prev->values[prev->last_value].offset) { prevoffset = prev->values[prev->last_value].offset + prev->first_offset; prevpcr = prev->values[prev->last_value].pcr + prev->first_pcr; /* prevbr: bitrate(prev) (FIXME : Cache) */ prevbr = gst_util_uint64_scale (PCR_SECOND, prev->values[prev->last_value].offset, prev->values[prev->last_value].pcr); GST_DEBUG ("Previous group bitrate (%" G_GUINT64_FORMAT " / %" GST_TIME_FORMAT ") : %" G_GUINT64_FORMAT, prev->values[prev->last_value].offset, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (prev->values[prev->last_value]. pcr)), prevbr); } else { GST_DEBUG ("Using overall bitrate"); prevoffset = prev->values[prev->last_value].offset + prev->first_offset; prevpcr = prev->values[prev->last_value].pcr + prev->first_pcr; prevbr = gst_util_uint64_scale (PCR_SECOND, prev->first_offset, prev->pcr_offset); } lastoffset = cur->values[cur->last_value].offset + cur->first_offset; GST_DEBUG ("Offset first:%" G_GUINT64_FORMAT " prev:%" G_GUINT64_FORMAT " cur:%" G_GUINT64_FORMAT, first->first_offset, prevoffset, lastoffset); GST_DEBUG ("PCR first:%" GST_TIME_FORMAT " prev:%" GST_TIME_FORMAT " cur:%" GST_TIME_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (first->first_pcr)), GST_TIME_ARGS (PCRTIME_TO_GSTTIME (prevpcr)), GST_TIME_ARGS (PCRTIME_TO_GSTTIME (cur->values[cur->last_value].pcr + cur->first_pcr))); if (prevpcr - cur->first_pcr > (PCR_MAX_VALUE * 9 / 10)) { gfloat diffprev; guint64 guess_offset; /* Let's assume there is a PCR wraparound between the previous and current * group. * [ prev ]... PCR_MAX | 0 ...[ current ] * The estimated pcr_offset would therefore be: * current.first + (PCR_MAX_VALUE - prev.first) * * 1) Check if bitrate(prev) would be consistent with bitrate (cur - prev) */ guess_offset = PCR_MAX_VALUE - prev->first_pcr + cur->first_pcr; lastbr = gst_util_uint64_scale (PCR_SECOND, lastoffset - prevoffset, guess_offset + cur->values[cur->last_value].pcr - (prevpcr - prev->first_pcr)); GST_DEBUG ("Wraparound prev-cur (guess_offset:%" GST_TIME_FORMAT ") bitrate:%" G_GUINT64_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (guess_offset)), lastbr); diffprev = (float) 100.0 *(ABSDIFF (prevbr, lastbr)) / (float) prevbr; GST_DEBUG ("Difference with previous bitrate:%f", diffprev); if (diffprev < 10.0) { GST_DEBUG ("Difference < 10.0, Setting pcr_offset to %" G_GUINT64_FORMAT, guess_offset); cur->pcr_offset = guess_offset; if (diffprev < 1.0) { GST_DEBUG ("Difference < 1.0, Removing ESTIMATED flags"); cur->flags &= ~PCR_GROUP_FLAG_ESTIMATED; } } /* Indicate the the previous group is before a wrapover */ prev->flags |= PCR_GROUP_FLAG_WRAPOVER; } else { guint64 resetprev; /* Let's assume there was a PCR reset between the previous and current * group * [ prev ] ... x | x - reset ... [ current ] * * The estimated pcr_offset would then be * = current.first - (x - reset) + (x - prev.first) + 100ms (for safety) * = current.first + reset - prev.first + 100ms (for safety) */ /* In order to calculate the reset, we estimate what the PCR would have * been by using prevbr */ /* FIXME : Which bitrate should we use ??? */ GST_DEBUG ("Using prevbr:%" G_GUINT64_FORMAT " and taking offsetdiff:%" G_GUINT64_FORMAT, prevbr, cur->first_offset - prev->first_offset); resetprev = gst_util_uint64_scale (PCR_SECOND, cur->first_offset - prev->first_offset, prevbr); GST_DEBUG ("Estimated full PCR for offset %" G_GUINT64_FORMAT ", using prevbr:%" GST_TIME_FORMAT, cur->first_offset, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (resetprev))); cur->pcr_offset = prev->pcr_offset + resetprev + 100 * PCR_MSECOND; GST_DEBUG ("Adjusted group PCR_offset to %" GST_TIME_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (cur->pcr_offset))); /* Indicate the the previous group is before a reset */ prev->flags |= PCR_GROUP_FLAG_RESET; } } else { /* FIXME : Detect gaps if bitrate difference is really too big ? */ cur->pcr_offset = prev->pcr_offset + cur->first_pcr - prev->first_pcr; GST_DEBUG ("Assuming there is no gap, setting pcr_offset to %" GST_TIME_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (cur->pcr_offset))); /* Remove the reset and wrapover flag (if it was previously there) */ prev->flags &= ~PCR_GROUP_FLAG_RESET; prev->flags &= ~PCR_GROUP_FLAG_WRAPOVER; } /* Remember prev for the next group evaluation */ prev = cur; } } static PCROffsetGroup * _new_group (guint64 pcr, guint64 offset, guint64 pcr_offset, guint flags) { PCROffsetGroup *group = g_slice_new0 (PCROffsetGroup); GST_DEBUG ("Input PCR %" GST_TIME_FORMAT " offset:%" G_GUINT64_FORMAT " pcr_offset:%" G_GUINT64_FORMAT " flags:%d", GST_TIME_ARGS (PCRTIME_TO_GSTTIME (pcr)), offset, pcr_offset, flags); group->flags = flags; group->values = g_new0 (PCROffset, DEFAULT_ALLOCATED_OFFSET); /* The first pcr/offset diff is always 0/0 */ group->values[0].pcr = group->values[0].offset = 0; group->nb_allocated = DEFAULT_ALLOCATED_OFFSET; /* Store the full values */ group->first_pcr = pcr; group->first_offset = offset; group->pcr_offset = pcr_offset; GST_DEBUG ("Created group starting with pcr:%" GST_TIME_FORMAT " offset:%" G_GUINT64_FORMAT " pcr_offset:%" GST_TIME_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (group->first_pcr)), group->first_offset, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (group->pcr_offset))); return group; } static void _insert_group_after (MpegTSPCR * pcrtable, PCROffsetGroup * group, PCROffsetGroup * prev) { if (prev == NULL) { /* First group */ pcrtable->groups = g_list_prepend (pcrtable->groups, group); } else { GList *tmp, *toinsert, *prevlist = NULL, *nextlist = NULL; /* Insert before next and prev */ for (tmp = pcrtable->groups; tmp; tmp = tmp->next) { if (tmp->data == prev) { prevlist = tmp; nextlist = tmp->next; break; } } if (!prevlist) { /* The non NULL prev given isn't in the list */ GST_WARNING ("Request to insert before a group which isn't in the list"); pcrtable->groups = g_list_prepend (pcrtable->groups, group); } else { toinsert = g_list_append (NULL, group); toinsert->next = nextlist; toinsert->prev = prevlist; prevlist->next = toinsert; if (nextlist) nextlist->prev = toinsert; } } } static void _use_group (MpegTSPCR * pcrtable, PCROffsetGroup * group) { PCROffsetCurrent *current = pcrtable->current; memset (current, 0, sizeof (PCROffsetCurrent)); current->group = group; current->pending[0] = group->values[group->last_value]; current->last_value = current->pending[0]; current->write = 1; current->prev = group->values[group->last_value]; current->first_pcr = group->first_pcr; current->first_offset = group->first_offset; } /* Create a new group with the specified values after prev * Set current to that new group */ static void _set_current_group (MpegTSPCR * pcrtable, PCROffsetGroup * prev, guint64 pcr, guint64 offset, gboolean contiguous) { PCROffsetGroup *group; guint flags = 0; guint64 pcr_offset = 0; /* Handle wraparound/gap (only if contiguous with previous group) */ if (contiguous) { guint64 lastpcr = prev->first_pcr + prev->values[prev->last_value].pcr; /* Set CLOSED flag on previous group and remember pcr_offset */ prev->flags |= PCR_GROUP_FLAG_CLOSED; pcr_offset = prev->pcr_offset; /* Wraparound ? */ if (lastpcr > pcr) { /* In offset-mode, a PCR wraparound is only actually consistent if * we have a very high confidence (99% right now, might need to change * later) */ if (lastpcr - pcr > (PCR_MAX_VALUE * 99 / 100)) { GST_WARNING ("WRAPAROUND detected. diff %" GST_TIME_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (lastpcr - pcr))); /* The previous group closed at PCR_MAX_VALUE */ pcr_offset += PCR_MAX_VALUE - prev->first_pcr + pcr; } else { GST_WARNING ("RESET detected. diff %" GST_TIME_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (lastpcr - pcr))); /* The previous group closed at the raw last_pcr diff (+100ms for safety) */ pcr_offset += prev->values[prev->last_value].pcr + 100 * PCR_MSECOND; } } else if (lastpcr < pcr - 500 * PCR_MSECOND) { GST_WARNING ("GAP detected. diff %" GST_TIME_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (pcr - lastpcr))); /* The previous group closed at the raw last_pcr diff (+500ms for safety) */ pcr_offset += prev->values[prev->last_value].pcr + 500 * PCR_MSECOND; } else /* Normal continuation (contiguous in time) */ pcr_offset += pcr - prev->first_pcr; } else if (prev != NULL) /* If we are not contiguous and it's not the first group, the pcr_offset * will be estimated */ flags = PCR_GROUP_FLAG_ESTIMATED; group = _new_group (pcr, offset, pcr_offset, flags); _use_group (pcrtable, group); _insert_group_after (pcrtable, group, prev); if (!contiguous) _reevaluate_group_pcr_offset (pcrtable, group); } static inline void _append_group_values (PCROffsetGroup * group, PCROffset pcroffset) { /* Only append if new values */ if (group->values[group->last_value].offset == pcroffset.offset && group->values[group->last_value].pcr == pcroffset.pcr) { GST_DEBUG ("Same values, ignoring"); } else { group->last_value++; /* Resize values if needed */ if (G_UNLIKELY (group->nb_allocated == group->last_value)) { group->nb_allocated += DEFAULT_ALLOCATED_OFFSET; group->values = g_realloc (group->values, group->nb_allocated * sizeof (PCROffset)); } group->values[group->last_value] = pcroffset; } GST_DEBUG ("First PCR:%" GST_TIME_FORMAT " offset:%" G_GUINT64_FORMAT " PCR_offset:%" GST_TIME_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (group->first_pcr)), group->first_offset, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (group->pcr_offset))); GST_DEBUG ("Last PCR: +%" GST_TIME_FORMAT " offset: +%" G_GUINT64_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (pcroffset.pcr)), pcroffset.offset); } /* Move last values from current (if any) to the current group * and reset current. * Note: This does not set the CLOSED flag (since we have no next * contiguous group) */ static void _close_current_group (MpegTSPCR * pcrtable) { PCROffsetCurrent *current = pcrtable->current; PCROffsetGroup *group = current->group; if (group == NULL) return; GST_DEBUG ("Closing group and resetting current"); /* Store last values */ _append_group_values (group, current->pending[current->last]); memset (current, 0, sizeof (PCROffsetCurrent)); /* And re-evaluate all groups */ } static void record_pcr (MpegTSPacketizer2 * packetizer, MpegTSPCR * pcrtable, guint64 pcr, guint64 offset) { PCROffsetCurrent *current = pcrtable->current; gint64 corpcr, coroffset; packetizer->nb_seen_offsets += 1; pcrtable->last_pcrtime = PCRTIME_TO_GSTTIME (pcr); /* FIXME : Invert logic later (probability is higher that we have a * current estimator) */ /* Check for current */ if (G_UNLIKELY (current->group == NULL)) { PCROffsetGroup *prev = NULL; GList *tmp; /* No current estimator. This happens for the initial value, or after * discont and flushes. Figure out where we need to record this position. * * Possible choices: * 1) No groups at all: * Create a new group with pcr/offset * Initialize current to that group * 2) Entirely within an existing group * bail out (FIXME: Make this detection faster) * 3) Not in any group * Create a new group with pcr/offset at the right position * Initialize current to that group */ GST_DEBUG ("No current window estimator, Checking for group to use"); for (tmp = pcrtable->groups; tmp; tmp = tmp->next) { PCROffsetGroup *group = (PCROffsetGroup *) tmp->data; GST_DEBUG ("First PCR:%" GST_TIME_FORMAT " offset:%" G_GUINT64_FORMAT " PCR_offset:%" GST_TIME_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (group->first_pcr)), group->first_offset, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (group->pcr_offset))); GST_DEBUG ("Last PCR: +%" GST_TIME_FORMAT " offset: +%" G_GUINT64_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (group->values[group->last_value]. pcr)), group->values[group->last_value].offset); /* Check if before group */ if (offset < group->first_offset) { GST_DEBUG ("offset is before that group"); break; } /* Check if within group */ if (offset <= (group->values[group->last_value].offset + group->first_offset)) { GST_DEBUG ("Already observed PCR offset %" G_GUINT64_FORMAT, offset); return; } /* Check if just after group (i.e. continuation of it) */ if (!(group->flags & PCR_GROUP_FLAG_CLOSED) && pcr - group->first_pcr - group->values[group->last_value].pcr <= 100 * PCR_MSECOND) { GST_DEBUG ("Continuation of existing group"); _use_group (pcrtable, group); return; } /* Else after group */ prev = group; } _set_current_group (pcrtable, prev, pcr, offset, FALSE); return; } corpcr = pcr - current->first_pcr; coroffset = offset - current->first_offset; /* FIXME : Detect if we've gone into the next group ! * FIXME : Close group when that happens */ GST_DEBUG ("first:%d, last:%d, write:%d", current->first, current->last, current->write); GST_DEBUG ("First PCR:%" GST_TIME_FORMAT " offset:%" G_GUINT64_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (current->first_pcr)), current->first_offset); GST_DEBUG ("Last PCR: +%" GST_TIME_FORMAT " offset: +%" G_GUINT64_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (current->pending[current->last].pcr)), current->pending[current->last].offset); GST_DEBUG ("To add (corrected) PCR:%" GST_TIME_FORMAT " offset:%" G_GINT64_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (corpcr)), coroffset); /* Do we need to close the current group ? */ /* Check for wrapover/discont */ if (G_UNLIKELY (corpcr < current->pending[current->last].pcr)) { /* FIXME : ignore very small deltas (< 500ms ?) which are most likely * stray values */ GST_DEBUG ("PCR smaller than previously observed one, handling discont/wrapover"); /* Take values from current and put them in the current group (closing it) */ /* Create new group with new pcr/offset just after the current group * and mark it as a wrapover */ /* Initialize current to that group with new values */ _append_group_values (current->group, current->pending[current->last]); _set_current_group (pcrtable, current->group, pcr, offset, TRUE); return; } /* If PCR diff is greater than 500ms, create new group */ if (G_UNLIKELY (corpcr - current->pending[current->last].pcr > 500 * PCR_MSECOND)) { GST_DEBUG ("New PCR more than 500ms away, handling discont"); /* Take values from current and put them in the current group (closing it) */ /* Create new group with pcr/offset just after the current group * and mark it as a discont */ /* Initialize current to that group with new values */ _append_group_values (current->group, current->pending[current->last]); _set_current_group (pcrtable, current->group, pcr, offset, TRUE); return; } if (G_UNLIKELY (corpcr == current->last_value.pcr)) { GST_DEBUG ("Ignoring same PCR (stream is drunk)"); return; } /* update current window */ current->pending[current->write].pcr = corpcr; current->pending[current->write].offset = coroffset; current->last_value = current->pending[current->write]; current->last = (current->last + 1) % PCR_BITRATE_NEEDED; current->write = (current->write + 1) % PCR_BITRATE_NEEDED; GST_DEBUG ("first:%d, last:%d, write:%d", current->first, current->last, current->write); GST_DEBUG ("First PCR:%" GST_TIME_FORMAT " offset:%" G_GUINT64_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (current->first_pcr)), current->first_offset); GST_DEBUG ("Last PCR: +%" GST_TIME_FORMAT " offset: +%" G_GUINT64_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (current->pending[current->last].pcr)), current->pending[current->last].offset); /* If we haven't stored enough values, bail out */ if (current->write != current->first) { GST_DEBUG ("Not enough observations to calculate bitrate (first:%d, last:%d)", current->first, current->last); return; } /* If we are at least 1s away from reference value AND we have filled our * window, we can start comparing bitrates */ if (current->pending[current->first].pcr - current->prev.pcr > PCR_SECOND) { /* Calculate window bitrate */ current->cur_bitrate = gst_util_uint64_scale (PCR_SECOND, current->pending[current->last].offset - current->pending[current->first].offset, current->pending[current->last].pcr - current->pending[current->first].pcr); GST_DEBUG ("Current bitrate is now %" G_GUINT64_FORMAT, current->cur_bitrate); /* Calculate previous bitrate */ current->prev_bitrate = gst_util_uint64_scale (PCR_SECOND, current->pending[current->first].offset - current->prev.offset, current->pending[current->first].pcr - current->prev.pcr); GST_DEBUG ("Previous group bitrate now %" G_GUINT64_FORMAT, current->prev_bitrate); /* FIXME : Better bitrate changes ? Currently 10% changes */ if (ABSDIFF (current->cur_bitrate, current->prev_bitrate) * 10 > current->prev_bitrate) { GST_DEBUG ("Current bitrate changed by more than 10%% (old:%" G_GUINT64_FORMAT " new:%" G_GUINT64_FORMAT ")", current->prev_bitrate, current->cur_bitrate); /* If we detected a change in bitrate, this means that * d(first - prev) is a different bitrate than d(last - first). * * Two conclusions can be made: * 1) d(first - prev) is a complete bitrate "chain" (values between the * reference value and first pending value have consistent bitrate). * 2) next values (from second pending value onwards) will no longer have * the same bitrate. * * The question remains as to how long the new bitrate change is going to * last for (it might be short or longer term). For this we need to restart * bitrate estimation. * * * We move over first to the last value of group (a new chain ends and * starts from there) * * We remember that last group value as our new window reference * * We restart our window filing from the last observed value * * Once our new window is filled we will end up in two different scenarios: * 1) Either the bitrate change was consistent, and therefore the bitrate * will have remained constant over at least 2 window length * 2) The bitrate change was very short (1 window duration) and we will * close that chain and restart again. * X) And of course if any discont/gaps/wrapover happen in the meantime they * will also close the group. */ _append_group_values (current->group, current->pending[current->first]); current->prev = current->pending[current->first]; current->first = current->last; current->write = (current->first + 1) % PCR_BITRATE_NEEDED; return; } } /* Update read position */ current->first = (current->first + 1) % PCR_BITRATE_NEEDED; } /* convert specified offset into stream time */ GstClockTime mpegts_packetizer_offset_to_ts (MpegTSPacketizer2 * packetizer, guint64 offset, guint16 pid) { PCROffsetGroup *last; MpegTSPCR *pcrtable; GList *tmp; GstClockTime res; guint64 lastpcr, lastoffset; GST_DEBUG ("offset %" G_GUINT64_FORMAT, offset); if (G_UNLIKELY (!packetizer->calculate_offset)) return GST_CLOCK_TIME_NONE; if (G_UNLIKELY (packetizer->refoffset == -1)) return GST_CLOCK_TIME_NONE; if (G_UNLIKELY (offset < packetizer->refoffset)) return GST_CLOCK_TIME_NONE; PACKETIZER_GROUP_LOCK (packetizer); pcrtable = get_pcr_table (packetizer, pid); if (g_list_length (pcrtable->groups) < 1) { PACKETIZER_GROUP_UNLOCK (packetizer); GST_WARNING ("Not enough observations to return a duration estimate"); return GST_CLOCK_TIME_NONE; } if (g_list_length (pcrtable->groups) > 1) { GST_LOG ("Using last group"); /* FIXME : Refine this later to use neighbouring groups */ tmp = g_list_last (pcrtable->groups); last = tmp->data; if (G_UNLIKELY (last->flags & PCR_GROUP_FLAG_ESTIMATED)) _reevaluate_group_pcr_offset (pcrtable, last); /* lastpcr is the full value in PCR from the first first chunk of data */ lastpcr = last->values[last->last_value].pcr + last->pcr_offset; /* lastoffset is the full offset from the first chunk of data */ lastoffset = last->values[last->last_value].offset + last->first_offset - packetizer->refoffset; } else { PCROffsetCurrent *current = pcrtable->current; if (!current->group) { PACKETIZER_GROUP_UNLOCK (packetizer); GST_LOG ("No PCR yet"); return GST_CLOCK_TIME_NONE; } /* If doing progressive read, use current */ GST_LOG ("Using current group"); lastpcr = current->group->pcr_offset + current->pending[current->last].pcr; lastoffset = current->first_offset + current->pending[current->last].offset; } GST_DEBUG ("lastpcr:%" GST_TIME_FORMAT " lastoffset:%" G_GUINT64_FORMAT " refoffset:%" G_GUINT64_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (lastpcr)), lastoffset, packetizer->refoffset); /* Convert byte difference into time difference (and transformed from 27MHz to 1GHz) */ res = PCRTIME_TO_GSTTIME (gst_util_uint64_scale (offset - packetizer->refoffset, lastpcr, lastoffset)); PACKETIZER_GROUP_UNLOCK (packetizer); GST_DEBUG ("Returning timestamp %" GST_TIME_FORMAT " for offset %" G_GUINT64_FORMAT, GST_TIME_ARGS (res), offset); return res; } /* Input : local PTS (in GHz units) * Return : Stream time (in GHz units) */ static GstClockTime mpegts_packetizer_pts_to_ts_internal (MpegTSPacketizer2 * packetizer, GstClockTime pts, guint16 pcr_pid, gboolean check_diff) { GstClockTime res = GST_CLOCK_TIME_NONE; MpegTSPCR *pcrtable; PACKETIZER_GROUP_LOCK (packetizer); pcrtable = get_pcr_table (packetizer, pcr_pid); if (!GST_CLOCK_TIME_IS_VALID (pcrtable->base_time) && pcr_pid == 0x1fff && GST_CLOCK_TIME_IS_VALID (packetizer->last_in_time)) { pcrtable->base_time = packetizer->last_in_time; pcrtable->base_pcrtime = pts; } /* Use clock skew if present */ if (packetizer->calculate_skew && GST_CLOCK_TIME_IS_VALID (pcrtable->base_time)) { GST_DEBUG ("pts %" GST_TIME_FORMAT " base_pcrtime:%" GST_TIME_FORMAT " base_time:%" GST_TIME_FORMAT " pcroffset:%" GST_TIME_FORMAT, GST_TIME_ARGS (pts), GST_TIME_ARGS (pcrtable->base_pcrtime), GST_TIME_ARGS (pcrtable->base_time), GST_TIME_ARGS (pcrtable->pcroffset)); res = pts + pcrtable->pcroffset + packetizer->extra_shift; /* Don't return anything if we differ too much against last seen PCR */ if (G_UNLIKELY (check_diff && pcr_pid != 0x1fff && ABSDIFF (res, pcrtable->last_pcrtime) > 15 * GST_SECOND)) { res = GST_CLOCK_TIME_NONE; } else { GstClockTime tmp = pcrtable->base_time + pcrtable->skew; if (tmp + res >= pcrtable->base_pcrtime) { res += tmp - pcrtable->base_pcrtime; } else if (!check_diff || ABSDIFF (tmp + res + PCR_GST_MAX_VALUE, pcrtable->base_pcrtime) < PCR_GST_MAX_VALUE / 2) { /* Handle wrapover */ res += tmp + PCR_GST_MAX_VALUE - pcrtable->base_pcrtime; } else { /* Fallback for values that differ way too much */ res = GST_CLOCK_TIME_NONE; } } } else if (packetizer->calculate_offset && pcrtable->groups) { gint64 refpcr = G_MAXINT64, refpcroffset; PCROffsetGroup *group = pcrtable->current->group; /* Generic calculation: * Stream Time = PTS - first group PCR + group PCR_offset * * In case of wrapover: * Stream Time = PTS + MAX_PCR - first group PCR + group PCR_offset * (which we actually do by using first group PCR -= MAX_PCR in order * to end up with the same calculation as for non-wrapover) */ if (group) { /* If we have a current group the value is pretty much guaranteed */ GST_DEBUG ("Using current First PCR:%" GST_TIME_FORMAT " offset:%" G_GUINT64_FORMAT " PCR_offset:%" GST_TIME_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (group->first_pcr)), group->first_offset, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (group->pcr_offset))); refpcr = group->first_pcr; refpcroffset = group->pcr_offset; if (pts < PCRTIME_TO_GSTTIME (refpcr)) { /* Only apply wrapover if we're certain it is, and avoid * returning bogus values if it's a PTS/DTS which is *just* * before the start of the current group */ if (PCRTIME_TO_GSTTIME (refpcr) - pts > GST_SECOND) { pts += PCR_GST_MAX_VALUE; } else refpcr = G_MAXINT64; } } else { GList *tmp; /* Otherwise, find a suitable group */ GST_DEBUG ("Find group for current offset %" G_GUINT64_FORMAT, packetizer->offset); for (tmp = pcrtable->groups; tmp; tmp = tmp->next) { PCROffsetGroup *tgroup = tmp->data; GST_DEBUG ("Trying First PCR:%" GST_TIME_FORMAT " offset:%" G_GUINT64_FORMAT " PCR_offset:%" GST_TIME_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (tgroup->first_pcr)), tgroup->first_offset, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (tgroup->pcr_offset))); /* Gone too far ? */ if (tgroup->first_offset > packetizer->offset) { /* If there isn't a pending reset, use that value */ if (group) { GST_DEBUG ("PTS is %" GST_TIME_FORMAT " into group", GST_TIME_ARGS (pts - PCRTIME_TO_GSTTIME (group->first_pcr))); } break; } group = tgroup; /* In that group ? */ if (group->first_offset + group->values[group->last_value].offset > packetizer->offset) { GST_DEBUG ("PTS is %" GST_TIME_FORMAT " into group", GST_TIME_ARGS (pts - PCRTIME_TO_GSTTIME (group->first_pcr))); break; } } if (group && !(group->flags & PCR_GROUP_FLAG_RESET)) { GST_DEBUG ("Using group !"); refpcr = group->first_pcr; refpcroffset = group->pcr_offset; if (pts < PCRTIME_TO_GSTTIME (refpcr)) { if (PCRTIME_TO_GSTTIME (refpcr) - pts > GST_SECOND) pts += PCR_GST_MAX_VALUE; else refpcr = G_MAXINT64; } } } if (refpcr != G_MAXINT64) res = pts - PCRTIME_TO_GSTTIME (refpcr) + PCRTIME_TO_GSTTIME (refpcroffset); else GST_WARNING ("No groups, can't calculate timestamp"); } else GST_WARNING ("Not enough information to calculate proper timestamp"); PACKETIZER_GROUP_UNLOCK (packetizer); GST_DEBUG ("Returning timestamp %" GST_TIME_FORMAT " for pts %" GST_TIME_FORMAT " pcr_pid:0x%04x", GST_TIME_ARGS (res), GST_TIME_ARGS (pts), pcr_pid); return res; } /* Input : local PTS (in GHz units) * Return : Stream time (in GHz units) */ GstClockTime mpegts_packetizer_pts_to_ts_unchecked (MpegTSPacketizer2 * packetizer, GstClockTime pts, guint16 pcr_pid) { return mpegts_packetizer_pts_to_ts_internal (packetizer, pts, pcr_pid, FALSE); } /* Input : local PTS (in GHz units) * Return : Stream time (in GHz units) */ GstClockTime mpegts_packetizer_pts_to_ts (MpegTSPacketizer2 * packetizer, GstClockTime pts, guint16 pcr_pid) { return mpegts_packetizer_pts_to_ts_internal (packetizer, pts, pcr_pid, TRUE); } /* Stream time to offset */ guint64 mpegts_packetizer_ts_to_offset (MpegTSPacketizer2 * packetizer, GstClockTime ts, guint16 pcr_pid) { MpegTSPCR *pcrtable; guint64 res; PCROffsetGroup *nextgroup = NULL, *prevgroup = NULL; guint64 querypcr, firstpcr, lastpcr, firstoffset, lastoffset; PCROffsetCurrent *current; GList *tmp; if (!packetizer->calculate_offset) return -1; PACKETIZER_GROUP_LOCK (packetizer); pcrtable = get_pcr_table (packetizer, pcr_pid); if (pcrtable->groups == NULL) { PACKETIZER_GROUP_UNLOCK (packetizer); return -1; } querypcr = GSTTIME_TO_PCRTIME (ts); GST_DEBUG ("Searching offset for ts %" GST_TIME_FORMAT, GST_TIME_ARGS (ts)); /* First check if we're within the current pending group */ current = pcrtable->current; if (current && current->group && (querypcr >= current->group->pcr_offset) && querypcr - current->group->pcr_offset <= current->pending[current->last].pcr) { GST_DEBUG ("pcr is in current group"); nextgroup = current->group; goto calculate_points; } /* Find the neighbouring groups */ for (tmp = pcrtable->groups; tmp; tmp = tmp->next) { nextgroup = (PCROffsetGroup *) tmp->data; GST_DEBUG ("Trying group PCR %" GST_TIME_FORMAT " (offset %" G_GUINT64_FORMAT " pcr_offset %" GST_TIME_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (nextgroup->first_pcr)), nextgroup->first_offset, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (nextgroup->pcr_offset))); /* Check if we've gone too far */ if (nextgroup->pcr_offset > querypcr) { GST_DEBUG ("pcr is before that group"); break; } if (tmp->next == NULL) { GST_DEBUG ("pcr is beyond last group"); break; } prevgroup = nextgroup; /* Maybe it's in this group */ if (nextgroup->values[nextgroup->last_value].pcr + nextgroup->pcr_offset >= querypcr) { GST_DEBUG ("pcr is in that group"); break; } } calculate_points: GST_DEBUG ("nextgroup:%p, prevgroup:%p", nextgroup, prevgroup); if (nextgroup == prevgroup || prevgroup == NULL) { /* We use the current group to calculate position: * * if the PCR is within this group * * if there is only one group to use for calculation */ GST_DEBUG ("In group or after last one"); lastoffset = firstoffset = nextgroup->first_offset; lastpcr = firstpcr = nextgroup->pcr_offset; if (current && nextgroup == current->group) { lastoffset += current->pending[current->last].offset; lastpcr += current->pending[current->last].pcr; } else { lastoffset += nextgroup->values[nextgroup->last_value].offset; lastpcr += nextgroup->values[nextgroup->last_value].pcr; } } else { GST_DEBUG ("Between group"); lastoffset = nextgroup->first_offset; lastpcr = nextgroup->pcr_offset; firstoffset = prevgroup->values[prevgroup->last_value].offset + prevgroup->first_offset; firstpcr = prevgroup->values[prevgroup->last_value].pcr + prevgroup->pcr_offset; } PACKETIZER_GROUP_UNLOCK (packetizer); GST_DEBUG ("Using prev PCR %" G_GUINT64_FORMAT " offset %" G_GUINT64_FORMAT, firstpcr, firstoffset); GST_DEBUG ("Using last PCR %" G_GUINT64_FORMAT " offset %" G_GUINT64_FORMAT, lastpcr, lastoffset); res = firstoffset; if (lastpcr != firstpcr) res += gst_util_uint64_scale (querypcr - firstpcr, lastoffset - firstoffset, lastpcr - firstpcr); GST_DEBUG ("Returning offset %" G_GUINT64_FORMAT " for ts %" GST_TIME_FORMAT, res, GST_TIME_ARGS (ts)); return res; } void mpegts_packetizer_set_reference_offset (MpegTSPacketizer2 * packetizer, guint64 refoffset) { GST_DEBUG ("Setting reference offset to %" G_GUINT64_FORMAT, refoffset); PACKETIZER_GROUP_LOCK (packetizer); packetizer->refoffset = refoffset; PACKETIZER_GROUP_UNLOCK (packetizer); } void mpegts_packetizer_set_pcr_discont_threshold (MpegTSPacketizer2 * packetizer, GstClockTime threshold) { PACKETIZER_GROUP_LOCK (packetizer); packetizer->pcr_discont_threshold = threshold; PACKETIZER_GROUP_UNLOCK (packetizer); } void mpegts_packetizer_set_current_pcr_offset (MpegTSPacketizer2 * packetizer, GstClockTime offset, guint16 pcr_pid) { guint64 pcr_offset; gint64 delta; MpegTSPCR *pcrtable; PCROffsetGroup *group; GList *tmp; gboolean apply = FALSE; /* fast path */ PACKETIZER_GROUP_LOCK (packetizer); pcrtable = get_pcr_table (packetizer, pcr_pid); if (pcrtable == NULL || pcrtable->current->group == NULL) { PACKETIZER_GROUP_UNLOCK (packetizer); return; } pcr_offset = GSTTIME_TO_PCRTIME (offset); /* Pick delta from *first* group */ if (pcrtable->groups) group = pcrtable->groups->data; else group = pcrtable->current->group; GST_DEBUG ("Current group PCR %" GST_TIME_FORMAT " (offset %" G_GUINT64_FORMAT " pcr_offset %" GST_TIME_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (group->first_pcr)), group->first_offset, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (group->pcr_offset))); /* Remember the difference between previous initial pcr_offset and * new initial pcr_offset */ delta = pcr_offset - group->pcr_offset; if (delta == 0) { GST_DEBUG ("No shift to apply"); PACKETIZER_GROUP_UNLOCK (packetizer); return; } GST_DEBUG ("Shifting groups by %" GST_TIME_FORMAT " for new initial pcr_offset %" GST_TIME_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (delta)), GST_TIME_ARGS (offset)); for (tmp = pcrtable->groups; tmp; tmp = tmp->next) { PCROffsetGroup *tgroup = (tmp->data); if (tgroup == group) apply = TRUE; if (apply) { tgroup->pcr_offset += delta; GST_DEBUG ("Update group PCR %" GST_TIME_FORMAT " (offset %" G_GUINT64_FORMAT " pcr_offset %" GST_TIME_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (tgroup->first_pcr)), tgroup->first_offset, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (tgroup->pcr_offset))); } else GST_DEBUG ("Not modifying group PCR %" GST_TIME_FORMAT " (offset %" G_GUINT64_FORMAT " pcr_offset %" GST_TIME_FORMAT, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (tgroup->first_pcr)), tgroup->first_offset, GST_TIME_ARGS (PCRTIME_TO_GSTTIME (tgroup->pcr_offset))); } PACKETIZER_GROUP_UNLOCK (packetizer); }