/* GStreamer * Copyright (C) <1999> Erik Walthinsen * Copyright (C) <2007> Jan Schmidt * * 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., 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include #include "mpegvideoparse.h" /* FIXME: there are still some things to do in this element. * + Handle Sequence Display Extension to output the display size * rather than the encoded size. * + Do all the other stuff (documentation, tests) to get it into * ugly or good. * + low priority: * - handle seeking in raw elementary streams * - calculate timestamps for all un-timestamped frames, taking into * account frame re-ordering. Doing this probably requires introducing * an extra end-to-end delay however, so might not be really desirable. * - Collect a list of regions and the sequence headers that apply * to each region so that we properly handle SEQUENCE_END followed * by a new sequence. At the moment, the caps will change if the * sequence changes, but if we then seek to a different spot it might * be wrong. Fortunately almost every stream only has 1 sequence. */ GST_DEBUG_CATEGORY (mpv_parse_debug); #define GST_CAT_DEFAULT mpv_parse_debug static GstStaticPadTemplate src_template = GST_STATIC_PAD_TEMPLATE ("src", GST_PAD_SRC, GST_PAD_ALWAYS, GST_STATIC_CAPS ("video/mpeg, " "mpegversion = (int) [ 1, 2 ], " "parsed = (boolean) true, " "systemstream = (boolean) false, " "width = (int) [ 16, 4096 ], " "height = (int) [ 16, 4096 ], " "pixel-aspect-ratio = (fraction) [ 0/1, MAX ], " "framerate = (fraction) [ 0/1, MAX ]") ); static GstStaticPadTemplate sink_template = GST_STATIC_PAD_TEMPLATE ("sink", GST_PAD_SINK, GST_PAD_ALWAYS, GST_STATIC_CAPS ("video/mpeg, " "mpegversion = (int) [ 1, 2 ], " "parsed = (boolean) false, " "systemstream = (boolean) false") ); /* MpegVideoParse signals and args */ enum { /* FILL ME */ LAST_SIGNAL }; enum { ARG_0 /* FILL ME */ }; static void gst_mpegvideoparse_class_init (MpegVideoParseClass * klass); static void gst_mpegvideoparse_base_init (MpegVideoParseClass * klass); static void gst_mpegvideoparse_init (MpegVideoParse * mpegvideoparse); static void gst_mpegvideoparse_dispose (GObject * object); static GstFlowReturn gst_mpegvideoparse_chain (GstPad * pad, GstBuffer * buf); static gboolean mpv_parse_sink_event (GstPad * pad, GstEvent * event); static void gst_mpegvideoparse_flush (MpegVideoParse * mpegvideoparse); static GstStateChangeReturn gst_mpegvideoparse_change_state (GstElement * element, GstStateChange transition); static void mpv_send_pending_segs (MpegVideoParse * mpegvideoparse); static void mpv_clear_pending_segs (MpegVideoParse * mpegvideoparse); static GstElementClass *parent_class = NULL; /*static guint gst_mpegvideoparse_signals[LAST_SIGNAL] = { 0 }; */ GType mpegvideoparse_get_type (void) { static GType mpegvideoparse_type = 0; if (!mpegvideoparse_type) { static const GTypeInfo mpegvideoparse_info = { sizeof (MpegVideoParseClass), (GBaseInitFunc) gst_mpegvideoparse_base_init, NULL, (GClassInitFunc) gst_mpegvideoparse_class_init, NULL, NULL, sizeof (MpegVideoParse), 0, (GInstanceInitFunc) gst_mpegvideoparse_init, }; mpegvideoparse_type = g_type_register_static (GST_TYPE_ELEMENT, "MpegVideoParse", &mpegvideoparse_info, 0); } return mpegvideoparse_type; } static void gst_mpegvideoparse_base_init (MpegVideoParseClass * klass) { GstElementClass *element_class = GST_ELEMENT_CLASS (klass); gst_element_class_add_pad_template (element_class, gst_static_pad_template_get (&src_template)); gst_element_class_add_pad_template (element_class, gst_static_pad_template_get (&sink_template)); gst_element_class_set_details_simple (element_class, "MPEG video elementary stream parser", "Codec/Parser/Video", "Parses and frames MPEG-1 and MPEG-2 elementary video streams", "Wim Taymans , " "Jan Schmidt "); } static void gst_mpegvideoparse_class_init (MpegVideoParseClass * klass) { GObjectClass *gobject_class; GstElementClass *gstelement_class; gstelement_class = (GstElementClass *) klass; gobject_class = G_OBJECT_CLASS (klass); parent_class = g_type_class_peek_parent (klass); gobject_class->dispose = (GObjectFinalizeFunc) (gst_mpegvideoparse_dispose); gstelement_class->change_state = gst_mpegvideoparse_change_state; } static void mpv_parse_reset (MpegVideoParse * mpegvideoparse) { mpegvideoparse->seq_hdr.mpeg_version = 0; mpegvideoparse->seq_hdr.width = mpegvideoparse->seq_hdr.height = -1; mpegvideoparse->seq_hdr.fps_n = mpegvideoparse->seq_hdr.par_w = 0; mpegvideoparse->seq_hdr.fps_d = mpegvideoparse->seq_hdr.par_h = 1; mpv_clear_pending_segs (mpegvideoparse); } static void mpv_send_pending_segs (MpegVideoParse * mpegvideoparse) { while (mpegvideoparse->pending_segs) { GstEvent *ev = mpegvideoparse->pending_segs->data; gst_pad_push_event (mpegvideoparse->srcpad, ev); mpegvideoparse->pending_segs = g_list_delete_link (mpegvideoparse->pending_segs, mpegvideoparse->pending_segs); } mpegvideoparse->pending_segs = NULL; } static void mpv_clear_pending_segs (MpegVideoParse * mpegvideoparse) { while (mpegvideoparse->pending_segs) { GstEvent *ev = mpegvideoparse->pending_segs->data; gst_event_unref (ev); mpegvideoparse->pending_segs = g_list_delete_link (mpegvideoparse->pending_segs, mpegvideoparse->pending_segs); } } static void gst_mpegvideoparse_init (MpegVideoParse * mpegvideoparse) { mpegvideoparse->sinkpad = gst_pad_new_from_static_template (&sink_template, "sink"); gst_pad_set_chain_function (mpegvideoparse->sinkpad, gst_mpegvideoparse_chain); gst_pad_set_event_function (mpegvideoparse->sinkpad, mpv_parse_sink_event); gst_element_add_pad (GST_ELEMENT (mpegvideoparse), mpegvideoparse->sinkpad); mpegvideoparse->srcpad = gst_pad_new_from_static_template (&src_template, "src"); gst_pad_use_fixed_caps (mpegvideoparse->srcpad); gst_element_add_pad (GST_ELEMENT (mpegvideoparse), mpegvideoparse->srcpad); mpeg_packetiser_init (&mpegvideoparse->packer); mpv_parse_reset (mpegvideoparse); } void gst_mpegvideoparse_dispose (GObject * object) { MpegVideoParse *mpegvideoparse = GST_MPEGVIDEOPARSE (object); mpeg_packetiser_free (&mpegvideoparse->packer); gst_buffer_replace (&mpegvideoparse->seq_hdr_buf, NULL); G_OBJECT_CLASS (parent_class)->dispose (object); } static gboolean mpegvideoparse_handle_sequence (MpegVideoParse * mpegvideoparse, GstBuffer * buf) { MPEGSeqHdr new_hdr; guint8 *cur, *end; cur = GST_BUFFER_DATA (buf); end = GST_BUFFER_DATA (buf) + GST_BUFFER_SIZE (buf); memset (&new_hdr, 0, sizeof (MPEGSeqHdr)); if (G_UNLIKELY (!mpeg_util_parse_sequence_hdr (&new_hdr, cur, end))) return FALSE; if (new_hdr.width < 16 || new_hdr.width > 4096 || new_hdr.height < 16 || new_hdr.height > 4096) { GST_WARNING_OBJECT (mpegvideoparse, "Width/height out of valid range " "[16, 4096]"); return FALSE; } if (memcmp (&mpegvideoparse->seq_hdr, &new_hdr, sizeof (MPEGSeqHdr)) != 0) { GstCaps *caps; GstBuffer *seq_buf; /* * Profile indication - 1 => High, 2 => Spatially Scalable, * 3 => SNR Scalable, 4 => Main, 5 => Simple * 4:2:2 and Multi-view have profile = 0, with the escape bit set to 1 */ const gchar *profiles[] = { "high", "spatial", "snr", "main", "simple" }; /* * Level indication - 4 => High, 6 => High-1440, 8 => Main, 10 => Low, * except in the case of profile = 0 */ const gchar *levels[] = { "high", "high-1440", "main", "low" }; /* Store the entire sequence header + sequence header extension for output as codec_data */ seq_buf = gst_buffer_copy (buf); gst_buffer_replace (&mpegvideoparse->seq_hdr_buf, seq_buf); gst_buffer_unref (seq_buf); caps = gst_caps_new_simple ("video/mpeg", "systemstream", G_TYPE_BOOLEAN, FALSE, "parsed", G_TYPE_BOOLEAN, TRUE, "mpegversion", G_TYPE_INT, new_hdr.mpeg_version, "width", G_TYPE_INT, new_hdr.width, "height", G_TYPE_INT, new_hdr.height, "framerate", GST_TYPE_FRACTION, new_hdr.fps_n, new_hdr.fps_d, "pixel-aspect-ratio", GST_TYPE_FRACTION, new_hdr.par_w, new_hdr.par_h, "interlaced", G_TYPE_BOOLEAN, !new_hdr.progressive, "codec_data", GST_TYPE_BUFFER, seq_buf, NULL); if (new_hdr.mpeg_version == 2) { const gchar *profile = NULL, *level = NULL; if (new_hdr.profile > 0 && new_hdr.profile < 6) profile = profiles[new_hdr.profile - 1]; if ((new_hdr.level > 3) && (new_hdr.level < 11) && (new_hdr.level % 2 == 0)) level = levels[(new_hdr.level >> 1) - 1]; if (new_hdr.profile == 8) { /* Non-hierarchical profile */ switch (new_hdr.level) { case 2: level = levels[0]; case 5: level = levels[2]; profile = "4:2:2"; break; case 10: level = levels[0]; case 11: level = levels[1]; case 13: level = levels[2]; case 14: level = levels[3]; profile = "multiview"; break; default: break; } } if (profile) gst_caps_set_simple (caps, "profile", G_TYPE_STRING, profile, NULL); else GST_DEBUG ("Invalid profile - %u", new_hdr.profile); if (level) gst_caps_set_simple (caps, "level", G_TYPE_STRING, level, NULL); else GST_DEBUG ("Invalid level - %u", new_hdr.level); } GST_DEBUG ("New mpegvideoparse caps: %" GST_PTR_FORMAT, caps); if (!gst_pad_set_caps (mpegvideoparse->srcpad, caps)) { gst_caps_unref (caps); return FALSE; } gst_caps_unref (caps); if (new_hdr.bitrate > 0) { GstTagList *taglist; taglist = gst_tag_list_new_full (GST_TAG_BITRATE, new_hdr.bitrate, NULL); gst_element_found_tags_for_pad (GST_ELEMENT_CAST (mpegvideoparse), mpegvideoparse->srcpad, taglist); } /* And update the new_hdr into our stored version */ mpegvideoparse->seq_hdr = new_hdr; } return TRUE; } #ifndef GST_DISABLE_GST_DEBUG static const gchar * picture_start_code_name (guint8 psc) { guint i; const struct { guint8 psc; const gchar *name; } psc_names[] = { { 0x00, "Picture Start"}, { 0xb0, "Reserved"}, { 0xb1, "Reserved"}, { 0xb2, "User Data Start"}, { 0xb3, "Sequence Header Start"}, { 0xb4, "Sequence Error"}, { 0xb5, "Extnsion Start"}, { 0xb6, "Reserved"}, { 0xb7, "Sequence End"}, { 0xb8, "Group Start"}, { 0xb9, "Program End"} }; if (psc < 0xB0 && psc > 0) return "Slice Start"; for (i = 0; i < G_N_ELEMENTS (psc_names); i++) if (psc_names[i].psc == psc) return psc_names[i].name; return "UNKNOWN"; }; static const gchar * picture_type_name (guint8 pct) { guint i; const struct { guint8 pct; const gchar *name; } pct_names[] = { { 0, "Forbidden"}, { 1, "I Frame"}, { 2, "P Frame"}, { 3, "B Frame"}, { 4, "DC Intra Coded (Shall Not Be Used!)"} }; for (i = 0; i < G_N_ELEMENTS (pct_names); i++) if (pct_names[i].pct == pct) return pct_names[i].name; return "Reserved/Unknown"; } #endif /* GST_DISABLE_GST_DEBUG */ static gboolean mpegvideoparse_handle_picture (MpegVideoParse * mpegvideoparse, GstBuffer * buf) { guint8 *cur, *end; guint32 sync_word = 0xffffffff; cur = GST_BUFFER_DATA (buf); end = GST_BUFFER_DATA (buf) + GST_BUFFER_SIZE (buf); cur = mpeg_util_find_start_code (&sync_word, cur, end); while (cur != NULL) { if (cur[0] == 0 || cur[0] > 0xaf) GST_LOG_OBJECT (mpegvideoparse, "Picture Start Code : %s", picture_start_code_name (cur[0])); /* Cur points at the last byte of the start code */ if (cur[0] == MPEG_PACKET_PICTURE) { guint8 *pic_data = cur - 3; MPEGPictureHdr hdr; /* pic_data points to the first byte of the sync word now */ if (!mpeg_util_parse_picture_hdr (&hdr, pic_data, end)) return FALSE; if (hdr.pic_type != MPEG_PICTURE_TYPE_I) GST_BUFFER_FLAG_SET (buf, GST_BUFFER_FLAG_DELTA_UNIT); GST_LOG_OBJECT (mpegvideoparse, "Picture type is %s", picture_type_name (hdr.pic_type)); /* FIXME: Can use the picture type and number of fields to track a * timestamp */ break; } cur = mpeg_util_find_start_code (&sync_word, cur, end); } return TRUE; } #if 0 static guint64 gst_mpegvideoparse_time_code (guchar * gop, MPEGSeqHdr * seq_hdr) { guint32 data = GST_READ_UINT32_BE (gop); guint64 seconds; guint8 frames; seconds = ((data & 0xfc000000) >> 26) * 3600; /* hours */ seconds += ((data & 0x03f00000) >> 20) * 60; /* minutes */ seconds += (data & 0x0007e000) >> 13; /* seconds */ frames = (data & 0x00001f80) >> 7; return seconds * GST_SECOND + gst_util_uint64_scale_int (frames * GST_SECOND, seq_hdr->fps_d, seq_hdr->fps_n); } #endif static void gst_mpegvideoparse_flush (MpegVideoParse * mpegvideoparse) { GST_DEBUG_OBJECT (mpegvideoparse, "mpegvideoparse: flushing"); mpegvideoparse->next_offset = GST_BUFFER_OFFSET_NONE; g_list_foreach (mpegvideoparse->gather, (GFunc) gst_mini_object_unref, NULL); g_list_free (mpegvideoparse->gather); mpegvideoparse->gather = NULL; g_list_foreach (mpegvideoparse->decode, (GFunc) gst_mini_object_unref, NULL); g_list_free (mpegvideoparse->decode); mpegvideoparse->decode = NULL; mpeg_packetiser_flush (&mpegvideoparse->packer); mpv_clear_pending_segs (mpegvideoparse); } static GstFlowReturn mpegvideoparse_drain_avail (MpegVideoParse * mpegvideoparse) { MPEGBlockInfo *cur; GstBuffer *buf = NULL; GstFlowReturn res = GST_FLOW_OK; cur = mpeg_packetiser_get_block (&mpegvideoparse->packer, &buf); while ((cur != NULL) && (res == GST_FLOW_OK)) { /* Handle the block */ GST_LOG_OBJECT (mpegvideoparse, "Have block of size %u with pack_type %s and flags 0x%02x", cur->length, picture_start_code_name (cur->first_pack_type), cur->flags); if ((cur->flags & MPEG_BLOCK_FLAG_SEQUENCE) && buf != NULL) { /* Found a sequence header */ if (!mpegvideoparse_handle_sequence (mpegvideoparse, buf)) { GST_DEBUG_OBJECT (mpegvideoparse, "Invalid sequence header. Dropping buffer."); gst_buffer_unref (buf); buf = NULL; } } else if (mpegvideoparse->seq_hdr.mpeg_version == 0 && buf) { /* Don't start pushing out buffers until we've seen a sequence header */ GST_DEBUG_OBJECT (mpegvideoparse, "No sequence header yet. Dropping buffer of %u bytes", GST_BUFFER_SIZE (buf)); gst_buffer_unref (buf); buf = NULL; } if (buf != NULL) { /* If outputting a PICTURE packet, we can calculate the duration and possibly the timestamp */ if (cur->flags & MPEG_BLOCK_FLAG_PICTURE) { if (!mpegvideoparse_handle_picture (mpegvideoparse, buf)) { /* Corrupted picture. Drop it. */ GST_DEBUG_OBJECT (mpegvideoparse, "Corrupted picture header. Dropping buffer of %u bytes", GST_BUFFER_SIZE (buf)); mpegvideoparse->need_discont = TRUE; gst_buffer_unref (buf); buf = NULL; } } } if (buf != NULL) { GST_DEBUG_OBJECT (mpegvideoparse, "mpegvideoparse: pushing buffer of %u bytes with ts %" GST_TIME_FORMAT, GST_BUFFER_SIZE (buf), GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buf))); gst_buffer_set_caps (buf, GST_PAD_CAPS (mpegvideoparse->srcpad)); if (mpegvideoparse->need_discont) { GST_DEBUG_OBJECT (mpegvideoparse, "setting discont flag on outgoing buffer"); GST_BUFFER_FLAG_SET (buf, GST_BUFFER_FLAG_DISCONT); mpegvideoparse->need_discont = FALSE; } mpv_send_pending_segs (mpegvideoparse); res = gst_pad_push (mpegvideoparse->srcpad, buf); buf = NULL; } /* Advance to the next data block */ mpeg_packetiser_next_block (&mpegvideoparse->packer); cur = mpeg_packetiser_get_block (&mpegvideoparse->packer, &buf); } if (buf != NULL) gst_buffer_unref (buf); return res; } static GstFlowReturn gst_mpegvideoparse_chain_forward (MpegVideoParse * mpegvideoparse, gboolean discont, GstBuffer * buf) { GstFlowReturn res; guint64 next_offset = GST_BUFFER_OFFSET_NONE; GST_DEBUG_OBJECT (mpegvideoparse, "mpegvideoparse: received buffer of %u bytes with ts %" GST_TIME_FORMAT " and offset %" G_GINT64_FORMAT, GST_BUFFER_SIZE (buf), GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buf)), GST_BUFFER_OFFSET (buf)); /* If we have an offset, and the incoming offset doesn't match, or we have a discont, handle it first by flushing out data we have collected. */ if (mpegvideoparse->next_offset != GST_BUFFER_OFFSET_NONE) { if (GST_BUFFER_OFFSET_IS_VALID (buf)) { if (mpegvideoparse->next_offset != GST_BUFFER_OFFSET (buf)) discont = TRUE; next_offset = GST_BUFFER_OFFSET (buf) + GST_BUFFER_SIZE (buf); } else { next_offset = mpegvideoparse->next_offset + GST_BUFFER_SIZE (buf); } } /* Clear out any existing stuff if the new buffer is discontinuous */ if (discont) { GST_DEBUG_OBJECT (mpegvideoparse, "Have discont packet, draining data"); mpegvideoparse->need_discont = TRUE; mpeg_packetiser_handle_eos (&mpegvideoparse->packer); res = mpegvideoparse_drain_avail (mpegvideoparse); mpeg_packetiser_flush (&mpegvideoparse->packer); if (res != GST_FLOW_OK) { gst_buffer_unref (buf); goto done; } } /* Takes ownership of the data */ mpeg_packetiser_add_buf (&mpegvideoparse->packer, buf); /* And push out what we can */ res = mpegvideoparse_drain_avail (mpegvideoparse); done: /* Update our offset */ mpegvideoparse->next_offset = next_offset; return res; } /* scan the decode queue for a picture header with an I frame and return the * index in the first buffer. We only scan the first buffer and possibly a * couple of bytes of the next buffers to find the I frame. Scanning is done * backwards because the first buffer could contain many picture start codes * with I frames. */ static guint scan_keyframe (MpegVideoParse * mpegvideoparse) { guint64 scanword; guint count; GList *walk; GstBuffer *head; guint8 *data; guint size; /* we use an 8 byte buffer, this is enough to hold the picture start code and * the picture header bits we are interested in. We init to 0xff so that when * we have a valid picture start without the header bits, we will be able to * detect this because it will generate an invalid picture type. */ scanword = ~G_GUINT64_CONSTANT (0); GST_LOG_OBJECT (mpegvideoparse, "scan keyframe"); /* move to the second buffer if we can, we should have at least one buffer */ walk = mpegvideoparse->decode; g_return_val_if_fail (walk != NULL, -1); head = GST_BUFFER_CAST (walk->data); count = 0; walk = g_list_next (walk); while (walk) { GstBuffer *buf = GST_BUFFER_CAST (walk->data); data = GST_BUFFER_DATA (buf); size = GST_BUFFER_SIZE (buf); GST_LOG_OBJECT (mpegvideoparse, "collect remaining %d bytes from %p", 6 - count, buf); while (size > 0 && count < 6) { scanword = (scanword << 8) | *data++; size--; count++; } if (count == 6) break; walk = g_list_next (walk); } /* move bits to the beginning of the word now */ if (count) scanword = (scanword << (8 * (8 - count))); GST_LOG_OBJECT (mpegvideoparse, "scanword 0x%016" G_GINT64_MODIFIER "x", scanword); data = GST_BUFFER_DATA (head); size = GST_BUFFER_SIZE (head); while (size > 0) { scanword = (((guint64) data[size - 1]) << 56) | (scanword >> 8); GST_LOG_OBJECT (mpegvideoparse, "scanword at %d 0x%016" G_GINT64_MODIFIER "x", size - 1, scanword); /* check picture start and picture type */ if ((scanword & G_GUINT64_CONSTANT (0xffffffff00380000)) == G_GUINT64_CONSTANT (0x0000010000080000)) break; size--; } return size - 1; } /* For reverse playback we use a technique that can be used for * any keyframe based video codec. * * Input: * Buffer decoding order: 7 8 9 4 5 6 1 2 3 EOS * Keyframe flag: K K * Discont flag: D D D * * - Each Discont marks a discont in the decoding order. * - The keyframes mark where we can start decoding. For mpeg they are either * set by the demuxer or we have to scan the buffers for a syncword and * picture header with an I frame. * * First we prepend incomming buffers to the gather queue, whenever we receive * a discont, we flush out the gather queue. * * The above data will be accumulated in the gather queue like this: * * gather queue: 9 8 7 * D * * Whe buffer 4 is received (with a DISCONT), we flush the gather queue like * this: * * while (gather) * take head of queue and prepend to decode queue. * if we copied a keyframe, decode the decode queue. * * After we flushed the gather queue, we add 4 to the (now empty) gather queue. * We get the following situation: * * gather queue: 4 * decode queue: 7 8 9 * * After we received 5 (Keyframe) and 6: * * gather queue: 6 5 4 * decode queue: 7 8 9 * * When we receive 1 (DISCONT) which triggers a flush of the gather queue: * * Copy head of the gather queue (6) to decode queue: * * gather queue: 5 4 * decode queue: 6 7 8 9 * * Copy head of the gather queue (5) to decode queue. This is a keyframe so we * can start decoding. * * gather queue: 4 * decode queue: 5 6 7 8 9 * * Decode frames in decode queue, we don't actually do the decoding but we * will send the decode queue to the downstream element. This will empty the * decoding queue again. * * Copy head of the gather queue (4) to decode queue, we flushed the gather * queue and can now store input buffer in the gather queue: * * gather queue: 1 * decode queue: 4 * * When we receive EOS, the queue looks like: * * gather queue: 3 2 1 * decode queue: 4 * * Fill decode queue, first keyframe we copy is 2: * * gather queue: 1 * decode queue: 2 3 4 * * After pushing the decode queue: * * gather queue: 1 * decode queue: * * Leftover buffer 1 cannot be decoded and must be discarded. */ static GstFlowReturn gst_mpegvideoparse_flush_decode (MpegVideoParse * mpegvideoparse, guint idx) { GstFlowReturn res = GST_FLOW_OK; GstBuffer *head = NULL; while (mpegvideoparse->decode) { GstBuffer *buf; buf = GST_BUFFER_CAST (mpegvideoparse->decode->data); if (idx != -1) { GstBuffer *temp; if (idx > 0) { /* first buffer, split at the point where the picture start was * detected and store as the new head of the decoding list. */ head = gst_buffer_create_sub (buf, 0, idx); /* push the remainder after the picture sync point downstream, this is the * first DISCONT buffer we push. */ temp = gst_buffer_create_sub (buf, idx, GST_BUFFER_SIZE (buf) - idx); /* don't need old buffer anymore and swap new buffer */ gst_buffer_unref (buf); buf = temp; } GST_BUFFER_FLAG_SET (buf, GST_BUFFER_FLAG_DISCONT); idx = -1; } else { /* next buffers are not discont */ GST_BUFFER_FLAG_UNSET (buf, GST_BUFFER_FLAG_DISCONT); } GST_DEBUG_OBJECT (mpegvideoparse, "pushing buffer %p, ts %" GST_TIME_FORMAT, buf, GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buf))); res = gst_pad_push (mpegvideoparse->srcpad, buf); mpegvideoparse->decode = g_list_delete_link (mpegvideoparse->decode, mpegvideoparse->decode); } if (head) { /* store remainder of the buffer */ mpegvideoparse->decode = g_list_prepend (mpegvideoparse->decode, head); } return res; } static GstFlowReturn gst_mpegvideoparse_chain_reverse (MpegVideoParse * mpegvideoparse, gboolean discont, GstBuffer * buf) { GstFlowReturn res = GST_FLOW_OK; /* if we have a discont, move buffers to the decode list */ if (G_UNLIKELY (discont)) { GST_DEBUG_OBJECT (mpegvideoparse, "received discont,gathering buffers"); while (mpegvideoparse->gather) { GstBuffer *gbuf; guint keyframeidx; gbuf = GST_BUFFER_CAST (mpegvideoparse->gather->data); /* remove from the gather list */ mpegvideoparse->gather = g_list_delete_link (mpegvideoparse->gather, mpegvideoparse->gather); /* copy to decode queue */ mpegvideoparse->decode = g_list_prepend (mpegvideoparse->decode, gbuf); GST_DEBUG_OBJECT (mpegvideoparse, "copied decoding buffer %p, len %d", gbuf, g_list_length (mpegvideoparse->decode)); /* check if we copied a keyframe, we scan the buffers on the decode queue. * We only need to scan the first buffer and at most 3 bytes of the second * buffer. We return the index of the keyframe (or -1 when nothing was * found) */ while ((keyframeidx = scan_keyframe (mpegvideoparse)) != -1) { GST_DEBUG_OBJECT (mpegvideoparse, "copied keyframe at %u", keyframeidx); res = gst_mpegvideoparse_flush_decode (mpegvideoparse, keyframeidx); } } } if (buf) { /* add buffer to gather queue */ GST_DEBUG_OBJECT (mpegvideoparse, "gathering buffer %p, size %u", buf, GST_BUFFER_SIZE (buf)); mpegvideoparse->gather = g_list_prepend (mpegvideoparse->gather, buf); } return res; } static GstFlowReturn gst_mpegvideoparse_chain (GstPad * pad, GstBuffer * buf) { MpegVideoParse *mpegvideoparse; GstFlowReturn res; gboolean discont; mpegvideoparse = GST_MPEGVIDEOPARSE (gst_object_get_parent (GST_OBJECT (pad))); discont = GST_BUFFER_IS_DISCONT (buf); if (mpegvideoparse->segment.rate > 0.0) res = gst_mpegvideoparse_chain_forward (mpegvideoparse, discont, buf); else res = gst_mpegvideoparse_chain_reverse (mpegvideoparse, discont, buf); gst_object_unref (mpegvideoparse); return res; } static gboolean mpv_parse_sink_event (GstPad * pad, GstEvent * event) { gboolean res = TRUE; MpegVideoParse *mpegvideoparse = GST_MPEGVIDEOPARSE (gst_pad_get_parent (pad)); switch (GST_EVENT_TYPE (event)) { case GST_EVENT_NEWSEGMENT: { gdouble rate, applied_rate; GstFormat format; gint64 start, stop, pos; gboolean update; gst_event_parse_new_segment_full (event, &update, &rate, &applied_rate, &format, &start, &stop, &pos); if (format == GST_FORMAT_BYTES) { /* FIXME: Later, we might use a seek table to seek on elementary stream files, and that would allow byte-to-time conversions. It's not a high priority - most mpeg video is muxed and then the demuxer handles seeking. In the meantime, here's some commented out logic copied from mp3parse */ #if 0 GstClockTime seg_start, seg_stop, seg_pos; /* stop time is allowed to be open-ended, but not start & pos */ if (!mp3parse_bytepos_to_time (mp3parse, stop, &seg_stop)) seg_stop = GST_CLOCK_TIME_NONE; if (mp3parse_bytepos_to_time (mp3parse, start, &seg_start) && mp3parse_bytepos_to_time (mp3parse, pos, &seg_pos)) { gst_event_unref (event); event = gst_event_new_new_segment_full (update, rate, applied_rate, GST_FORMAT_TIME, seg_start, seg_stop, seg_pos); format = GST_FORMAT_TIME; GST_DEBUG_OBJECT (mp3parse, "Converted incoming segment to TIME. " "start = %" G_GINT64_FORMAT ", stop = %" G_GINT64_FORMAT "pos = %" G_GINT64_FORMAT, seg_start, seg_stop, seg_pos); } #endif } if (format != GST_FORMAT_TIME) { /* Unknown incoming segment format. Output a default open-ended * TIME segment */ gst_event_unref (event); /* set new values */ format = GST_FORMAT_TIME; start = 0; stop = GST_CLOCK_TIME_NONE; pos = 0; /* create a new segment with these values */ event = gst_event_new_new_segment_full (update, rate, applied_rate, format, start, stop, pos); } gst_mpegvideoparse_flush (mpegvideoparse); /* now configure the values */ gst_segment_set_newsegment_full (&mpegvideoparse->segment, update, rate, applied_rate, format, start, stop, pos); GST_DEBUG_OBJECT (mpegvideoparse, "Pushing newseg rate %g, applied rate %g, format %d, start %" G_GINT64_FORMAT ", stop %" G_GINT64_FORMAT ", pos %" G_GINT64_FORMAT, rate, applied_rate, format, start, stop, pos); /* Forward the event if we've seen a sequence header * and therefore set output caps, otherwise queue it for later */ if (mpegvideoparse->seq_hdr.mpeg_version != 0) res = gst_pad_push_event (mpegvideoparse->srcpad, event); else { res = TRUE; mpegvideoparse->pending_segs = g_list_append (mpegvideoparse->pending_segs, event); } break; } case GST_EVENT_FLUSH_STOP: GST_DEBUG_OBJECT (mpegvideoparse, "flush stop"); gst_mpegvideoparse_flush (mpegvideoparse); res = gst_pad_push_event (mpegvideoparse->srcpad, event); break; case GST_EVENT_EOS: /* Push any remaining buffers out, then flush. */ GST_DEBUG_OBJECT (mpegvideoparse, "received EOS"); if (mpegvideoparse->segment.rate >= 0.0) { mpeg_packetiser_handle_eos (&mpegvideoparse->packer); mpegvideoparse_drain_avail (mpegvideoparse); gst_mpegvideoparse_flush (mpegvideoparse); } else { gst_mpegvideoparse_chain_reverse (mpegvideoparse, TRUE, NULL); gst_mpegvideoparse_flush_decode (mpegvideoparse, 0); } res = gst_pad_push_event (mpegvideoparse->srcpad, event); break; default: res = gst_pad_push_event (mpegvideoparse->srcpad, event); break; } gst_object_unref (mpegvideoparse); return res; } static GstStateChangeReturn gst_mpegvideoparse_change_state (GstElement * element, GstStateChange transition) { MpegVideoParse *mpegvideoparse; GstStateChangeReturn ret; g_return_val_if_fail (GST_IS_MPEGVIDEOPARSE (element), GST_STATE_CHANGE_FAILURE); mpegvideoparse = GST_MPEGVIDEOPARSE (element); switch (transition) { case GST_STATE_CHANGE_READY_TO_PAUSED: gst_segment_init (&mpegvideoparse->segment, GST_FORMAT_UNDEFINED); break; default: break; } ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition); switch (transition) { case GST_STATE_CHANGE_PAUSED_TO_READY: mpv_parse_reset (mpegvideoparse); gst_mpegvideoparse_flush (mpegvideoparse); break; default: break; } return ret; } static gboolean plugin_init (GstPlugin * plugin) { GST_DEBUG_CATEGORY_INIT (mpv_parse_debug, "legacympegvideoparse", 0, "MPEG Video Parser"); return gst_element_register (plugin, "legacympegvideoparse", GST_RANK_NONE, GST_TYPE_MPEGVIDEOPARSE); } GST_PLUGIN_DEFINE (GST_VERSION_MAJOR, GST_VERSION_MINOR, "mpegvideoparse", "MPEG-1 and MPEG-2 video parser", plugin_init, VERSION, GST_LICENSE, GST_PACKAGE_NAME, GST_PACKAGE_ORIGIN)