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gstreamer/subprojects/gst-plugins-good/ext/adaptivedemux2/hls/gsthlsdemux-util.c
Edward Hervey 74f25cca31 hlsdemux2: Look for mpegts synchronization point further 
Some mpeg-ts streams have extra data at the beginning. While it's not ideal, we
should be able to cope with it.

Therefore increase the initial search window for at least 4 consecutive
synchronization points to 1kB.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2626>
2022-06-17 12:30:09 +00:00

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/* GStreamer
* Copyright (C) 2016 Jan Schmidt <jan@centricular.com>
* Copyright (C) 2016 Tim-Philipp Müller <tim@centricular.com>
*
* gsthlsdemux-util.c:
*
* 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 <stdio.h>
#include <gmodule.h>
#include <gst/gst.h>
#include <gst/tag/tag.h>
#include <string.h>
#include "gsthlsdemux.h"
GST_DEBUG_CATEGORY_EXTERN (gst_hls_demux2_debug);
#define GST_CAT_DEFAULT gst_hls_demux2_debug
/* Mpeg-TS Packet */
#define TS_PACKET_SYNC_BYTE 0x47
#define TS_PACKET_TRANSPORT_ERROR_INDICATOR(packet) \
((packet)[1] & 0x80)
#define TS_PACKET_PAYLOAD_UNIT_START(packet) \
((packet)[1] & 0x40)
#define TS_PACKET_PID(packet) \
((guint16) ((packet)[1] & 0x1f) << 8 | (packet)[2])
#define TS_PACKET_TRANSPORT_SCRAMBLING_CONTROL(packet) \
((packet)[3] & 0xc0)
#define TS_PACKET_HAS_ADAPTATION_FIELD(packet) \
((packet)[3] & 0x20)
#define TS_PACKET_HAS_PAYLOAD(packet) \
((packet)[3] & 0x10)
#define TS_PACKET_CONTINUITY_COUNTER(pacet) \
((packet)[3] & 0x0f)
#define TS_PACKET_ADAPTATION_FIELD(packet) \
(TS_PACKET_HAS_ADAPTATION_FIELD(packet) ? \
(packet) + 4 : NULL)
/* Adaptation field size. Note: can be 0 */
#define TS_PACKET_ADAPTATION_FIELD_SIZE(packet) \
(packet)[4]
#define TS_PACKET_PAYLOAD_OFFSET(packet) \
(TS_PACKET_HAS_ADAPTATION_FIELD (packet) ? \
4 + TS_PACKET_ADAPTATION_FIELD_SIZE (packet) + 1 : \
4)
#define TS_PACKET_PAYLOAD(packet) \
(TS_PACKET_HAS_PAYLOAD (packet) ? \
(packet) + TS_PACKET_PAYLOAD_OFFSET(packet) : \
NULL)
/* PES Packet */
#define PES_IS_VALID(pes) ((pes)[0] == 0x00 && \
(pes)[1] == 0x00 && \
(pes)[2] == 0x01)
#define PES_STREAM_ID(pes) ((pes)[3])
#define PES_PACKET_LENGTH(pes) \
((guint16) (((pes)[4] << 8) | (pes)[5]))
#define PES_STREAM_TYPE_HAS_HEADER(stream_type) \
(stream_type != 0xac)
#define PES_HEADER_DATA_LENGTH(pes) ((pes)[8])
#define PES_PAYLOAD_DATA_OFFSET(pes) \
(9 + PES_HEADER_DATA_LENGTH (pes))
#define PES_HAS_PTS(pes) ((pes)[7] & 0x80)
#define PES_HAS_DTS(pes) ((pes)[7] & 0x40)
/* SI/PSI Packet */
#define TS_SECTION_POINTER(payload) ((payload)[0])
#define TS_PACKET_GET_SECTION(payload) ((payload) + TS_SECTION_POINTER(payload))
/* PAT section */
#define PAT_PROGRAM_OFFSET(pat, idx) \
(7 + (idx) * 4)
#define PAT_PROGRAM_PID_OFFSET(pat, idx) \
(PAT_PROGRAM_PID_OFFSET(pat,idx) + 2)
#define PAT_GET_PROGRAM_PID(pat, idx) \
(pat[ + PAT_PROGRAM_OFFSET(pat, idx) + 2)
static inline gboolean
read_ts (const guint8 * data, guint64 * target)
{
/* sync:4 == 00xx ! pts:3 ! 1 ! pts:15 ! 1 | pts:15 ! 1 */
if ((*data & 0x01) != 0x01)
return FALSE;
*target = ((guint64) (*data++ & 0x0E)) << 29;
*target |= ((guint64) (*data++)) << 22;
if ((*data & 0x01) != 0x01)
return FALSE;
*target |= ((guint64) (*data++ & 0xFE)) << 14;
*target |= ((guint64) (*data++)) << 7;
if ((*data & 0x01) != 0x01)
return FALSE;
*target |= ((guint64) (*data++ & 0xFE)) >> 1;
return TRUE;
}
#define PES_PTS_OFFSET(pes) (9)
#define PES_PTS(pes, dest) (read_ts ((pes) + PES_PTS_OFFSET(pes), dest))
#define PES_DTS_OFFSET(pes) (PES_HAS_PTS(pes) ? 9 + 5 : 9)
#define PES_DTS(pes, dest) (read_ts ((pes) + PES_DTS_OFFSET(pes), dest))
/* Check for sync byte, error_indicator == 0 and packet has payload.
* Adaptation control field (data[3] & 0x30) may be zero for TS packets with
* null PIDs. Still, these streams are valid TS streams (for null packets,
* AFC is supposed to be 0x1, but the spec also says decoders should just
* discard any packets with AFC = 0x00) */
#define IS_MPEGTS_HEADER(data) (data[0] == 0x47 && \
(data[1] & 0x80) == 0x00 && \
((data[3] & 0x30) != 0x00 || \
((data[3] & 0x30) == 0x00 && (data[1] & 0x1f) == 0x1f && (data[2] & 0xff) == 0xff)))
#define PCRTIME_TO_GSTTIME(t) (((t) * (guint64)1000) / 27)
#define MPEGTIME_TO_GSTTIME(t) (((t) * (guint64)100000) / 9)
static gboolean
have_ts_sync (const guint8 * data, guint size, guint packet_size, guint num)
{
while (num-- > 0) {
if (size < packet_size)
return FALSE;
if (!IS_MPEGTS_HEADER (data))
return FALSE;
data += packet_size;
size -= packet_size;
}
return TRUE;
}
#define GST_MPEGTS_TYPEFIND_MIN_HEADERS 4
static gint
find_offset (const guint8 * data, guint size, guint * out_packet_size)
{
guint sync_points = CLAMP (size / 188, GST_MPEGTS_TYPEFIND_MIN_HEADERS, 100);
guint off;
const gint packet_size = 188;
/* FIXME: check 192 as well, and maybe also 204, 208 */
for (off = 0; off < MIN (size, 1024); ++off) {
if (have_ts_sync (data + off, size - off, packet_size, sync_points)) {
*out_packet_size = packet_size;
return off;
}
}
return -1;
}
static gboolean
handle_pmt (const guint8 * data, guint size, guint packet_size)
{
const guint8 *p = data;
guint32 hdr = GST_READ_UINT32_BE (p);
guint slen, pcr_pid, pilen;
GST_MEMDUMP ("PMT", data, size);
data = p + 4;
if ((hdr & 0x00000020) != 0) /* has_adaptation_field */
data += 1 + p[4]; /* adaptation_field_len */
data += 1 + data[0]; /* pointer_field */
if (data[0] != 0x02) /* table_id */
return FALSE;
//gst_util_dump_mem (data, 8);
/* we assume the entire PMT fits into a single packet and this is it */
if (data[6] != 0 || data[6] != data[7])
return FALSE;
slen = GST_READ_UINT16_BE (data + 1) & 0x0FFF;
if (slen > (gsize) (p + packet_size - (data + 1 + 2)) || slen < 5 + 2 + 4)
return FALSE;
data += 3 + 5;
slen -= 5; /* bytes after section_length field itself */
slen -= 4; /* crc at end */
pcr_pid = GST_READ_UINT16_BE (data) & 0x1fff;
if (pcr_pid != 0x1fff) {
GST_DEBUG ("pcr_pid: %04x", pcr_pid);
}
data += 2;
/* Skip global descriptors */
pilen = GST_READ_UINT16_BE (data + 1) & 0x0FFF;
data += 2 + pilen;
return FALSE;
}
static gboolean
pat_get_pmt_pid (const guint8 * data, guint size, guint packet_size,
gint * pmt_pid)
{
const guint8 *p = data;
guint32 hdr = GST_READ_UINT32_BE (p);
guint slen;
data = p + 4;
if ((hdr & 0x00000020) != 0) /* has_adaptation_field */
data += 1 + p[4]; /* adaptation_field_len */
data += 1 + data[0]; /* pointer_field */
if (data[0] != 0) /* table_id */
return FALSE;
/* we assume the entire PAT fits into a single packet and this is it */
if (data[6] != 0 || data[6] != data[7])
return FALSE;
slen = GST_READ_UINT16_BE (data + 1) & 0x0FFF;
if (slen > (gsize) (p + packet_size - (data + 1 + 2)) || slen < 5 + 4 + 4)
return FALSE;
data += 3 + 5;
slen -= 5; /* bytes after section_length field itself */
slen -= 4; /* crc at end */
while (slen >= 4) {
guint program_num = GST_READ_UINT16_BE (data);
guint val = GST_READ_UINT16_BE (data + 2) & 0x1fff;
if (program_num != 0) {
GST_DEBUG (" program %04x: pmt_pid : %04x", program_num, val);
*pmt_pid = val;
return TRUE;
}
data += 4;
slen -= 4;
}
return FALSE;
}
static GstClockTime
get_first_mpegts_time (const guint8 * data, gsize size, guint packet_size)
{
GstClockTime internal_time = GST_CLOCK_TIME_NONE;
const guint8 *p;
gint pmt_pid = -1;
for (p = data; size >= packet_size; p += packet_size, size -= packet_size) {
if (p[0] != TS_PACKET_SYNC_BYTE) {
GST_WARNING ("Lost sync");
break;
}
/* We only care about start packets which have some form of payload (pes or
section) */
if (TS_PACKET_PAYLOAD_UNIT_START (p) && TS_PACKET_HAS_PAYLOAD (p)) {
guint16 pid;
const guint8 *payload;
const guint8 *afc;
/* Skip packets which have error indicator set or are scrambled */
if (G_UNLIKELY (TS_PACKET_TRANSPORT_ERROR_INDICATOR (p) ||
TS_PACKET_TRANSPORT_SCRAMBLING_CONTROL (p)))
continue;
pid = TS_PACKET_PID (p);
payload = TS_PACKET_PAYLOAD (p);
afc = TS_PACKET_ADAPTATION_FIELD (p);
GST_LOG ("PID 0x%04x", pid);
if (afc && afc[0])
GST_MEMDUMP ("afc", afc, afc[0]);
GST_MEMDUMP ("payload", payload, 32);
if (pmt_pid != -1 && PES_IS_VALID (payload)) {
guint64 ts;
GstClockTime pts, dts;
pts = dts = GST_CLOCK_TIME_NONE;
GST_DEBUG ("PID 0x%04x stream_id 0x%02x PES start", pid,
PES_STREAM_ID (payload));
GST_MEMDUMP ("PES data", payload + PES_PAYLOAD_DATA_OFFSET (payload),
32);
/* Grab PTS/DTS */
if (PES_HAS_PTS (payload) && PES_PTS (payload, &ts)) {
pts = MPEGTIME_TO_GSTTIME (ts);
GST_LOG ("PID 0x%04x PTS %" G_GUINT64_FORMAT " %" GST_TIME_FORMAT,
pid, ts, GST_TIME_ARGS (pts));
}
if (PES_HAS_DTS (payload) && PES_DTS (payload, &ts)) {
dts = MPEGTIME_TO_GSTTIME (ts);
GST_LOG ("PID 0x%04x DTS %" G_GUINT64_FORMAT " %" GST_TIME_FORMAT,
pid, ts, GST_TIME_ARGS (dts));
}
/* Pick the lowest value */
if (GST_CLOCK_TIME_IS_VALID (dts)) {
if (GST_CLOCK_TIME_IS_VALID (pts)) {
/* Only take the PTS if it's lower than the dts and does not differ
* by more than a second (which would indicate bogus values) */
if (pts < dts && ABS (pts - dts) < GST_SECOND)
internal_time = pts;
else
internal_time = dts;
} else {
internal_time = dts;
}
goto out;
} else if (GST_CLOCK_TIME_IS_VALID (pts)) {
internal_time = pts;
goto out;
}
} else if (pid == 0x00) {
GST_DEBUG ("PAT !");
if (!pat_get_pmt_pid (p, packet_size, packet_size, &pmt_pid)) {
GST_WARNING ("Invalid PAT");
goto out;
}
} else if (pmt_pid != -1 && pid == pmt_pid) {
GST_DEBUG ("PMT !");
/* FIXME : Grab the list of *actual* elementary stream PID to make sure
* we have checked the first PTS of each stream (and not just the first
* one we saw, which might not be the smallest */
handle_pmt (p, packet_size, packet_size);
}
}
}
out:
return internal_time;
}
GstHLSParserResult
gst_hlsdemux_handle_content_mpegts (GstHLSDemux * demux,
GstHLSDemuxStream * hls_stream, gboolean draining, GstBuffer ** buffer)
{
GstMapInfo info;
gint offset;
const guint8 *data;
GstClockTime internal_time = GST_CLOCK_TIME_NONE;
guint packet_size;
gsize size;
if (!gst_buffer_map (*buffer, &info, GST_MAP_READ))
return GST_HLS_PARSER_RESULT_ERROR;
data = info.data;
size = info.size;
offset = find_offset (data, size, &packet_size);
if (offset < 0) {
gst_buffer_unmap (*buffer, &info);
return GST_HLS_PARSER_RESULT_ERROR;
}
GST_LOG ("TS packet start offset: %d", offset);
data += offset;
size -= offset;
internal_time = get_first_mpegts_time (data, size, packet_size);
GST_DEBUG_OBJECT (hls_stream, "Using internal time %" GST_TIME_FORMAT,
GST_TIME_ARGS (internal_time));
gst_buffer_unmap (*buffer, &info);
if (!GST_CLOCK_TIME_IS_VALID (internal_time))
return GST_HLS_PARSER_RESULT_NEED_MORE_DATA;
/* We have the first internal time, figure out if we are in sync or not */
return gst_hlsdemux_handle_internal_time (demux, hls_stream, internal_time);
}
GstHLSParserResult
gst_hlsdemux_handle_content_isobmff (GstHLSDemux * demux,
GstHLSDemuxStream * hls_stream, gboolean draining, GstBuffer ** buffer)
{
GstMapInfo info;
GstByteReader br, sub;
guint32 box_type;
guint header_size;
guint64 box_size;
GstHLSParserResult ret = GST_HLS_PARSER_RESULT_NEED_MORE_DATA;
GstClockTime smallest_ts = GST_CLOCK_TIME_NONE;
if (!gst_buffer_map (*buffer, &info, GST_MAP_READ))
return GST_HLS_PARSER_RESULT_ERROR;
gst_byte_reader_init (&br, info.data, info.size);
while (gst_byte_reader_get_remaining (&br) &&
gst_isoff_parse_box_header (&br, &box_type, NULL, &header_size,
&box_size)) {
GST_DEBUG ("box %" GST_FOURCC_FORMAT " size:%" G_GUINT64_FORMAT,
GST_FOURCC_ARGS (box_type), box_size);
GST_MEMDUMP ("box content", br.data + br.byte, MIN (256,
box_size - header_size));
switch (box_type) {
case GST_ISOFF_FOURCC_MOOV:
{
GstMoovBox *moov;
gst_byte_reader_get_sub_reader (&br, &sub, box_size - header_size);
moov = gst_isoff_moov_box_parse (&sub);
if (moov) {
GST_DEBUG ("Got moov box");
if (hls_stream->moov)
gst_isoff_moov_box_free (hls_stream->moov);
hls_stream->moov = moov;
}
break;
}
case GST_ISOFF_FOURCC_MOOF:
{
GstMoofBox *moof;
gst_byte_reader_get_sub_reader (&br, &sub, box_size - header_size);
moof = gst_isoff_moof_box_parse (&sub);
if (moof) {
guint i, j;
GST_DEBUG ("Got moof box");
/* Use the track information from stream->moov */
for (i = 0; i < hls_stream->moov->trak->len; i++) {
GstTrakBox *trak =
&g_array_index (hls_stream->moov->trak, GstTrakBox, i);
GST_LOG ("trak #%d %p", i, trak);
for (j = 0; j < moof->traf->len; j++) {
GstTrafBox *traf = &g_array_index (moof->traf, GstTrafBox, j);
if (traf->tfhd.track_id == trak->tkhd.track_id) {
GstClockTime ts = 0;
guint64 decode_time = traf->tfdt.decode_time;
if (decode_time != GST_CLOCK_TIME_NONE)
ts = gst_util_uint64_scale (decode_time, GST_SECOND,
trak->mdia.mdhd.timescale);
GST_LOG ("Found decode_time %" GST_TIME_FORMAT " for trak %d",
GST_TIME_ARGS (ts), traf->tfhd.track_id);
if (smallest_ts == GST_CLOCK_TIME_NONE || ts < smallest_ts)
smallest_ts = ts;
}
}
}
gst_isoff_moof_box_free (moof);
} else {
GST_WARNING ("Failed to parse moof");
}
if (smallest_ts != GST_CLOCK_TIME_NONE)
goto out;
break;
}
case GST_ISOFF_FOURCC_MDAT:
GST_DEBUG ("Reached `mdat`, returning");
goto out;
break;
default:
GST_LOG ("Skipping unhandled box %" GST_FOURCC_FORMAT,
GST_FOURCC_ARGS (box_type));
gst_byte_reader_skip (&br, box_size - header_size);
break;
}
}
out:
gst_buffer_unmap (*buffer, &info);
if (smallest_ts != GST_CLOCK_TIME_NONE) {
ret = gst_hlsdemux_handle_internal_time (demux, hls_stream, smallest_ts);
}
return ret;
}
GstHLSParserResult
gst_hlsdemux_handle_content_id3 (GstHLSDemux * demux,
GstHLSDemuxStream * hls_stream, gboolean draining, GstBuffer ** buffer)
{
GstMapInfo info;
guint32 tag_size;
gsize size;
GstTagList *taglist;
GstSample *priv_data = NULL;
GstBuffer *tag_buf;
guint64 pts;
GstHLSParserResult ret = GST_HLS_PARSER_RESULT_DONE;
GstClockTime internal;
/* We need at least 10 bytes, starting with "ID3" for the header */
size = gst_buffer_get_size (*buffer);
if (size < 10)
return GST_HLS_PARSER_RESULT_NEED_MORE_DATA;
/* Read the tag size */
tag_size = gst_tag_get_id3v2_tag_size (*buffer);
/* Check we've collected that much */
if (size < tag_size)
return GST_HLS_PARSER_RESULT_NEED_MORE_DATA;
/* Parse the tag */
taglist = gst_tag_list_from_id3v2_tag (*buffer);
if (taglist == NULL) {
return GST_HLS_PARSER_RESULT_ERROR; /* Invalid tag, stop trying */
}
/* Extract the timestamps */
if (!gst_tag_list_get_sample (taglist, GST_TAG_PRIVATE_DATA, &priv_data))
goto out;
if (!g_str_equal ("com.apple.streaming.transportStreamTimestamp",
gst_structure_get_string (gst_sample_get_info (priv_data), "owner")))
goto out;
/* OK, now as per section 3, the tag contains a 33-bit PCR inside a 64-bit
* BE-word */
tag_buf = gst_sample_get_buffer (priv_data);
if (tag_buf == NULL)
goto out;
if (!gst_buffer_map (tag_buf, &info, GST_MAP_READ))
goto out;
GST_MEMDUMP ("id3 tag", info.data, info.size);
pts = GST_READ_UINT64_BE (info.data);
internal = MPEGTIME_TO_GSTTIME (pts);
GST_LOG ("Got internal PTS from ID3: %" G_GUINT64_FORMAT " (%" GST_TIME_FORMAT
")", pts, GST_TIME_ARGS (internal));
gst_buffer_unmap (tag_buf, &info);
ret = gst_hlsdemux_handle_internal_time (demux, hls_stream, internal);
out:
if (priv_data)
gst_sample_unref (priv_data);
if (taglist)
gst_tag_list_unref (taglist);
return ret;
}
/* Grabs the next numerical value from the bytereader, skipping any spaces.
*
* It will stop/return at the next non-digit/non-space position */
static gboolean
byte_reader_get_next_uint_string (GstByteReader * br, guint * out)
{
guint value = 0;
gboolean res = FALSE;
while (gst_byte_reader_get_remaining (br)) {
guint8 d = gst_byte_reader_peek_uint8_unchecked (br);
if (g_ascii_isdigit (d)) {
value = value * 10 + (d - '0');
res = TRUE;
} else if (d != ' ' && d != '\t') {
/* we're done and not advancing */
break;
}
gst_byte_reader_skip_unchecked (br, 1);
}
if (res)
*out = value;
return res;
}
/* Grabs the next numerical value from the bytereader, skipping any spaces.
*
* It will stop/return at the next non-digit/non-space position */
static gboolean
byte_reader_get_next_uint64_string (GstByteReader * br, guint64 * out)
{
guint64 value = 0;
gboolean res = FALSE;
while (gst_byte_reader_get_remaining (br)) {
guint8 d = gst_byte_reader_peek_uint8_unchecked (br);
if (g_ascii_isdigit (d)) {
value = value * 10 + (d - '0');
res = TRUE;
} else if (d != ' ' && d != '\t') {
/* we're done and not advancing */
break;
}
gst_byte_reader_skip_unchecked (br, 1);
}
if (res)
*out = value;
return res;
}
static gboolean
parse_webvtt_time (GstByteReader * br, GstClockTime * t,
const gchar ** remainder)
{
GstClockTime val = 0;
gboolean res = FALSE;
while (!res && gst_byte_reader_get_remaining (br)) {
guint numval;
if (byte_reader_get_next_uint_string (br, &numval)) {
guint8 next = gst_byte_reader_peek_uint8_unchecked (br);
if (next == ':' || next == '.') {
/* value was hours, minutes or seconds */
val = val * 60 + numval;
gst_byte_reader_skip (br, 1);
} else {
/* Reached the milliseconds, convert to GstClockTime */
val = val * GST_SECOND + numval * GST_MSECOND;
res = TRUE;
}
}
}
if (res) {
*t = val;
if (remainder) {
if (gst_byte_reader_get_remaining (br))
*remainder = (const gchar *) gst_byte_reader_peek_data_unchecked (br);
else
*remainder = NULL;
}
}
return res;
}
static inline void
br_skipwhitespace (GstByteReader * br)
{
while (gst_byte_reader_get_remaining (br)) {
guint8 d = gst_byte_reader_peek_uint8_unchecked (br);
if (d != ' ' && d != '\t')
return;
gst_byte_reader_skip_unchecked (br, 1);
}
}
/* Returns TRUE if br starts with str
*
* Skips any spaces/tabs before and after str */
static gboolean
br_startswith (GstByteReader * br, const gchar * str, gboolean skip_ws)
{
guint len = strlen (str);
const guint8 *data;
if (skip_ws)
br_skipwhitespace (br);
if (!gst_byte_reader_peek_data (br, len, &data))
return FALSE;
if (strncmp ((gchar *) data, str, len))
return FALSE;
gst_byte_reader_skip_unchecked (br, len);
if (skip_ws)
br_skipwhitespace (br);
return TRUE;
}
static gboolean
gst_hls_demux_webvtt_read_x_timestamp_map (gchar * data, GstClockTime * local,
GstClockTime * mpegts)
{
GstByteReader br;
gst_byte_reader_init (&br, (guint8 *) data, strlen (data));
if (!br_startswith (&br, "X-TIMESTAMP-MAP=", FALSE))
return FALSE;
if (br_startswith (&br, "MPEGTS:", TRUE)) {
if (!byte_reader_get_next_uint64_string (&br, mpegts))
return FALSE;
/* Convert to GstClockTime */
*mpegts = MPEGTIME_TO_GSTTIME (*mpegts);
if (!br_startswith (&br, ",", TRUE))
return FALSE;
if (!br_startswith (&br, "LOCAL:", TRUE))
return FALSE;
if (!parse_webvtt_time (&br, local, NULL))
return FALSE;
} else if (br_startswith (&br, "LOCAL:", TRUE)) {
if (!parse_webvtt_time (&br, local, NULL))
return FALSE;
if (!br_startswith (&br, ",", TRUE))
return FALSE;
if (!br_startswith (&br, "MPEGTS:", TRUE))
return FALSE;
if (!byte_reader_get_next_uint64_string (&br, mpegts))
return FALSE;
/* Convert to GstClockTime */
*mpegts = MPEGTIME_TO_GSTTIME (*mpegts);
} else {
return FALSE;
}
GST_DEBUG ("local time:%" GST_TIME_FORMAT ", mpegts time:%" GST_TIME_FORMAT,
GST_TIME_ARGS (*local), GST_TIME_ARGS (*mpegts));
return TRUE;
}
static gboolean
utf8_string_contains_alnum (gchar * string)
{
gunichar c;
while ((c = g_utf8_get_char (string))) {
if (g_unichar_isalnum (c))
return TRUE;
string = g_utf8_next_char (string);
}
return FALSE;
}
#define T_H(t) ((t) / (GST_SECOND * 60 * 60))
#define T_M(t) ((t) / (GST_SECOND * 60) % 60)
#define T_S(t) ((t) / GST_SECOND % 60)
#define WEBVTT_TIME_FORMAT "02u:%02u:%02u.%03u"
#define WEBVTT_TIME_ARGS(t) \
(guint) ((t) / (GST_SECOND * 60 * 60)) , \
(guint) ((t) / (GST_SECOND * 60) % 60), \
(guint) ((t) / GST_SECOND % 60), \
(guint) ((t) / GST_MSECOND % 1000)
static gboolean
process_webvtt_cue_timing_setting_line (const gchar * input,
GstClockTime * start, GstClockTime * stop, const gchar ** cue_settings)
{
GstByteReader br;
gst_byte_reader_init (&br, (guint8 *) input, strlen (input));
/* Handle cue timing start */
if (!parse_webvtt_time (&br, start, NULL))
return FALSE;
/* --> */
if (gst_byte_reader_get_remaining (&br) < 12 ||
g_ascii_strncasecmp ((const gchar *)
gst_byte_reader_peek_data_unchecked (&br), "-->", 3))
return FALSE;
gst_byte_reader_skip (&br, 4);
/* Handle cue timing stop */
if (!parse_webvtt_time (&br, stop, cue_settings))
return FALSE;
return TRUE;
}
static GstClockTimeDiff
convert_webvtt_to_stream_time (GstHLSTimeMap * map, GstClockTime localtime,
GstClockTime mpegtime, GstClockTime vtt_value)
{
GstClockTimeDiff res;
if (localtime == GST_CLOCK_TIME_NONE || mpegtime == GST_CLOCK_TIME_NONE) {
GST_DEBUG ("No X-TIMESTAMP-MAP, assuming values are MPEG-TS values");
res = gst_hls_internal_to_stream_time (map, vtt_value);
/* VTT only uses positive values */
if (res < 0)
res = 0;
} else {
GST_DEBUG ("Converting %" GST_TIME_FORMAT,
GST_TIME_ARGS (vtt_value + mpegtime - localtime));
res =
gst_hls_internal_to_stream_time (map, vtt_value + mpegtime - localtime);
if (res == GST_CLOCK_STIME_NONE) {
GST_WARNING ("Couldn't convert value, using original value %"
GST_TIME_FORMAT, GST_TIME_ARGS (vtt_value));
res = vtt_value;
} else if (res < 0) {
res = 0;
}
}
return res;
}
GstHLSParserResult
gst_hlsdemux_handle_content_webvtt (GstHLSDemux * demux,
GstHLSDemuxStream * hls_stream, gboolean draining, GstBuffer ** buffer)
{
GstHLSParserResult ret = GST_HLS_PARSER_RESULT_DONE;
gchar *original_content;
guint i, nb;
gchar **original_lines;
GstClockTime localtime = GST_CLOCK_TIME_NONE;
GstClockTime mpegtime = GST_CLOCK_TIME_NONE;
GstClockTime low_stream_time = GST_CLOCK_STIME_NONE;
GstClockTime high_stream_time = GST_CLOCK_STIME_NONE;
gboolean found_timing = FALSE;
gboolean found_text = FALSE;
GPtrArray *builder;
GstM3U8MediaSegment *current_segment = hls_stream->current_segment;
GstClockTimeDiff segment_start, segment_end;
GstClockTimeDiff tolerance;
gboolean out_of_bounds = FALSE;
GstHLSTimeMap *map;
/* We only process full webvtt fragments */
if (!draining)
return GST_HLS_PARSER_RESULT_NEED_MORE_DATA;
original_content = gst_hls_buf_to_utf8_text (*buffer);
if (!original_content)
return GST_HLS_PARSER_RESULT_ERROR;
segment_start = current_segment->stream_time;
segment_end = segment_start + current_segment->duration;
tolerance = MAX (current_segment->duration / 2, 500 * GST_MSECOND);
map = gst_hls_find_time_map (demux, current_segment->discont_sequence);
builder = g_ptr_array_new_with_free_func (g_free);
original_lines = g_strsplit_set (original_content, "\n\r", 0);
nb = g_strv_length (original_lines);
for (i = 0; i < nb; i++) {
gchar *line = original_lines[i];
GST_LOG ("Line: %s", line);
if (g_str_has_prefix (line, "X-TIMESTAMP-MAP=")) {
if (!gst_hls_demux_webvtt_read_x_timestamp_map (line, &localtime,
&mpegtime)) {
GST_WARNING ("webvtt timestamp map isn't valid");
ret = GST_HLS_PARSER_RESULT_ERROR;
goto out;
}
g_ptr_array_add (builder, g_strdup (line));
} else if (strstr (line, " --> ")) {
GstClockTime start, stop;
const gchar *leftover;
if (process_webvtt_cue_timing_setting_line (line, &start, &stop,
&leftover)) {
GstClockTimeDiff start_stream, stop_stream;
gchar *newline;
GST_LOG ("Found time line %" GST_TIME_FORMAT " -> %" GST_TIME_FORMAT,
GST_TIME_ARGS (start), GST_TIME_ARGS (stop));
start_stream =
convert_webvtt_to_stream_time (map, localtime, mpegtime, start);
stop_stream =
convert_webvtt_to_stream_time (map, localtime, mpegtime, stop);
GST_LOG ("Stream time %" GST_STIME_FORMAT " --> %" GST_STIME_FORMAT,
GST_STIME_ARGS (start_stream), GST_STIME_ARGS (stop_stream));
if (stop_stream < (segment_start - tolerance) ||
start_stream > (segment_end + tolerance)) {
GST_WARNING ("Out of bounds");
out_of_bounds = TRUE;
}
if (low_stream_time == GST_CLOCK_STIME_NONE
|| stop_stream < low_stream_time)
low_stream_time = stop_stream;
if (high_stream_time == GST_CLOCK_STIME_NONE
|| start_stream > high_stream_time)
high_stream_time = start_stream;
/* Apply the stream presentation offset */
start_stream += hls_stream->presentation_offset;
stop_stream += hls_stream->presentation_offset;
/* Create the time-shifted WebVTT cue line */
if (leftover) {
newline =
g_strdup_printf ("%" WEBVTT_TIME_FORMAT " --> %"
WEBVTT_TIME_FORMAT " %s", WEBVTT_TIME_ARGS (start_stream),
WEBVTT_TIME_ARGS (stop_stream), leftover);
} else {
newline =
g_strdup_printf ("%" WEBVTT_TIME_FORMAT " --> %"
WEBVTT_TIME_FORMAT, WEBVTT_TIME_ARGS (start_stream),
WEBVTT_TIME_ARGS (stop_stream));
}
GST_LOG ("Generated line '%s'", newline);
g_ptr_array_add (builder, newline);
found_timing = TRUE;
} else {
GST_WARNING ("Failed to parse time line '%s'", line);
/* Abort ? */
}
} else if (found_timing && !found_text) {
gchar *linecopy = g_strdup (line);
g_ptr_array_add (builder, linecopy);
if (utf8_string_contains_alnum (linecopy)) {
GST_DEBUG ("Non-empty line '%s'", line);
found_text = TRUE;
}
} else {
g_ptr_array_add (builder, g_strdup (line));
}
}
out:
if (ret) {
gchar *newfile;
/* Add NULL-terminator to string list */
g_ptr_array_add (builder, NULL);
newfile = g_strjoinv ("\n", (gchar **) builder->pdata);
GST_DEBUG ("newfile:\n%s", newfile);
gst_buffer_unref (*buffer);
*buffer = gst_buffer_new_wrapped (newfile, strlen (newfile));
}
GST_DEBUG_OBJECT (hls_stream,
"Stream time %" GST_STIME_FORMAT " -> %" GST_STIME_FORMAT,
GST_STIME_ARGS (low_stream_time), GST_STIME_ARGS (high_stream_time));
g_ptr_array_unref (builder);
g_strfreev (original_lines);
g_free (original_content);
if (out_of_bounds) {
GstM3U8MediaSegment *candidate_segment;
/* The computed stream time falls outside of the guesstimated stream time,
* reassess which segment we really are in */
GST_WARNING ("Cue %" GST_STIME_FORMAT " -> %" GST_STIME_FORMAT
" is outside of segment %" GST_STIME_FORMAT " -> %"
GST_STIME_FORMAT, GST_STIME_ARGS (low_stream_time),
GST_STIME_ARGS (high_stream_time),
GST_STIME_ARGS (current_segment->stream_time),
GST_STIME_ARGS (current_segment->stream_time +
current_segment->duration));
candidate_segment =
gst_hls_media_playlist_seek (hls_stream->playlist, TRUE,
GST_SEEK_FLAG_SNAP_NEAREST, low_stream_time);
if (candidate_segment) {
g_assert (candidate_segment != current_segment);
GST_DEBUG_OBJECT (hls_stream,
"Stream time corresponds to segment %" GST_STIME_FORMAT
" duration %" GST_TIME_FORMAT,
GST_STIME_ARGS (candidate_segment->stream_time),
GST_TIME_ARGS (candidate_segment->duration));
/* Recalculate everything and ask parent class to restart */
hls_stream->current_segment->stream_time = candidate_segment->stream_time;
gst_hls_media_playlist_recalculate_stream_time (hls_stream->playlist,
hls_stream->current_segment);
gst_m3u8_media_segment_unref (candidate_segment);
}
}
if (!found_text) {
GST_DEBUG_OBJECT (hls_stream, "Replacing buffer with droppable buffer");
GST_BUFFER_PTS (*buffer) =
current_segment->stream_time + hls_stream->presentation_offset;
GST_BUFFER_DURATION (*buffer) = current_segment->duration;
gst_buffer_set_flags (*buffer, GST_BUFFER_FLAG_DROPPABLE);
}
return ret;
}
/* Get a utf8-validated string of the contents of the buffer */
gchar *
gst_hls_buf_to_utf8_text (GstBuffer * buf)
{
GstMapInfo info;
gchar *playlist;
if (!gst_buffer_map (buf, &info, GST_MAP_READ))
goto map_error;
if (!g_utf8_validate ((gchar *) info.data, info.size, NULL))
goto validate_error;
/* alloc size + 1 to end with a null character */
playlist = g_malloc0 (info.size + 1);
memcpy (playlist, info.data, info.size);
gst_buffer_unmap (buf, &info);
return playlist;
validate_error:
gst_buffer_unmap (buf, &info);
map_error:
return NULL;
}
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