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mpegtsdemux: implement key_unit seeking for MPEG2 video

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This commit is contained in:
Janne Grunau 2011-03-28 10:20:43 +02:00 committed by Edward Hervey
parent 3ce1ec7c9c
commit ff15d6fa80
5 changed files with 230 additions and 29 deletions
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4
gst/mpegtsdemux/Makefile.am
View file

@ -6,6 +6,7 @@ libgstmpegtsdemux_la_SOURCES = \
mpegtsbase.c \
mpegtspacketizer.c \
mpegtsparse.c \
payload_parsers.c \
tsdemux.c
libgstmpegtsdemux_la_CFLAGS = \
@ -23,6 +24,7 @@ noinst_HEADERS = \
mpegtsbase.h \
mpegtspacketizer.h \
mpegtsparse.h \
payload_parsers.h \
tsdemux.h
Android.mk: Makefile.am $(BUILT_SOURCES)
@ -37,4 +39,4 @@ Android.mk: Makefile.am $(BUILT_SOURCES)
-ldl \
-:PASSTHROUGH LOCAL_ARM_MODE:=arm \
LOCAL_MODULE_PATH:='$$(TARGET_OUT)/lib/gstreamer-0.10' \
> $@
> $@

3
gst/mpegtsdemux/mpegtsbase.c
View file

@ -1272,8 +1272,7 @@ mpegts_base_handle_seek_event (MpegTSBase * base, GstPad * pad,
gst_pad_push_event (base->sinkpad, gst_event_new_flush_stop ());
}
if (flags & (GST_SEEK_FLAG_KEY_UNIT | GST_SEEK_FLAG_SEGMENT |
GST_SEEK_FLAG_SKIP)) {
if (flags & (GST_SEEK_FLAG_SEGMENT | GST_SEEK_FLAG_SKIP)) {
GST_WARNING ("seek flags 0x%x are not supported", (int) flags);
goto done;
}

128
gst/mpegtsdemux/payload_parsers.c Normal file
View file

@ -0,0 +1,128 @@
/*
* payload_parsers.c
* Copyright (C) 2011 Janne Grunau
*
* Authors:
* Janne Grunau <janne.grunau@collabora.co.uk>
*
* 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.
*/
#include "payload_parsers.h"
#include <gst/base/gstbitreader.h>
#define PICTURE_START_CODE 0x00000100
#define GROUP_START_CODE 0x000001B8
typedef struct Mpeg2PictureHeader
{
guint16 temporal_reference;
guint8 picture_coding_type;
guint16 vbv_delay;
/* picture_coding_type == 2 || picture_coding_type */
guint8 full_pel_forward_vector;
guint8 forward_f_code;
/* picture_coding_type == 3 */
guint8 full_pel_backward_vector;
guint8 backward_f_code;
} Mpeg2PictureHeader;
static guint8 *
find_start_code (guint32 * start_code, guint8 * buffer, guint8 * buffer_end)
{
if (G_UNLIKELY (buffer == NULL) || G_UNLIKELY (buffer_end == NULL)
|| G_UNLIKELY (start_code == NULL))
return NULL;
while (buffer <= buffer_end) {
*start_code <<= 8;
*start_code |= *buffer++;
if ((*start_code & 0xffffff00) == 0x00000100)
return buffer;
}
return NULL;
}
static gboolean
parse_mpeg2_picture_header (Mpeg2PictureHeader * hdr, guint8 * buffer,
guint8 * buffer_end)
{
GstBitReader br = GST_BIT_READER_INIT (buffer, buffer_end - buffer);
if (gst_bit_reader_get_remaining (&br) < 40)
return FALSE;
hdr->temporal_reference = gst_bit_reader_get_bits_uint16_unchecked (&br, 10);
hdr->picture_coding_type = gst_bit_reader_get_bits_uint8_unchecked (&br, 3);
hdr->vbv_delay = gst_bit_reader_get_bits_uint16_unchecked (&br, 16);
if (hdr->picture_coding_type == 2 || hdr->picture_coding_type == 3) {
hdr->full_pel_forward_vector =
gst_bit_reader_get_bits_uint8_unchecked (&br, 1);
hdr->forward_f_code = gst_bit_reader_get_bits_uint8_unchecked (&br, 3);
}
if (hdr->picture_coding_type == 3) {
hdr->full_pel_backward_vector =
gst_bit_reader_get_bits_uint8_unchecked (&br, 1);
hdr->backward_f_code = gst_bit_reader_get_bits_uint8_unchecked (&br, 3);
}
return TRUE;
}
gboolean
gst_tsdemux_has_mpeg2_keyframe (guint32 * state,
MpegTSPacketizerPacket * packet)
{
//guint32 i = 0;
guint8 *data = packet->payload;
guint8 *data_end = packet->data_end;
GST_LOG ("state: 0x%08x", *state);
while (data <= data_end) {
data = find_start_code (state, data, data_end);
if (!data)
return FALSE;
GST_LOG ("found start code: 0x%08x", *state);
if (*state == GROUP_START_CODE) {
GST_DEBUG ("found group start code");
*state = 0xffffffff;
return TRUE;
} else if (*state == PICTURE_START_CODE) {
Mpeg2PictureHeader hdr = { 0 };
gboolean success;
*state = 0xffffffff;
success = parse_mpeg2_picture_header (&hdr, data, data_end);
GST_DEBUG ("found picture start code, %sparsed, picture coding type: %d",
success ? "" : "not ", hdr.picture_coding_type);
return success && hdr.picture_coding_type == 1;
}
}
return FALSE;
}

29
gst/mpegtsdemux/payload_parsers.h Normal file
View file

@ -0,0 +1,29 @@
/*
* payload_parsers.h
* Copyright (C) 2011 Janne Grunau
*
* Authors:
* Janne Grunau <janne.grunau@collabora.co.uk>
*
* 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.
*/
#include "mpegtspacketizer.h"
typedef gboolean (*payload_parse_keyframe) (guint32 *state, MpegTSPacketizerPacket * packet);
gboolean
gst_tsdemux_has_mpeg2_keyframe (guint32 *state, MpegTSPacketizerPacket * packet);

95
gst/mpegtsdemux/tsdemux.c
View file

@ -37,6 +37,7 @@
#include "gstmpegdesc.h"
#include "gstmpegdefs.h"
#include "mpegtspacketizer.h"
#include "payload_parsers.h"
/* latency in mseconds */
#define TS_LATENCY 700
@ -515,25 +516,34 @@ discont:
return res;
}
/* performs a accurate seek to the last packet with pts < seektime */
/* performs a accurate/key_unit seek */
static GstFlowReturn
gst_ts_demux_perform_accurate_seek (MpegTSBase * base, GstClockTime seektime,
TSPcrOffset * pcroffset, gint64 length, gint16 pid)
gst_ts_demux_perform_auxiliary_seek (MpegTSBase * base, GstClockTime seektime,
TSPcrOffset * pcroffset, gint64 length, gint16 pid, GstSeekFlags flags,
payload_parse_keyframe auxiliary_seek_fn)
{
GstTSDemux *demux = (GstTSDemux *) base;
GstFlowReturn res = GST_FLOW_ERROR;
gboolean done = FALSE;
gboolean found_keyframe = FALSE, found_accurate = FALSE;
GstBuffer *buf;
MpegTSPacketizerPacket packet;
MpegTSPacketizerPacketReturn pret;
gint64 offset = pcroffset->offset;
gint64 scan_offset = MIN (length, 50 * MPEGTS_MAX_PACKETSIZE);
guint32 state = 0xffffffff;
TSPcrOffset key_pos = { 0 };
GST_DEBUG ("auxiliary seek for %" GST_TIME_FORMAT " from offset: %"
G_GINT64_FORMAT " in %" G_GINT64_FORMAT " bytes for PID: %d "
"%s %s", GST_TIME_ARGS (seektime), pcroffset->offset, length, pid,
(flags & GST_SEEK_FLAG_ACCURATE) ? "accurate" : "",
(flags & GST_SEEK_FLAG_KEY_UNIT) ? "key_unit" : "");
GST_DEBUG ("accurate seek for %" GST_TIME_FORMAT " from offset: %"
G_GINT64_FORMAT " in %" G_GINT64_FORMAT " bytes for PID: %d",
GST_TIME_ARGS (seektime), pcroffset->offset, length, pid);
if ((flags & GST_SEEK_FLAG_KEY_UNIT) && !auxiliary_seek_fn) {
GST_ERROR ("key_unit seek for unkown video codec");
goto beach;
}
mpegts_packetizer_flush (base->packetizer);
@ -558,25 +568,52 @@ gst_ts_demux_perform_accurate_seek (MpegTSBase * base, GstClockTime seektime,
" at offset: %" G_GINT64_FORMAT, packet.pid,
GST_TIME_ARGS (packet.pcr), packet.offset);
if (packet.payload != NULL && packet.payload_unit_start_indicator
&& packet.pid == pid) {
guint64 pts = 0;
if (packet.payload != NULL && packet.pid == pid) {
res = gst_ts_demux_parse_pes_header_pts (demux, &packet, &pts);
if (res == GST_FLOW_OK) {
GstClockTime time = calculate_gsttime (pcroffset, pts * 300);
if (packet.payload_unit_start_indicator) {
guint64 pts = 0;
res = gst_ts_demux_parse_pes_header_pts (demux, &packet, &pts);
if (res == GST_FLOW_OK) {
GstClockTime time = calculate_gsttime (pcroffset, pts * 300);
GST_DEBUG ("packet has PTS: %" GST_TIME_FORMAT,
GST_DEBUG ("packet has PTS: %" GST_TIME_FORMAT,
GST_TIME_ARGS (time));
if (time <= seektime) {
pcroffset->gsttime = time;
pcroffset->pcr = packet.pcr;
pcroffset->offset = packet.offset;
if (time <= seektime) {
pcroffset->gsttime = time;
pcroffset->pcr = packet.pcr;
pcroffset->offset = packet.offset;
} else
found_accurate = TRUE;
} else
done = TRUE;
} else
goto next;
goto next;
/* reset state for new packet */
state = 0xffffffff;
}
if (flags & GST_SEEK_FLAG_KEY_UNIT) {
gboolean is_keyframe = auxiliary_seek_fn (&state, &packet);
if (is_keyframe) {
found_keyframe = TRUE;
key_pos = *pcroffset;
GST_DEBUG ("found keyframe: time: %" GST_TIME_FORMAT " pcr: %"
GST_TIME_FORMAT " offset %" G_GINT64_FORMAT,
GST_TIME_ARGS (pcroffset->gsttime),
GST_TIME_ARGS (pcroffset->pcr), pcroffset->offset);
}
}
}
switch (flags & (GST_SEEK_FLAG_ACCURATE | GST_SEEK_FLAG_KEY_UNIT)) {
case GST_SEEK_FLAG_ACCURATE | GST_SEEK_FLAG_KEY_UNIT:
done = found_accurate && found_keyframe;
*pcroffset = key_pos;
break;
case GST_SEEK_FLAG_ACCURATE:
done = found_accurate;
break;
case GST_SEEK_FLAG_KEY_UNIT:
done = found_keyframe;
break;
}
next:
mpegts_packetizer_clear_packet (base->packetizer, &packet);
@ -584,6 +621,9 @@ gst_ts_demux_perform_accurate_seek (MpegTSBase * base, GstClockTime seektime,
scan_offset += 50 * MPEGTS_MAX_PACKETSIZE;
}
if (done)
res = GST_FLOW_OK;
beach:
mpegts_packetizer_flush (base->packetizer);
return res;
@ -741,13 +781,17 @@ gst_ts_demux_perform_seek (MpegTSBase * base, GstSegment * segment, guint16 pid)
GST_DEBUG ("seeking finished after %d loops", loop_cnt);
if (segment->flags & GST_SEEK_FLAG_ACCURATE) {
if (segment->flags & GST_SEEK_FLAG_ACCURATE
|| segment->flags & GST_SEEK_FLAG_KEY_UNIT) {
payload_parse_keyframe keyframe_seek = NULL;
MpegTSBaseProgram *program = demux->program;
if (program->streams[pid]) {
switch (program->streams[pid]->stream_type) {
case ST_VIDEO_MPEG1:
case ST_VIDEO_MPEG2:
keyframe_seek = gst_tsdemux_has_mpeg2_keyframe;
break;
case ST_VIDEO_MPEG4:
case ST_VIDEO_H264:
case ST_VIDEO_DIRAC:
@ -760,8 +804,8 @@ gst_ts_demux_perform_seek (MpegTSBase * base, GstSegment * segment, guint16 pid)
seekpcroffset.pcr = pcr_start.pcr;
seekpcroffset.offset = pcr_start.offset;
res =
gst_ts_demux_perform_accurate_seek (base, seektime, &seekpcroffset,
pcr_stop.offset - pcr_start.offset, pid);
gst_ts_demux_perform_auxiliary_seek (base, seektime, &seekpcroffset,
pcr_stop.offset - pcr_start.offset, pid, segment->flags, keyframe_seek);
}
segment->last_stop = seekpcroffset.gsttime;
@ -810,8 +854,7 @@ gst_ts_demux_do_seek (MpegTSBase * base, GstEvent * event, guint16 pid)
accurate = flags & GST_SEEK_FLAG_ACCURATE;
flush = flags & GST_SEEK_FLAG_FLUSH;
if (flags & (GST_SEEK_FLAG_KEY_UNIT | GST_SEEK_FLAG_SEGMENT |
GST_SEEK_FLAG_SKIP)) {
if (flags & (GST_SEEK_FLAG_SEGMENT | GST_SEEK_FLAG_SKIP)) {
GST_WARNING ("seek flags 0x%x are not supported", (int) flags);
goto done;
}