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harcoded DTS computation for mpeg 

Originally committed as revision 2624 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Fabrice Bellard 2003-12-18 13:03:37 +00:00
parent d60a8f85d7
commit e45f19437e
1 changed files with 58 additions and 11 deletions
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69
libavformat/mpeg.c
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@ -346,7 +346,7 @@ static int get_packet_payload_size(AVFormatContext *ctx, int stream_index,
if (s->is_mpeg2)
buf_index += 3;
if (pts != AV_NOPTS_VALUE) {
if (dts != AV_NOPTS_VALUE)
if (dts != pts)
buf_index += 5 + 5;
else
buf_index += 5;
@ -410,7 +410,7 @@ static void flush_packet(AVFormatContext *ctx, int stream_index,
header_len = 0;
}
if (pts != AV_NOPTS_VALUE) {
if (dts != AV_NOPTS_VALUE)
if (dts != pts)
header_len += 5 + 5;
else
header_len += 5;
@ -444,7 +444,7 @@ static void flush_packet(AVFormatContext *ctx, int stream_index,
put_byte(&ctx->pb, 0x80); /* mpeg2 id */
if (pts != AV_NOPTS_VALUE) {
if (dts != AV_NOPTS_VALUE) {
if (dts != pts) {
put_byte(&ctx->pb, 0xc0); /* flags */
put_byte(&ctx->pb, header_len - 3);
put_timestamp(&ctx->pb, 0x03, pts);
@ -460,7 +460,7 @@ static void flush_packet(AVFormatContext *ctx, int stream_index,
}
} else {
if (pts != AV_NOPTS_VALUE) {
if (dts != AV_NOPTS_VALUE) {
if (dts != pts) {
put_timestamp(&ctx->pb, 0x03, pts);
put_timestamp(&ctx->pb, 0x01, dts);
} else {
@ -497,28 +497,75 @@ static void flush_packet(AVFormatContext *ctx, int stream_index,
stream->frame_start_offset = 0;
}
/* XXX: move that to upper layer */
/* XXX: we assume that there are always 'max_b_frames' between
reference frames. A better solution would be to use the AVFrame pts
field */
static void compute_pts_dts(AVStream *st, int64_t *ppts, int64_t *pdts,
int64_t timestamp)
{
int frame_delay;
int64_t pts, dts;
if (st->codec.codec_type == CODEC_TYPE_VIDEO &&
st->codec.max_b_frames != 0) {
frame_delay = (st->codec.frame_rate_base * 90000LL) /
st->codec.frame_rate;
if (timestamp == 0) {
/* specific case for first frame : DTS just before */
pts = timestamp;
dts = timestamp - frame_delay;
} else {
timestamp -= frame_delay;
if (st->codec.coded_frame->pict_type == FF_B_TYPE) {
/* B frames has identical pts/dts */
pts = timestamp;
dts = timestamp;
} else {
/* a reference frame has a pts equal to the dts of the
_next_ one */
dts = timestamp;
pts = timestamp + (st->codec.max_b_frames + 1) * frame_delay;
}
}
#if 1
printf("pts=%0.3f dts=%0.3f pict_type=%c\n",
pts / 90000.0, dts / 90000.0,
av_get_pict_type_char(st->codec.coded_frame->pict_type));
#endif
} else {
pts = timestamp;
dts = timestamp;
}
*ppts = pts & ((1LL << 33) - 1);
*pdts = dts & ((1LL << 33) - 1);
}
static int mpeg_mux_write_packet(AVFormatContext *ctx, int stream_index,
const uint8_t *buf, int size, int64_t pts)
const uint8_t *buf, int size,
int64_t timestamp)
{
MpegMuxContext *s = ctx->priv_data;
AVStream *st = ctx->streams[stream_index];
StreamInfo *stream = st->priv_data;
int64_t dts, new_start_pts, new_start_dts;
int64_t pts, dts, new_start_pts, new_start_dts;
int len, avail_size;
compute_pts_dts(st, &pts, &dts, timestamp);
/* XXX: system clock should be computed precisely, especially for
CBR case. The current mode gives at least something coherent */
if (stream_index == s->scr_stream_index)
s->last_scr = pts;
#if 0
printf("%d: pts=%0.3f scr=%0.3f\n",
stream_index, pts / 90000.0, s->last_scr / 90000.0);
printf("%d: pts=%0.3f dts=%0.3f scr=%0.3f\n",
stream_index,
pts / 90000.0,
dts / 90000.0,
s->last_scr / 90000.0);
#endif
/* XXX: currently no way to pass dts, will change soon */
dts = AV_NOPTS_VALUE;
/* we assume here that pts != AV_NOPTS_VALUE */
new_start_pts = stream->start_pts;
new_start_dts = stream->start_dts;