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lavf: use dts difference instead of AVPacket.duration in find_stream_info()

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AVPacket.duration is mostly made up and thus completely useless, this is
especially true for video streams.
Therefore use dts difference for framerate estimation and
the max_analyze_duration check.

The asyncts test now needs -analyzeduration, because the default is 5
seconds and the audio stream in the sample appears at ~10 seconds.
This commit is contained in:
Anton Khirnov 2012-06-28 15:49:51 +02:00
parent 681ed00099
commit fe1c1198e6
3 changed files with 42 additions and 8 deletions
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10
libavformat/avformat.h
View File

@ -718,9 +718,17 @@ typedef struct AVStream {
int64_t duration_gcd;
int duration_count;
double duration_error[MAX_STD_TIMEBASES];
int64_t codec_info_duration;
int nb_decoded_frames;
int found_decoder;
/**
* Those are used for average framerate estimation.
*/
int64_t fps_first_dts;
int fps_first_dts_idx;
int64_t fps_last_dts;
int fps_last_dts_idx;
} *info;
int pts_wrap_bits; /**< number of bits in pts (used for wrapping control) */

38
libavformat/utils.c
View File

@ -2288,6 +2288,8 @@ int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
for (i=0; i<ic->nb_streams; i++) {
ic->streams[i]->info->last_dts = AV_NOPTS_VALUE;
ic->streams[i]->info->fps_first_dts = AV_NOPTS_VALUE;
ic->streams[i]->info->fps_last_dts = AV_NOPTS_VALUE;
}
count = 0;
@ -2395,12 +2397,31 @@ int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
read_size += pkt->size;
st = ic->streams[pkt->stream_index];
if (st->codec_info_nb_frames>1) {
if (av_rescale_q(st->info->codec_info_duration, st->time_base, AV_TIME_BASE_Q) >= ic->max_analyze_duration) {
if (pkt->dts != AV_NOPTS_VALUE && st->codec_info_nb_frames > 1) {
/* check for non-increasing dts */
if (st->info->fps_last_dts != AV_NOPTS_VALUE &&
st->info->fps_last_dts >= pkt->dts) {
av_log(ic, AV_LOG_WARNING, "Non-increasing DTS in stream %d: "
"packet %d with DTS %"PRId64", packet %d with DTS "
"%"PRId64"\n", st->index, st->info->fps_last_dts_idx,
st->info->fps_last_dts, st->codec_info_nb_frames, pkt->dts);
st->info->fps_first_dts = st->info->fps_last_dts = AV_NOPTS_VALUE;
}
/* update stored dts values */
if (st->info->fps_first_dts == AV_NOPTS_VALUE) {
st->info->fps_first_dts = pkt->dts;
st->info->fps_first_dts_idx = st->codec_info_nb_frames;
}
st->info->fps_last_dts = pkt->dts;
st->info->fps_last_dts_idx = st->codec_info_nb_frames;
/* check max_analyze_duration */
if (av_rescale_q(pkt->dts - st->info->fps_first_dts, st->time_base,
AV_TIME_BASE_Q) >= ic->max_analyze_duration) {
av_log(ic, AV_LOG_WARNING, "max_analyze_duration reached\n");
break;
}
st->info->codec_info_duration += pkt->duration;
}
{
int64_t last = st->info->last_dts;
@ -2460,10 +2481,15 @@ int avformat_find_stream_info(AVFormatContext *ic, AVDictionary **options)
for(i=0;i<ic->nb_streams;i++) {
st = ic->streams[i];
if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
if (st->codec_info_nb_frames>2 && !st->avg_frame_rate.num && st->info->codec_info_duration)
/* estimate average framerate if not set by demuxer */
if (!st->avg_frame_rate.num && st->info->fps_last_dts != st->info->fps_first_dts) {
int64_t delta_dts = st->info->fps_last_dts - st->info->fps_first_dts;
int delta_packets = st->info->fps_last_dts_idx - st->info->fps_first_dts_idx;
av_reduce(&st->avg_frame_rate.num, &st->avg_frame_rate.den,
(st->codec_info_nb_frames-2)*(int64_t)st->time_base.den,
st->info->codec_info_duration*(int64_t)st->time_base.num, 60000);
delta_packets*(int64_t)st->time_base.den,
delta_dts*(int64_t)st->time_base.num, 60000);
}
// the check for tb_unreliable() is not completely correct, since this is not about handling
// a unreliable/inexact time base, but a time base that is finer than necessary, as e.g.
// ipmovie.c produces.

2
tests/fate/filter.mak
View File

@ -22,7 +22,7 @@ FATE_SAMPLES_AVCONV += $(FATE_AMIX)
FATE_ASYNCTS += fate-filter-asyncts
fate-filter-asyncts: SRC = $(SAMPLES)/nellymoser/nellymoser-discont.flv
fate-filter-asyncts: CMD = pcm -i $(SRC) -af asyncts
fate-filter-asyncts: CMD = pcm -analyzeduration 10000000 -i $(SRC) -af asyncts
fate-filter-asyncts: CMP = oneoff
fate-filter-asyncts: REF = $(SAMPLES)/nellymoser/nellymoser-discont.pcm