The decoded data from the first frame is not returned; it is used to prime the decode engine. The container should therefore treat the first packet's duration as zero for trimming so total duration is correct.
When the first and last packet are in the same page, the last packet's duration was previously wrong because the first packet's duration was included. Ignoring the first packet's duration in the container fixes this. Fixes: https://trac.ffmpeg.org/ticket/6367 Signed-off-by: Guangyu Sun <[email protected]> --- libavformat/oggparsevorbis.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/libavformat/oggparsevorbis.c b/libavformat/oggparsevorbis.c index ed81a431f6..599bc53499 100644 --- a/libavformat/oggparsevorbis.c +++ b/libavformat/oggparsevorbis.c @@ -454,6 +454,7 @@ static int vorbis_packet(AVFormatContext *s, int idx) struct oggvorbis_private *priv = os->private; int duration, flags = 0; int skip_packet = 0; + int first_page; int ret, new_extradata_size; PutByteContext pb; @@ -464,7 +465,8 @@ static int vorbis_packet(AVFormatContext *s, int idx) * here we parse the duration of each packet in the first page and compare * the total duration to the page granule to find the encoder delay and * set the first timestamp */ - if ((!os->lastpts || os->lastpts == AV_NOPTS_VALUE) && !(os->flags & OGG_FLAG_EOS) && (int64_t)os->granule>=0) { + first_page = !os->lastpts || os->lastpts == AV_NOPTS_VALUE; + if (first_page && !(os->flags & OGG_FLAG_EOS) && (int64_t)os->granule>=0) { int seg, d; uint8_t *last_pkt = os->buf + os->pstart; uint8_t *next_pkt = last_pkt; @@ -563,6 +565,10 @@ static int vorbis_packet(AVFormatContext *s, int idx) } os->pduration = duration; + /* First frame only primes the decoder; no samples are output. + * Use zero duration for the container so trimming is correct. */ + if (first_page && os->segp == 1) + os->pduration = 0; } /* final packet handling _______________________________________________ ffmpeg-devel mailing list -- [email protected] To unsubscribe send an email to [email protected]
