> On Dec 31, 2020, at 6:51 PM, Marton Balint <c...@passwd.hu> wrote: > > > > On Thu, 31 Dec 2020, Zhao Zhili wrote: > >> Rounding min_ts towards +infinity and max_ts towards -infinity can >> make ts out of the [min_ts, max_ts] range, and then leads to seek >> failure. For example, > > I think this is intentional to adhere to the docs of the function: > > "Seeking will be done so that the point from which all active streams > can be presented successfully will be closest to ts and within min/max_ts." > > If you round down min_ts, you might return a packet with a timestamp less > than the original min_ts, which contradicts the documentation. >
Yes, it’s not comply with the documentation strictly. On the other side, does the documentation have strong guarantee about the rounding error? Rounding error is less of a surprise than seek failure in my opinion. ffmpeg.c seek_to_start() call avformat_seek_file() with max_ts equal to ts. If avformat_seek_file() should be kept as it is, then the caller should be fixed. > Regards, > Marton > > >> >> max_ts = ts = -25057 >> time_base = (num = 1, den = 14112000) >> >> After rescale, ts = -353604, and max_ts = -353605. >> --- >> libavformat/utils.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/libavformat/utils.c b/libavformat/utils.c >> index 503e583ad0..69a0f901b2 100644 >> --- a/libavformat/utils.c >> +++ b/libavformat/utils.c >> @@ -2500,10 +2500,10 @@ int avformat_seek_file(AVFormatContext *s, int >> stream_index, int64_t min_ts, >> ts = av_rescale_q(ts, AV_TIME_BASE_Q, time_base); >> min_ts = av_rescale_rnd(min_ts, time_base.den, >> time_base.num * (int64_t)AV_TIME_BASE, >> - AV_ROUND_UP | AV_ROUND_PASS_MINMAX); >> + AV_ROUND_DOWN | AV_ROUND_PASS_MINMAX); >> max_ts = av_rescale_rnd(max_ts, time_base.den, >> time_base.num * (int64_t)AV_TIME_BASE, >> - AV_ROUND_DOWN | AV_ROUND_PASS_MINMAX); >> + AV_ROUND_UP | AV_ROUND_PASS_MINMAX); >> stream_index = 0; >> } >> -- >> 2.28.0 >> >> _______________________________________________ >> ffmpeg-devel mailing list >> ffmpeg-devel@ffmpeg.org >> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel >> >> To unsubscribe, visit link above, or email >> ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
