[FFmpeg-trac] #6915(avformat:new): DASH audio segments duration doesn't match exactly with video segments duration.
FFmpeg
trac at avcodec.org
Thu Dec 21 08:32:12 EET 2017
#6915: DASH audio segments duration doesn't match exactly with video segments
duration.
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Reporter: beloko | Owner:
Type: defect | Status: new
Priority: normal | Component: avformat
Version: git-master | Resolution:
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
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Comment (by j_karthic):
Well, if we round the target duration to '''nearest integer''' as per the
spec, part of the problem is resolved. Right now we are '''ceiling to the
upper integer''' which is not according to HLS specifications.
{{{
4.3.3.1. EXT-X-TARGETDURATION
The EXT-X-TARGETDURATION tag specifies the maximum Media Segment
duration. The EXTINF duration of each Media Segment in the Playlist
file, when rounded to the nearest integer, MUST be less than or equal
to the target duration; longer segments can trigger playback stalls
or other errors. It applies to the entire Playlist file. Its format
is:
#EXT-X-TARGETDURATION:<s>
where s is a decimal-integer indicating the target duration in
seconds. The EXT-X-TARGETDURATION tag is REQUIRED.
}}}
So as per the spec, the EXT-X-TARGETDURATION should rounded to 4 instead
of 5.
But when I submitted a patch for fixing such an issue in hlsenc, it was
rejected by Steven. See thread http://ffmpeg.org/pipermail/ffmpeg-
devel/2017-September/215630.html more details. During that time, I was not
able to provide a concrete example with mediastreamvalidator like @beloko
has done now. But I thought the spec was very clear about it without any
room for confusion.
@stevenliu
If you have a change of mind after seeing these results, please let me
know. Maybe I will send a new patch which fixes the target duration in
dashenc, and we can take forward our discussions there.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/6915#comment:7>
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