[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 12:24:14 EET 2017
#6915: DASH audio segments duration doesn't match exactly with video segments
duration.
------------------------------------+------------------------------------
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 |
------------------------------------+------------------------------------
Comment (by stevenliu):
Replying to [comment:9 j_karthic]:
> Replying to [comment:8 stevenliu]:
> > Replying to [comment:7 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.
> >
> > The spec said "EXT-X-TARGETDURATION must > EXTINF", we have talk and
you have sent twice patch about it. you can see the spec said "MUST be
less than or equal to the target duration.", attention the MUST, MUST,
MUST, we should don't care the tool, we should care the spec. If the tool
different with the spec, that maybe apple's mistake, you should push
apple.
> I think you missing the important line "'''when rounded to the nearest
integer'''" in the spec. I am also only talking about the spec. This is
just a pure argument, about interpreting that English line. This is where
I feel some other people in the ffmpeg community should also pitch in
moderate a discussion, rather than leaving it as "'''Maintainer is always
right'''".
'''Maintainer''' not always right, but can you give me the mean '''MUST be
less than or equal to the target duration''' how should i understand it?
> >
> > >
> > >
> > >
> > >
> > >
--
Ticket URL: <https://trac.ffmpeg.org/ticket/6915#comment:10>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker
More information about the FFmpeg-trac
mailing list