[FFmpeg-devel] [WANTED] Fix incorrect audio duration reporting

[Michael Niedermayer]

On Sat, Mar 13, 2021 at 04:04:32PM +0100, Paul B Mahol wrote:
> On Sat, Mar 13, 2021 at 3:48 PM Michael Niedermayer <michael at niedermayer.cc>
> wrote:
> 
> > On Sat, Mar 13, 2021 at 03:11:34PM +0100, Paul B Mahol wrote:
> > > On Sat, Mar 13, 2021 at 1:30 PM Michael Niedermayer
> > <michael at niedermayer.cc>
> > > wrote:
> > >
> > > > On Thu, Mar 11, 2021 at 07:33:53PM +0100, Paul B Mahol wrote:
> > > > > Hi,
> > > > >
> > > > > With latest master and with any audio only file, using "ffmpeg -i
> > file -f
> > > > > null -" reports incorrect duration.
> > > >
> > > > ./ffmpeg -i ~/videos/1sec-zero.mp3 -f null -
> > > > shows durations at 2 points in the output
> > > > Duration: 00:00:01.03, start: 0.023021, bitrate: 129 kb/s
> > > > size=N/A time=00:00:00.98 bitrate=N/A speed= 620x
> > > >
> > > > the first is exactly the same in ffmpeg 4.3, 3.4 and 2.8.17
> > > > The 2nd is a regression since 50b49f833ae2f7d33bd2a99776fed6cb692c171a
> > > >
> > >
> > > Check it with wav files.
> >
> > No difference between master and 4.3 or 3.4
> > ./ffmpeg  -i ~/videos/1sec-zero.wav -f null -
> >  Duration: 00:00:01.01, bitrate: 1536 kb/s
> > size=N/A time=00:00:01.00 bitrate=N/A speed=1.02e+03x
> >
> > Duration: 00:00:01.01, bitrate: 1536 kb/s
> > size=N/A time=00:00:01.00 bitrate=N/A speed= 993x
> >
> 
> Now try with filtering, loudnorm or dynaudnorm, there is even bigger
> difference.

./ffmpeg  -i ~/videos/1sec-zero.wav -af loudnorm -f null -

size=N/A time=00:00:01.00 bitrate=N/A speed=61.9x
vs.
size=N/A time=00:00:00.00 bitrate=N/A speed=   0x
yes that seems caused by the first hunk of 50b49f833ae2f7d33bd2a99776fed6cb692c171a

so ccing the author as this would otherwise be likely missed

Thanks

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No great genius has ever existed without some touch of madness. -- Aristotle
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