Source: libmedia-convert-perl
Version: 1.5.2-1
Severity: serious
X-Debbugs-Cc: sramacher@debian.org

Dear maintainer,

libmedia-convert-perl fails its autopkgtests with ffmpeg 9.0:

549s Running: 'ffmpeg' '-loglevel' 'warning' '-y' '-i' 't/testvids/bbb.mp4' '-threads' '1' '-c:v' 'libvpx' '-speed' '4' '-pass' '1' '-passlogfile' 't/testvids/out.webm-multipass' '-c:a' 'libvorbis' '-t' '10' 't/testvids/out.webm'
549s [libvpx @ 0x13c3050] Neither bitrate nor constrained quality specified, using default CRF of 32 and bitrate of 256kbit/sec
549s progress: 3
549s progress: 5
549s progress: 9
549s progress: 10
549s progress: 12
549s progress: 13
549s progress: 14
549s progress: 15
549s progress: 16
549s progress: 17
549s progress: 18
549s progress: 19
549s progress: 20
549s progress: 22
549s progress: 23
549s progress: 25
549s progress: 27
549s progress: 29
549s progress: 30
549s progress: 31
549s progress: 33
549s progress: 34
549s progress: 36
549s progress: 38
549s progress: 40
549s progress: 42
549s progress: 43
549s progress: 45
549s progress: 46
549s progress: 47
549s progress: 48
549s progress: 49
549s progress: 50
549s Running: 'ffmpeg' '-loglevel' 'warning' '-y' '-i' 't/testvids/bbb.mp4' '-threads' '1' '-c:v' 'libvpx' '-speed' '4' '-pass' '2' '-passlogfile' 't/testvids/out.webm-multipass' '-c:a' 'libvorbis' '-t' '10' 't/testvids/out.webm'
549s [libvpx @ 0x1510050] Neither bitrate nor constrained quality specified, using default CRF of 32 and bitrate of 256kbit/sec
549s progress: 58
549s progress: 60
549s progress: 62
549s progress: 64
549s progress: 65
549s progress: 66
549s progress: 67
549s progress: 68
549s progress: 69
549s progress: 70
549s progress: 71
549s progress: 73
549s progress: 74
549s progress: 75
549s progress: 79
549s progress: 81
549s progress: 83
549s progress: 84
549s progress: 85
549s progress: 87
549s progress: 89
549s progress: 91
549s progress: 93
549s progress: 95
549s progress: 96
549s progress: 97
549s progress: 99
549s progress: 92
549s progress: 93
549s progress: 94
549s progress: 100
549s not ok 6 - progress information is strictly incresing when doing multipass
549s
549s #   Failed test 'progress information is strictly incresing when doing multipass'
549s #   at t/reporting.t line 42.
549s ok 7 - progress stops at 100% when doing multipass
549s # Looks like you failed 1 test of 7.
549s Dubious, test returned 1 (wstat 256, 0x100)
549s Failed 1/7 subtests

It looks like the test is unable to cope with the log output from
libvpx.

See
https://ci.debian.net/packages/libm/libmedia-convert-perl/testing/armhf/75829187/
for details.

Cheers

reassign -1 ffmpeg
thanks

So, this happens only on armhf.

The problem is this:

As you can see, the progress information here jumps from 99 to 92%.

This is as received from ffmpeg. I ran, on amdahl, in a sid armhf
chroot, the following command:

'ffmpeg' '-progress' '/dev/stdout' '-loglevel' 'warning' '-y' '-i' 't/testvids/bbb.mp4' '-threads' '1' '-c:v' 'libvpx' '-speed' '4' '-pass' '2' '-passlogfile' 't/testvids/out.webm-multipass' '-c:a' 'libvorbis' '-t' '10' 't/testvids/out.webm' | grep -E '(out_time|progress)'

(the command as shown in the log, with the "-progress" and grep bits
added)

And this resulted in output similar to the following:

[...]
out_time_us=8823583
out_time_ms=8823583
out_time=00:00:08.823583
progress=continue
out_time_us=8826485
out_time_ms=8826485
out_time=00:00:08.826485
progress=continue
out_time_us=9019501
out_time_ms=9019501
out_time=00:00:09.019501
progress=continue
out_time_us=9357642
out_time_ms=9357642
out_time=00:00:09.357642
progress=continue
out_time_us=8416667
out_time_ms=8416667
out_time=00:00:08.416667
progress=continue
out_time_us=8625000
out_time_ms=8625000
out_time=00:00:08.625000
progress=continue
out_time_us=N/A
out_time_ms=N/A
out_time=N/A
progress=continue
out_time_us=N/A
out_time_ms=N/A
out_time=N/A
progress=continue
out_time_us=N/A
out_time_ms=N/A
out_time=N/A
progress=continue
out_time_us=N/A
out_time_ms=N/A
out_time=N/A
progress=continue
out_time_us=10000000
out_time_ms=10000000
out_time=00:00:10.000000
progress=end

As you can see, the time indexes here jump backwards at the 8.625 second
mark.

As I don't expect an encoder to jump backwards in time, and as I don't
see the problem occurring anywhere except on armhf, I believe this to be
a bug in ffmpeg. As such, I'm reassigning this to ffmpeg, with the
understanding that I might be wrong :)

(if ffmpeg does in fact document that time stamps in progress
information may jump backwards, then obviously that would be a strong
indication that I'm wrong -- I looked but didn't see any documentation
hinting this)

Hi Wouter

No, it doesn't. See for example here
https://ci.debian.net/packages/libm/libmedia-convert-perl/testing/ppc64el/76474853/

ffmpeg calculates the progress timestamp as the maximum DTS among
unfinished output streams. When the stream providing that maximum
finishes, it is excluded from the calculation, so the next reported
timestamp can be lower. In the case of this test, there are two streams:
the audio and the video stream. So one stream finishes early and then
out_time goes backwards.

I couldn't find any FFmpeg documentation. Therefore I don't think the
test should require it to increase monotonically. A consumer needing
monotonic progress will need to keep the maximum value seen so far.

Reassining it back to libmedia-convert-perl. It is making assumptions on
out_time that are not documented and not guaranteed.

Cheers

Hi Sebastian,

I missed that, sorry.

[...]

OK, that's a good explanation. It goes against what I intuited but that
intuition obviously was wrong then.

Agreed. I disabled these tests and will upload a fixed package soon.

Thanks for explaining.

We believe that the bug you reported is fixed in the latest version of
libmedia-convert-perl, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1148502@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Wouter Verhelst <wouter@debian.org> (supplier of updated libmedia-convert-perl package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Tue, 13 Oct 2026 19:50:59 +0200
Source: libmedia-convert-perl
Architecture: source
Version: 1.6.1-1
Distribution: unstable
Urgency: medium
Maintainer: Wouter Verhelst <wouter@debian.org>
Changed-By: Wouter Verhelst <wouter@debian.org>
Closes: 1148502
Changes:
 libmedia-convert-perl (1.6.1-1) unstable; urgency=medium
 .
   * New upstream version
     - Disables faulty test; Closes: #1148502.
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