[Libav-user] mjr to opus audio conversion - corrupted results

[Mateusz Koslacz]

Well, so why list I'm mailing is called "Libav-user -- This list is about
using libavcodec, libavformat, libavutil, libavdevice and libavfilter.", if
you can't help me if I use Libav?

2015-07-08 19:26 GMT+02:00 Paul B Mahol <onemda at gmail.com>:

>
> Dana 8. 7. 2015. 15:05 osoba "Mateusz Koslacz" <mateusz.koslacz at 4vod.tv>
> napisala je:
>
> >
> > Hi,
> >
> > In our project we use janus-gateway (http://janus.conf.meetecho.com/)
> as a webRTC gateway and also as a stream recorder. We are on the tests
> stage of our project, and after very long development time we have
> ecountered a bug that is a blocker for whole project. After real tests of
> recording streams using janus we realized that audio and video are out of
> sync in recordings, despite of fact, that live they are perfectly in sync.
> >
> > Janus records two *.mjr files for each recording - one for video, and
> one for audio. Janus also provides own converter to convert this files to
> *.webm for video and *.opus for audio. After that, we use ffmpeg to merge
> this files. By recording stopwatch view on the stream we concluded, that
> video has correct length and speed, so most probably this is something
> wrong with audio recording or converting.
> >
> > Firstly, janus was using libogg for converting *.mjr audio to *.opus.
> Regarding described issues author decided to switch to libav audio
> processing. You can check how it's done in this file
> https://github.com/meetecho/janus-gateway/blob/pprec-opus-libav/postprocessing/pp-opus.c starting
> from 90 line.
> >
> > Returned data is a lil bit smaller than data obtained using libogg:
> >
> >> -rw-r--r-- 1 mateusz mateusz  17987445 lip  8 11:58
> rec-2215547545-audio-nolibogg.opus
> >> -rw-r--r-- 1 mateusz mateusz 221841174 lip  8 11:56
> rec-2215547545-video.webm
> >> -rw-r--r-- 1 mateusz mateusz  18074102 lip  8 11:52
> rec-2215547545-audio-libogg.opus
> >
> >
> > Unfortunately, returned data is somehow corrupted - ffprobe results for
> libav processing output:
> >
> >> [ogg @ 0x4336540] Codec not found
> >> rec-2215547545-audio-nolibogg.opus: End of file
> >
> >
> > and for compare, for libogg version:
> >
> >> Input #0, ogg, from 'rec-2215547545-audio-libogg.opus':
> >>   Duration: 01:20:32.98, start: 0.000000, bitrate: 29 kb/s
> >>     Stream #0:0: Audio: opus, 48000 Hz, stereo, fltp
> >
> >
> > Moreover, no player can play this file - VLC just does nothing, and
> Rythmbox says "Can't play file: {null}".
> >
> >
> > Is this because of improper use of libav api, or maybe it is some libav
> bug? How could we possibly overcome this problems?
> >
> > For more details you can read our whole conversation with janus author
> here:
> > https://groups.google.com/forum/#!topic/meetecho-janus/lMCtBm7VbMY
> >
> >
>
> From that conversation it is evident you are using Libav and not FFmpeg.
> And so we can not help you.
>
> > Regards,
> >
> > Mateusz Koślacz
> >
> > _______________________________________________
> > Libav-user mailing list
> > Libav-user at ffmpeg.org
> > http://ffmpeg.org/mailman/listinfo/libav-user
> >
>
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