[FFmpeg-user] ProRes422 with 8 audio tracks converted to mp4 -- muffles audio 4

[Kieran O Leary]

On Thu, 22 Nov 2018, 17:28 Harvey Pikelberger <communque at gmail.com wrote:

>
> > On Nov 22, 2018, at 8:50 AM, Carl Eugen Hoyos <ceffmpeg at gmail.com>
> wrote:
> >
> > 2018-11-22 17:44 GMT+01:00, Harvey Pikelberger <communque at gmail.com>:
> >
> >> ffmpeg -i ffmpeg -i SoundMappingTest-I-8Discreet.mov -map 0 -g 48 -c:v
> >> libx264 -profile:v baseline -crf 16 -c:a aac -b:a 256k -vf
> scale=1280:720
> >> -pix_fmt yuv420p SoundMappingTest-I-8Discreet.mp4
> >
> > You (apparently) cannot copy the timecode track from mov to mp4
> > but this is what you request with "-map 0".
> >
> > Default behaviour would be to transcode one video and one audio
> > track.
> >
>
> Questions:
> Does the timecode issue explain the 'Conversion Failed'?
>


Yes I think so. Did you try adding -dn to your command line so that it
ignores data tracks?

It seemed that the error that stopped the conversion was what appeared in
> the subsequent notes, having to do with not recognizing the codec:
> - Could not find tag for codec none in stream #2, codec not currently
> supported in container
> - Could not write header for output file #0 (incorrect codec parameters
> ?): Invalid argument
> - Error initializing output stream 0:1 --
>
> Also, my understanding of -map 0 was that it maps not one video / one
> audio but maintains the track map, matching all tracks from source to
> destination file.
>

I think it just maps all tracks,I'm not sure about order though.

That's, in fact, the behavior I'm seeing when I run the same command using
> a DNx source file with the same 8 tracks of audio.
>
> Also note: The above CLI didn't fail to convert from ProRes / QT in FFmpeg
> v4.0.1
> The conversion went through, only with LFE sound on track 4.   Now in
> FFmpeg v4.1 we're getting the error -- but only for the ProRes source, not
> the DNx source.  That works fine.
>

It sounds like maybe the default  behaviour has changed alright. It now
looks like you have to specify that you don't want the timecode track when
using -dn.

Best,

Kieran