[vlc] Re: Sound problem when trying to read DV from input

[Sébastien Aperghis-Tramoni]

Sébastien Aperghis-Tramoni wrote:

> Now I have the image and the sound, but the sound is extremely awful: 
> there's a very loud noise which cover most of the normal sound. Trying 
> with a headset to avoid a potential audio loop, I hear that it's the 
> right channel which has this noise.

FYI, it seems that the problem comes from the fact that VideoLAN can't 
cleanly decode DV audio sound other than 16 bits. My camcorder was 
configured to send 12 bits audio; after switching to 16 bits, the sound 
in VideoLAN was perfect. My guess is that the rawdv demuxer just assume 
16 bits audio without checking the actual data size. This would also 
explains why the right channel was borked: I suppose the left channel 
used 4 bits from the right channel (which were mostly zero because in 
my tests there wasn't much sound to transmit) while the right channel 
took 8 bits from a random place, hence an awful and loud noise.

> I was unable to fond documentation on this :demux option, or on this 
> rawdv demuxer.

That point is also an issue: it seems there are many, many useful 
options completely undocumented, not even mentioned anywhere.


Sébastien Aperghis-Tramoni
  -- - --- -- - -- - --- -- - --- -- - --[ http://maddingue.org ]
Close the world, txEn eht nepO

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