[FFmpeg-devel] [PATCH] deprecate SAMPLE_FMT_S24

Michael Niedermayer michaelni
Sun Aug 17 15:57:05 CEST 2008

On Sun, Aug 17, 2008 at 03:32:30PM +0200, Aurelien Jacobs wrote:
> Peter Ross wrote:
> > This patch flags SAMPLE_FMT_S24 as deprecated.
> So what will happen if a user suply a 32-bits pcm sample and re-encode
> it with a supposedly lossless encoder which only support 24-bits ?
> There is no way to tell the user that the encoding won't be lossless.
> There is also no way for the 24-bits encoder to apply dithering to
> 32-bits samples (it would mess-up the real 24-bits samples stored in
> 32-bits).
> Also, what happens if you transcode a 24-bits sample to wav (pcm) ?
> The "encoder" will have no way to know that it's a 24-bits sample
> and will store it as 32-bits. This is a huge waste of bytes.
> IMO, SAMPLE_FMT_S24 is useful, even if it's treated internally the
> exact same way as SAMPLE_FMT_S32. This allows encoders to behave
> more sensibly if desired.

and 20bit 22bit 18bit ...

I think a field in AVCodecContext that simply contains the number of
bits in there would be more flexible.
But i have no strong oppinion on this, we can keep SAMPLE_FMT_S24 if you

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Frequently ignored awnser#1 FFmpeg bugs should be sent to our bugtracker. User
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