[FFmpeg-user] Input 5.1 DTS, output 2.0 MP3: Atrocious Quality

[Moritz Barsnick]

On Sat, May 16, 2015 at 13:07:01 +0200, Moritz Barsnick wrote:
> [auto-inserted resampler 0 @ 0xb713840] ch:6 chl:5.1(side) fmt:fltp r:48000Hz -> ch:2 chl:stereo fmt:fltp r:48000Hz
> [auto-inserted resampler 0 @ 0xb3b55c0] ch:6 chl:5.1(side) fmt:fltp r:48000Hz -> ch:2 chl:stereo fmt:s16 r:48000Hz

> (Unfortunately, my math tells me that the former matrix is bound to
> cause overflows with value-restricted numerical formats. There's
> something I don't seem to understand there. And is LFE really ignored
> when downmixing?)

Ah, I see the difference now. In one case, it's outputting to floating
point, so no clipping is expected. In the other case (depending on
encoder obviously), it's assuming integer output.

Moritz