[FFmpeg-devel] [PATCH] lavc/ac3dec: disable DRC by default

rcombs rcombs at rcombs.me
Sun Feb 2 00:02:43 EET 2020



> On Feb 1, 2020, at 15:55, Derek Buitenhuis <derek.buitenhuis at gmail.com> wrote:
> 
>>> and the defacto way to handle decoding AC-3.
>> 
>> Is it, though? My understanding is that AV receivers usually only enable AC3 DRC in "night mode" or the like, and few even provide a fully-tunable setting for it. Apple's decoder in AudioToolbox (implemented on top of Dolby's) doesn't provide the feature at all (I haven't checked what Win32 Media Foundation does yet). So where does this "de facto" situation come from, other than lavc itself?
> 
> Because the spec defines what is de facto - it is what defines what AC-3 *is*.
> You are choosing to ignore it here because you don't like what's in it.

This is "de jure"; "de facto" means how it's actually implemented in practice.

>> Meanwhile, Dolby's own decoder applies digital dialog normalization by default (contrary to how the spec says it should be applied downstream), and I haven't seen anyone arguing that lavc should do that.
> 
> Own decoder from where? Is it officially Dolby branded, or is this Apple again?

Their own decoder IP and reference tool; it's non-public, and it's what Apple's is built on top of.

> 
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> 
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".



More information about the ffmpeg-devel mailing list