HydrogenAudio

Lossless Audio Compression => WavPack => Topic started by: BearcatSandor on 2021-01-09 20:28:42

Title: FFMPEG compression equivilents
Post by: BearcatSandor on 2021-01-09 20:28:42
The FFMPEG documentation for the flac encoder list levels of "compression_level (-f, -h, -hh, and -x) but those don't seem to be options for -compression_level which takes numeric arguments.

What are the corresponding numeric arguments and levels?  Googling this, my paws are empty.

Thank you
Title: Re: FFMPEG compression equivilents
Post by: danadam on 2021-01-09 21:47:00
Your question is unclear to me. Do you have any link to this "list levels of compression_level (-f, -h, -hh, and -x)"?
Title: Re: FFMPEG compression equivilents
Post by: danadam on 2021-01-09 21:56:59
Ok, I got it. I got confused because you said "flac" when you meant "wavpack".
Title: Re: FFMPEG compression equivilents
Post by: danadam on 2021-01-09 22:44:18
The "compression_level" is handled here:
https://github.com/FFmpeg/FFmpeg/blob/release/4.3/libavcodec/wavpackenc.c#L155

One of the things it does, it sets "s->decorr_filter" which is used to pick an element from "decorr_filters" table, which is defined here:
https://github.com/FFmpeg/FFmpeg/blob/release/4.3/libavcodec/wavpackenc.h#L640
as:
Code: [Select]
static const WavPackDecorrSpec * const decorr_filters[] = {
    &fast_specs[0], &default_specs[0], &high_specs[0], &very_high_specs[0],
};

From that, it would seem that:
and values above 4 probably correspond to "-x[n]" option.

Oh, and if you don't provide "-compression_level" then ffmpeg will default to s->decorr_filter = 0, which would be wavpack's "-f". Not sure if that's intentional (assuming I'm right in the first place).
Title: Re: FFMPEG compression equivilents
Post by: lvqcl on 2021-01-09 23:09:47
FFmpeg just dropped libwavpack encoder (https://hydrogenaud.io/index.php?topic=120038.0)
Title: Re: FFMPEG compression equivilents
Post by: danadam on 2021-01-09 23:36:14
There already was some investigation about corresponding compression values: https://hydrogenaud.io/index.php?topic=118278.msg976262#msg976262
SimplePortal 1.0.0 RC1 © 2008-2021