[FFmpeg-user] cutoff argument not passed to libmp3lame

[Moritz Barsnick]

On Mon, Dec 19, 2016 at 20:45:59 +0100, Bernhard Döbler wrote:
> FFMpeg Doc says
> cutoff
>     Set cutoff bandwidth in Hz.
> 
> https://ffmpeg.org/ffmpeg-codecs.html

More precisely in this section:
https://ffmpeg.org/ffmpeg-codecs.html#Codec-Options

What that documentation doesn't say is that it isn't generally valid.

Furthermore, the encoders aac, libfdk_aac, libopus, libvorbis document
it in their own sections (and make use of the option), the encoder ac3
also seems to use the option.

Indeed, libmp3lame.c probably only needs a call in
mp3lame_encode_init() to pass the option on to the encoding library:

        if (avctx->cutoff)
                lame_set_lowpassfreq(s->gfp, avctx->cutoff);

I can provide (and perhaps test) a simple patch to ffmpeg-devel, if
nobody beats me to it.

Moritz