On Sat, Jan 19, 2019 at 12:13:49AM +0100, Arne Babenhauserheide wrote:
> The following patch now avoids breaking ffmpeg-3.4.
> 
> From f4406df33f1ed6dd64757f43ea7354fd5a88d2d3 Mon Sep 17 00:00:00 2001
> From: Arne Babenhauserheide <arne_bab@web.de>
> Date: Sat, 12 Jan 2019 01:24:58 +0100
> Subject: [PATCH]     gnu: Add libaom and activate AV1 support in ffmpeg.
> 
>     * gnu/packages/video.scm (libaom): New variable.
>     * gnu/packages/video.scm (ffmpeg): Add libaom support.
>     [inputs] new input libaom.
>     [arguments] new configure-flag --enable-libaom.
>     * gnu/packages/video.scm (ffmpeg-3.4): filter out libaom.
>     [inputs] remove inherited libaom
>     [arguments] remove inherited configure-flag --enable-libaom

Sorry, this fell through the cracks.

I noticed that ffmpeg-for-stepmania (FFmpeg 2) isn't addressed by this
patch.

So, I built ffmpeg-3.4 without filtering out the libaom stuff and it
does build, so I'm wondering how it breaks?