[BUG] Log event for certain VP9 encoded Youtube videos

[GlassedSilver]

Describe the bug

ERROR: Postprocessing: Conversion failed!

To Reproduce
Since around early 2021 some VPN9 encodes from Youtube cause issues with FFMPEG above version 3.0.1.
This has been fixed two months ago.

Expected behavior
conversions (muxes) to happen gracefully.

Screenshots
n/a

Environment

• YoutubeDL-Material version 4.2
  Installation type: docker
  Docker tag: nightly
  Commit hash: 4fd60c8
  Build date: 2022-04-09

Ideally you'd copy the info as presented on the "About" dialogue
in YoutubeDL-Material.
(for that, click on the three dots on the top right and then
check "installation details". On later versions of YoutubeDL-
Material you will find pretty much all the crucial information
here that we need in most cases!)

Additional context
n/a

[GlassedSilver]

await fix for ffmpeg install in DOCKERFILE from alpine/edge/community repo

[GlassedSilver]

Sadly we ought to wait for (and track the version we want to target) at yt-dlp/yt-dlp#871

https://github.com/yt-dlp/FFmpeg-Builds only provides Linux x86_64 builds that have the patches we need

[GlassedSilver]

fixed in #551

We're not getting ffmpeg and ffprobe from alpine's repo anymore, at least not for now. we use static binaries straight from master that get created every few weeks or so by what I assume is an FFmpeg team member, at least their site is listed by ffmpeg for people who want master-based builds in static format.