I hereby provide more information concerning the video file included in the bug report. I also found a workaround to the bug, but do not know why it works at all. This should probably be forwarded to upstream, Debian firefox-esr maintainers and/or Debian ffmpeg maintainers.
file(1) reports it as a WebM (video/webm) file. mkvinfo(1) reports (using the --summary option): > Track 1: video, codec ID: V_VP8, mkvmerge/mkvextract track ID: 0, language: > und, default duration: 33.367ms (29.970 frames/fields per second for a video > track), pixel width: 1280, pixel height: 720, display width: 1280, display > height: 720 > Track 2: audio, codec ID: A_OPUS, mkvmerge/mkvextract track ID: 1, language: > eng, channels: 2, sampling freq: 48000, bits per sample: 32 If I extract the audio track using mkvextract(1), Firefox can play it. Gstreamer plays the video file, tested with the following invocation: > gst-launch-1.0 playbin > 'uri=https://bugs.debian.org/cgi-bin/bugreport.cgi?att=1;bug=829600;filename=katzenmilch-have-a-nice-day-maybe.webm;msg=5' ffmpeg does not play the video file, but exits with status code 1 and the error “Output file #0 does not contain any stream”. The workaround that I found simply disables ffmpeg, maybe that should be the default? 1. Navigate to “about:config”. 2. Search for “media.ffmpeg.enabled” 3. Set “media.ffmpeg.enabled” to “false”. Greetings, -- Nils Dagsson Moskopp // erlehmann <http://dieweltistgarnichtso.net>
