Making ffmpeg decoding report accessible to user (was: provide option for decoding hard timeout (was: Reporting gross decode failures))

[acdha]

http://chris.improbable.org/experiments/browser/video/waters_of_destiny.mp4 is malformed. It plays back despite this using the native Windows or OS X APIs but most other software chokes (see http://chris.improbable.org/experiments/browser/video/waters_of_destiny.html).

I was hoping that QCTools could be used to reliably catch problems like this as early as possible in the process. When processing that video, QCTools 0.5 hangs on frame 9797:

This may be an argument for a hard timeout as it's been chewing 120% CPU for around 20 minutes on the same frame. I've saved a sample here: https://gist.github.com/0703fc6af3623de1d265

The good news is that despite this, the glitch shows up rather prominently in the graphs so it's easy to discover – the decoding first fails at frame 1337 and since it isn't quietly ignored like e.g QuickTime the lack of thumbnails and the huge diff make it easy to localize:

[acdha]

Looks like this was fixed in 0.6 – there's still no overt indication of decode failures on the list but the the video parsing completes now and the decoding failure is incredibly obvious in the graphs.

[dericed]

Thanks for testing. At some point perhaps we should make the decoding log accessible, so I'm going to change to ticket to that.

[acdha]

Great, thanks – even a simple status badge would be handy for our content team triaging incoming deliveries from partners