by rummy » Mon Feb 25, 2013 7:22 pm
hmm, not a trivial question, not because it's difficult, but because I only really know what works on my system (debian squeeze on a Pink E02).
What I found what that there were NO thumbnails produced for any mp4 videos.
So I did some digging and found that the software didn't seem to be finding ffmpeg, but I did see that it was looking for ffmpeg in /usr/local/cloudengines.
So then I inserted an executable script called ffmpeg at that location and "inspected" what it was being called with.
It's called more than once per movie (I was forcing rescans and touching one of the movies).
Any way, long story short, as far as I can tell ffmpeg is called 3 different times..
1. with very few arguments, this seems to be to get hold of "metadata" like frame size.
2. with a bunch of argument, a pair of which is -vframes 1
looking at the docs for ffmpeg this tells it to extract 1 frame.. a thumbnail if ever I saw one.
3. with a bunch of different args... I guessed this was to transcode akka optimize for mobile viewing.
A bit more playing and I found the -pre xce flag was missing and needed an environment variable.
anyway, I didn't like the default thumbnail extraction of the first frame, so I added the -ss 00:00:05 to take the frame at 5 seconds in as my thumbnail.