avbin plugin yields black images the first 5 frames about imageio

[almarklein]

Fixed per #26

[almarklein]

The fix creates some other issues. Notably, because now some frames are skipped, the video is shorter, which causes problems with the reported length (a feature that I added in #24).

Currently the avbin plugin is in a bit of a hacky state, so we need to decide how to deal with this problem.

A few options:

• Fix the problem for real. This would be preferred, but I don't know if this is possible.
• Report a length of np.inf and skip black frames. I don't like this.
• Report a finite length and just accept that we have black frames.
• Skip the empty frames in the _open() function, and reduce the reported nframes with the number of frames skipped. This assumes empty frames only occur at the beginning. This means that the frames will be out of phase with ffmpeg, but at least all frames are non-empty.

A note: it seems that the cockatoo has at least 10 empty frames when run on Travis. Locally it's 5 or so. So this might be dependent on the system as well.

[almarklein]

BTW: if you want to get the latest version of the avbin plugin, you need to pull in the latest master:

git checkout master
git remote add upstream https://github.com/imageio/imageio.git
git pull upstream master

To create a PR from here again:

git checkout -b new-branch-name
... do work
git commit -a
git push origin new-branch-name

[dave-epstein]

I still have this problem with avbin, is there any known fix? Reading the same videos using the ffmpeg and the avbin plugins, the ffmpeg plugin works fine.

[almarklein]

@dave-epstein since avbin is not maintained anymore (last release is from 2012), so I would not wait for a fix :) Actually, imageio should probably deprecate its plugin for it ...

[dave-epstein]

Fair enough :) Would you recommend using ffmpeg then? Or is there a faster way to read a video into frames (maybe using a different tool altogether)?

[almarklein]

Yes, ffmpeg is not perfect, but is the best-supported way (at least in imageio) to read video.