add motion vector extraction from side data

[cvley]

Hi, I need motion vector extraction from video, so I implement related functions.

Pls. review them, thanks 😄

[codecov-io]

Codecov Report

Merging #33 into master will decrease coverage by 0.32%. The diff coverage is 0%.

@@            Coverage Diff             @@
##           master      #33      +/-   ##
==========================================
- Coverage   32.11%   31.79%   -0.33%     
==========================================
  Files           4        4              
  Lines        2525     2551      +26     
==========================================
  Hits          811      811              
- Misses       1667     1693      +26     
  Partials       47       47

Impacted Files	Coverage Δ
avutil/avutil.go	31.75% <0%> (-1.17%)	:arrow_down:

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[imkira]

@cvley Thank you for your PR. Please take a look at the review. Can you also add some simple tests where you call all new functions? Thanks

[cvley]

@imkira Thanks for your reviews. I will work on it 😄

[cvley]

@imkira I have fixed the code and add a simple test, please review them.

By the way, I'd like to generate a random video in the test to perform motion vectors extraction, is it OK?

Thanks.

[imkira]

@cvley No problem about the random video.

During tests I'm currently downloading to a directory called fixtures

https://bintray.com/imkira/go-libav/download_file?file_path=sample_iPod.m4v https://bintray.com/imkira/go-libav/download_file?file_path=sample_iTunes.mov https://bintray.com/imkira/go-libav/download_file?file_path=sample_mpeg4.mp4

And referencing them like this: https://github.com/imkira/go-libav/blob/126f4da001527349ba3f1c933fdb4e8eb6923698/avformat/avformat_test.go#L60

Do any of these work for your tests?

If not, please send me the file to [email protected] and I will upload it for the tests. Thanks

[imkira]

Any update on this @cvley ?