Movie preview - use frame after 5 seconds

[MorrisJobke]

please review @karlitschek @DeepDiver1975 @schiesbn @georgehrke @Kondou-ger @PVince81

superseeds #5739 because #5767 was merged.

Fixes #5738

[Niduroki]

Still wondering, what we should do, if the video is smaller than 5 seconds.

ffmpeg will output an empty file. I'd say we should check for this and display the default-mimetype-file in that case.

[ghost]

Test passed.
Refer to this link for build results: https://ci.owncloud.org/job/pull-request-analyser/2011/

[DeepDiver1975]

I'd say we should check for this and display the default-mimetype-file in that case.

sounds reasonable - can you give that a try? THX

[PVince81]

I guess it's not possible to get the video length / total frames count from the header using libs ? (might be overkill, yes...)

[MorrisJobke]

@Kondou-ger Can you take care of the mentioned improvement?

[DeepDiver1975]

[DeepDiver1975]

In cases the video doesn't contain enough data to generate the thumbnails the mime type icon was displayed.
I'd consider this a reasonable approach.

A more advanced approach might be to use avconv possibility to export a series of frames and select the first being not bla{n|c}k - but this is something we can implement in a later stage.

👍 for me for this pull request.

[georgehrke]

👍

[ghost]

Test failed.
Refer to this link for build results: https://ci.owncloud.org/job/pull-request-analyser/2086/

[DeepDiver1975]

failing unit test is unrelated - needs to be fixed in master