Video thumbnails

[Robert Helling]

Hi,

first of all thanks to everybody who was on yesterday’s video call. That was both useful and any enjoyed seeing you (many of you for the first time)!

I had some more thoughts regarding the discussion of how to generate thumbnails for videos. After hearing how difficult that seems to be to do within Qt and all kinds of licensing problems with even shipping the necessary codecs it seems to me there is no way around using external tools. For playback just rely on the OS to playback a video (just as we do for opening images).

To produce thumbnails (which seems to be even more urgent) I looked again into ffmpeg and that appears to be the tool of choice: It is available for all relevant operating systems, many users probably already have it installed (e.g. as part of VLC) and if not installing it is pretty straight forward (if no patents prevent you to do so but that would not be our problem). We would simply have a preference with the path to the ffmpeg binary. Then (maybe triggered by the user) we could run a command like

ffmpeg -i myvideo.avi -vf fps=1/60 img%03d.jpg

(for more details see https://trac.ffmpeg.org/wiki/Create%20a%20thumbnail%20image%20every%20X%20seconds%20of%20the%20video )/ in a directory per video file and then take those thumbnails as a representation of the video inside subsurface. This would have to done only once per video, the rest would be treated just like the image we already have.

This solution sounds to me both sufficiently user friendly as well as straight forward to implement.

What do you think?

Best
Robert

--
.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oOo.oO
Robert C. Helling     Elite Master Course Theoretical and Mathematical Physics
                      Scientific Coordinator
                      Ludwig Maximilians Universitaet Muenchen, Dept. Physik
                      Phone: +49 89 2180-4523  Theresienstr. 39, rm. B339
                      http://www.atdotde.de

Enhance your privacy, use cryptography! My PGP keys have fingerprints
A9D1 A01D 13A5 31FA 6515  BB44 0820 367C 36BC 0C1D    and
DCED 37B6 251C 7861 270D  5613 95C7 9D32 9A8D 9B8F





-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 235 bytes
Desc: Message signed with OpenPGP
URL: <http://lists.subsurface-divelog.org/pipermail/subsurface/attachments/20180706/59728a5a/attachment.sig>