6.0.0 video thumbnailer...

[Maik Qualmann]

Do we want to use libffmpegthumbnailer as additional dependencies? Also used 
by Dolphin here. For that I already have a nearly finished patch, because I 
tested it some time ago and it worked very well and fast. I will reactivate 
the patch to test...

Maik

Am Sonntag, 4. März 2018, 17:49:39 CET schrieb Gilles Caulier:
> Hi all,
> 
> Since i written the FFMPEG video metadata parser in 6.0.0 branch, i'm
> trying to register a huge video collection from my host computer.
> 
> Here, more than 2500 MKV files are present, plus a lots of MP4, MOV, and
> another media taken with cellular and camera.
> 
> The registration have been very fast. 2500 file parsed in 2 minutes and
> ready to use. System has SSD, Sqlite, 8 cores, and 32Gb of RAM. No crash
> all work fine... excepted... the video thumbnails.
> 
> I facing random dysfunctions with video files. Sometime thumbs are there,
> sometime not. Using F5 always give a different results until i try to
> insist and i can see the DB locked and revival...
> 
> The video thumbnailer is based on QtAV frame extractor. My QtAV is last
> stable 1.12.0. I suspect a bug somewhere in QtAV, as i can see thumbnailer
> code including a lots of mutex to prevent concurrency.
> 
> This is typically abnormal. FFMPEG API is re-entrant as i checked with the
> multi-threaded metadata parser unit test.
> 
> As we depend now directly of FFMPEG API, I propose to rewrite the video
> thumbnailer with libav C function.
> 
> We have code ready to use with ffmpeg API here :
> 
> https://cgit.kde.org/ffmpegthumbs.git/tree/
> 
> Your viewpoint ?
> 
> Gilles