(pull-request #980)

When we upload a video (higher than HD) in Piwigo 2.10, it will generate the video in HD to help users to see videos in their gallery if they have a heavy file. To create this feature, we added a new trigger at the end of the upload process called :

trigger_notify('upload_file_end', $example);

The video is generate with ffmpeg in command line and stored in 'pwg_format'.

See https://github.com/Piwigo/Piwigo/issues/1179 and https://github.com/Piwigo/Piwigo/commit/5bf85c982b2b7f3e63fefb2d8cfea7a8bcc9e591