GNOME Bugzilla – Bug 610857
[assrender] noticeable delay in loading of files with ASS tracks
Last modified: 2011-08-19 05:02:54 UTC
Let's say I have 350MB MKV with ASS tracks. When I attempt to load these files, there will be a delay of 1-3 seconds before the video and audio load. If I use a 700MB MKV with an ASS track, that delay increases to around 5 seconds. However, if I remove the ASS tracks from both files, they load more or less instantaneously.
Created attachment 154521 [details] gst-debug of loading delay
After commenting out all references to ass_set_fonts, the delay disappears and files load within a second. Of course, doing this breaks proper assrender function.
Not that it changes things, but upon more precise timing, my 700 MB file takes 8 seconds to display video if an ASS track is present.
One more note, this delay does not occur with other libass implementations (VLC, MPlayer, etc).
Created attachment 154556 [details] 1st debug log with slomo's modification
Created attachment 154557 [details] 2nd debug log with slomo's modification
Ok, then we have to find the difference between our and their usage of libass. One thing I noticed is, that they only use a single ass_library_t and ass_renderer_t and one ass_track_t per stream.
Not sure if it's related, but Greg has told me that the following lines are useless: ass_set_fonts (render->ass_renderer, NULL, "Sans"); ass_set_fonts (render->ass_renderer, NULL, "Sans", 1, NULL, 1);
Does it make a difference if you remove these lines? :)
Nope. Unfortunately...
Commit d06e9c40e648a627b5b7c5b86c171bf84340530b is causing this. The commit immediately prior allows for instant loading of ASS tracks.
Hmmm. Even after altering the previous code to search for x-font-ttf instead of x-truetype-font, there is still a loading delay.
Is this still a problem with the latest releases?
Eric, can you please update the bug in case you are able to reproduce the problem with latest release ?
Please feel free to reopen this bug if the problem still occurs with a newer version of GStreamer Core 0.10.35, Base Plugins 0.10.35, Good Plugins 0.10.30 stable release, tia.