GNOME Bugzilla – Bug 701111
matroskademux: seeking in Sintel 4K png-in-matroska file is dogslow
Last modified: 2018-05-07 14:30:49 UTC
Since the 4K version of Sintel is huge and almost impossible to find nowadays, I made a shortened sample (with Avidemux, without re-encoding). Simply download http://jeff.ecchi.ca/public/sintel-4k-torture-sample.mkv and try seeking it in various places. The typical seeking time with totem/pitivi on gst 1.x is 15 to 30 seconds. VLC manages to have typical seeking times of 2-3 seconds (sometimes 4-5). mplayer somehow manages to seek instantly (?!) Core 2 Quad Q9300 CPU, no hardware decoding acceleration.
Let's move it to the demuxer for now.
Created attachment 350381 [details] do_seek.c test case Little test program.
Intel(R) Core(TM) i7-4702HQ CPU @ 2.20GHz, decoding with gst-libav. Key-unit seeks: 100 seeks, min: 95ms, max 332ms, avg 220ms Accurate seeks: 100 seeks, min: 157ms, max 2912ms, avg 1039ms The file is 23 seconds long and has 5 cue entries. The first and second index entry are 10 seconds apart. I'm a bit confused because the bug title talks about this being a PNG file (and it's what I remember too), but the file I just downloaded from the link has in fact H.264. Either way, it's not clear to me there is anything outrageous happening here any longer. Can we close this, or was this about a different file after all?
Closing. Jeff, if you can reproduce the slowness with tim's example program , re-open aand provide the actual file.