No rendering of SSA subtitles
Using sample: http://streams.videolan.org/streams/matroska/MKV_anime_files/%5bBSS%5d_kurenai_-06%5b1280x720_h264%5d%5b0356526F%5d.mkv
0x21b6e70] main decoder debug: looking for decoder module matching "any": 28 candidates
[0x21b6e70] libass decoder debug: adding embedded font PURI10.TTF
[ass] Fontconfig disabled, only default font will be used.
[0x21b6e70] main decoder debug: using decoder module "libass"