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35-45% HLS transcode speed-up :-)

Posted: Tue Feb 11, 2014 9:00 pm
by warpme
Hi *
Lets put something nice here :)

x264 lib has capability to tune performance/quality for given deployment scenario. I've created patch (#12055) allowing user to select preset & tune for achieving desired speed-qualty compromise for HLS transcode.
Original MythTV code is using defaults preset/tune: "medium/<null>". Setting preset to "ultrafast" and tune to "movie" gives me hard-to-notice-difference picture and 35-45% transcoding speedup.

On my 3220T (IVB i3, 35W) transcode 3-5Mb/s 1080i@50 source movie to 720p@4.5Mb is approx 35-40% now faster than realtime while default settings give me 90-95% of realtime (so I can't watch 720p@4.5Mb under Torc on iPad4). So practically afar i.e. 30min of watching I have 13min of 720p@4.5Mb already transcoded ahead. And all this for most demanding setting in Torc. Nice!

Setting preset/tune currently is arranged exactly the same way like transcode threads. E.g. to change preset from default 'medium' to 'ultrafast', run mysql clinet in terminal and issue:

Code: Select all

INSERT settings ( value, data, hostname ) VALUES ( 'HTTPLiveStreamPreset', 'ultrafast', NULL);
Hope iPAD/Android user will enjoy this the same like me :-)

br