[vlc-devel] live stream HD playback challenge - job offer

Rémi Denis-Courmont remi at remlab.net
Mon Mar 7 22:21:26 CET 2011


Le mardi 1 mars 2011 11:26:57 John Baaserud, vous avez écrit :
>  *   We use VLC on ION and ION2.
>  *   VAAPI and VDPAU-VIDEO installed (vlc and ffmpeg compiled with support
> for these)
>  *   VLC (MPEG-4 TS h264 1080i50) no-ffmpeg-hw = 100% cpu,
>  *   VLC (MPEG-4 TS h264 1080i50) with ffmpeg-hw = 90%-100% cpu,
>  *   We have tested mplayer (MPEG-4 TS h264 1080i50) -vo vdpau = 2%-10% cpu,

I guess that mplayer is just demultiplexing the Transport Stream and leaving 
the GPU do everything past that. As you may know, VLC needs to get a hold of 
the decoded pictures from VAAPI into main memory for filtering/post-
processing, before the pictures are finally sent to the GPU for rendering. 
Depending on the GPU, this may cause huge performance penalties.

VLC could be hacked heavily to not grab the decoded pictures and directly 
create a video window from the FFmpeg/VAAPI. This is quite a bit of work.

However, anything that relies on video filtering, notably subtitles and On-
Screen Display, and all video post-processing options will be lost. Or then 
you need to rewrite entire chunks of the VLC code base. I'm not saying it is a 
good or bad idea. I just want to ensure you understand the implications.

Rémi Denis-Courmont

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