[FFmpeg-devel] [PATCH 0/2] VDA decoder for ffmpeg

Xidorn Quan quanxunzhen at gmail.com
Wed Aug 22 05:07:10 CEST 2012

On Wed, Aug 22, 2012 at 6:39 AM, Sebastien Zwickert <dilaroga at gmail.com>wrote:

> 2vuy format is the "native" decoder format it won't do an internal color
> space conversion.

I noticed that yuvs is available only in 10.7 and later yesterday
after sending this patch, and I'll try to solve this problem.

The version of my OS X is 10.7+, and I found that my VDA natively
supports outputing pictures with pixel format UYVY422 (2vuy),
YUYV422 (yuvs), YUV420P (y420), NV12 (420v), and some other RGB.
I tested their performance and found you are right that 2vuy is
the most native one with the lowest CPU usage, yuvs takes second
place with remarkable usage rising but still better than converting
by libswscale.

I tested decoding an 1080p H.264 video outputing to null:
pixfmt   CPU usage      by libswscale
 2vuy   about 4%-5%     (no convert)
 yuvs   about 9%-10%    about 22%-24%
 420v   about 13%-14%   about 40%-43%
 y420   about 14%-15%   about 6%-8%

In sum, it might be a good idea to let caller to decide which pixel
format should be used. I'll fix this today and send a new patch
based on this patchset.

Xidorn Quan

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