Videoconvert various load ??

[Peter Maersk-Moller]

Hi

Trying to measure the load of videoconvert using various format types, I
get a for me unexpected result using the formats
RGB/BGR/ARGB/ABGR/RGBA/BGRA. The pipeline used is this:

gst-launch-1.0 -v filesrc
location=big_buck_bunny_720p_H264_AAC_25fps_3400K.MP4  ! decodebin !
videoconvert dither=0 ! "video/x-raw,format=$format" ! fakesink sync=1

The test platform is OS X Yosemite on a Macbook Pro with Quad core + HT and
GStreamer 1.5.90.


   1. RGB ~ 39-40%
   2. BGR ~ 38-40%
   3. ARGB ~ 27-30%
   4. ABGR ~ 29-32%
   5. RGBA ~ 29-32%
   6. BGRA ~ 20-21%

The output of decodebin is I420. First observation is that the RGB/BGR
seems to require approx 50% more than ARGB/ABGR/RGBA and apparently 100%
more than BGRA, but in reality much more since the CPU measurement include
mp4 demux and h264 decoding. Using dither=0 I would expect the routines are
using more or less the same amount of work although the alpha formats
require some extra work for setting the alpha bytes to 1 (255).

Is the BGRA implemented with an inferior I420->RGB conversion quality wise
as a quick fix (earlier version in the 1.2.x series had some performance
issues) that needs to be re-addressed or is the BGRA implemented with a new
optimized method not yet implemented for the other conversion types?

Best regards

Peter MM
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