Gstreamer, liborc and OS X

[Sebastian Dröge]

On Di, 2014-01-07 at 14:25 +0100, Peter Maersk-Moller wrote:
> Hi.
> 
> Since GStreamer now depends on liborc for efficient videoscaling and
> videoconversion as opposed to ffmpeg/libav for earlier versions, what are
> the chances of running GStreamer on OS X?
> 
> Liborc contains little or no info on howto build for OS X. Has the prebuilt
> GStreamer binaries solved this? And if yes, then how?
> 
> I know it is a border case between GStreamer and liborc, but with how
> liborc is currently being used in GStreamer, it is a rather important issue
> for GStreamer as I see it.

The prebuilt binaries include orc and have all GStreamer code built with
orc support. What problem do you see when compiling orc on OSX and using
it?


Also note that in 0.10 GStreamer did not depend on ffmpeg/libav for
video scaling and conversion. The videoscale plugin was the same we have
now (and also used orc in later versions, or was plain C code in earlier
versions) and instead of videoconvert we had ffmpegcolorspace.
ffmpegcolorspace was a copy of some ffmpeg code, but contained plain C
code and no assembly optimizations. I think the performance problem
you're seeing is caused by the old ffmpegcolorspace having a fast-path
for your exact conversion while videoconvert currently does a generic
conversion (i.e. converts to AYUV or ARGB first, then to the target
format). If we implement some more fast paths it should be faster than
with ffmpegcolorspace in theory, especially if implemented with orc.

I'm talking about this btw
https://bugzilla.gnome.org/show_bug.cgi?id=721701

-- 
Sebastian Dröge, Centricular Ltd - http://www.centricular.com
Expertise, Straight from the Source
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