x264enc on android: very slow.

[Nicolas Dufresne]

Le lundi 29 juillet 2013 à 21:28 +0800, Haiming Wang a écrit : 
> Hi Nicolas,
> 
> 
>   Thank you very much for your help.   
> 
> 
>   Regarding the colorspace conversation, as I mentioned in my previous
> email,   I used a pipeline in which I replaced all the elements just
> after ffmpegcolorspace with fakesink , and I found the speed is still
> quite quick. The framerate is around the same as the camera preview
> frame rate(15fps),  So I believe the bottle neck should not be at
> color space conversation.

I don't fully understand what you have done to prove there was no
colorspace conversion issues, neither in what replacing the encoder by
fakesink show that. But I'm just giving you hints and this is might not
be your issue. I had problem produce 30 fps in QSIF sized stream in the
past because of that NV12 to I420 conversion issue on both iOS and
Android. This is fixed upstream but not in any released version. Sharing
more details about your build would help in figuring if you might have
an affected build.

>   Regarding the profiling tool,  what profiling tool do you suggest me
> to use?  I have some experience with gprof on android,  but it was
> said the tool doesn't support multi-thread very well.  It's also not
> easy to use.  Do you have any suggestion about the tool?

I have never used any profiling tools on Android. Last time I had the
iOS profiling tool to show be the bottleneck. I have been told that
oprofile and prof may way, but will require a rooted device and a kernel
rebuild.

> 
>   You also suggest me using a simpler profile.   Does the profile here
> means h264 profile?   Can it be configed by x264enc properties? 

Yes, h264 profile is usually set through caps, but that might not be
true if you are using 0.10.

>   Yes,  I also considered to use the hardware encoder on android.
> However I didn't think the performance of the software is so
> unacceptable.  I see some software encoder running on Android, and the
> frame rate can reach 15 fps, and the performance is quite acceptable.
> I want to know if there are some settings for x264enc, which can
> improve the performance.

That being said, I realized it's not written yet, see:

https://bugzilla.gnome.org/show_bug.cgi?id=705129

Also, as Arun have said, if you are using the SDK, it is built without
NEON acceleration. Adding that does increase the performance a lot.

regards,
Nicolas