[x264-devel] h.264 encoding live stream from a web cam

[i-love-spam]

24.08.09, 04:20, "Jason Garrett-Glaser" <darkshikari at gmail.com>:
> > Thanks for prompt reply!
> >
> > I prefer to use ffmpeg, since I use h263 from ffmepg, and many other utilities.
> > Are there any drawbacks to using ffmpeg than x264 directly?
> ffmpeg's option system with regards to x264 is braindead; the defaults
> that it uses are completely broken.  You basically have to re-set all
> the x264 defaults and then go back through and apply your settings.
> Of course, if you can do all this and be sure you don't screw up,
> you're fine.

It appears that the version I was using was direct264, so I switched to x264 latest from git.
Without changing anything, I have now problems with video. Now, for the first 2-3 
seconds av_encode_video returns error, but after that it starts to return OK and the pictures 
are 2-3 sec old. Basically, it has some buffering now. Probably direct264 also had some extra 
changes related to that buffering. I'll check with x264 tool to see what settings I should use instead.



> The presets in ffpresets/libx264* in the ffmpeg source tree show
> command-line examples of how to set sane x264 settings.  The "default"
> preset has what used to be the x264 defaults, though it is now
> slightly inaccurate since the x264 defaults changed to High Profile.
> > By the way, are the any info on running x264 on wince devices? Is there arm optimized code, or x264 is x86 only?
> You're asking at a good time--in a day or two now we will be
> committing the results of one of the two successful Google Summer of
> Code projects this for year--ARM support and assembly optimizations
> for NEON SIMD.  This should vastly improve performance on Cortex A8
> and Cortex A9 ARM chips, allowing for high-performance mobile encoding
> at ultra low power.
> Dark Shikari

When I updated I compared differences between libx264 and direct264 and my changes to x264 and I noticed that there is some arm specific stuff.
Probably, google with their android os should be interested to have high performance h264 lib for arm.
What about decoding of h264: ffmepg has it's own decoder. Is there decoder in x264, or it's encoder only? ffmpeg has arm optimized decoder and 
I even was able to play a video stream from my camera on my mobile :)