[FFmpeg-devel] [RFC] FFmpeg libavcodec/crystalhd.c: Optimize for reduced latency

[Philip Langdale]

On 2013-02-06 08:12, thomas schorpp wrote:

> Please test and confirm, can anyone test if this crystalhd decoder
> works with Bino now
> (h264_crystalhd codec force patch is in the Bino bugtracker, without
> Bino takes the FFmpeg h.264 software codec),
> did not work here with Philip's timing, only still pictures on
> seeking and Bino decoder timeout messages,
> it's always crashing in assertions for XCB(?) at GUI actions on my
> debian stable/bpo environment.

I can't test with Bino but mplayer seems to be working as well as 
before.

Note that your kernel driver patch is buggy - it breaks suspend because 
the
suspend call into the driver fails if the device is not decoding when 
you
suspend (There's no hw_ctx).

> I'm investigating the broadcom libcrystalhd3 for possible
> optimizations now, but FFmpeg performs at 30fps already
> using
> ffmpeg -c:v h264_crystalhd -i test.1080p.x264.mp4 -an -f rawvideo -y 
> /dev/null
> This should be the maximum hardware performance anyway.

Yeah, improving the library may help with CPU consumption but it won't 
speed
up transcoding. And transcoding with this hardware is a terrible idea 
because
of the wasteful colourspace conversions anyway :-)

> y
> tom
>
> Patch v0.6 against debian ffmpeg-dmo-1.0.1 attached, sorry git HEAD
> breaks to many apps on debian stable/testing(?),

I thought debian didn't have a proper ffmpeg package anymore. I've lost
track of what's going on there.

Anyway, I'm happy to merge these changes once you're satisfied with 
them.
Seems like a clear improvement at this point.

--phil