Other Parts Discussed in Thread: DM3730
I'm trying to benchmark H264 encoding performance on an OMAP3. The goal
is to do real time live network streaming with low latency for a video
conferincing type application.
I'm running on an DM3730.
I'm using Linux kernel version 2.6.32 with gstreamer 0.10.36
and the gstreamer-ti_svn.bb recipe from openembedded
classic (0b667441e530865a5b93b0b412b7fdd9be48ba63 from
git://github.com/openembedded/openembedded.git) (which uses svn srcrev
822 from svn://gforge.ti.com/svn/gstreamer_ti/trunk)
My gstreamer pipeline is "v4l2src ! queue ! dmaienc_h264 ! fakesink"
To do benchmarking, I've inserted an identity filter before and after
the dmaienc_h264, and have connected to the "handoff" signal. This way,
I can tell how much time dmaienc_h264 spends processing a buffer.
My v4l2src is a real camera, with a real world scene that is relatively
static. The camera always produces frames at 30fps, UYVY.
When running at 320x240 (v4l2src ! video/x-raw-yuv,width=320,height=240
! ... ), things go well, and dmaienc_h264 takes anywhere from 3.7ms to
15.5 ms per frame.
When running at 640x480, however, things don't go so well. dmaienc_h264
takes anywhere from 30ms to 52ms per frame, and cannot keep up with real
time encoding requirements. If I omit the queue, frames get dropped,
which violates other requirements for this project.
My baseline encoding settings are "dmaienc_h264 intraframeinterval=4
ratecontrol=1 encodingpreset=0 targetbitrate=700000", although I have
tried a number of variations to get that encoding time to come down,
without success.
So here are my questions:
Is this behavior expected? If it is not expected, what am I doing wrong?
How can I get real time low latency H264 encoding at 640x480?
