AW: AW: AW: Serial port interface on frame grabber

[vk_gst]

Hi James,

1. I managed to dig a bit deeper and tune the following elements: filesrc,
filesink, imxvpuenc_h264, avdec_h264. With this tuning, and the usb-serial
adapter(cable) and a baud of 19200, I managed to stream the video from imx6
board to PC. However, the latency is very high, approx. 5-6 seconds with
19200 Baud. At the receiving side, the video frames looks stuck and the
transition of frames is quite slow. 
The whole latency reduced when I configured the Baud at 1MBaud.

2. I still have to try this out on the custom modem we have here. The
maximum baud I can configure for the custom modem here is around 1M Baud,
however the effective Bandwidth available  for video will be around 25Kbps.
So I do not think the video latency will be any better as compared to 19200
Baud.  Do you have any suggestions to speed this up.

3. I am posting the commands below which I used to get the video working
through serial port. May be you can have a look and suggest me if I can fine
tune it more.

imx6: 
gst-launch-1.0 -v videotestsrc pattern=18 ! video/x-raw,width=100,height=50
! imxvpuenc_h264 bitrate=5 ! h264parse ! filesink location=/dev/ttyUSB0
blocksize=1024 max-bitrate=19000 sync=false

PC:
gst-launch-1.0 -v filesrc location=/dev/ttyUSB1 blocksize=1024 ! $CAPS !
h264parse ! avdec_h264 lowres=2 skip-frame=0 ! autovideosink sync=false


4. I was also wondering if I could add a buffer on the receiving side, so
that the video is more smooth. Although I completely understand, that the
buffering up video data will result me in getting old video frames and not
the real time video frames. But I would just want to try out if its possible
to do that.  Does gstreamer allow any elements like a pseudo RAM where I can
buffer up the frames and play it after some initial delay, so that the
resulting video is smooth?





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