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Video streaming trade off.

David Ziv
Intellectual 420 points
Other Parts Discussed in Thread: CC3200

I'm trying to develop a video streamer based on CC3200 and Camera boost.

VGA format, the Camera web socket application, note that max frame rate is 5fps, and 200mSec of delay.

What is causing the delay 200mSec and why only 5fps?

Thanks

  • 0
    Prodigy 10 points
    Hello, I am confused ,too.
    I have not used MT9D111 before. However, captured by OV2640, a JPEG picture in VGA soulution is 20~30 KB per frame . And CC3200 can transmit at a speed of 6Mbps. If so, its frame rate should reach at least 24 fps.
    Due to I don't have any camera module now, I can't test :(
  • 0 in reply to Shen
    TI__Expert 7215 points

    Hi,

    Sorry for the confusion. Let me explain. 

    5fps is experimental result for websocket camera application but it might be different based on how camera sensor,DMA is configured. Let me point to certain delays inherent to websocket camera application:

    1. CC3200 uses DMA to read data from Camera Module. Camera FIFO is 64 words so DMA setup is required for every 256Bytes of frame data. This will cause some delay in reading the VGA frame. So fps might not be same as mentioned in sensor datasheet.
    2. Another important aspect is that, in websocket camera application, sensor is started and stopped for every captured frame. Stopping it for every frame also impacts to fps.

    Also Camera Sensor PLL clock is set to 40MHz which it can be increased to upto 80MHz, which will result in 10fps. Also Camera XCLK can be increased to get better fps. But application need to ensure that enough CPU cycles are available for DMA configuration for a stable operation.

    Also application can let sensor running when it is sending data to increase the overall fps. Obviously it will need more buffer and synchronization.

     

  • 0 in reply to Kaushal Kukkar
    TI__Expert 6700 points
    Hi David,

    Did the above post answered your query? If so please press the verify button to close the thread.

    Thanks and Regards,
    Praveen
  • 0 in reply to Praveen Kumar N
    Intellectual 420 points

    The trade off are clear, is there throughput/BW estimation?

    Assuming I'm using best camera sensor with max clock (120MHz) and 1600x1200 resolution. (Fifo 64 byte)

    What will be the potential frame rate?

    Thanks

  • 0 in reply to David Ziv
    TI__Expert 7215 points

    Hi David,

    CC3200 supports I/O toggling upto 60Mhz. So one can't go beyond this clock speed.

    Also Maximum PCLK is 48Mhz.

    Given above, The frame rate will depend on how fast MCU can read from camera sensor. It will depend on how DMA is configured and how much CPU instructions are required for DMA setup.

    Not sure If above answers your query but point is that one need to profile it at different PCLK and at different resolution. 

    Currently I don't see we have such throughput/BW estimation for this particular use case.