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Latency for YUV422 to RGB conversion

sweta bhatt
Expert 2345 points

Hi,

Does anyone know what is the latency for YUV422 to RGB conversion for 720p or 1080p frame ? We use ezsdk_5_03_01_15 as reference.

Thanks,
Sweta

  • 0
    TI__Mastermind 20245 points

    Hi,

    How are you doing that. Which path are you using for doing YUV to RGB conversion. Capture driver on V4L2/Open Max etc.

    Regards,

    Hardik Shah

  • 0 in reply to HardikShah
    Expert 2345 points

    Hi Hardik,

    We need to take care of this in our design. Right now, I just need information for latency of both ways (V4L2 based capture and Openmax based).

    This is for a customer inquiry, we are at proposal stage. After getting better numbers, decision will be made on design front.

    Latency is main factor for this.


    Regards,
    Sweta

  • 0 in reply to sweta bhatt
    TI__Guru** 116170 points

    Shweta,

    The YUV422 to RGB conversion can also be done on the DSP. On the DSP YUV422 to RGB conversion with cache enabled takes about 12 clocks/pixel including the IPC overheads of ARM calling the DSP. This number has further room for improvement with use of EDMA on the DSP.

    Regards,

    Rahul

  • 0 in reply to Rahul Prabhu
    TI__Mastermind 20245 points

    Hi,

    My points may not make sense to you because I am not fully aware of your use case. Better to describe the full case and then ask for specific questions.

    1. You can get RGB out from capture driver.

    2. RGB can be displayed using only the grpx pipeline of HDVPSS.

    3. There  is no openmax component for grpx driver. So you will have to develop openmax component and latency from capture will be same as capture to display in EZSDK. You can find latency figures at http://processors.wiki.ti.com/index.php/Latency_Measurement_on_Capture_Encode_Decode_Display_Demo

    4. Another option is to use V4L2 capture + FBDEV and with this you may get slight less latency because of fbdev is not a queuing model. We have not measure exact latency here as of now.

    5. If you are doing any processing on RGB data than you have to add that latency to the above figures.

    Regards,

    Hardik Shah