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PAL frame-rate control

ranchu
Guru 20755 points
Hello, I would like to ask your help in understanding how the frame-rate of 25 fps is achieved in RDK chain of capture-encode, and capture-display. I see in demo_vcap_venc_vdis.c, a call to Venc_setInputFrameRate with parameter 25 fps for PAL case, But I don't find a control rate for Vcap & Vdis for 25 fps. Can someone give me a pointer how this is done ? Best Regards, Ran
  • 0
    TI__Expert 5615 points

    Ran,

    The encoder must know what is the frame rate. It is one of the inputs to the rate control mechanism.

    Regards,

    Yair

  • 0 in reply to Yair Hougui
    Guru 20755 points
    Hi Yair, Thanks for the reply. There is a way to control the capture frame rate too. It is achieved by skipping frames in the capture driver. In MCFW user's guide it is said in the section "Progressive / Interlaced McFW Usecases" : "Secondary output fps can be controlled using Vcap_setFrameRate(). Any random frame rate is not supported ." Yair, Is the primary output can also be controlled with Vcap_setFrameRate ? Regards, Ran
  • 0 in reply to ranchu
    TI__Guru**** 476595 points

    Hi,

     

    No, display does not suppor frame rate controlled. This can be only controlled by not providing frames in time to the display driver in which case display will repeat the frames causing frame repeat and ultimately kind of frame skip for display. Frame skip is supported in the capture by not capturing those frames, but this cannot be done in display since if we skip frame, you will blank frames which is not acceptable.

     

    Thanks,

    Brijesh Jadav 

  • 0 in reply to Brijesh Jadav
    Guru 20755 points
    Hi Brijesh, One more thing I would like to understand please, does the display will repeat the last frame in cases such as video hang input and case of hang of bitstream to decoder (in decoder->display usecase). Are there other cases when the display will output black screen ? Thank you very much, Ran