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Passing SD and HD video to multiple outputs

Ashwin Bihari
Intellectual 430 points
Other Parts Discussed in Thread: TVP5151

In my custom application I have a requirement to route incoming SD and HD video to multiple outputs. The outputs are S-Video (in either NTSC/PAL) and the HDMI. The incoming HD video is going through a TVP70025 and into the DM8148 through VIN0. The incoming SD video is going through a TVP5151 and into the DM8148 through VIN1.

I know there are HD and SD compositors to do a bunch of work with the incoming video streams for output. There are indications in the DM8148 TRM that the HD compositor is only going to support HD output to either DVO1/2 or HDMI and the SD compositor is only going to support SD output to S-video/Composite. 

Is there any way that I can take a SD video input and send that video to both the HDMI and S-Video output? I would need to do the same for HD video in the future when that support is needed.

Currently, I'm  using framebuffers to display the video and I also am using a framebuffer to display a menu system using a Qt application.

So currently, I have /dev/fb0 mapped to HDMI for video and /dev/fb1 mapped to HDMI for menu. I get the correct output on the HDMI display. I will need to, in the short term, switch to use the S-Video as my primary output, so I will switch fb0 and fb1 to S-Video for the same purpose. Now my client requires that I send this blended content to the HDMI as well (regardless if it's a SD or HD incoming video).

My reading of the HDVPSS and how it functions so far seems to indicate that this isn't going to be possible, but can anyone confirm that?

  • 0
    Intellectual 430 points

    Anybody from TI willing to guess on this?

  • 0
    TI__Guru**** 477995 points

    Hi Ashwin,

    Well, DVO1/2 and HDMI can support SD resolutions, but to display HD frame on SD output, you will need to down scale the input image, in the same way, to display SD frame on HD output, you will need to up scale the input image. You could do by using one of scalars.

    Regards,

    Brijesh Jadav

  • 0 in reply to Brijesh Jadav
    Intellectual 430 points

    Hi Brijesh,

    I appreciate the response, and am glad that it's doable with a bit of effort. As someone stumbling through all the video stuff on the DM8148 right now, are there areny Wiki pages, E2E posts or anything that provide some guidance on how to handle/use the scalers?

    Also, would it be possible to configure it such that we can take HD or SD video on fb0 or video1 blended with a Qt application output on fb1 or video2 and sent to the scalers to appropriately up-or-downscale depending on what the incoming video is?

    My end goal is that I have incoming video that can be either HD or SD and I need to overlay a menu/UI elements generated by a Qt application and send the blended combination to both the HDMI and S-Video output. 

    As a worst case scenario, I could convince my client to just accept the up-or-downscaled video on the HDMI and the blended output on S-Video.

    I'm curious as to where the scalers would fit in the stack, if they can be setup pretty early in the path (before reaching the DM8148) then I imagine that the blending and me directing it to different places is no problem?

    Thanks

    ~Ashwin

  • 0 in reply to Ashwin Bihari
    TI__Guru**** 477995 points

    Hi Ashwin,

     

    Please use OMX component for the scalar. To get more infromation on OMX, please contact your local TI representative.

    Storing the output of the blendeding of video and grpx into memory is not supported.

     

    Regards,

    Brijesh Jadav