Chip to convert PAL 720x576i to RGB 24-bit Parallel

Hi everyone,

What would be the best solution to convert a CVBS (PAL) signal into a parallel RGB888 ? 

I was expecting to use the ADV7186 but it is under NDA. After some reading of this forum, I often see the ADV7842 / ADV7844 as a solution but I am not sure about the compatilibty of the input signal (PAL 720x576i@50Hz).

If it is compatible, what latency may I expect between the input signal and the output signal (latency induced by the conversion chain) ?

If it is not, is ADI has a solution ?

Best regards,

Viony

  • The ADV7842 can do PAL to RGB888 conversion.  Latency will depend on what features you have turned on in the ADV7842.  For example if you want to use 3D comb filter you may have a 3 line delay.  While not using this feature the delay might be about 50 -100 pixel clocks worth.  It all depends on which features are turned on.

  • Thank you for your answer GuenterL.

    So you do confirm that my PAL 720x576i is compatible to output an RGB 24-bit in parallel ? Shall I (or May I) use the Interlace-to-Progressive feature ?

    Is there any device from ADI that allows to make video scaling of this output video and overlay support (basically what the ADV7186 does) ?

    Best regards,

    Viony

  • 1) Yes, you can use the Interlace to Progressive module.  It will have at least one line of delay.

    2) The ADV8005 allows both active video and OSD overlays.  I suspect it would be overkill for your application.  Not sure what you system looks like.

  • Thank you for the information.

    Regarding the system I am looking for :

    PAL 720x576@50Hz -> Chip to decode PAL & output RGB 24-bit parallel -> RGB to LVDS -> LCD

    Today with our current discussion the chip that could be used is the ADV7284 but ideally, since my LCD resolution doesn't match the PAL resolution, I would like to upscale it. I would also like to add an icon on this video (overlay).

    Regarding the ADV8005 after reading quickly its datasheet I assume I'll have to output via HDMI, which doesn't fit my need. Probably I'll to add an FPGA to achieve the upscale and the overlay.

    Viony.

  • Any time you scale a format, it adds a lot of complexity. Pixels and line counts change along with timing.  I'd still use the ADV7842 and feed it's output to an FPGA to add the other features you need.