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AM437x DSS feature

Michi Yama
Guru 10030 points

Hi, I have one question regarding AM437x DSS module.

My customer would like to resize te display data from VGA size to SVGA or XGA size.
Becuase LCD size will be changed from VGA to SVGA/XGA( Current customer model uses VGA LCD panel).

If new LCD panel(SVGA or XGA resolution) is conneced to current customer's system without resize of the display data, only a part of new LCD panel is used for displaying data. So cutomer would like the display data to resize from VGA to SVGA/XGA.

 I think AM437x's DSS has video Up/Down sampling features. I think display data can be resized by using this feature as hardware solution. But I don't know whether this feature is only adapted for video input data or not.

Please let me know.

I appreciate your quick reply.

Best regards,

Michi 

  • 0
    TI__Guru**** 161600 points

    Hi Michi,

    AM437x contains a video up/down sampling feature, see Section 13.3.3.3.4 Up-/Down-Sampling. Also check Video Path1 & Video Path2 in Figure 13-34. Display Controller Architecture Overview.

    The up & down sampling takes RGB24, RGB16, and YUV4:2:2 data from the memory & resizes it before passing towards the video output. So it is not for video input data only, but you need to pass the appropriate format to it.

    Best Regards,

    Yordan

  • 0 in reply to Yordan Kovachev
    Guru 10030 points
    Dear Yordan-san,

    Thank you for your quick reply.

    You said "The up & down sampling takes RGB24, RGB16, and YUV4:2:2 data from the memory & resizes it before passing towards the video output. "
    Regarding the above your commen, the belo my thought is right?
    * Input video data is also written in frame memory.
    * the up/down sampling feature in the DSS module is applied to the data in frame memory (DRAM).
    * In the above reason, up/down sampling feature in the DSS module can be used all display data including video data.

    Is the above my understanding right?
    Is this up/down sampling feature in the DSS module, is this applied only to AM437x? Or other processor like OMAP, DRA7xx also are same ?

    I appreciate your kindly support.

    Best regards,
    Michi
  • 0 in reply to Michi Yama
    TI__Guru**** 161600 points

    Hi,

    Michi Yama said:
    Regarding the above your commen, the belo my thought is right?
    * Input video data is also written in frame memory.
    * the up/down sampling feature in the DSS module is applied to the data in frame memory (DRAM).
    * In the above reason, up/down sampling feature in the DSS module can be used all display data including video data.

    My understanding is the same.

    Michi Yama said:
    Is this up/down sampling feature in the DSS module, is this applied only to AM437x? Or other processor like OMAP, DRA7xx also are same ?

    OMAP & DRA7xx devices have a scaler unit, which can perform up & down sampling, but the implementation of the DSS & the scaler unit is different from Sitara (AM437x). Because the DRA7xx devices are NDA only, I cannot share more info on their functionality & features.

    Best Regards,

    Yordan

  • 0 in reply to Michi Yama
    Expert 1510 points

    If you are using linux (either SDK 7.1 or SDK 8.0), there are example applications the demonstrate DSS scaling, color space conversion, and blending. The demo app takes 2 camera input streams (usually at 800x600), and uses the DSS to resize them (anywhere from 640x480 to 1920x1080), and blend them together with a GUI.

    Here is the source for the fbdev based demo.

    Also take a look at the Sitara Linux SDK DSS page. It has some good information even if you aren't using linux.

    Note that AM437x has the equivalent of an OMAP3 DSS, except that it is missing a few features (like rotation). Otherwise, scaling, color space conversion, and blending are all still there.