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AD9889 and 1080p30 Problem

Hello,

I am using an AD9889, sucessfully transmitting 720p60 signal.

Now I tried to send 1080p30. The Video Timing is set according to CEA-861-D (verified with a scope)

The PLL is locked and I can verify the AD9889 is sending clock and data.

The AD9889 correctly recognizes the format as VIC 34, and also claims that it sends this code to the TV.

However the TV says: "Invalid Format"   (as opposed to "No Signal", which it displays when i try to send 720p30 CEA-861-E)

According to the EDID the TV supports 1080p30, VIC 34  ( it does not list 720p30 in the EDID).

720p60, 1080p30 and 720p30 all use the same videoclock of 74,25MHz.

I am not using HDCP.

Has anyone an idea why this happens ?

Is there, maybe,  anything on the ASD9889 to be setup differently for 720 vs. 1080 or 60vs 30 fps ?

Many Thanx

Ernst

  • Hi Ernst,

    Have you driven the TV directly with the same source? Or tried a different TV? What is the make and model of the TV?

    There are a remarkable number of interoperability issues with HDMI sources/sinks.  It doesn't sound like anything is verifiably wrong so this might simply be an issue like that.  Just because the EDID mentions the format sadly does not guarantee it's actually supported.  1080p/30 is a rare enough used format that this could be the case.

    Dave

  • Hello Dave,

    thank You for the quick reply.

    The source is always the same board.

    First I had a SONY KDL26P3000. This one displayed the 720p60 fine, but balked on the 720p30 and 1080p30 - it said "Out of Range"; according to the  datasheet it only supports 48-62fps. I did not try the 1080i on this one.

    So i was looking for an alternative and found the LG 22LE5500. It is explicitly advertised as supporting Cinema mode (well, maybe they mean 1080p24 only). The datasheet says: PAL/SECAM/NTSC, HDTV (480p -1080p @24fps, 50fps, 30fps,60fps, VGA~SXGA)

    Thought from the EDID it is clear that it does not support all possible combinations of these.   There are 1080p24, p25 and p30 in the EDID (these are mentioned as the CEA-861 VICs)  There are no detailed Timing records for the low framerates in the EDID.

    You are absolutley right that p30 is seldom used, but then it also does not like my 1080i (it could be that there is something wrong on my Videoprocessor setup, i will verify the SYNC signals in the VSYNC/Field signaling area more thoroughly)

    I was also playing around with sync pulswidth and Hsync/VSync  front offset; depending on settings I get "No Signal" or "Invalid Format". Interestingly the AD9889 still recognized some of these, even when the TV said "No Signal".  So, seems the AD9889 is a bit more forgiving.

    Is there another table of commonly used setups beside CEA-861 ?

    By the way if You know a good reference TV supporting p30, please let me know.

    Or maybe there is an HDMI receiver Evaluation Board available from AD which would allow me to better diagnose the problem ?

    It is very helpfull to get a confirmation, that the AD9889 does not need some special setup for 720 or 1080 or 30 and 60fps ( I could not find it in the programmers guide, anyway ...  - I have Rev. A, is this the latest ?)

    Best regards

    Ernst

  • I solved the Problem.

    I have to set the numer of active pixels to one less than 1920, then the LG happily displays all 1080 formats (i60,  p30, p25and p24).

    When i use 720p it accepts 1280 and 1279 pixels per line.

    Question remains:

    Is this a bug in the Videoprocessor specs (in some places,. e.g the horizontal interval,  it takes one less than the number of pixels ? ( I already see myself before the storage scope, counting pixelclocks ...)

    Or a bug in the monitor ?

    Or a bad timing problem, maybe a SYNC a bit too early or late ?  but why not on 720p ---  all the formats I use, use the same pixel clock ..

    Best

    regards

    Ernst

  • Hi Ernst,

    Honestly it could be any of those.  This is why there are HDMI plugfests to test interoperability.

    The AD9889B doesn't really care what you send it-- it'll send out whatever it gets.  The probably is more complicated on the receiver side in the display when it has to decide how to display the image.

    Of the TVs in my lab, only 1 of them will display 1080p/30.  It's an older Panasonic model.  I never trust the EDIDs on general principle in terms of capabilities but TVs have been getting steadily better about having reliable EDIDs.

    Dave

  • This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

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    EZ Admin