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Playback always seems to be yuv422 for SDI 4K

PostPosted: Thu Oct 12, 2017 2:52 pm
by Sunrise Wang
Hi,

Apologies if this has already been asked before, I tried searching and couldn't find anything.

When playing back from the DeckLink SDI 4K, the output always appears to be yuv422, even though I've set the playback to something like rgbx10 (including performing the relevant conversions). I found this out when I was feeding the output of the card directly back into the input, the auto input detection was always picking up the signal as yuv 422, and playing it back correctly.

Is there an automatic conversion that happens somewhere? and is this a card specific thing? If so, is there a way to configure this somewhere so that this conversion doesn't occur?

Thanks in advance for your help

Re: Playback always seems to be yuv422 for SDI 4K

PostPosted: Thu Oct 19, 2017 7:17 am
by Cameron Nichols
Hi Sunrise,

Can you detail the output display mode you are using? Be aware that only YUV modes are supported outputs in NTSC/PAL/2160p/4K video formats. You can check either by running DeviceList sample application or via DoesSupportVideoMode method[1].

Kind Regards
Cameron Nichols

References
[1] DeckLink SDK manual - 2.5.3.1 IDeckLinkOutput::DoesSupportVideoMode method

Re: Playback always seems to be yuv422 for SDI 4K

PostPosted: Thu Nov 02, 2017 1:10 pm
by Sunrise Wang
Hi Cameron,

Sorry for the late reply on this. My current setup is as follows:

-I enumerate all of the modes, and for each mode use DoesSupportVideoMode to check if the pixel format + mode combination is supported. If they are, I add them to a list which I can later use to select the mode + pixel format to run.
-I feed the playback of my capture card back into the capture slot, and start the capture with auto detect enabled
-Regardless of what pixel format/mode combination I use, the captured signal is always either yuv 8 bit or v210.

DoesSupportVideoMode seems to return bmdDisplayModeSupported for the rgba and rgbx10 formats for most modes as well. My capture card is a SDI 4k.

Thanks a lot for your help!
Sunrise

Re: Playback always seems to be yuv422 for SDI 4K

PostPosted: Fri Nov 10, 2017 7:35 am
by Cameron Nichols
Hi Sunrise,

Can you let me know which video mode and pixel format you are targeting on output?

Kind Regards
Cameron

Re: Playback always seems to be yuv422 for SDI 4K

PostPosted: Mon Nov 13, 2017 7:35 am
by Sunrise Wang
Hi Cameron,

So this was happening with all modes an pixel format combinations, but for the sake of testing, rgba with 1080p60 should be enough to replicate this.

Thanks for your help
Sunrise

Re: Playback always seems to be yuv422 for SDI 4K

PostPosted: Mon Nov 13, 2017 1:28 pm
by Sunrise Wang
Oh apologies, so 1080p 30, since I believe I can't do 60fps with 4:4:4 rgb enabled (which I assume allows me to output in rgb mode?)

Re: Playback always seems to be yuv422 for SDI 4K

PostPosted: Tue Nov 14, 2017 1:25 pm
by Sunrise Wang
Hi Cameron,

I found the cause of the issue, thanks for the help! It turns out the mini converters were converting my formats to yuv for some reason.

Thanks,

Sunrise