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Gstreamer video sink: bad color depth, color banding?

Question asked by David Kosir on Dec 16, 2013
Latest reply on Jan 15, 2014 by David Kosir
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We are trying Sabre Lite (i.MX6Q) with provided Ubuntu image (3.0.35_4.1.0 kernel), connected to HDTV with HDMI, 1920x1080@60,if=RGB24.

Gstreamer pipeline we used is simple and its reproducible with h264 or mpeg2 videos (probably any video but we didn't test others).

 

gst-launch-0.10 filesrc location=path/to/file typefind=true ! aiurdemux ! queue max-size-time=0 max-size-buffers=0 ! vpudec ! mfw_v4lsink

 

I've taken photos that show the problem and attached them. Please notice background color gradient and ignore bad photo quality as it was taken by phone.

Best description would be that video sink has poor color depth, there is effect of color banding.

Same video, when played on PC, doesn't have such issues.

 

We have tired to find root of the problem, as for now we have managed to conclude that it is not display or decoder problem:

We have tested 3 different TV models and one monitor, and all display same issue.

We have dumped raw video (after decoder) to file and played it on PC, there where no such issues.

 

While writing this, we have added bpp=32 to 1920x1080@60,if=RGB24 boot arguments and it looks a better, but still not good as same video displayed on PC monitor or TV decoder.

That might lead us to root of the problem.

 

Also, there are topics that touched this problem but never received proper answers:

GStreamer i.MX6 Multi-Overlay

Color banding in video using mfw_isink with GStreamer

 

Any ideas?

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