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CVBS TV encoder on i.MX53

Question asked by Mlinux L on Feb 5, 2015
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I'm using two kernel version (3.12 and 3.16) and currently i have got correct VGA analogue video output from TVE encoder on both version of kernel.

I need to say that i have also got correct CVBS video output over 16bit RGB565 parallel display and ADV7393 external video encoder, but this is not my goal (picture in this solution is not so good, have some glitches and additional cost).

These days (actually months) i'm trying to get CVBS video output from internal Television Encoder TVEv2.


I have patched DTS, TVE, Display Interface (DI), Display Processor (DP), Display Controller (DC), some other files and i get strange not synchronized video on CVBS output.

At first, i have got CVBS from TVE Internal Color Bar Generator and everything is ok. So hardware is ok.

Then i got picture from framebuffer with wrong colorspace (RGB24) and after my patch i have got correct color space (YUV444) from Display Processor (DP).

The trouble is that i can not get appropriate synchronized picture.

It only displays the first line 90' rotated picture of the framebuffer and Extend it all over the display or i get some similar problems with synchronization.

I write colorbar test picture to framebuffer with "root@imx53: fbv /home/pic/Bars_720_576.png"

When i use VGA mode from DI1 everything is ok, even with parallel display from DI0.

The last few weeks i am doing the same, i do not know what else to do, i've tried everything.

I do not quite understand the synchronization between DC and DI, i think there is a mistake somewhere.

Maybe i have wrong pixelclock (13.5 MHz), HSYNC (15.6 kHz), VSYNC(50Hz), resolution 720x288p@50 (it is nor real interlaced format), wrong picture format (YUV444), wrong any other sync clock i don't know..

Do you maybe have any experience with CVBS video output and can you help my in any way?

At least to give me some instructions where it could be a mistake. Anything would be helpful.

I have attached some picture from my video output to this message.

- I i'm not sure does TVE CVBS can work with YUV444 or only with YUV422 video format. According to datasheet it can operate with both 444 and 422 formats?
- Also i'm not sure can TVE CVBS work with progressive video input and internally enabled progressive to interlaced conversion or strictly need interlaced video format for this video mode?

- Because my video source is in YUV format, can i patch framebuffer to receive YUV444 instead RGB16 so i do not need colorspace conversion from YUV to RGB in my gstreamer pipeline (aplication) and do not need to spend extra CPU resources for sending video to fbdevsink plugin? In this case i can also disable DP RGB->YUV conversion.
- Has anyone ever got CVBS on any kernel version? I suppose that it should be working on LTIB 2.6.35 kernel, but what is with newer kernel version?


As you can see i have a lot of questions and help from freescale experts..



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