Video processing

Hi,

Can anyone please give me any direction concerning the following?

I have a video front-end on my platform (TVP5150) that produces normally YUV
parallel data. Because I also need the video lines that are outside the
visible frame (teletext data), I have to switch to raw video data to have it
all. Both the iMX27 (multimedia arm) and TVP5150 do support RAW video.

Normally the process syncs on the YUV data (SAV, EAV markers in the record),
but in RAW mode I guess I need the external horizontal and vertical sync?

Do you have any experience with this, or any hints to get it up and running?

--
Maarten

Silver
Fri Jun 06 10:43:17 PDT 2008

RAW - do you mean RGB?
I have used this part, but not with a freescale, only with TI parts. If
memory serves me correctly the teletext data uses a different data path to
the video data, essentially you get a YUV422 video stream with H/V syncs
embedded and a Teletext stream completely independently of the video, the
TVP5150 strips the teletext out of each frame so you do not have to.
I can only assume that at this point you want to do something with the
teletext then send it back out of the mx21.

Is it something like this?
TV signal -> TVP5150 - YUV -> MX21 (manipulate video data) -> TV

(I may have suggested this before, kinda deja vu), instead of shifting into
RGB space then rendering back to YUV why not just render the modified
teletext data as YUV? Teletext is only a couple of lines per frame, (about
90 bytes total per frame ).

e.g. Take the 2 lines of 'RGB' teletext data and convert to 2 fields of YUV
then copy it into the RAM where the frame is stored, not disturbing the
syncs of course. Then send the frame on its merry way - allow the mx21
hardware to do all other conversion on the video signal such as converting
to RGB.

Perhaps I am missing something important, such as what you are really trying
to accomplish, like the bigger picture.


Geoff
--

Maarten
Sat Jun 07 00:07:00 PDT 2008

Hi Silver,

unfortunatly the teletext slicer from the TVP5150 has a to low bandwidth.
With its to small internal buffer and I2C as the datapath, it is much to slow
to handle (european) teletext.
Now I read the datasheet again, I may be wrong with the function of the RAW
mode The raw mode of the TVP is described as : 'The TVP5150AM1 decoder can
output raw A/D video data at 2x sampling rate for external VBI slicing. This
is transmitted as an ancillary data block during the active horizontal
portion of the line and during vertical blanking.'

Could this mean that the outputformatter (ITU656) still does its work and
you have ADDITIONALLY the VBI data? This could make it easier, but still I
might need some help to solve this under CE.

--
Maarten


"Silver" wrote:

> RAW - do you mean RGB?
> I have used this part, but not with a freescale, only with TI parts. If
> memory serves me correctly the teletext data uses a different data path to
> the video data, essentially you get a YUV422 video stream with H/V syncs
> embedded and a Teletext stream completely independently of the video, the
> TVP5150 strips the teletext out of each frame so you do not have to.
> I can only assume that at this point you want to do something with the
> teletext then send it back out of the mx21.
>
> Is it something like this?
> TV signal -> TVP5150 - YUV -> MX21 (manipulate video data) -> TV
>
> (I may have suggested this before, kinda deja vu), instead of shifting into
> RGB space then rendering back to YUV why not just render the modified
> teletext data as YUV? Teletext is only a couple of lines per frame, (about
> 90 bytes total per frame ).
>
> e.g. Take the 2 lines of 'RGB' teletext data and convert to 2 fields of YUV
> then copy it into the RAM where the frame is stored, not disturbing the
> syncs of course. Then send the frame on its merry way - allow the mx21
> hardware to do all other conversion on the video signal such as converting
> to RGB.
>
> Perhaps I am missing something important, such as what you are really trying
> to accomplish, like the bigger picture.
>
>
> Geoff
> --
>
>