Hello,
We are having a problem where the video input captured from NTSC
sources, while appearing correct, is actually shifted down by 4 scan
lines (2 lines for each field), with blank or garbage lines appearing at
the top. This issue does not occur for PAL capture.
In the past, we worked with TI DSPs such as the DM642, connected through
the Video Port to a Philips or TI video decoder chip. The software used
the TI VPort driver under DSP/BIOS. Under this system, the issue was
easy to overcome: To configure a video port, one had to fill in a struct
of type VPORTCAP_Params. The fields fldYStrt1, fldYStrt1, fldYStop1,
fldYStop2 controlled exactly which lines of the video were to be
captured. We set these values to {1, 1, 240, 240} respectively for PAL
and increased all four values by 2 for NTSC, and the capture worked well
- the garbage lines on the top were removed, and 4 lines of valid video
were captured on the bottom.
Unfortunately, with the DM6446 chip and the Linux V4L2 environment, I
cannot find the equivalent parameter anywhere. I have looked in the
capture driver source code, with no luck. Various attempts to change the
parameters given to the capture system, such as changing
v4l2_format.fmt.pix.height, gave nothing but errors. Does anyone have a
clue?
Thank you,
-itay
--
Itay Chamiel
Software Engineer
Mango DSP
itayc at mangodsp.com
_______________________________________________
Davinci-linux-open-source mailing list
Davinci-linux-open-source@linux.davincidsp.com
http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
