By Date: <-- -->
By Thread: <-- -->

Add V4L2_FIELD_ALTERNATE support to SAA7134

Hartmut Hackmann wrote: 
Hi, Chris

Chris Byrne wrote: 
- Adds V4L2_FIELD_ALTERNATE support to the saa7134 driver
- Fixed field swap in non-interlaced modes (bottom = top)

Signed-off-by: Chris Byrne <chris.byrne (at) monstavision.com>

<snip>

I must say:
I don't understand your second patch because at non-interlace,
top and bottom field are identical by definition.

Sorry, I wasn't being clear. By non-interlaced modes I am referring to non interleaving modes (e.g. V4L2_FIELD_TOP, V4L2_FIELD_BOTTOM) which only contain a single field. This is in contrast to say V4L2_FIELD_INTERLACED which returns both fields interleaved to create a single frame.

Perhaps I'm misunderstanding you but the top and bottom fields are not identical. There is a one line offset difference between them. Depending on your input it can be quite obvious when they are swapped.

How about:
- Corrected top and bottom fields being swapped when capturing fields instead of frames

But you should set the option noninterlaced=1 to saa7134.ko
We should make this the default, it can be left active at
interlace.

I'm unsure what this would accomplish. Setting this forces the field identification to toggle regardless of the input. Problem is that the fields are being misidentified in the first place.

I can imagine 2 reasons for your corrupted image problem:
- either a buffer collision
- or a DMA buffer overflow in the SAA7134 due to excessive
  load on the PCI bus. Note that there is a recovery algorithm
  that prevents total image corruption.

Ok, thanks. I'll have a look to see if the recovery algorithm is taking effect. It is just very strange that the same line is being corrupted on two different machines.

Thanks again,
 Chris

--
video4linux-list mailing list
Unsubscribe mailto:video4linux-list-request (at) redhat.com?subject=unsubscribe
https://www.redhat.com/mailman/listinfo/video4linux-list