Re: saa7146: please test the vb2 conversion!

[Stefan Herdler <herdler@nurfuerspam.de>]

Hi Hans,

I'm sorry for my late replay, but it was quiet troublesome to build
a kernel with the patch, also running on the rest of my hardware.


On 24/03/23 22:21, Stefan Herdler wrote:
> Hi Hans,
>
> great to read, that it is finally done, thank you for your work!
>
>
> On 24/03/23 11:40 Hans Verkuil wrote:
>> On 24/03/2023 11:37, Hans Verkuil wrote:
>>> Hi all,
>>>
>>> I finished the vb2 conversion and tested what I could test. I am missing
>>> 'full featured' hardware, so I could not test the analog video capture part
> There is some miss understanding.
> At VDR 'full featured' refers to all DVB-cards with decoder and OSD.
>
> I wasn't aware, that this definition doesn't seem to be common, sorry.
>>> of that. It's not clear to me if VBI capture is also supported on those
>>> cards, if so, then that needs to be tested as well.

I have talked to the "cable-guys" and they didn't know about VBI capture.

The whole analog capture of this cards was never very popular with VDR.
The signal had to be encoded on the fly, this was never reliable as the
PVR-cards with encoder.

I think it is o.k. to leave it untested.
>>>
>>> Note that there is one userspace-facing change: the VBI output settings
>>> are kept, even if the vbi device is closed by the application.
>>>
>>> Before you had to open the vbi device, format the slice VBI output, and
>>> write sliced VBI data to it. Closing the device would reset how VBI output
>>> behaves. That is not in spec with the V4L2 API. The format is kept after
>>> the device is closed.
>>>
>>> Any application that uses VBI output and that wants to keep the same
>>> behavior would have to call VIDIOC_S_FMT with a struct v4l2_sliced_vbi_format
>>> with a service_set field set to 0 to indicate that you don't want to
>>> output any VBI anymore.

VBI output is used to switch the aspect-ratio via WSS.
this should be supported by any av7110 card.

The software is run a daemon or plugin, so the userspace-facing change
shouldn't matter.

I'll test this as soon as possible.




I've done only basic testing so far, but unfortunately it already failed.

The test:
Switch to a channel[*] and view the decoded video with tvtime.

The resulting picture is corrupted.
Almost green with some pink traces at the outlines.

It reminds me to YCbCr component-yideo on a RGB-input.
Maybe the input-format of saa7146 not set correctly?

The OSD is equally affected, but the card seems to run stable.



* I used VDR for this, but it shouldn't matter.

Regards
Stefan

>>>
>>> If this is a problem, then I can make a module option that selects the old
>>> behavior.
>>>
>>> BTW, if anyone has a spare full-featured card (i.e. with analog video capture
>>> as well), then I would love to take it off your hands so that I can test that
>>> myself!
> There are only DVB-C boards with analog features.
>
> I personally never had cable-TV nor own any DVB-C cards.
> But I try to find such a card with an analog module on it.
>>>
>>> This series has been tested on the two Hexium boards, the mxb board, and two
>>> av7710 boards (DVB-C and DVB-T).
>
> I can test on the DVB-S hardware.
>
> But let me finish the API-documentation fist, it is almost done.
> There are only the complains from chackpatch left to fix, I hope it is done quickly.
>
>
> Regards
> Stefan
>
>
>>
>> It does help if I point to the patches :-)
>>
>> The patch series is here:
>>
>> https://patchwork.linuxtv.org/project/linux-media/list/?series=10140
>>
>> It's also in my git tree:
>>
>> https://git.linuxtv.org/hverkuil/media_tree.git/log/?h=saa7146-clean
>>
>> Regards,
>>
>> 	Hans