Duncan Webb wrote:
>> Duncan Webb wrote:
>>> Hi all,
>>>
>>> I've been noticing some quality issues with ivtv over the last months or
>>> so and am wondering if anybody else has the same issues.
>> One other observation is that the default Video standard is now
>> 0x0000000f whereas it was 0x000000ff. Will this have an effect on the
>> quality?
>>
>> I've not yet had time to see if the default setting make a difference
>> with the quality of the picture on the PVR-500.
>
> Sorry to reply to my own post yet again.
>
> I think that I've found why the picture quality is poorer with the PVR-500.
>
> The temporal_filter is being set to 8.
>
> The question is why, as I've not yet tracked down the reason. It's quite
> possible that I've screwed up something in my own code mapping the old
> codec information to the v4l2 external controls.
>
> Is it possible that the driver sets the temporal_filter during other
> operations, such as set format?
>
> Why is this only being set with the PVR-500 and not with the PVR-350?
Well this is pretty obvious why when I determined that it was
VIDIOC_S_FMT call that was changing the temporal_filter.
in driver/ivtv-ioctl.c
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 18)
if (itv->params.width != 720 || itv->params.height !=
(itv->is_50hz ? 576 : 480))
itv->params.video_temporal_filter = 0;
else
itv->params.video_temporal_filter = 8;
#endif
Any reason for the temporal_filter being over written?
Duncan
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