[Openchrome-users] interleave problem with openchrome driver with SP8000 and TV out

[Ivor Hewitt]

On Monday 28 November 2005 15:13, druyts pascal wrote:
> I noticed a strange distortion problem on the TV output on a epia SP8000.
> The problem looks like an interleave problem, but the strange thing is that
> the MPEG stream is not interleaved and does not present any distortion.
> Even stranger, when pausing the movie, the image is flickering, I am not
> sure of what is going on, but it could be that odd and even lines are
> getting continuously swapped.
>
> I know that there are filters to reduce the inconvenience, but those filter
> blur the image and load the CPU, which is already eavily loaded to play the
> MPEG stream. My understanding is that those filters should only have to be
> used if the original stream has been badly recorded.
>
> I also tested the via driver (which  needed minor modifications to compile
> with a 2.6.13 kernel). With that driver, the "interleave" problem does not
> show up and I therefore attribute the problem to the openchrome driver.
> Unfortunetely, the via driver also has  a problem, some pixels --say 5 to
> 10 neighbouring pixels one or several horizontal line, but not always the
> same--- have a bad color (usualy dark), as if  the buffer being unreadable
> when the graphic card needs it (because it is accesed by the driver? I
> don't know much about the driver implementation, don't flame me if this
> hypothesis is stupid).
>
> I am using MythTV with the last svn version of the openchrome driver, XvMC
> is not enabled (I understood I have to recompile MythTV with XvMCPro
> enabled to test the HW acceleration) and the ouput is on a PAL TV.
>
> As a conclusion, the output of the via driver is more pleasant than that of
> the openchrome drive, but also shows some problem. I would however prefer
> to use the openchrome driver, beacuse it is open source of course, but also
> because it is , if I understood well,  my only chance to use the hardware
> mpeg decoding in MythTV because Myth does not support  the VeXP extension.
>
> Any idea on how I could resolve this "interleave" problem?
>
Hi,

FYI the VIA driver defaults to using an excessive output hardware deflicker 
filter. This will result in a picture that does not flicker at all. But if 
you are outputting to a high quality screen you will notice an excessively 
blurred picture.
You can enable this hardware flicker filter on the openchrome driver by using 
the "TVDeflicker" option and then you can compare the output.

If you are outputting to an interlaced PAL TV, however, you will get the best 
video picture image with flicker filter disabled and using a bob 
deinterlacing method.
You will still perceive flickering on non video images (i.e. menus and such) 
unless they are "tuned" by the artist who created them for output on a TV.

Cheers,

-- 
Ivor Hewitt.