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List:       linux-video
Subject:    video capture at high res.
From:       R Krajcarski <rjkrajca () engmail ! uwaterloo ! ca>
Date:       2000-01-31 15:28:27


Hello, I'm using the Hauppauge WinTV card, to try and capture stills of
video streams.  I'm hoping to get resolutions of 768x576, or 640x480, but
I only need a frequency of say 10 FPS.  Using some existing programs (like
xcaptest.c) I'm finding that at resolutions higher then 320x240 the image
jitters significantly.  I'm wondering if this is caused by interlacing of
the signal?  If so I figure that I should be able to manually interleave
the signals resulting from the V4L2_FMT_FLAG_TOPFIELD (and ...BOTFIELD).
Anyway, I'm not having much luck so far, and I was wondering if anyone has
had success in capturing images at these resolutions.

Thanks for any help or suggestions you can offer

Rob Krajcarski


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List:       linux-video
Subject:    Re: video capture at high res.
From:       Justin Schoeman <justin () suntiger ! ee ! up ! ac ! za>
Date:       2000-01-31 15:36:36

> 
> Hello, I'm using the Hauppauge WinTV card, to try and capture stills of
> video streams.  I'm hoping to get resolutions of 768x576, or 640x480, but
> I only need a frequency of say 10 FPS.  Using some existing programs (like
> xcaptest.c) I'm finding that at resolutions higher then 320x240 the image
> jitters significantly.  I'm wondering if this is caused by interlacing of
> the signal?  If so I figure that I should be able to manually interleave
> the signals resulting from the V4L2_FMT_FLAG_TOPFIELD (and ...BOTFIELD).
> Anyway, I'm not having much luck so far, and I was wondering if anyone has
> had success in capturing images at these resolutions.
> 
> Thanks for any help or suggestions you can offer
> 
> Rob Krajcarski

I assume you are using NTSC source?  If so, it is a known problem, but I 
haven't yet found the solution.  PAL capture seems to work perfectly, but NTSC 
capture has a nasty habit of losing sync.

Unfortunately, I am very busy at the moment, and won't have time to look at it 
for quite a while yet.

-justin


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List:       linux-video
Subject:    Re: video capture at high res.
From:       Ragga Muffin <ragga () pyxis23 ! ec ! t ! kanazawa-u ! ac ! jp>
Date:       2000-01-31 15:44:33


Justin Schoeman <justin@suntiger.ee.up.ac.za> wrote:

>I assume you are using NTSC source?  If so, it is a known problem, but I 
>haven't yet found the solution.  PAL capture seems to work perfectly, but
>NTSC capture has a nasty habit of losing sync.

Could you specify if this is a problem in the V4L, V4L2 drivers or in
xcaptest ?

I'm doing capture using a bt848 at 320x240 for the moment because I still 
need to figure out the image post-processing stuff we are doing. 
But I'd like to raise the resolution later to 640x480. So please
enlighten me.

Tnx
--
Give me Debian or pencil and paper


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List:       linux-video
Subject:    Re: video capture at high res.
From:       Justin Schoeman <justin () suntiger ! ee ! up ! ac ! za>
Date:       2000-01-31 16:16:07

> 
> Justin Schoeman < justin@suntiger.ee.up.ac.za> wrote:
> 
> >I assume you are using NTSC source?  If so, it is a known problem, but I 
> >haven't yet found the solution.  PAL capture seems to work perfectly, but
> >NTSC capture has a nasty habit of losing sync.
> 
> Could you specify if this is a problem in the V4L, V4L2 drivers or in
> xcaptest ?
> 
> I'm doing capture using a bt848 at 320x240 for the moment because I still 
> need to figure out the image post-processing stuff we are doing. 
> But I'd like to raise the resolution later to 640x480. So please
> enlighten me.

This problem seems to be limmited to the v4l2 driver.

-justin


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