Further tests indicate that the data for a capture (I am using mmap) is incomplete and confused by the remains in the buffer of the previous image. The incompleteness has a pattern which results in the grid I explained - but the image I get is a mixture of the latest and earlier images. If I have not waited correctly for sync or am reading the wrong buffer (effectively the same!) would I get an effect like this? BTW the image I see is undistorted so I am sure the RGB format is correct - it's just got bits missing in a near-regular pattern. Ivor ----- Original Message ----- From: "Benedict Bridgwater" <bennyb@xxxxxxxxx> To: <video4linux-list@xxxxxxxxxx> Sent: Wednesday, April 18, 2001 2:46 PM Subject: Re: weird effects > Ivor, do you have any other way of testing RGB24 capture locally? Maybe > you could run X in 24bpp and use the test program? If the "RGB24" > rendering is known good it could still be a mismatch between the > capturing and rendering ends in terms of little/bid-endianness or line > padding or RGB byte ordering or 24/32bpp representation of RGB24... > > Ben > > Ivor Cox wrote: > > > > Hi Ben, thanks for the reply. > > The rendering was on another machine (via network) and is reliable - i.e. > > RGB24 from other capture sources ans OS's show ok - so I am assuming the > > patterns are in the raw data. > > > > Cheers > > > > Ivor > > > > ----- Original Message ----- > > From: "Ben Bridgwater" <bennyb@xxxxxxxxx> > > To: <video4linux-list@xxxxxxxxxx> > > Sent: Wednesday, April 18, 2001 3:21 AM > > Subject: Re: weird effects > > > > > Ivor Cox wrote: > > > > > > > Hi,I am porting a video capture app to linux and have had good success > > > > so far except ... I am capturing using a miro PCTV card and on redhat > > > > linux k2.2.16. The capture mode is set to PAL and BGR24. I get a > > > > picure consistent with that - dimensions and colour, but there are > > > > regular vertical and horizontal lines obscuting the image in all three > > > > components (RGB). Is it possible this mode is not fully supported? Dos > > > > anyone recognize this effect? A simple demo program downloaded and > > > > compiled runs ok but it captures in a format which matches the display > > > > - my app is not constrained like that and uses RGB24. Hope you can > > > > help Ivor Cox > > > > > > It sounds like your conversion from RGB24 to the display format may be > > > wrong - lots of colorful effects are possible! > > > > > > Ben > > > > > > > > > > > > > > > _______________________________________________ > > > Video4linux-list mailing list > > > Video4linux-list@xxxxxxxxxx > > > https://listman.redhat.com/mailman/listinfo/video4linux-list > > > > _______________________________________________ > > Video4linux-list mailing list > > Video4linux-list@xxxxxxxxxx > > https://listman.redhat.com/mailman/listinfo/video4linux-list > > > > _______________________________________________ > Video4linux-list mailing list > Video4linux-list@xxxxxxxxxx > https://listman.redhat.com/mailman/listinfo/video4linux-list
