Date: Fri, 26 Jun 1998 16:58:48 -0400 From: Mark Handley <mjh@east.isi.edu> To: Roger Hardiman <roger@cs.strath.ac.uk> Cc: freebsd-multimedia@FreeBSD.ORG Subject: Re: Improvements to the bt848 driver - SW Pan and Zoom. Message-ID: <21172.898894728@north.lcs.mit.edu> In-Reply-To: Your message of "Fri, 26 Jun 1998 11:01:41 BST." <35937185.27CF@cs.strath.ac.uk>
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>I've been thinking about an improvement to the bt848 driver. >The same could be made to the meteor driver too. > >I'd like to grab from a sub-section of the video image. >This allows the software pan and zoom functions you can get with >a fixed camera with a wide angle lense. > >Currently, the bt848 driver captures the full NTSC (or PAL) image >and scales it down to the desired image size, say 192x128 pixels. The downside unfortunately is interlacing. If you grab say, 320x240 (from an NTSC source), you typically grab only the even (or odd) fields, and don't get interlace artifacts. If you grab 320x240 as a subsection of the 640x480 (or PAL) image, you get interlace artifacts because you need to grab both fields. Thus it will look worse that the scaled video and these artifacts also adversely affect most video codecs. Cheers, Mark To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-multimedia" in the body of the message
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