> > They probably meant 320x480 (320 pixels/line) and 480 lines. Which is not entirely accurate..
NTSC is analog -- the number of vertical scanlines is fixed at 525, of which 486 are visible, or for convenience sake when dealing with MPEG-type encoding algorithms (which work on blocks of 16) 480. Horizontal 'resolution' is dependant on a variety of factors; source, method of transmission, receiving equipment, etc. You should be able to capture (given that the capture card is of high quality) as much detail as possible from the source (if it is a high-quality picture from a local station received by antenna) with a resolution of 540x480. If you are on cable, depending on the quality of your cable system, 480x480 should capture full detail. Satellite is a different matter. Systems like Bell ExpressVu, Starchoice, Dish and DirecTV are encoded already into MPEG-2 format, usually at a resolution of 480x480 on the regular channels, at (IMO) a far too low bitrate. However, because the receivers only have analog outputs, that signal is converted back to analog NTSC and recaptured by MythTV -- capturing at 480x480 probably won't quite capture the entire resolution, but it's a lost cause, anyway. 352x480 will give you something approximately equivilent to a excellent VHS recording at SP mode. Anythingx240 will be discarding have the scanlines vertically, and will look terrible. Resolutiion does not affect file size, bitrate does. However, if you reduce the resolution, the encoded image will be more similar to the source in terms of artefacts. This is because there are fewer pixels to be compressed into any given bitrate. Also a restriction you should note is that if you want to go to DVD without reencoding, you are limited to the resolutions 352x240, 352x480, 704x480 and 720x480. My personal opinion on the matter of 'what is acceptable quality': I capture everyday recordings at 352x480, with a bitrate of 3150kbps. Some minor artefacts are visible in the image, comparable to satellite (if you consider satellite quality to be acceptable, this bitrate should be fine for you). My "high quality" setting is 720x480 (yes, this is overkill, but necessary if you want to go to DVD) at a bitrate of IIRC 6200kbps. This should yield an acceptable image, with almost no visible artefacts when viewed on an SDTV. (think premium satellite channel). You might find this chart interesting: http://www.mediachance.com/dvdlab/tutorial/bitrate.html .. though because the Hauppauge cards do not have the benefit of being able to do 2-pass encoding (and the encoder, while good, is not the best), you'll find that you'll need a slightly higher bitrate than the chart indicates. For example, I consider 3150kbps to be on the low end of good at 352x480 when encoded with the PVR-350). -- Ian Trider [EMAIL PROTECTED] _______________________________________________ mythtv-users mailing list mythtv-users@mythtv.org http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
