[mythtv-users] Very Basic Question

[Cory Papenfuss]

> VHS-recordings have an even lower resolution than TV so you can up the
> bitrate all you want, it won't make it look any better.

 	Whatever you do, don't make the extremely common mistake of 
thinking that VHS having "240 lines of resolution" means that a 320x240 is 
an appropriate capture.  In analog video land, "lines of resolution" is 
related to *horizontal* resolution, not vertical.  There's other stuff 
involved, but reasonable (NTSC) figures are:

S-vid: Potentially 720x480
Composite: 480x480, *maybe* 540x480-ish
Cable: See Composite (same thing, only RF-modulated)
VHS/8mm: 352x480


 	Bitrates are another matter... For captures, the quality is 
primarily noise dominated.  Commercial DVDs are in the 4-5 Mbps range, but 
they've got the advantage of nice, clean sources.  Lower resolution and 
increased noise seem to tradeoff for broadcast captures.  A 480x480 at 4-5 
Mbps is probably pretty good.

-Cory


-- 

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* Cory Papenfuss                                                        *
* Electrical Engineering candidate Ph.D. graduate student               *
* Virginia Polytechnic Institute and State University                   *
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