720x480 Versus 480x480 Captures

[Jeomite]

I was wondering if there is a quality difference if I capture @ 720x480 versus 480x480. Because I notice it takes up more disk space if I captured @ 720x480.

I plan on encoding the captured AVI to MPEG-2 SVCD Standard (480x480).

[Xitanium]

dont waste your time, tv signals are ABOUT 300x480 really, 352x480 is best if ur player can handle it (most can), or, MAYBE 480x480 but not 720x480, otherwise tvs would look like a dvd.

[iant]

I'm afraid I'm going to dispute that point. It may just be personal taste but I've found that the higher the capture resolution, the better the final mpeg turns out.
I suggest getting a tape, capture the same segment at the two resolutions, convert them and judge for yourself.
It all depends what you consider is good enough.
Have Fun.
Ian

[wildcatfan]

There is a point of diminishing return however...but when you capture at a higher res. when you resize down you hide some of the artifacts due to the resampling of the resizing filters so that may actually improve the quality a bit. (you lose sharpness but blend some of the defects away)

Michael

[Lamont Cranston]

I also agree, within limits, the higher the capture resolution the higher the quality of the mpeg image. If I capture a vcd image at 320 x 240 and encode it using the LSX35 encoder I get a quality level of 22 (LSX35 calculation). The same video captured at 352 x 480 gives a quality level of 42. The is a also a significant difference in the visual quality and a reduction in the noise which inturn reduces blocking in your mpeg image. There is definitly a law of diminishing returns but my experience has taught me to capture at dvd resolutions for both vcds and dvds.

If you are concerned about running out of disk space or processor perfromance try using Mainconcept's DV codec and capture/compress your analog sources in DV format with AVI_IO, VirtualDub, VS5. I see about a 10% reduction in processor usage and the capture file size is about 1/3 the size of a save video clip compressed with the PICVideo codec. Mainconcept tech support says you can use the codec recompression up to 8 time with nearly no effect. You can filter and frameserve with VirtualDub.

Caveat: Mainconcept codec supported frame sizes:
FrameSizes in Pixel (for 1.25 and 16:9)
PAL 720x576, 25 Fps
NTSC 720x480, 30/29.97 Fps

For you LSX35 users. With AVI_IO you can capture DV video type 2 or transcode your DV Video type 1 to type 2 and encode your video with LSX35 using MainConcept's codec.

Download the demo from mainconcept.com and give it a try. I hope this helps.



<font size=-1>[ This Message was edited by: Lamont Cranston on 2001-08-13 04:23:06 ]</font>