My XVCD attempts and resulting questions

[fmctm1sw]

I made a couple of short XVCDs and tested out my DVD player. I tried a basic VCD and only changed the bitrate to 2520kbs. Then I made another one at 3000kbps (both with tmpg). Both worked well. Nero didn't give me any trouble either about "non-compliance." I then started with a basic VCD again and went to a 640x480 resolution with 3000bps. Nero determined that as non-compliant for the resloution but said nothing of the bitrate. I am continuing this process but now I have a few questions.

1] The 640x480 file I created @3000 was the same size as the 352x240 VCD file @3000. How in the world is that possible?

2] Does bitrate have anything to do with "compliance?" In which case I could have squeezed more bitrate of my stack of VCDs that all have about 600M out of 700M.

3] At what point would incresing the bitrate be overkill?

[crahak]

1) Only bitrate dictates the size. You can decide how many pixels you want to "spend" the bitrate onto.

2) Yes. You're always ways above compliant VCD bitrates. As long as your player supports it...

3) Depends on the source, but generally speaking, no.

[hwoodwar]

I'll try to answer your questions in the order given.

1. It makes total sense 3000kbits/sec is 3000kbits/sec it doesn't matter what the resolution because it is "kbits" per second, not pixtels/sec.

2. An XVCD is taking any of the set VCD specifications and changing them so they are different from that specification. Since VCDs have a fixed, contant video bitrate of 1150kbits/sec, you can change that to "any" value higher or lower and you will still be creating an XVCD.

3. This is a very subjective one, that you may get lots of different answers. To me overkill would be a point, where for a specific resolution, adding video bitrate does not seem to increase the quality (or only provides a trivial increase in quality after that point)of the image, up to the point that my DVD player can still handle that bitrate.

An example from my own experience with my own hardware /software: I create XCVDs (or they could be called XSVCDs depending upon how you look at it.) These are MPEG-2 files with 352 x 480 resoultion. I set motion search precision to High and use 2-Pass VBR with settings of min 1000, average 2000-2500 and max 3500-4000. My DVD players seem to handle up to about a max video bitrate of 5000kbits/sec before they start to display problems for these files. I have found that using a max video bitrate over 4000 kbits/sec only produces a trivial quality improvement. Therefore for this situation with my harware/software I would consider anything over a max of 4000 kbits/sec "overkill"

[fmctm1sw]

Thanks for the insight. I made a XVCD at 352x480 @2500 and 480x480 @3000 and they both worked but came up "letterboxed." I am even quite certain I had "full screen, keep aspect ratio" selected.