The maximum bitrate for 352 x 288 PAL

[AlanCake]

Hi All

Trying to get my head around the idea of what is the maximum bitrate that you could usefully use on an XVCD of this size.

In theory there would be 352 x 288 (101376) pixels to get filled, so, I know that you can usefully improve the quality by increasing the bitrate higher than the standard 1150.

My own DVD player can probably handle up to, say, 2500. Is this though really the maximum in terms of quality? Would a bitrate of 4000 still look better on my 352 x 288 canvas?

At what point does the difference become negligible and is there some kind of formula which links the number of pixels to the bitrate ie that each pixel takes up a certain amount of space and therefore you cannot fill them beyond that point.

Hope this makes sense.

Kind regards

Alan

[vitualis]

I don't really know the answer to your question and I'm kind of curious myself...

Presumably though, you would continue to get improvements in quality until you have a bitrate high enough such that the compression is lossless. However, as the bitrate gets pushed higher, you're in a state of diminishing returns.

Regards.

[SH0CKER]

I have a Pioneer DVD-RV31 and have found that using TMPGEnc, both 352x240 and 352x288 look the same during playback. Theres no real noticeable diffrence. As for bitrate, 2500 can be used,but I may have found some better ways to convert if you can't play SVCDs.

I'm testing them now and if they work for me then I'll post them on a READ ME post.

[AlanCake]

Yes I'd be interested in seeing anything you come up with.

Many thanks

Alan

[AntnyMD]

In my opinion, the quality does not significantly improve with MPEG1 352x240 after you pass a bitrate of about 2000. For future use purposes, I encode my XVCDs at 1700 CBR and audio sampled at 48kHz. This falls just under the maximum for DVD MPEG1, so my XVCDs will be easy to transfer to DVD media once it becomes inexpensive.

[SH0CKER]

Wait for another year and a half or so for DVD-R media and burners to become more affordable? Thats gonna be too long a time for me. Id rether spend the extra $3.00 and have a good avi or Divx backup and a working, good quality VCD.

I've tried what you've done AntnyMD and thats not good enough quality for me. The picture is too fuzzy. I have a Svid cable running to a 33" JVC. the 44.1khz and 224kbits/sec is very good sound quality and you cant notice a large enough improvement in sound to justify going to 48khz. I was using a bitrate of 1900 minimum.

Again Look for a post that says READ ME which I hope will be up in the next day or so.

[AntnyMD]

SH0CKER:

The picture plays back reasonably well on my television at home through a basic RCA cable -- but the main reason I'm keeping the video bitrate at 1700 CBR is because the DVD spec for MPEG1 provides only for a maximum of 1.8Mbps. DVD authoring software should reject any file over 1.8Mbps.

As for 48kHz audio, when I copy DVDs, the audio is already in 48kHz samples, so to resample to 44.1kHz just adds extra time. Besides, the DVD spec requires all audio to be 48kHz, so I think I'm saving myself a step by not downsampling. After all, it's XVCD (so I'm encoding it to the DVD spec [352x240/480 video; audio sampled at 48kHz]), and the quality of anything is always subjective.

<font size=-1>[ This Message was edited by: AntnyMD on 2001-11-09 13:58:48 ]</font>

<font size=-1>[ This Message was edited by: AntnyMD on 2001-11-09 14:33:07 ]</font>