XviD vs MPEG

[adyga]

hi@all
searching for a certain criteria to solve a problem is one of my favourite and essential tools to get information, although I need a little help in here once and for all.
I searched the forum, redirected to other interesting sites and I had spent more than 3 hours reading and reading, actually not all are free-confusing, one useful FAQ to mention is Crusty's Unofficial XviD FAQhttp://ronald.vslcatena.nl/docs/xvidfaq.html. also read this nice article about MPEGhttp://www.digitalfaq.com/capture/avivsmpeg.htm.
I am going to capture a live footage from TV (digital satellite source) PAL @352x288, so I decided on 2 compressing formats to choose from (I dont have a DVD burner so I stick with my CD-r burner )
1-Mpeg2
2-AVI (XviD compression single-pass)
my question is:
How is Mpeg2 quality compared almost equal to XviD's in terms of bitrate if we maintained the resolution and framerate ?
of course there is a lot of theory and sofisticated stuff to keep in mind looking in the article on AVIvsMPEGhttp://www.digitalfaq.com/capture/avivsmpeg.htm there is a clear idea for MPEG capturing on which is the safest bitrate for a certain resolution&framerate to choose from. so in my situation capturing with MPEG2 PAL @352x288 needs a safe bitrate of 2000kb/s(sometimes 3000kb/s for intense motion).so whats the bitrate to choose for XviD in single-pass to assure there are no excessive quality loss (specially in speedy actions), then to recompress it using multipass to find the optimal bitrate for the best quality and/or size(well I understand that in single-pass I need more bitrate than in multipass to catch up with the speedy motions).
What about capturing PAL@ 704x576 or other resolutions ?
also a fast question: how to make mp2 track equal in quality to its of mp3 what bitrate to choose if we say my mp3 has a 128kb/s 44100Hz ? and how to check if a track being mp3 128kb/s 44100Hz was not of a worse bitrate or sampling rate not using the ordinary listen-and-compare thing?
please correct me if I'm wrong, looking forward for your answer !
Thanks in advance

[bugster]

There is no direct comparison of bitrates between mpeg-2 and mpeg-4 (xvid) possible. The two compression methods are different enough that any attempt to compare the two directly to cover all possible types of video is pretty much meaningless, you need to experiment and decide for yourself.

Having said all that, now this: You want to capture and encode at the same time (in real time) so one thing to bear in mind is that mpeg-2 compression requires significantly less CPU time than mpeg-4. So when performing real time compression this is an important factor, along with the speed of your CPU. You want to capture at 352 * 288 which is VCD resolution. VCD uses mpeg-1 at 1150kbits and does show some macroblocking, upping the bitrate to 1500-2000 should reduce this to pretty much zero. 3000kbits at this res is very much overkill IMHO.

Xvid at this res would probably be great at 500 or 600kbits, though I am less well versed in xvid so I may be a bit out.

Hope this helps

[deckard8]

I capture using VirtualDub / XviD - max bitrate 704x576 - all other options off
(this is important otherwise because other options put strain on the cpu causing slowdown/dropped frames. Capture in the highest resolution your system can handle without dropped frames if quality is your aim, then resize when you encode if that is required. Although many don't agree, captures at 352x288 doesn't compare with captures at 704x576. There is no obvious quality loss from original source (not to my eyes anyway.)
Both Mpeg2 and DivX offer great visual quality if encoded correctly. The choice of final format depends on the final file size and the media it will be stored/played on. If your are going to burn it to cdr, there is no choice - DivX/Xvid offer much greater quality at low bitrates enable you to store a DVD quality film even on 1 cdr. If burning to DVD your bitrate will have to be much higher than a comparable DivX so more disc space is needed to store it.
Comparing audio quality between an mp2 and an mp3 is subjective and depends on the listeners ear, but to me an mp2 encoded at 160kb/s 44k sounds as good as an mp3 encoded at 128kb/s 44k

[junkmalle]

If you don't need files of a specific size don't even bother with bitrates. Capture Divx/Xvid in constant quality mode (Quantization mode). Pick a quantization value that gives you the image quality you want (probably in the 3 to 4 range) and let the file come out to whatever size it does.

[Garibaldi]

Both Mpeg2 and DivX offer great visual quality if encoded correctly. The choice of final format depends on the final file size and the media it will be stored/played on. If your are going to burn it to cdr, there is no choice - DivX/Xvid offer much greater quality at low bitrates enable you to store a DVD quality film even on 1 cdr. If burning to DVD your bitrate will have to be much higher than a comparable DivX so more disc space is needed to store it.

I agree. If you are going to watch the vids on a computer or the disk is just going to be used as a backup than DivX or XviD is the wya to go. But if you want to watch them on your dvd player you have to use either mpeg1 vcd or mpeg 2 svcd or dvd.

[adyga]

I am very pleased with your answers guys, you have enlighted my thoughts.
I now capture in MPEG2 PAL@704x576 6000kb/s (because of less CPU power to handle with such resolution) and then re-encode it using multipass XviD with 3000kb/s that gave me the best results (going down to 2500kb/s made a significant loss in quality). the best backup solution for me. even if its going to be 22.5 MB per 1 minute of footage, still the best settings for it.
in the Future I will consider capturing in a quality fitted for DVD backup, but now I will stick with my CD-rs

[junkmalle]

PAL@704x576... XviD with 3000kb/s... gave me the best results (going down to 2500kb/s made a significant loss in quality).

That's pretty high. You must be recording from VHS or a noisy TV channel.

Single pass Xvid in Quantization mode will give you just as good quality in half the time.

[sacajaweeda]

Although many don't agree, captures at 352x288 doesn't compare with captures at 704x576.

I doubt you'll have much trouble finding people that will agree that captures @ 352x240/288 don't stack up with a Full D1 cap.

Now, 352x480/576 vs Full D1 OTOH......