'Downgrading' an AVI file

[johnt]

My question is, what is the best feature to concentrate on when preparing a video to play on an older, slower computer - colour depth, frame size, audio encoding, the codecs themselves or whatever?

Presumably, it's all of the above, but which gives the best results for the least loss of quality?

In this particular case, I have a one-hour classical music video - 24-bit colour, 336 x 256, MPEG-3 audio at 40khz, DivX5 video, 654Mb file size. Looks great on my machine, but the other, older computer (400 Celeron, 128Mb Ram, average graphics card) just can't keep up with it (especially in full screen!).

I dropped the colour back to 16-bit (and the PC's screen settings), but this didn't make a real lot of difference, tried encoding it in as an MPEG4 with slightly lower audio quality - again, still not quite there.

I tried some of the music videos I've collected on the older computer and noticed that some were just as bad, and some were actually quite good. Once in particular had nice colour, good sound and appeared to have reasonable clarity. When I looked at this .mpeg file in Win2K Explorer, all that the Properties tab revealed was that it was "Mpeg encoded" - no frame size, no audio quality, nothing else. So this leads to a supplementary question - is there a tool that provides all these file details?

I apologise if I'm going over some old ground that has been covered elsewhere on this forum - there's so much great information here that it's hard for a newbie to not only absorb it all but also to work out what's relevant in a particular situation.

Thanks for any suggestions.

[johnt]

Sorry, I just answered the part of my question about file details when I opened the file in VirtualDub and looked under File Information.:p

[timmyg]

the first thing you should do is turn down the post processing go to divx in your start menu and then open decoder configuration turn this down to minimum. Divx5 only supports 24 or 32bit compression but I don’t think theirs any restrictions on xvid, apart from that close all non vital progs virus checker and all. Use a fast player dont use any windows media player apart from 6.4 your pc doesn’t stand a chance. If this doesn’t work you need to turn down resolution or bit rate im not sure witch audio codec requires most cpu time.

[mustaneekeri]

If u are encoding music videos it's not a good idea to lower audio quality, it won't take so much CPU power anyway, compared to video.
If possible it might also help if u could upgrade ur video card, because if the playback goes worse in full screen it's more of GPU issue than CPU
U could allso try a player program that is less CPU intensive. couple of such programs would be BSPlayer and GlobalDivX player.
The suggestions timmyg made are also good.

[johnt]

Thanks for your help. I lowered the post-processing settings and installed BSplayer, which was enough to provide good quality playback on the PC (in full-screen and without having to alter the file itself)!