What are the Advatages/Disadvantages in different video formats?

[Remyisme]

I'm talking mostley about WMV, AVI and Mpeg.

I'd like to know if one format is better than another?

I had few video files, that i dloaded on the net, they were Mpegs/AVIs, and their dimesions were all wrong, the picture was too wide, but i put them in the windows movie maker and saved them as "high quality video(small)" so the dimensions automatically become 320x240. But than from an Mpeg they became to be WMV.

I already burned this files to disc. So they already saved as WMV.

but I later discovered that i could do the same thing using virtualDub, only than the files would be saved in AVI format.

So I wonder if WMV better than AVI, or AVI better than WMV, should I worry about it? Does it matter?
Can you tell me, if there could be any problems viewing the WMV files in future?
I just worryed for a moment that may be I shoulda saved them as AVi, cause that's better than WMV.

Is it? Should i worry about anything?

[ozymango]

Do you by chance still have the original files you downloaded, before doing any conversion? Standard rule of thumb is, any master is better than any copy of that master (assuming this is not direct digital copy, no conversion). So the best quality of all, should be contained in the originals. If you've still got those, hang on to 'em.

But if not, no major worries -- I'm assuming that you did not look at your copies and immediately go, "Wow, the quality is terrible!" So I'm guessing your conversions are probably decent as-is. As for wmv quality vs avi quality, it depends on bit rate and codec. Got a few minutes?

Short version: The "avi" format is not really a separate format, it's a "container" that can hold various audio/video streams that have been compressed using various codecs. Home DV (camcorder) video is "avi," using the DV codec. There are motion jpeg codecs, "lossy" codecs," that can be contained in an "avi" file. And on and on; "xvid" and "divx" codecs can also be contained in the "avi" format.

WMV, on the other hand, is a specific codec and specific, proprietary file type, made by Microsoft. It is a very good codec (or can be, at the right bit rates), and is well supported by MS. So I would definitely have no worries about saving files in WMV format, as it is viewable on different platforms and I very seriously doubt Microsoft has any immediate plans to stop supporting WMV.

Depending on how many files you're working with and your overall goals, there may be a better format choice for you; fire away with more questions if this helped (or if it didn't help!).

[uxbridge]

Not so sure this will help, however:

assuming you start with an high quality, non-compressed video e.g. video capture 768x576.
assuming you decide to compress to a specific file size, e.g. a CD-ROM size (700-800 MB)

then:

WMV is the best codec
MPEG4 (always packed into na AVI file) is arguably worse
Mpeg2 is the worse of them all.

Things are different with files downloaded. Most of the people who prepare them are not bothered about quality, but just to fit a DVD into a CD-R fooled by people who tell them Divx can make miracles......
You typically get a bad quality Divx.

In that case it does not matter what you use to transcode it, the result is always the same, bad quality as the original assuming you encode to a file same size.

Ciao

[Remyisme]

thank you guys so much for explaining!

ozymango, no I don't have the originals anymore, but i think i can get them back if there's a need, I could try at least.
but i have checked the video quality of them after they became WMV files, and their quality didn't become any worse. i checked them very carefully, and didn't have any regrets.
i only was afraid that may be avi/mpeg is more playable and more prefered, and i was a little scared that WMV is less good than AVi/Mpeg.

So I see youre saying, I shouldn't worry, than i'll leave it as it is.

[Nelson37]

The problem I see with WMV is that it is totally controlled by Microsoft, who could well decide to change it for some reason that could make future players incompatible with your older files. That is the type of thing which could not happen with MPG-2, but for which M$ is well known.

Just as a for instance, say they decide that all files MUST have a DRM license built-in, which yours do not. Of course, for a reasonable fee, they could solve that problem for you.

How many standalone WMV players have you seen? Versus how many MPG2 players?

Size, compressibility, and speed are not the only factors to be concerned with.

[Remyisme]

but if such thing happens with microsoft, i could always convert my filles in to other formats, thats' not gonna be a problem right?

[Abond]

It is a problem though. wmv is highly compressed format, and the result of conversion is full of artefacts.

[ozymango]

but if such thing happens with microsoft, i could always convert my filles in to other formats, thats' not gonna be a problem right?

Personally, I wouldn't sweat it -- I'm sure that if MS ever decided to abandon support for the current WMV codec, they'd give a lot of warning. And I don't seriously think it's even a possibility. MS can be boneheaded at times, but not at that level.

Can I guarantee that? No. But if you think about it for even a minute, you realize that there are currently more computers out there that can play a WMV codec, period, than there are working 8-track, open reel audio, u-matic, or Beta machines out there combined -- and people still manage to find a way to listen to and watch those old formats. A codec is trivial in comparison.

They stopped making the original VW Beetle more than a few years ago and I can still easily get all sorts of parts and support to keep mine running. When did Compuserve drop support for the .gif file extension? See, no matter what hardware or software you use, it'll probably be obsolete some day. But it'll be a long, long time before you need to worry about it.