MPG vs AVI

[kajaco]

Got a newbie question here: What's the difference between an MPEG file and an AVI file compressed with an MPEG codec? Are there certain advantages/disadvantages to either one?

[Vejita-sama]

I think you might be confusing avi with DivX (or xvid). avi and DivX are not the same thing, even thou they have the same file extension.

Long story short:

MPEG1 - very basic, only supports progressive source (ie. not interlaced). Compression is ok. Can be played on PC, VCD players, or DVD players.

MPEG2 - supports progessive and interlaced source. Also supports multiple angles, multiple audio tracks, selectable subtitles, etc. DVDs are recorded to MPEG2, as are SVCDs. Compression is ok. Can be played on PC or DVD players (SVCDs players are pretty rare in the USA).

DiVX - MPEG4 compression, you get pick any compression you want (20-50:1) can only be played on PC. No special features, as it's PC only you only really want to encode a progressive source.

So bottomline for PC only, great compression (ie. less space) DiVX is great, but you can't watch them on your TV (w/o a PC video out card).

MPEG1 and MPEG2 for x(S)VCDs or DVDs.

As an aside MPEG1 and MPEG2 produce the exact same video quaility at the same bitrate and resolution. The key is the bitrate and resolution (the VCD and SVCD standards call for different resolutions and bitrate). So an xVCD and xSVCD at the same bitrate and resolution will look the same. Given that more DVD players support VCD (and xVCD) than SVCD/xSVCD some people prefer to make xVCDs

[siriusfire]

V-S

Thanks for that really informative post - this may explain a few things.... I've been producing a video using MGI Video Wave 4 and it offors to save the final version as MPEG 1 however it allows you to select the bit rate for MPEG 1 - does this mean its actually producing an MPEG4???? Also if you choose to save as a AVI it give you 4 options - DV, DV (PAL), "Full Screen Playback (TV/VCR)" and 'Video in a Window - AVI" are these all completely different even though they are all AVI files????

Thanks in anticipation....

[Vejita-sama]

There are a lot of different codecs out there. I don't know your program, so I can't say exactly what you'd get. However...

MPEG1 is just a certain compression format. You can make/encode a MPEG1 video with any bitrate or resolution you want. The VCD standard calls for MPEG1 352x240 video = 1150 kbit/s & audio = 224 kbit/s. But you can make xVCDs at anything you want.

SVCD standard calls for MPEG2 480x480 video = 2520 kbit/s & audio = 224 kbit/s. But again you can go xSVCD.

There is no DivX (MPEG4) standard. There are in fact a lot of different codecs that all call themselves DivX (see the tools section to the left or do a forum search).

I would suspect that the different output options for your programs are to make actually avis (M$ original video codec) at different resolutions and bitrates (ie. quaility) based on what you want to do with it.