Is a MPEG an AVI?

[mcmikemc]

A buddy of mine was trying to tell me that a MPEG is an AVI file just encoded with the MPEG codec. This guy has known to be wrong in the past many times but he got me thinking so I am asking you guys.

Is a MPEG an AVI?

[jimmalenko]

whoa, here we go ...

Technically he is sort-of right, although he probably doesn't know why he is sort-of right

You can have an AVI that is encoded with a MPEG-4 codec.

[mcmikemc]

So does that mean that an MPEG (1,2,4) is always an AVI?

[Baldrick]

AVI is a container format, it is not a video codec. It can store different video and audio codecs but not mpeg1 and mpeg2 video. Use gspot to identify the video and audio codecs used in a avi.

[jimmalenko]

So does that mean that an MPEG (1,2,4) is always an AVI?

To be honest I don't know about MPEG-1/2.

Balders got it anyways

[BJ_M]

AVI is just a wrapper -- a AVI may contain a mpeg file or some other type (ussually) ...

saying avi means nothing ... same with QT , they are just wrappers for what is inside ..

a mpeg file is NOT an avi .... but an avi MIGHT be a mpeg

[BJ_M]

AVI is a container format, it is not a video codec. It can store different video and audio codecs but not mpeg1 and mpeg2 video. Use gspot to identify the video and audio codecs used in a avi.

actually ............... though extremely rare -- an AVI can contain a mpeg1/2 file ..
It is possable ..

[BJ_M]

see here for info on such a thing


http://www.graphcomp.com/info/specs/ms/editmpeg.htm

[Baldrick]

okey....i'm still learning new stuff here...i thought i knew everything...

[BJ_M]

no -- I AM still learning stuff here (and everywhere else) ...

i just read alot

[glockjs]

are we gonna have a quiz on this stuff later?

[junkmalle]

This is further complicated by the fact that you can rename an MPG file AVI, or vice versa, and many players will figure out the correct file type and play it.

[glockjs]

This is further complicated by the fact that you can rename an MPG file AVI, or vice versa, and many players will figure out the correct file type and play it.

yeah u can rename mp3 files to midi and media player will still play it. the software is just smarter these day. but the file still IS what it IS

[mcmikemc]

Okay so let me recap.

1) A MPEG (1,2,4) is never an AVI unless somebody chaned the extension which means it is still the original file.

2) An AVI may contain a MPEG file.

P.S. I talked to the guy again that told me this and he said that an AVI is a file that has video and audio in the same file that can be played at the same time. I assume he is wrong from what you guys have told me.

[BJ_M]

2 is true
1 is not always true as you included mpeg4 in the mix ..
mpeg4 can be an avi and ussually is (DiVX, XVID, H264, WMV are all types of mpeg4)



your buddy doesnt know as much as what he thinks he does .. but he is on the right track non the less ...

[mcmikemc]

Well # 2 is either right or wrong do to the qualifier ("may") I threw in there.

So that crap he told me about an AVI being any file that has video and audio in it is just bs?

[solarfox]

AVI originally stood for "Audio/Video Interleaved" -- so, yes, an .AVI file contains both audio and video that are played simultaneously.

Technically, the audio and video data can be encoded in any format you care to use -- as Baldrick and BJ_M pointed out already, AVI is just a wrapper or container for the data; it isn't a codec in and of itself. All the AVI format does is provide a standard framework which specifies how the blocks of encoded data are to be stored and tagged, so that any program capable of using AVI files can determine which blocks are audio, which are video, and what codec(s) were used.

That being said, it's fairly unusual to see AVI files that actually contain MPEG-1 or MPEG-2 video. There's nothing that forbids it, it's just not a common practice.

An .MPG (or .MPEG) file, on the other hand, is explicitly an MPEG-encoded video and/or audio file, which conforms exclusively to the MPEG specifications and only uses MPEG encoding. It's like .GIF or .JPG, in that the file extension is specifically tied to one particular encoding method and is only supposed to be used with files of that type.

And yes, you may occasionally run into .AVI files which are actually MPEGs, or .MPG files which turn out to be AVIs -- but all that means is that some maroon re-named them without paying attention to what he was doing. (Or worse, he thought that all you had to do to "convert" the file from one format to another was re-name it -- and yes, there are people who think that; how do you think all those JPG files that actually turn out to be GIFs, PNGs, or even PCXs(!) get out there?)

[mcmikemc]

Thanks for all the info guys. You have cleared this up for me.