which is better, .avi or .mpeg?

[directjj]

Say you have two video files with similar or identical content and one has .mpeg extension and the other .mpeg extension so you want to delete on to save disk space.

Which file is likely to be of higher quality, or is it impossible to answer that question simply based on file extension?

[drfsupercenter]

Based on file extension, no. It depends on the codec used. Uncompressed AVIs are great quality but huge files. Compression is key. MPEG-2 is the DVD standard, if that helps you.

[benbryant]

If you want to edit them in the future, AVI won't get degraded but MPEG will. Therefore, if you definitely know for sure that you won't need to edit the file again, just delete AVI file

Regards

[celtic_druid]

Also depends on the streams in the avi. An avi containing MPEG-4 video isn't really any more editible than an MPEG1/2 mpg file. For editing you want RAW or a keyframe only codec like DV. A lossless codec would be fine to, even if it isn't keyframe only.

As said, just by the extension, you can't really tell much.

[drfsupercenter]

Were you aiming for a smaller filesize? If you didn't care about the size, a lossless AVI codec, like celtic_druid said, would be the best choice. That way, if editing the file, you keep the same quality, but also has good quality to watch too.

[paglamon]

And which lossless codec do u suggest Celtic?How good is MJPEG?

[celtic_druid]

Be carefull since not all MJPEG codecs are lossless. Depends on contents and if you care more about speed or compression. Not really what the original poster was asking. Perhaps if people want to discuss editing, lossless codecs, etc. someone can start a new thread?

[directjj]

Based on file extension, no. It depends on the codec used. Uncompressed AVIs are great quality but huge files. Compression is key. MPEG-2 is the DVD standard, if that helps you.

Are all files with .avi extension "Uncompressed" and non-lossy?

Is there a utility that will scan files in a directory and revew quality related information, or can I use the Windows Details view to make a determination?

E.G. in Windows Explorer Details View, if I right click and tell it to show Codecs I get the following for 4 AVI files:

DIVX, MP3
cvid, PCM
cvid, PCM
DX50, MP3

Nothing shows up in this column for the mpeg files.

I have a utility called Gspot which shows the container and can reveal the codecs in a file on a file by file basis. It shows all kinds of information which I dont understand.

Gspot shows one .mpeg file with container Mime Type: video/quicktime and no other information in the Video Codec box.

Gspot shows another .mpeg file with container MPEG-1 System Stream << { 1 vid, 1 aud, 1 other } Sys Bitrate: 1262 kb/s VBR and in the Video Codec box it shows: MPEG1_Payload

You can open multiple files in Gspot in which case you can use batch mode and hit the "+" key to cycle through the files you chose to open.

[celtic_druid]

The best way to determine quality is to, believe it or not, watch it. If it looks like crap, then it is crap quality.

That said.
cvid is I think the fourCC for Cinepak, so I would go from worst to best.
cvid
DIVX
DX50
That is just a list really of what they are capable of though. The cinepak encode could still look and sound better.

Looks like one of your mpeg files is infact a .mov.