Difference Between Mpeg-1 audio Layer 1 & Layer 2?

[Keithchr]

Hi,

Please can someone tell me what the difference is between the above?
Below is the info on two files pasted from AVIcodec...

1)

File: 63 MB (63 MB), duration: 0:06:17, type: DSH, 1 audio stream (s), quality: 63 %
Video: 53 MB, 1190 Kbps, 29.970 fps, 352*240 (4:3), = MPEG Video, Supported
Audio: 10.6 MB, 224 Kbps, 44100 Hz, 2 channels, 0x50 = Mpeg-1 audio Layer 1, Supported

2)

File: 26 MB (44 MB), duration: 0:02:44, type: MPG, 1 audio stream(s), quality: 80 %
Video:39 MB, 2028 Kbps, 29.970 fps, 352*240 (4:3), MPG1 = MPEG 1 (VCD), Supported
Audio : 4.38 MB, 224 Kbps, 44100 Hz, 2 channels, 0x51 = Mpeg-1 audio Layer 2 [0xc0], Supported

I know they are both NTSC mpg files so what is the difference please.
Am I on the right track by noticing that file 1) has something called "type: DSH" whereas file 2) is Type: MPG.

Lastly, can anyone tell me what the % quality means as shown above.

I am new to this, but learning fast thanks to you guys

[Josef K]

...can someone tell me what the difference is between the above?

From this site:

Using MPEG audio, one may achieve a typical data reduction of

1:4 by Layer 1 (corresponds to 384 kbps for a stereo signal),
1:6...1:8 by Layer 2 (corresponds to 256..192 kbps for a stereo signal),
1:10...1:12 by Layer 3 (corresponds to 128..112 kbps for a stereo signal)

As to the quality percentages, that is a software calculation.