Direct Mpeg4 capture vs post compressed Mpeg4

[Funkateer]

I have to files from the same source (VHS) and with the same compression (Mpeg4v1), but the filesize is very different depending on the way they were made. The nukber of frames is the same.

One (lets call this one file 'A') is captured using VirtuaDub (352x288 RGB compressed directly to Mpeg4v1@900kbps) and the other (I will refer to as 'B') first captured as MJPEG (704x576), compressed with same Mpeg4v1 settings in VirtualDub after applying the 2:1 reduction filter).

File 'B' is 685MB and file 'A' is 764MB. The diferrence is in the Deltaframes. File 'B' is 633468K of Delta frames and file 'A' is 727931K total.

File B is of notably better quality than file A, even though it is smaller in size.

Just a note for the record.

[zeb7]

File B smaller because it had less noise than A ,all the mpeg4 encoders are VBR
(the encoder didnt need the extra bits/s )

zeB7