Hi, I'm joining a bunch of existing AVIs into larger avi's using the avi/divx/xvid encoder. Obviously encoding by bitrate just re-encodes at that bitrate, but I'm not sure about the target quantizer. Seemingly one just sets the quantizer value according to whatever balance of file size and video quality is desired.
My query comes from the fact that the output file size is not consistent. eg. joining two 1GB files into one file with quantizer value of 5.5 results in output file of anywhere between 1.4GB and 2.4GB - differing only with different input files. I wonder if that is due to the fact that the different input files have different quality and compression needs, so the quantizer can do more with some and less with others. Yes?
eg. consider these two joins:
- VidA-pt1.avi and VidA-pt2.avi are both simplisitic video, like a cartoon, encoded at constant bit rate, converted to VidA.avi.
- VidB-pt1.avi and VidB-pt2.avi are both complex action video, converted to VidB.avi.
So, perhaps the quantizer produces a more compressed video for VidA than VidB?
Perhaps the quantizer has nothing to do with this and different output sizes (from diff input files) are merely an indication of differing compression levels in different input files?
?