What are your Export settings?
One observation that I have made is that multi-pass Encoding can vary fairly dramatically, as the Encoder does not know how well it'll do, until into the process. Do not know if that is what you are seeing.
Here's an example of our Export Settings:
File Type: Quicktime
Height & Width: 1280x720
Video Codec: H.264
Frame Rate: 30
Field Type: Progressive
Aspect: Square Pixels
have Set Key Frame Distance checked, 30 frames
Have set Bitrate checked, 5000 kbps
Audio Codec: AAC
Sample Rate 48000Hz, stereo
The file estimation shows 4mb, however when it's exported, the file size is 500MB-1GB, depending on the quality we have set. The file estimation used to give us a fairly good estimation of file size. This is useful when we're trying to export something to upload on a website that has a file size limitation.
OK, that IS a major difference. Did you change H.264 CODEC's? I have no clue why it would once get you closer with the same settings, but now does not.
Thanks for the info and good luck,
We're not aware of changing any CODECs. We also don't understand why it will sometimes show us an estimated file size (although it's way off) and sometimes it won't show us any estimated file size at all. Is there a setting or option we may have accidentally changed?
This seems to vary from Codec to codec. CS3 gives a pretty good estimation of a WMV encode, but doesn't try to come up with a number for a QT encode. Also, Premiere's maths can be off a bit if the sequence is other than video + audio. For instance, a piece with a little bit of video at the start and audio that continues on past the end of the video will yield a video much much smaller in size than PP's estimation. This makes me wonder if PP uses the opening parts of a sequence to do it's calculations.