One of my exported videos has a MUCH smaller size

[colinp]

I've been exporting my project into MP4 videos and experimenting with different export options.  Most of these MP4 files are around 15-20 MB in size.  I've noticed one is much smaller, at around 4 MB.  It plays back with acceptable quality for my purposes.  But now I cannot seem to reproduce a second file anywhere near this smaller size.  Windows tells me the first file's properties, it says the video has a data rate of 62 kbps and a total bitrate of 63 kbps.  I think I exported it with a frame size of 854 x 480, and with a variable frame rate and a maximum of 15 fps.  When I try exporting with these options and "Very Low Quality / Smallest Filesize" the resulting file is still around 13 MB and it has a total bitrate of 212 kbps.  Where can I make the adjustments that reproduce the much smaller file size, especially the 63 kbps?

[borate]

Have you checked out the many options listed on the Video Quality/Bitrate drop-down screen?  

[Jay Van Wetering]

I have a similar question.  I have been capturing AV through a USB port using "AV to USB2.0",  "Microphone (4- AV to USB2.0)", and "720 x 480 [3:2], 30 fps, YUY2" .

The last 2 videos captured were both 2hrs, 3 minutes... but the file sizes differ significantly.   File 1:  10,361,534 KB;  File 2: 5,887,905 KB.

 I am at a loss to explain this behavior.