[BlueApple]

So I downloaded a movie from ITMS last night, the "get info" from iTune says:

Bit Rate: 128 kbps
Total Bit Rate: 1637 kbps

In QuickTime Player's "movie info" says

Data Rate: 1611.54 kbps


Question:
1.) Do "Total Bit Rate" from iTune and "Data Rate" from QuickTime Player mean the same thing?

2.) The same videos with 320x240 and 640x480 have the same bit rate, 128kbps, but the "total bit rate" is nearly twice as much. So what does "Total Bit Rate" mean?