How can muxing overhead decline when the average bitrate is increased?

[Matthew]

I took a short clip and encoded it at different bitrates using CCE CBR (1500->9000 in steps of 500), then muxed each clip using Maestro. No audio, although that doesn't affect this phenomenon.

Size of m2vs, in order of bitrate:

26,385,004
35,180,004
43,975,004
52,770,004
61,565,004
70,360,004
79,155,004
87,950,004
96,745,004
105,540,004
114,335,004
123,130,004
131,925,004
140,720,004
149,515,004
158,310,004

Size of VOBs, in order of bitrate:

27,611,136
36,558,848
45,498,368
54,157,312
63,109,120
72,042,496
81,014,784
89,954,304
98,623,488
107,542,528
116,494,336
125,466,624
134,410,240
143,396,864
151,980,032
160,935,936

Overhead:

1500 overhead 1,226,132
2000 overhead 1,378,844
2500 overhead 1,523,364
3000 overhead 1,387,308
3500 overhead 1,544,116
4000 overhead 1,682,492
4500 overhead 1,859,780
5000 overhead 2,004,300
5500 overhead 1,878,484
6000 overhead 2,002,524
6500 overhead 2,159,332
7000 overhead 2,336,620
7500 overhead 2,485,236
8000 overhead 2,676,860
8500 overhead 2,465,028
9000 overhead 2,625,932

I'm curious, what explains this? :confused:

[RB]

My guess is that in some cases less padding was required.

[Matthew]

Thanks for the reply :)

Originally posted by RB
My guess is that in some cases less padding was required.

Regrettably I have no idea what that means :p