Bitrates with TmpgEnc...

[Fifou]

Ok, I've been working a long time with TmpgEnc but there's something I still don't understand : How to fix the maximum bitrate ? I mean by example in 2-pass VBR mode (or even in CBR!) You choose a maximum bitrate but Tsunami goes over that limit. Sometimes, on real fast motion scenes, it can go 300Kbits over the limit ! (according to Bitrate Viewer).

How to respect this limit ? Is there relation with the VBV Buffer size ? I tried to set it to the maximum (224) but there's still an overflow...

Does anybody noticed and solved this problem ?

[Al Bundy]

Yep I did and posted a similar question.

http://www.vcdhelp.com/forum/viewtopic.php?t=120201&highlight=

Received no real explanation though. Still don't have a clue why they call it max. bitrate and constant bitrate while they seem to be variable.
Don't have much problems with these "constant" and "max." bitrates so I accepted it.

CU

Al B

[bugster]

Remember, the MAX or Constant bitrates are per GOP and not per frame. So when encoding you can get spikes within a GOP but keep the value over the whole GOP within the specified limits. This probably explains the apparent spikes reported by utilities such as bitrate viewer.

[Al Bundy]

I think I get it. The (S)VCD specifications say 1150 kbit/sec (VCD) and 2524 kbit/sec (SVCD), that is per second.
It doesn't really matter how high the spike in the bitrate is, as long as the max. bitrate per second is not higher than the specification says.

- Is this correct?
- Is there a max. spike bitrate? How high can it get on a (S)VCD? Not really an important question, just curious.

CU

Al B

[bugster]

From what I understand that seems about right.