Spike in Main Concept bitrate

Jamz wrote on 1/7/2002, 3:14 PM
I arranged some short 4 minute video clips on a timeline with a 5 second blank space inserted in between. When rendered in main concept with the default dvd templates I get a bitrate spike of around 9.6 at the beginning of each clip for about 7 seconds. The only setting I changed was the average bitrate was kicked up to 6000. What's causing this? I asked this before but got no responses. Picture quality is important & I'm using PCM audio.

Comments

SonyEPM wrote on 1/7/2002, 4:52 PM
What tool are you using to monitor this?
Jamz wrote on 1/7/2002, 7:29 PM
When playing back in a set top DVD player & you bring up the on screen displays, there is a bit rate display which gives you a read out of the audio + video bitrate. I like the quality of the Main concept but this spike is a concern.
pelvis wrote on 1/7/2002, 8:59 PM
Could this be just a "slow updating" bitrate analyzer, showing you the start of the picture after black?

Is there an actual problem with the video image quality itself? That's what really counts...
Chienworks wrote on 1/7/2002, 9:06 PM
If i had to guess, i would say that the the spike is a natural result of going
from a blank frame to an image. There is a sudden very huge change of
content when the image starts. In order to have the image appear quickly,
an enormous number of bits have to be processed very quickly. Contrast
this with the blank frame before and the (relatively) smaller changes in
the video clip after it starts. The bitrate can be much lower before and
after the start of the clip, but must jump for at least that one frame.
Jamz wrote on 1/7/2002, 11:55 PM
That could be right. I found if I brought the maximum down from 8000 to 7000 the peaks were spiking to only 8.5 & the picture quality was still fine. When it was peaking around 9.6, that could possibly be a problem for some dvd players.