Question about video bitrate...

[mjvgiese]

Hey,
I'm using the guide to get one movie on One Disc using TMPG.
Here's my question. I usually use a video bitrate of 1150, but to fit on one disc I had to take the video bitrate down to 912. Is that going to make the video quality alot less?

Just curious......
Thanks....

[morey]

What i do in this situation is to encode 2 , 1minute clips in the different bitrates and burn them on to a cdrw to compare(even though my player dosnt like cdrw too much)

[SaSi]

Decreasing the bitrate will decrease quality. How low the bitrate should get for your eyes to discriminate that, it's up to you and the test morey suggested.

You could however take another approach. You can use Tmpgenc Two pass VBR and select an average bitrate calculated as follows:

If the total disk size is (e.g.) 800Mb, and the total movie size (in frames) is 180,000 frames, then you must fit 225 frames in each Mb in the CD. If you are doing a PAL movie, then you have 25 frames in each second. This converts the 225 frames into 9 seconds. Since 9 seconds must fit into 1 Mb, your average bitrate is (1048576 x 8 / 9 ) = 932067 bps or 932kbps. You should configure the two pass VBR for (say) 920kbps (to account for small errors in Tmpgenc calculations) and your movie will be encoded with the maximum quality Tmpgenc can so that it fits into the disk (and no space is wasted).