VBR vs. CBR

[drfsupercenter]

Well, I used BenBryant's method to convert a PAL DVD to NTSC, and then authored it with TMPGEnc DVD Author Pro. I did one in VBR and one in CBR. The only difference I notice is that VBR is about 2.5 GB and CBR is about 5. The picture looks the same. Which should I use, the VBR, or use Shrink on the CBR, and why?

[tigerman8u]

vbr (variable bitrate) applies more bitrate where it is needed ie high action scenes/ more complex scenes and less bitrate to low action/less complex scenes. This is why you can have a smaller file size. cbr (constant bitrate) uses the same bitrate for all scenes. vbr is more efficient and is normally the standrd to use for video bitrate. cbr is normally used for audio. I use vbr for all video and cbr for all audio.

[drfsupercenter]

So go with the VBR then? Does that comply with DVD standards?

[rainyday]

yep, the dvd's u watch are all vbr mpeg-2. (up to 10mbps peak bit rate)

[drfsupercenter]

IC. I will delete the CBR then

[techreactor]

IC. I will delete the CBR then

But be aware that sometimes the VBR logic is not able to calculate the correct bitrate required for a particular frame and thats when the artifacts will show up, this is usually seen if you use VBR with low Max bitrate values.