CBR question

[Jeff Carpenter]

Are you asking HOW to compresss a file? The manuals can help you with the details, but basically you use Compressor to compress to MPEG II video and AC3 audio (dolby) and then take those files and import them into DVD studio Pro.

Or are you asking something else about CBR?

[Stevejr]

Well I was confused a little. I guess CBR is the one pass in Compressor. VBR is the rest. I figured it out.

Thanks though.

[John Pale]

There is no CBR preset.
You can duplicate an existing preset, then go to the Inspector, click the second button from the left to open the Encoder pane, select the Quality pane and select One Pass CBR from the Mode drop down menu.

CBR is actually better for most projects under an hour, though the deceptive names of the VBR presets (Best Quality) might leave you to believe otherwise.

[Stevejr]

Hi John,

Trust me I have done days of research and experimentation on this. And you are the winner. Thank you. The project looks great. If CBR is better for smaller projects then why are they (Tech people) always recomending VBR.

[John Pale]

The folks on the DVD Studio Pro forum are pretty pro-CBR whenever its practical. One method is not inherently better quality than the other…they both have their uses.

VBR is really good for cramming as much video as you can onto a DVD without sacrificing too much quality. The theory being, the bit rate goes up in complex areas and goes down in the simple areas. You can have the complex areas use a bit rate of 7 and the simple areas go down to 4 or less. This can save a lot of space. The problem is Compressor will sometimes spike higher than your max bit rate when using VBR. The bit rate can go up to 8 or 9, which many DVD players cant handle on a DVD-R (replicated “hollywood” dvd’s are made with a different process and can be encoded with high bit rates without problem). Setting compression markers will only make the problem worse. Sometimes with VBR its a matter of trial and error, trying to find the proper spread between the min and max bit rate, to get good results. But why put yourself through it if its unnecessary. VBR is not needed on a short project like yours…you can just use a high bit rate that never changes. Fast encode and high quality.