Choice between VBR & CBR

[Xymox]

I use Cinemacraft for my encoding from DV avi's to MPEG2 used on PAL DVD's !

As (video) quality is my priority i decided to use the max bitrate setting to fit one DV tape on one DVDR, that equals a movie of about 60 minutes !

Before i make assumptions myself i want to ask you out there to advise on the best encoder settings :

I believe, as i want the video to be 60 minutes on 1 DVDR, i can best use CBR setting on allmost the highest setting (like 8000 - 8500), the audio will be at max bitrate setting.

VBR would be overkill as i want an average bitrate at 8000 - 8500 and would result in the same size movie with the same quality.

Why isn't there a setting on the CCE encoder to set the CBR at say 8500 and when it encodes a part with needs less bitrate (say 4000) it encodes 4000 for that part. This would result in the same quality, but a smaller file.

Why would i want a smaller file ?

On the DVD authoring i would like to use the spare room for menus and some intro animation (or animated buttons).

Can anyone give me some advice on this ?

[SLK001]

If you use CBR at the max bitrate (9.8Mbps), you can get about 1 hour of video on a DVD-R.

Why isn't there a setting on the CCE encoder to set the CBR at say 8500 and when it encodes a part with needs less bitrate (say 4000) it encodes 4000 for that part. This would result in the same quality, but a smaller file.

Well, there is... It's called VBR.

Why would i want a smaller file ?

This is like asking, "Why would I want more money?" Maybe to put more onto a single DVD-R?

But what you want to do is okay. CBR gives excellent quality, but at the expense of size.

Your video settings are fine, but how are you going to encode your audio? If you use LPCM, plan on around 700MByte per hour.

[Xymox]

The audio is MPEG2 i believe (the default setting for CCE, but then on the highset bitrate 3xx kbs i recall)

Isn't it that VBR allways will get to the average bitrate. So when i set the avg to 8500 and max to 8500. There will be no bitrate below it because there will be no bitrate higher.

[Craig Tucker]

Isn't it that VBR allways will get to the average bitrate. So when i set the avg to 8500 and max to 8500. There will be no bitrate below it because there will be no bitrate higher.

Well there is no point using those setting, that would be the same as using 8500CBR. The point of VBR is that the encoder will use the bitrate where it needs it most, so it would use then maximum bitrate on high action scenes and the minimum bitrate where there is no or little action. If you are going to use VBR then choose your average, which will be the value determined by the filesize restraint, eg 4500. You would then choose a higher max bitrate eg 8000, and a lower min bitrate, eg 2000. The encoder will make sure that the average bitrate is adhered to for the duration of the file so that the filesize can be easily predicted. But it will go upto 8000 for high action scenes where it is needed most and down to 2000 where ther is no action and so much less bitrate is required.

[bugster]

Isn't it that VBR allways will get to the average bitrate. So when i set the avg to 8500 and max to 8500. There will be no bitrate below it because there will be no bitrate higher.

VBR with same max and min is the same as CBR.

If you want to encode on part at 8000 and another at 4000 CBR, encode two seperate mpegs.

On the DVD authoring i would like to use the spare room for menus and some intro animation (or animated buttons).

Keep the intro down to 30 secs or less and you should have plenty of room. Make the intro 15mins and you could be struggling.

Menus and simple animated buttons take up very little space.