DVD Space

Maverick wrote on 11/11/2003, 6:13 PM
Hi

A little confused and, after a bit of research, still confused.

I had two projects which I wanted to combine onto one DVD with a menu to access both.

Each project is 40 minutes long. I have added an into to be played as the DVD is inserted which is about 10 second long. I have a menu leading to two submenus and each submenu has two object; one to play the film and the other a submenu each of which has 18 items.

With the default setting of 8Mbps I am not able to get everything on the DVD. Even setting to the lowest quality I am not able to get it all on yet the DVDs indicate 4.7GB (120 mins).

I rendered from V4 using separate Ac3 and PAL MPEG-2 video streams.

Can anyone please tell me what is wrong here.

Cheers

Comments

vonhosen wrote on 11/11/2003, 6:21 PM
The DVD indicating 4.7GB (120Mins) can be a little misleading.

Firstly media manufacturers count a GB as 1000x1000x1000
Your computer counts a GB as 1024x1024x1024
Your 4.7Gb is infact actually about 4.37GB

The 120mins refers to about 120mins in a specific recording mode on a stand alone DVD player, not a PC authored & burned DVD.

Fitting your project onto disc authored from a PC is about bitrate management.

Check this thread for more on this.

http://mediasoftware.sonypictures.com/forums/ShowMessage.asp?ForumID=22&MessageID=160614

With regards that link, if your menus are motion menus, you will have to count your menu lengths in your video total when adding up.
farss wrote on 11/11/2003, 6:26 PM
Check that you have selected 4.7 GB as the disk type in DVDA!

To fit more on consider using ac3 audio, with care!
Maverick wrote on 11/11/2003, 6:45 PM
> Check that you have selected 4.7 GB as the disk type in DVDA!

Cheers. After a bit of delving I found where to set it and it is now done. Never knew this needed to be done.

I ended up splitting my projects and the 40 minute project 1 now takes up 56% of the disc.

Ther are four things showing in the Optimize window;
a 1min 8 sec (101MB) video clip to be looped with its audio as a bcakground to each menu (does it take up extra disc space for each menu it is used?)

A scene selection of same duration and size

19 second intro of 7.6MB

2.474GB 41 minutes 52 second project with AC3 audio.

As I have said before the default setting in V4 was used with separate vid/aud streams for PAL 4:3 MPEG-2.

So it seems I still wouldn't get both projects on at 8Mbps. even reducing the bit rate to 0.19 Mbps stil wouldn't leave enoiugh room for the second 40 minutes.

I reckon I must be doing something wrong but can't see what.

Also, why does it keep indiacting that the AC3 audio needs to be recompressed?

ANy help, please.

riredale wrote on 11/11/2003, 6:58 PM
Maverick:
I'm not familiar with DVD-A so someone else can probably get more specific. Just keep in mind that a DVD is not about "duration," but rather file size. Depending on the bit rate you can put anything from one hour to 7 hours on a single disk.

It's been oft repeated, but the rule of thumb is: 600 / (number of minutes of video INCLUDING motion menus) = target bitrate including audio. So if you have 100 minutes of video you need to shoot for a target bitrate of 6Mb/sec or less. If you're using uncompressed audio, that's 1.6Mb/sec you need to subtract from the target, leaving an average video bitrate of just 4.4Mb/sec. If you can use AC-3 compression for your audio, subtract 0.2 instead, leaving a video bitrate of 5.8Mb/sec.

In your instance, you are putting 82 minutes on a disk. Your target average bitrate has to be less than 600/82= 7.3Mb/sec. If you are using AC-3 for the audio, that leaves an average bitrate of 7.1Mb/sec for the MPEG2 encoder.