What size target

[Flakse]

Hi

Im encoding a 90 min featurefilm from DV to Mpeg2 to put on a DVD. What is the aprox maximum size for the Mpeg2Video when there should have enough room to fit the AC3 dolby audio track?

In other words... what size will the audio track AC3 be when it is encodet in 224, and can I use all the 4.7GB on the DVD??

Flakse

[Gazorgan]

I'm trying to figure out how you got a 90 minute feature film on DV?

It's actually very simple:

224 kbps X 60 Seconds/minute x 90 minutes = 1209600 kb

1209600 kb X 1 Byte/8 Bits = 151200 Kb

151200 Kb x 1Mb/1024 Kb = 147.66 Mega Bytes for the Audio.

Set your video to 4 GB or less and you will be fine. You must allow for overhead on the DVD (file structure).

[Flakse]

Hi

Thanks for the quick answer.

I made a transfer from a Digibeta Deck to a Sony DV deck, and then via firewire from the sony DV deck to Avid DVxpress to Quicktime.

I ended up making a encoding at CBR7Mps for and that gave me 4.617.690 which is too much.

Since the encoding took about 26 hours it would be unsmart of me to make a VBR2pass, but maybe better/faster to go CBR6Mps!!

What do you think??

If I will go via VBR2pass how will I know the best settings when I want to land at aprox 4GB?

Flakse

[FOO]

Just make the DVD files anyway. DVDshrink
will quickly fix it if it's slightly oversize.

[Flakse]

OK

I didn't know about the shrink program.

Would you say that it is better to make a nice 7Mps encoding and then shrink it a little than maybe a 5Mps without shrinkin'?

Will the shrink not be notisable?

Flakse -

[Gazorgan]

Let's work backwards:


4 GB target size, 90 minute video.


4GB X 1024 MB/GB = 4096 MB

4096 MB / 90 minutes = 45.5 MB/minute

45.5 MB/minute X 1 Minute/60 Seconds = 0.76 MB/Second

0.76 MB/Sec x 1024 KB/1 MB = 777 KB/sec

777 KB/sec x 8 Bits/Byte = 6214 kbps.

Use CBR of 6000 and you should be okay.

You will notice that once you understand what you are doing, you can always get a total bitrate for any given movie length. From there, subtract off your Audio bitrate and you get your Video bitrate (assuming single audio track).

I didn't point out the bitrate calculator that does this for a reason. If you don't understand what you are doing, then you won't know what numbers to plug into the equations. Nor will you know if the result is real.

24 hours is very excessive for an encode using CBR(more like 2-4 hours). I suspect you have some improper settings (like motion search precision should be in the middle range, not 'best') for optimum speed.

[Flakse]

Hi

Thanks for giving me a calculation tutorial... it helps!!

I also think it is a long time. This is how I do it:

The DV material is not all corrected, therefor I use Premiere Pro to make the level of white and Black precisely at 0 and 100 using RGB level vectorscope. Once I have done this I think the croma is a little to high, and I lower that. Once I have done this I raise/position the picture up a little because of subtitles allready burned in and maybe scale it a little.

I really like the look of the encoder built in Premiere Pro and it gives me an oppertunity to correct different things before encoding. All these settings and the fact that I am working on a AMD1800+ 512mb does that it takes more than 24 hours to make. I don't know if I can speed up the proces any way!!

I will use the 6Mps setting.

Flakse