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Ideal Bitrate for 24 minute short film

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Rahul Gandotra
Ideal Bitrate for 24 minute short film
on Aug 22, 2010 at 3:01:18 am

I'm in the process of creating a dvd of my short film that was 24 minutes long. Of course, I would like the highest quality possible but it seems like the issues of spiking, maximum bit rate, etc. (having read them from previous posts) have got me all worried.

So I thought I should throw out the specs and details I'd be using. Any advice would be highly appreciated:

Computer Used: Macbook Pro 2.16 GHz Intel Core Duo (10.5.8)
Encoder Using: Cinema Craft Encoder MP
Host Software: Compressor 3.5.1
Authoring Program: DVD Studio Pro 4.2.2
Burn Type: Duplicating DVDs on my laptop (no replication)

Original Footage: 35mm
Quality of Footage: You can see a 90-second excerpt here:

http://www.nomadosphere.com/nomadosphere/aRoadHome.html

Length: 24 minutes
Source Footage: 1920 by 808 Tiff Files
Source Audio: 48kHz / 24bit AIFF
On one DVD, I would only have stereo
On the other DVD, I'd have the option of the 5.1 audio or stereo
Menus: 1 still frame menu (no motion menu)

Here are some questions to guide the thinking and answers:

01) What would be the maximum bitrate for the max bitrate setting to take into account spiking and avoid dvd player incompatibility?

02) What would be the minimum bitrate for the min bitrate setting?

03) Is there an ideal multipass number? Should I be using 99 or is that a waste of time and should use a lower number?

Some of my own research so far:

I've used a bit calculator that says that my average bit rate should be 6.8 Mbits/s and the max setting should be 7.8 Mbits/s.

Does this sound right for a DVD that is going to be duplicated on my own laptop?


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Michael Sacci
Re: Ideal Bitrate for 24 minute short film
on Aug 22, 2010 at 4:26:40 am

For DVD-R you should never go over 7.5 Mbps and I recommend no higher than 7.Mbps and this is with audio encoded as ac3.

As far as the multipass that is something you need to play with, there is no set it to this, compression is as much an art as any other process, you need to try, look and adjust.

[Rahul Gandotra] "Source Footage: 1920 by 808 Tiff Files"
Be careful here. This is a letterbox 16:9. You probably want to put it into a 1920x1080 sequence to get the correct padding on top and bottom before down rezing to SD 16:9.


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Rahul Gandotra
Re: Ideal Bitrate for 24 minute short film
on Aug 22, 2010 at 3:36:26 pm

Hi Michael,

Thanks for replying. So just to clarify:

The maximum bitrate should be set to 7.5Mbps.

and

The average bit rate to 6.8Mbps, i.e. taking into account that the AC3 audio files will end up being 192Kbps.

Would this be correct?

- Rahul



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Michael Sacci
Re: Ideal Bitrate for 24 minute short film
on Aug 22, 2010 at 5:36:52 pm

Well I would try it at 7Mbps max and maybe 6Mbps average, if I didn't like the results I would go up but never over 7.5Mbps max.


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Bouke Vahl
Re: Ideal Bitrate for 24 minute short film
on Aug 24, 2010 at 7:20:27 am

I don't see the logic in VBR.
With CBR, you still have plenty of space.

Michael is totally correct with the bitrate max.
(For burned disks that is.)
To get more compatibility, use Taio Yuden or Ritek disks, never cheap brands.

Few things more to add:
Even with CBR, mulitple passes can improve quality if you use Cinemacraft. (You need to set it to 6 at least to have the extra functionality kick in.)

But at this datarate, i doubt if you are able to see the difference.
It will be fast though, set it to 10 and let it run overnight.

Your biggest quality gain will be in proper downscaling. Work on that first.

Bouke

http://www.videotoolshed.com/
smart tools for video pros


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Rahul Gandotra
Re: Ideal Bitrate for 24 minute short film
on Aug 25, 2010 at 12:39:20 pm

Thanks for this information.

I'm in the process of doing my testing but your pointers are going to hold me in good stead as a good starting point.

Thanks again everyone!

- Rahul



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