How to calculate Bitrate to use?

[Rolandinhio]

Hi,

I'm trying The FilmMachine for a better quality DVD. I've been advised to manually set the bitrate to fill-up the DVD. My last attempt was:

Audio Bitrate = 192kbps, with an average video bitrate of 5013kbps - but this only produced a 1.6GB DVD, and the audio was poor.

It's been sugested to use audio at 448kbps, but this drops the video to 4757kbps - what can I afford to go upto in video bitrate and not exceed a 4.38 DVD?

Also the original AVI is MP3 114kbps audio that is perfect quality, it just gets lost with the conversion.

I'm using the AC3 Aften encoder option with TFM.

Thank you for your help.

Ron.

[KBeee]

256kbps seems to be the sweet spot for AC3 audio.
You need to enter your video playing time and audio bitrate into a bitrate calculator such as -
https://www.videohelp.com/calc.htm

[Rolandinhio]

Hi,

Entered the details into the Calc.

Play Time - 1hr57mins
Audio Bitrate - 256kbps

= Calculated Bitrate 4951kbps - DVD max bitrate 9537kbps

Whats the difference between the calculated and max bitrates?
Does this mean that I could say go upto 9000kbps, and leave a little to play with?

Thanks.

[guns1inger]

For 2 channel AC3, 192 - 256 kbps is the best range. For good source, 256 kbps. For your standard downloaded mp3 audio, 192 kbps is usually more than adequate. If you were doing an audio only disc from high quality PCM source, you might consider 384 kbps.

For 5.1, 384 - 448 is recommended.

If you are doing Constant Bitrate Encoding, the the calculated bitrate is the one you would use. If you are doing Variable Bitrate Encodes then the calculated bitrate would be entered into the encoder as the Average bitrate.

The DVD maximum bitrate shown on the calculator is the maximum allowable based on your audio bitrate, so you could put this as the maximum in a VBR encode. However given how low your average is, it is unlikely to ever get close to that amount.