About Videohelp Bitrate Calculator

[NormaJ]

I have been using this great tool since ever, and always fit my discs so fine. Right now, I start working with AC3 5.1 channels audio files, and that let's me totally outside. How should I use this tool when working with these audio files?

[erayboul]

Most AC-3 5.1 audio is encoded at 448 kbps. You should be able to choose that in the bitrate calculator under the Audio Bitrate pull-down.

[NormaJ]

Thanks, but this is not the deal. I mean, an audio file AC3 5.1 channels is much bigger than a 2 channels one, at the same 448 kbps bitrate, so the video bitrate value given back from the Calculator no longers fit the disk.
I apologize for my English.

[erayboul]

I'm not sure I understand what you mean. A audio file that has a bitrate of 448 kbps will be the same size regardless of whether it is AC-3 2.0 or 5.1 or some other combination. An AC-3 5.1 encoded file is only bigger than a 2.0 encoded one (which I normally encode at 192 kbps) because we need to use the higher bitrate to adequately encode the 5+1 channels. The bitrate calculator should return the proper average video bitrate if you choose the actual bitrate of your audio. In my case, I choose 192 for 2.0 AC3; 448 for 5.1 AC3, and 1536 for LPCM.

[jimmalenko]

I mean, an audio file AC3 5.1 channels is much bigger than a 2 channels one, at the same 448 kbps bitrate

No.

Filesize = running time x bitrate.

If running time is the same, and bitrate is the same, then filesize is the same. If you're getting bigger files, then you're not encoding at the same bitrate.