Nominal and overall bitrate

[Solon8]

Hi guys,
I'm using MeGUI, I read how to encode through several tutorials, but I like to know what I'm doing. So, could you tell me what's the difference between the overall bitrate and the nominal bitrate. The thread I read on another forum was not very clear, people wasn't agreeing.

For example: in MeGUI, while using the AutoEncode feature, the bitrate I give it is an overall bitrate. While using the OneClickEncoder feature, the bitrate I give in the x264 configuraiton (or in the Bitrate Calculator feature) is a nominal bitrate. Another question of mine would be why isn't it a nominal bitrate I give in the AutoEncode feature?

I read: "Your overall bitrate is a combination of your video stream and audio stream in your file with the majority coming from your video stream." But what does it do on my audio exactly?

Can you clear that for me, please? Thanks! :)

[Asmodian]

I do not use MeGUI anymore but I believe:

Nominal bitrate is the target average bitrate of the video file.

Overall bitrate is the target bitrate of the video file + the audio file + the container. I am not sure MeGUI attempts to calculate the container bitrate but I would guess it does, it is usually very low relative to the video+audio.

You set the nominal bitrate in x264 because x264 doesn't encode the audio. I don't know how the AutoEncode feature picks the audio and video bitrates but I assume it tries to keep everything under the target size, so it fits on a DVD for example, while also keeping quality of the two tracks in balance.