AC3 bitrate

[pstnn]

Hi,

quick question, when it says that an AC3 track is 448kbs or 640kbs, is that with all the channels added up? or is each channel 488/640?

thanks

[sneaker]

It's the sum of all channels' bitrates, not each.

[hello_hello]

It's all the channels combined.

You can check easily enough. If you have an ac3 file that's an hour long (as an example) and 448kbps, then...

bitrate * seconds * minutes / 8 = bytes.
bytes / 1000 = MBs

448 * 60 * 60 / 8 / 1000 = 201.6

so you should have a (roughly) 200MB size file, which obviously includes all the channels.

[pstnn]

Thanks guys,

does that mean that having a 448kbs 5.1 AC3 is equivalent in SQ to a 149kbps Stereo track (448 / 3)?

[Marsia Mariner]

Thanks guys,

does that mean that having a 448kbs 5.1 AC3 is equivalent in SQ to a 149kbps Stereo track (448 / 3)?

Nope. First, because the LFE channel requires a very-low bitrate; secondly, because the remainder of the available bitrate is not distributed equally among the other five channels.

[davejavu]

Typically stereo only AC3 tracks I've encountered have all been 192kbps.