what would be a good bitrate for 5.1 ogg/aac?

[takeru]

i have a 384kbit ac3 file and want to encode it to a 5.1 he-aac and 5.1 ogg file. seeing as how i never encoded that many 5.1 files yet, i was wondering if anyone can give a me suggestions as to a good bitrate to set. its kind of pointless for me to have a end result file almost the same size as the source file...

[KpeX]

384 is pretty low already, personally I wouldn't bother reencoding it, since you'll probably lose quality anyways. If you do, just multiply whatever stereo bitrate you like to use by 3, cause you're encoding 6 channels. 384 is already only 64 kb/channel, going much lower than that would not be advisable IMHO, but I have a feeling there are many people on this board that will tell you differently.

[The Belgain]

You might well be able to go a fair bit lower than that with Nero HC AAC (possibly down to about 256?) with reasonable (but not transparent) quality. Make sure to use an updated version of CoreAAC with SBR support to playback, otherwise it'll sound like crap.

[multicone]

Originally posted by The Belgain You might well be able to go a fair bit lower than that with Nero HC AAC (possibly down to about 256?) with reasonable (but not transparent) quality.

This is impossible to make. At this high bitrate Nero6 will use LC-AAC automatically, even if you choose HE-AAC before encoding.

Make sure to use an updated version of CoreAAC with SBR support to playback, otherwise it'll sound like crap.

You cannot use mkv for this right now the people from matroska said, and from OGM CoreAAC detect SBR content too late, and DirectShow chooses low sampling rate on output before, so it doesnt work for me at all :( .... is there special version of CoreAAC ?

[Soulhunter]

> what would be a good bitrate for 5.1 ogg/aac? <

Only your ears can tell it to you...! ;)

For me, I would hold the 384kbit ac3 file ! (384kbit is already to low for my ears... :D)

Bye

[The Belgain]

@multicone:

Bitrates up to about 200 ish I'd have thought would be HE AAC in Nero. Bear in mind that the "50-70 HE" profile will give bitrates about 180-190 ish when used on a 5.1 track. Those target bitrates Nero gives only apply to steroe files.

[r0cket]

Originally posted by KpeX
384 is pretty low already, personally I wouldn't bother reencoding it, since you'll probably lose quality anyways. If you do, just multiply whatever stereo bitrate you like to use by 3, cause you're encoding 6 channels. 384 is already only 64 kb/channel, going much lower than that would not be advisable IMHO, but I have a feeling there are many people on this board that will tell you differently.
64 kb/channel is not too low, especially when there's a channel coupling activated. and if you use, say, 96 kbps for stereo vorbis, than 5.1 should be 96*3=288 kbps.
btw, i don't use 5.1 encoding at all, so i'm quite retarded on channel coupling in vorbis - is it already implemented?