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Topic: 5.1-channel AAC: what, in your opinion, is a transparent bitrate? (Read 5273 times) previous topic - next topic
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5.1-channel AAC: what, in your opinion, is a transparent bitrate?

What, in your opinion, is a completely transparent bitrate for 5.1 AAC?  I've read anywhere from 320-448, though I have a hard time believing bitrates that low would be completely transparent.

Given excellent listening equipment, what bitrate would you need to keep complete transparency between AAC and DTS-MA on most movie sources?

Just looking for your opinions, not necessarily a "what's best" thread and I'm not interested in "encode a few samples and see for yourself" answers.  I want to know what you guys think. 

5.1-channel AAC: what, in your opinion, is a transparent bitrate?

Reply #1 –
During blind listening tests, we found that 5.1 AAC-LC is transparent on almost all material at 384 kbps. One exception is certain applause recordings.

Chris
If I don't reply to your reply, it means I agree with you.

5.1-channel AAC: what, in your opinion, is a transparent bitrate?

Reply #2 –
Thanks for your input!  That's an impressive result.

5.1-channel AAC: what, in your opinion, is a transparent bitrate?

Reply #3 –
Quote from: C.R.Helmrich on
One exception is certain applause recordings.
Can you elaborate on "certain" ? I wonder what made them special. Is it about low inter-channel correlation ?
 

5.1-channel AAC: what, in your opinion, is a transparent bitrate?

Reply #4 –
Quote from: Kees de Visser on
Quote from: C.R.Helmrich on
One exception is certain applause recordings.
Can you elaborate on "certain" ? I wonder what made them special. Is it about low inter-channel correlation ?

Well, we tested one recording which was not from a live concert but specifically recorded for testing. Yes, almost no correlation, and directly miked close to the clapping audience, i.e. the claps were very "crisp".

I should also mention that on the other end of the audio input range (extremely stationary and tonal), there is the infamous 5.0 pitch pipe recording, which is also not fully transparent at 384-kb AAC-LC. But as with the applause, these are two extreme tests and hardly/never occur in real-life situations.

Chris
If I don't reply to your reply, it means I agree with you.