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Topic: Comprehensive AAC listening test anywhere? (Read 7786 times) previous topic - next topic
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Comprehensive AAC listening test anywhere?

I have recently been reading about AAC standards as well as MPEG-4 standards and about different AAC-encoders.
I did found interesting listening test about HE-AAC v2 vs HE-AAC v1
http://www.mp3-tech.org/tests/aac_48/results.html or http://www.hydrogenaud.io/forums/index.php?showtopic=42679
and some test between different AAC-encorders or multiformat tests AAC vs something else.

BUT as I do see things and above mentioned test somewhat confirms about AAC encoding is that HE-AAC v2 is only intended for very low bitrates (24-32kbps) and HE-AAC is somewhat better (on music) above that but is still intended for bitrates around 48-64kbps. And again above that you should use AAC-LTP (Long Term Prediction) for quality purposes.

I haven't seen any other listening test where these are compared and typically AAC-encoders are using AAC-LC profile which is quite bad as seen on many test using FAAC-compiler (allways defaulting on AAC-LC profile although it could be used with "--obj-type LTP" setting).

It seems that AAC-LC (Low-Complexity) profile was compulsory stripped-down compromise when computing power on handheld devices were much lower but there is no sane reason to use it still today. AAC-LTP has been on MPEG-4 standards from year 1999 onwards (years before HE-AAC) so there should be no compatibility issues either. HE-AAC v1 and v2 are only extensions to AAC-LC so that extremely low bitrates are somewhat possible (but nothing to do with quality improving on "normal" bitrates and still excluding methods used in AAC-main and AAC-LTP profiles).

I'm not sure how different encoders are optimized to use different profiles. Do they change between HE-AAC v2 vs HE-AAC v1 vs AAC -LC (or AAC-main) depending on bitrate but I'm pretty sure none defaults to AAC-LTP on any bitrate!! Could it be that Apples AAC encoder is more clever in this way and has been victorious for that reason? But when every encoder should manually be set to AAC-LTP and using bitrates around 100kbs is there still the same differences as with default setting and will the quality be better than AAC-LC, AAC-main or HE-AAC v1 and v2?

Is there any (recent) test allready dealing with this or is anyone interested to do such?

I think only after testing which AAC-profile is best (and on which encoder) there is true basis to compare the best AAC encoder to others (Opus, Vorbis, MP3, etc). It seems that there have been some stumbling to compare some AAC-encoder with some settings to let's say Opus but what does it show? There is no reason to compare some AAC-encoder with compromised AAC-LC or HE-AAC profiles with newer audio-formats!

Comprehensive AAC listening test anywhere?

Reply #1 –
From a 9-year-old post:

Quote from: Garf on
Main profile is dead. Even the improvement over it introduced in MPEG-4 (LTP profile) is just as dead.

Comprehensive AAC listening test anywhere?

Reply #2 –
Quote from: tepatee on
There is no reason to compare some AAC-encoder with compromised AAC-LC or HE-AAC profiles with newer audio-formats!

Before "There is no reason..." be our guest to find one single high quality AAC-LTP or MP encoder AND one single soft player that will decode it properly.

There was no development in last 10 years on these profiles. Nobody works on these kind of encoders either decoders.

As for now. Get a fabulous day.
 

Comprehensive AAC listening test anywhere?

Reply #3 –
Quote from: IgorC on
Quote from: tepatee on
There is no reason to compare some AAC-encoder with compromised AAC-LC or HE-AAC profiles with newer audio-formats!

Before "There is no reason..." be our guest to find one single high quality AAC-LTP or MP encoder AND one single soft player that will decode it properly.

There was no development in last 10 years on these profiles. Nobody works on these kind of encoders either decoders.

As for now. Get a fabulous day.


Hi, I have a question. If the main profile is already dead for 10 years. So can I understand this as "the standard for ACC LC is just there for 10 years". If so, will there be difference between different ACC encoders such as nero, apple, fdk? They should all do the same thing according to the standard. Why there is so many listening test between different ACC encoders? Looking forward to your reply, thank you!

Comprehensive AAC listening test anywhere?

Reply #4 –
Quote from: regis on
If so, will there be difference between different ACC encoders such as nero, apple, fdk? They should all do the same thing according to the standard. Why there is so many listening test between different ACC ...

MPEG audio (and video) standards do not specify the encoder behavior, only how a decoder must decode given bit-streams (i.e. MP4/M4A file), that's why. How to write a good encoder is usually kept secret by involved companies. By the way: it's called AAC (Advanced Audio Coding), not ACC.

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