Alright, I have ran into a brick wall trying to decide at what bitrate I should encode my files in AAC at.

Now I have encoded alot of audio in mp3 and I usually shoot for a file size around 180-200 kbps VBRmp3, I find that on average an mp3 encoded at 192 kbps is relatively transparant to me or atleast to the point were any artifacts that were created by encoding are unnoticeable.

Now if I were to encode some audio in AAC format and have the quaility of this AAC to be the same as a ~192kbps Mp3 file (on Average) what bitrate in AAC would I want to shoot for?

Thanks!

There are many types of AAC and MP3 codecs out there which offer different strengths (or weakness) at different bitrates (and on different samples with different settings). The official recommended MP3 encoder is LAME v.3.90.3 (might change to 3.96 soon), and its recommended setting is --alt-preset standard. This setting should be transparent to most people on most sample ~200Kbit/s. Unfortunately there are no such official recommendations for AAC.

Having said that, two favorites are:

iTunes AAC at 128Kbit, 160Kbit, 192Kbit or even 224Kbit (probably overkill). You can decide which setting is right for you using ABX.

Nero AAC with Transparent profile (HIGH|Normal LC-AAC). Streaming or internet might be good as well, try them yourself.

edit: Welcome to HA.org

thanks for the advice music man.

Ok then a follow up question .... kinda.

Lets say you took an audio file and encoded it using LAME v.3.90.3 and --alt-preset standard which results in a nicely encoded mp3.

Now lets say you would like to encode the same thing using itunes AAC encoder instead. Which setting (ie 128kbps, 160kbps, 192kbps, 224kbps etc.) would be the closest in quality to that mp3 from above. (and yes i know it would very from song to song, but all im asking for is a best guess from you guys if that would be possible)

thanks again!

<edit>and if you have an opinion about a setting on a different encoder I would like to hear it aswell</edit>

I would guess that 192kbps iTunes AAC is quite close to Lame APS quality on average.

I second that. I was previously using LAME 3.90.3 -aps which is very transparent on most samples for me. I bought an iPod 4 months ago, so I started using iTunes. I have settled on 192kbps. I feel the sound quality is very close to LAME -aps, although each have problem samples. If I were listening on my home theater system, I might go for 224kbps to eliminate any doubts. But I only listen to AAC on my iPod, so 192kbps is very good for me. Also, at 224kbps, I can't quite get my entire music collection on my iPod, at 192kbps I can get about 98%. Just my .02...

i would say that by my ears,not back'ed by abx and totaly violating the TOS #8

that you can take AAC-LC bitrate and add 33%-50% and you got you mp3 vbr bitrates

around 160kbits would i used if i usally encoded at around 192kbits mp3 vbr

Have a read of the AAC page at the HA.org Knowledge Base. It has detailed information on the AAC format, as well as a list of codecs.