Topic: Whats all this .aac about then?? (Read 3650 times)

brainsoup · « **on:** February 14, 2004, 06:44:09 am »

Could someone try to explain what aac is to me? Ive heard that its the successor to mp3 but can't seem to find much information about it? Does Media Center support it? If so, how?
Sorry... lots of questions

Thank you

Chris

LonWar · « **Reply #1 on:** February 14, 2004, 07:41:20 am »

Here ya go, This should explain things...

http://www.vialicensing.com/products/mpeg4aac/standard.html

brainsoup · « **Reply #2 on:** February 14, 2004, 08:51:03 am »

Have downloaded iTunes and converted some songs to .aac, I have to agree - its good. Can Media Center rip into .aac? Or is it just something that iTunes do?

Galley · « **Reply #3 on:** February 14, 2004, 10:20:32 pm »

Plenty of apps can encode AAC files. RealPlayer 10, Nero 6, FooBar, etc.

brainsoup · « **Reply #4 on:** February 17, 2004, 02:51:25 pm »

OK... think I'm getting horribly confused. ? ? ?

I just got my hands on a lovely new Nokia 7600 today, which plays .aac files. I tried transferring some of the ones I encoded with ITunes, but had no luck - They had .m4a extension... is this different to .aac? I tried renaming this .m4a file to an .aac file but this didnt work either - what is the difference?

It would be great if there was a .aac encoder in existence that was better than the one bundled with my phone (which is awful... only rips CD tracks - but does not look up track names... ggrg!)

Can anyone help me at all? Am getting quite desperate!

JimH · « **Reply #5 on:** February 17, 2004, 03:12:22 pm »

Apple uses AAC files in their music service, but the files are encrypted so they may not play on devices (other than iPod) that play AAC files.

I'm not sure whether the same is true for files encoded with iTunes, but it could be. The fact that they are called .MPA would suggest that.

Real also uses encrypted AAC files in their service.

JustinChase · « **Reply #6 on:** February 17, 2004, 03:17:47 pm »

Jim,

Is the aac codec proprietary then?

Does it require you to buy a license to include it in MC?

Do you have any plans to include it?

Thanks

JimH · « **Reply #7 on:** February 17, 2004, 03:24:49 pm »

AAC is a Dolby codec that others license. We use the Quicktime playback engine to play the files.

JustinChase · « **Reply #8 on:** February 17, 2004, 03:40:00 pm »

Does that mean we cannot encode to aac with MC then?

JimH · « **Reply #9 on:** February 17, 2004, 03:53:40 pm »

Quote from: JustinChase on February 17, 2004, 03:40:00 pm

Does that mean we cannot encode to aac with MC then?

Correct. You could use an external encoder if you can find one.

brainsoup · « **Reply #10 on:** February 17, 2004, 04:11:52 pm »

I now have an external .aac encoder, but the files that are produced do not play in Media Center

, though they do play on my Nokia 7600... am having fun trying to see how small I can make music before it becomes unlistanable to - I only have 29mb, and thats for music, photos, Java games, wallpapers, ringtones - and anything else you can think of -

ipodman · « **Reply #11 on:** February 17, 2004, 04:13:16 pm »

Do you have quicktime intsalled?

I am no expert, but I think you need quicktime installed to play aac through media center....

brainsoup · « **Reply #12 on:** February 17, 2004, 04:14:48 pm »

yup.. have qt, itunes - you name it, I seem to have put it on in a last ditch attempt to get all this working together!!

I'm all puzzled

JimH · « **Reply #13 on:** February 17, 2004, 04:20:18 pm »

Quote from: ipodman on February 17, 2004, 04:13:16 pm

I think you need quicktime installed to play aac through media center....

You need the latest version of QT installed. I believe it gets installed with iTunes.

Check tools/options/file associations in MC 10. I don't believe 9.1 will play AAC.

Check file associations in QT, too.

brainsoup · « **Reply #14 on:** February 17, 2004, 04:24:40 pm »

i definately do have the latest version of QT installed, but I only have MC9.1 installed. MC manages to play the .m4a files that Itunes created, just not the ones that are created by the Nokia program or this external encoder that I found (both produce .aac files)

ipodman · « **Reply #15 on:** February 17, 2004, 04:26:53 pm »

I had a problem playing .aac in media center until I got the latest version of 10.x and I reinstalled quicktime fresh from apple's website.

after that,..ac played perfectly.

maybe the external encoder you have is lousy... do those songs play in itunes?

xen-uno · « **Reply #16 on:** February 17, 2004, 04:31:37 pm »

There's a few aac encoders here...

http://rarewares.hydrogenaudio.org/aac.html

brainsoup · « **Reply #17 on:** February 17, 2004, 04:44:36 pm »

The ones I create in iTunes play in MC (through QT) but not on my Nokia, or it's player

The ones I create in the Nokia software or through my external encoder do not play in MC, iTunes or QT...

brainsoup · « **Reply #18 on:** February 17, 2004, 04:49:18 pm »

ooohhh, this is interesting...

Quote

mp4creator

--------------------------------------------------------------------------------

is one of the most important MPEG4IP tools, because it can serve as a MP4 file multiplexer (as the name suggests), but also for extracting AAC files from a MP4 container, e.g. if a hardware device like the Philips Expanium CD portable can only read MPEG-2 AAC files with an *.aac extension. For this purpose mp4creator inserts new ADTS headers into the raw AAC bitstream, thereby copying the available informations from the MP4 header like bitrate etc., but also changing the MPEG version/Object Type ID from MPEG-4 AAC LC to MPEG-2 AAC LC in this case (with the new -mpeg-version switch).

Am i correct in thinking then that iTunes creates mp4 files with .aac files inside (but pure audio) wheras my player does not understand the mp4 container?

JustinChase · « **Reply #19 on:** February 17, 2004, 06:04:56 pm »

It sounds like iTunes will rip in aac, but I'm guessing it's somehow locked by iTunes, so I can't play it in MC. does this sound right?

Is there a recent encoder (based on mpeg4 technology) that I can use to convert some 160 bit mp3s to 128 bit aac files to give a listen to?

Galley · « **Reply #20 on:** February 18, 2004, 01:09:26 am »

Both .m4a and .m4p files play fine in MC10.

brainsoup · « **Reply #21 on:** February 18, 2004, 03:22:46 am »

It doesnt seem to be the mp4 or m4a files that are a problem in MC, it's the .aac files.

The mp4 and m4a files do not play on the nokia software or on the 7600 itself ?

brainsoup · « **Reply #22 on:** February 18, 2004, 04:01:38 am »

OK... I'm not entirely sure what I've done, but I now have dBpowerAMP converting the MP4 (.m4a) files from iTunes into .aac files that my Nokia can enjoy

It all seems like quite a lengthy process though - What is going on? And can Media Center get some more support for aac (I only have V9.1 at the moment but would upgrade to V10 if this was a feature that was included).

Things I would like to see in MC

Native support for the playback of .aac and .m4a files
Support to encode to .aac
Support to encode to .m4a
Utility to convert from .m4a to .aac and vice versa

This page has all the utils that are needed to encode and convert between m4a and aac, hope it helps someone!

http://www.dbpoweramp.com/codec-central-mp4.htm

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Author Topic: Whats all this .aac about then?? (Read 3650 times)