hi,
can anyone refer me to the format of m4a container?
till now i encountered files with suffix .aac, and could open them in ADTS or ADIF format.
Full Version: m4a files vs aac
I think m4a files uses MP4 container...Are using any tool to open upt the .aac files using ADTS or ADIF??
.m4a is only .mp4 with a different extension to give players a hint what to expect (audio only). .m4v is the same for video. Just look at the specs for the MP4 container.
m4a sounds much more musical and "analog" than raw AAC. Especially tracks with steep transients like high quality piano recordings make a huge difference. That's the reason Apple chose this in favor of plain mp4 and raw AAC.
Here are my ABX results:
Here are my ABX results:
CODE
foo_abx 1.3.3 report
foobar2000 v0.9.6
2009/03/01 15:16:30
File A: C:\Temp\test.m4a
File B: C:\Temp\test.aac
11:26:25 : Test started.
11:26:56 : 01/01 50.0%
11:27:06 : 02/02 25.0%
11:27:16 : 03/03 12.5%
11:27:25 : 04/04 6.3%
11:27:38 : 05/05 3.1%
11:27:52 : 06/06 1.6%
11:28:04 : 07/07 0.8%
11:28:13 : 08/08 0.4%
11:28:19 : 09/09 0.2%
11:28:45 : 10/10 0.1%
11:29:06 : 11/11 0.0%
11:29:23 : 12/12 0.0%
11:29:24 : Test finished.
----------
Total: 12/12 (0.0%)
foobar2000 v0.9.6
2009/03/01 15:16:30
File A: C:\Temp\test.m4a
File B: C:\Temp\test.aac
11:26:25 : Test started.
11:26:56 : 01/01 50.0%
11:27:06 : 02/02 25.0%
11:27:16 : 03/03 12.5%
11:27:25 : 04/04 6.3%
11:27:38 : 05/05 3.1%
11:27:52 : 06/06 1.6%
11:28:04 : 07/07 0.8%
11:28:13 : 08/08 0.4%
11:28:19 : 09/09 0.2%
11:28:45 : 10/10 0.1%
11:29:06 : 11/11 0.0%
11:29:23 : 12/12 0.0%
11:29:24 : Test finished.
----------
Total: 12/12 (0.0%)
QUOTE (rpp3po @ Mar 1 2009, 15:28) 
m4a sounds much more musical and "analog" than raw AAC. Especially tracks with steep transients like high quality piano recordings make a huge difference. That's the reason Apple chose this in favor of plain mp4 and raw AAC.
err the container doesn't have any impact on the way the encoded sound actually sounds when played seeing as both .m4a and .aac are aac streams
exactly how did you go about the abx and would you care to post samples? did you use different encoders? because if you did then this is the source of the abx differences.
He meant it as a clear joke, but people tend to forget that they should *explicitely* say so.
QUOTE ([JAZ] @ Mar 1 2009, 16:53)
He meant it as a clear joke, but people tend to forget that they should *explicitely* say so.
ah, i've been reading a lot of audiophool boards purely for the comedic value of people who actually believe in denons multi hundred dollar ethernet cable and similar idiocy. i chalk it up to that.
Does m4a container contain raw AAC or does it contain AAC with ADTS header. Please point to a document that authenticates this information.
http://en.wikipedia.org/wiki/MPEG-4_Part_14
(ADTS is defined by Part 7, and is not necessary to be contained, though it can be.)
(ADTS is defined by Part 7, and is not necessary to be contained, though it can be.)
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