Originally posted by: lnguyen
Originally posted by: Eug
Originally posted by: lnguyen
does anyone happen to know of AAC files encoded in itunes can be played by anything else other than itunes?
Yes, Winamp for instance.
In fact, the included encoder for Winamp 5 is for AAC.
well, i only ask because i couldn't seem to play an AAC i made in iTunes under winamp 5... it supports playback natively right? the dll is listed as "+aac" so i kinda just assumed it would.... or did i just make a stupid assumption?
I looked this all up, and what's going on is wierd. There are 2 different versions of AAC, MPEG2/AAC, and MPEG4/AAC. AOL/Nullsoft has a licence to MPEG2/AAC, whereas Apple's licence is MPEG4/AAC. Technologically, the two codecs are almost the same(indeed, an MPEG4/AAC reader should be able to read MPEG2/AAC), but there are some minor differences that break things between iTunes and Winamp. First and foremost, unlike MP4, MP2 does not explicitly define a "container" for files(i.e. the mp4/m4a/m4p containers that iTunes stuff is in), so the audio is in a raw file. Because there is no container, and MP2 does not specify anything about information tags(ID3, etc), Nullsoft decided to add ID3 tags to their AAC files, so that tag support could be there. This can break playback in some cases, as programs that do not know about ID3 tags will not know what to do with the data.
Getting that out of the way, this brings us to why Winamp and iTunes aren't compatible. iTunes expects all AAC content in an MP4 container, and since the Winamp stuff isn't in a container, iTunes does not know what to do with it(it's not likely iTunes would be able to deal with the ID3 tags anyhow). Winamp, on the other hand, doesn't know how to make a container or read one, so it can't read iTunes's files(either protected or unprotected). iTunes may also be using MP4/AAC techniques in their audio data(hint tracks and what-not are MP4), so it's possible that Winamp couldn't read the data anyways since it only knows MP2/AAC techniques(this is dependant on if Winamp were to know how to disreguard the extras from MP4, and they weren't crucial to getting the file to play).
The solution to all of this of course lies in the container files. According to several sources. the MP4 container itself is not proprietary, and as such, anyone can use it without a licence. This has been the sticking point at Nullsoft, since AOL legal has believed that they couldn't use the MP4 container because of licencing issues. If Winamp were to use the MP4 container, it would generate files that were readable by iTunes, and they could use the MP4 "standard" for tag storage, ensuring that the data stream is "clean" and everything(both tags and data) are readable by other programs. Winamp, in turn, would be able to understand iTunes' unprotected files, although the ability to play them hinges on if the MP2/AAC decoder is enough to read iTunes' songs. We'll just have to see what Nullsoft's next move is.