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From what i know m4a and aac are the same thing with mp4 allowing video while the former only allows audio.

Whats the difference between vorbis ogg and m4a? I looked it up and it seems that m4a/aac are patent free. What are reasons i may want to choose one from the other?

Assume source will always be lossless (wav/aiff/flac) and i am choosing the encoding to distribute with my game/demo

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up vote 9 down vote accepted

Ogg Vorbis is soup-to-nuts Open Source. Every bit of the Ogg Vorbis specification is available and there are no known patents that apply to Ogg Vorbis. It is often free and easy to work with. (That is, if your platform/framework of choice supports working with it. For instance, XNA/XACT don't support Vorbis, but if you are using XACT you will be giving it your lossless files anyway and using its built-in compression.)

AAC is the product of a working group of corporations with several commercial goals in mind. M4A/AAC is not patent-free, it is patent encumbered:

http://en.wikipedia.org/wiki/Advanced_Audio_Coding#Licensing_and_patents

You don't need to pay patent royalties to use AAC files as a consumer, but if you were to deploy an AAC codec, for instance as a library dependency in a game, you may need to get a patent license and pay for it. (I am not a lawyer. You should talk to a lawyer.) That said, many platforms that you might be working on may already have an existing codec in place. XNA supports AAC in many places, and so does many Apple libraries, as two examples. Developing a cross-platform game with AAC is a bit more difficult (and you may want a lawyer involved).

In terms of "quality", just about every music codec out there is sufficient at a high enough bit-rate. In my experience the "good" bit-rates for normal music listening for Ogg Vorbis and AAC are reasonably similar. I think Ogg Vorbis is a good format and certainly a useful one when you need something open source and free as in beer and speech. (I have a good chunk of my personal music library in Ogg Vorbis, in fact. I like supporting strong open source efforts when I can.)

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doom3 uses ogg files, and I guess idtech 4 does the same... –  jokoon Sep 27 '10 at 10:57
    
From the wiki and from this page vialicensing.com/aac_faq.aspx it looks like you can distribute freely but only pay to encode or decode. However wondering that VLC can play it i looked at #5 and it appears you only pay when you SELL something. So a free demo/game would be allowed. So for developers it appears you can encode all you want (automated build, manual or even on a website backend for users to upload) but you need to pay for an encoder unless its offered free. It only affects you if you are decoding or encoding inside of a bin being sold. –  acidzombie24 Sep 27 '10 at 20:13
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