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Old 2nd February 2010, 11:33 AM   #1
Chris_F is offline Chris_F  United States
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Default DD/DTS Decoding

I've been reading through some older posts on this subject, but they were mostly early 2000s and things have changed since then.

I'm putting together a dac/amp and I was interested in adding surround sound decoding to it. I realize that you have to sign a lot of paperwork and give a lot of money up front to use their proprietary decoders in your products, and even companies like Analog Devices wont release the IP cores to you until you've done this.

However, there is a tone of open source decoders out there, take AC3Filter for example, which can decode both DD and DTS. I was wanting to implement a decoder in a FPGA using these open source software decoders. I realize that most of you aren't patent attorneys, but I'll ask just the same.

1: Could I sell a product that decodes AC3 + DTS using open source software without feeling the wrath of Dolby or DTS? After all, it's not their decoder but an open source one.

2: If the answer to #1 is no because they can for what ever reason prevent you simply on the grounds that it would be selling a product that decodes their formats then: What if you simply had a bare bones DSP made from the FPGA with no support out of the box for AC3 or DTS but was programmable with various software "plugins", at which point you could simply release a free and open source plugin for it based off of AC3Filter. SURLY they can't stop that, otherwise AC3Filter couldn't exist in the first place, nor any device capable of running it.

Last edited by Chris_F; 2nd February 2010 at 11:35 AM.
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Old 3rd February 2010, 03:41 PM   #2
Chris_F is offline Chris_F  United States
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Anyone wanna take a stab at this? Even better if somebody has seen or heard of something like this.
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Old 3rd February 2010, 07:04 PM   #3
fzaad is offline fzaad  Europe
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Not without legal issues no matter how you provide it.
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Old 3rd February 2010, 11:23 PM   #4
Chris_F is offline Chris_F  United States
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Quote:
Originally Posted by fzaad View Post
Not without legal issues no matter how you provide it.
I have a hard time believing this. If so, then how do projects like AC3Filter exist in the first place?
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Old 4th February 2010, 08:29 AM   #5
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Quote:
Originally Posted by Chris_F View Post
I have a hard time believing this. If so, then how do projects like AC3Filter exist in the first place?
The Dolby Digital patents are about to expire (or already expired), I guess the same applies to DTS (legacy).

However, the Dolby double-D logo and DTS logo are still their trade marks. Your product won't be able to bare the logos unless you pay the $$, license their technologies and pass their certification test.

Why would any customer buy a product that claims to decode the streams but without the logos?

So we are back at square one again. The open source decoders may be legal, they don't have commercial values. The same applies to your DIY project in planning.

Besides, do you know if the open source decoders passed the certification test? I bet they didn't, otherwise they won't be free. And how compatible and robust would they be if they weren't tested in the same way as other commercial software and hardware decoders?
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Old 4th February 2010, 01:23 PM   #6
Chris_F is offline Chris_F  United States
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Quote:
Originally Posted by simmconn View Post
The Dolby Digital patents are about to expire (or already expired), I guess the same applies to DTS (legacy).

However, the Dolby double-D logo and DTS logo are still their trade marks. Your product won't be able to bare the logos unless you pay the $$, license their technologies and pass their certification test.

Why would any customer buy a product that claims to decode the streams but without the logos?

So we are back at square one again. The open source decoders may be legal, they don't have commercial values. The same applies to your DIY project in planning.

Besides, do you know if the open source decoders passed the certification test? I bet they didn't, otherwise they won't be free. And how compatible and robust would they be if they weren't tested in the same way as other commercial software and hardware decoders?
That's pretty much what I expected, thanks for the reply. It is mostly a hypothetical question, and if I ever do get around to selling something, DD/DTS support won't exactly be the main selling point, I was just interested in having the option. However, you don't seem to have a good understanding of open source software or it's community. It's not free because it's bad, it's free as in freedom (as Richard Stallman would say.) There are plenty of devices that make use of open source code. Anything that runs Linux for one.

Last edited by Chris_F; 4th February 2010 at 01:30 PM.
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