Need resource on digital audio and components

[Dark-Angel4ever]

-First i want to know if any one has resources on how to decode the diffrent audio formats like dts, thx... and the diffrent digital audio signales for a reciever. I really need it in a binary or hexadecimal format to creat my own decode electronicly. Also how to digitaly manipulate signals for EQ, and diffrent dsp signals for sound effects like night audio listening...

-seconde i want to know if any one knows about high quality DAC and ADC along with DSP chips aimed for audio application.

[dangus]

There was a thread on making a Dolby Digital decoder here, someplace. I'm reasonably sure there were some references to code there...

If you want a low-cost DD/DTS processor, pick up a used Pioneer receiver (some of those had RCA outs for driving external amps), or a standalone decoder like the Technics SH-AC500D, or a car surround decoder. (I picked up two Panasonic CY-AC300 processors off the clearance table of a local dealer for $25 each, new in box.) It may be feasible to convert a surround receiver with blown power amps to preamp outs.


I feel that DD/DTS are basically obsolete now that many Blu-ray (and HD-DVD) movies have lossless multichannel soundtracks. Audio over HDMI is the way to go now.

[Dark-Angel4ever]

thanks for the reply. well i was interested in the decoding part so i could manipulate the audio digitaly befor dumping it back in analog, once i can find information on digital audio mainpulation, how eq works, how to play with the dynamic range and so on...

[transphere]

I doubt you'll find any code or proper resources regarding these kind of audio standards, lots of proprietary stuff going on. Even so, I also wonder if doing "soft" decoding (so using a generic dsp) is all that efficient, this kind of stuff is mostly done using ASICs (dedicated hardware). Of course it should be possible to use such an ASIC, tap the digital audio out before going to any DAC and do some processing.

If you want some good resources on actual audio processing, have a look here. No much textbook info, but a great resource for real life working (pseudo)code.

[Dark-Angel4ever]

thanks alot. i was thinking of using some dsp fpga to do the processing.

[gfiandy]

Hi, You will really struggle to get hold of code to do this and if you do it will be pirate. Dolby, DTS and THX all charge licence fees to manufacturers to use their decoding algorithms and hence are quite careful about how they release them.

You best bet is to get a suround sound decoder that either has a digital ouput after the decoder (you won't find many of these) or that you can tap into to extract the digital stream after the decoder, then pass it to a seperate DSP to perform whatever post processing you want to.

Regards,
Andrew

[rfbrw]

Eq et al.