Hi all,
i have a new idea for a little project:
TOSLINK is working now, and it is no problem to output PCM Stereo.
The same Interface is able to transport more sophicsticated formats like DTS or AC-3. At first, i'd like to try AC-3, because i have the hardware to play it in my livingroom... my old receiver is not able to play DTS, so i have no chance to test anything
On the low-level hardware side, AC-3 uses the same fomat we are using already. This means, our Teensy 3 is able to play it.
NOT to encode it, this is way too heavy (It would mean to compress (like Mp3/aac) 6 channels in realtime!))
But, we are happy to play PCM-Wave-files from SD-Card. Why not extend it, and play 5.1 wavefiles ? I hope we don't need to decode anything, this is done by the receiver. I hope, it is sufficiant to "copy the wavefile to toslink" (pls excuse the simplification in this case).
Here are examples for such files:
http://www.diatonis.com/surround_sound_music.html
(Maybe it is the same format as for DVD ?)
You can play, for example "A Night full of stars AC-3" with "VLC media player". Most other players do not understand it.
Now to the details:
The spdif bitrate is the same as with PCM. That means we can use most of the already written code.
There is a flag in the SPDIF bitstream which tells the format. Currently, it is set to PCM.
I hope it is sufficiant to set it to AC-3..
We transmit 2 channels currently..with 16 bits.
I do not know how this would be for AC-3. Do we need 20 Bits ? 24 ? One Channel ?
These details are important to know.
This is the AC-3 specification:
http://atsc.org/standard/a522012-digital-audio-compression-ac-3-e-ac-3-standard-12172012/
Until now, i have no read it..
You see, until now, it's not more than an Idea. But I am confident that it is possible
If anyone has more information or ideas , I would be very pleased .
i have a new idea for a little project:
TOSLINK is working now, and it is no problem to output PCM Stereo.
The same Interface is able to transport more sophicsticated formats like DTS or AC-3. At first, i'd like to try AC-3, because i have the hardware to play it in my livingroom... my old receiver is not able to play DTS, so i have no chance to test anything
On the low-level hardware side, AC-3 uses the same fomat we are using already. This means, our Teensy 3 is able to play it.
NOT to encode it, this is way too heavy (It would mean to compress (like Mp3/aac) 6 channels in realtime!))
But, we are happy to play PCM-Wave-files from SD-Card. Why not extend it, and play 5.1 wavefiles ? I hope we don't need to decode anything, this is done by the receiver. I hope, it is sufficiant to "copy the wavefile to toslink" (pls excuse the simplification in this case).
Here are examples for such files:
http://www.diatonis.com/surround_sound_music.html
(Maybe it is the same format as for DVD ?)
You can play, for example "A Night full of stars AC-3" with "VLC media player". Most other players do not understand it.
Now to the details:
The spdif bitrate is the same as with PCM. That means we can use most of the already written code.
There is a flag in the SPDIF bitstream which tells the format. Currently, it is set to PCM.
I hope it is sufficiant to set it to AC-3..
We transmit 2 channels currently..with 16 bits.
I do not know how this would be for AC-3. Do we need 20 Bits ? 24 ? One Channel ?
These details are important to know.
This is the AC-3 specification:
http://atsc.org/standard/a522012-digital-audio-compression-ac-3-e-ac-3-standard-12172012/
Until now, i have no read it..
You see, until now, it's not more than an Idea. But I am confident that it is possible
If anyone has more information or ideas , I would be very pleased .
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