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Topic: Pass-Through of Compressed Audio to Yellowtec PUC Lite DDC without Decoding (Read 1777 times) previous topic - next topic
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Pass-Through of Compressed Audio to Yellowtec PUC Lite DDC without Decoding

Hello everyone,

I'm seeking assistance with finding and setting up a media player software that could pass-through compressed audio formats (such as AC3 and DTS) without decoding it, to a Yellowtec PUC Lite Digital-to-Digital Converter (DDC) connected to my computer via USB. I'm getting the audio stream from the AES3 out of the DDC.
I hope this is not a duplicata of another topic, I couldn't find any help regarding this specific issue I'm facing.
The Yellowtec PUC Lite I'm using comes with an ASIO driver. I've tried it already with several media player software without success
I managed to make it work perfectly with PCM audio, my issue here is only transmitting compressed audio formats without decoding it before.

Here are the details of my setup:
  • Yellowtec PUC Lite DDC connected via USB to my computer (USB IN) with AES3 OUT.
  • ASIO driver installed for the Yellowtec PUC Lite.
  • Windows operating system (Windows 10 Professional).
   
And the Media player softwares I've tried so far :
  • foobar2000 : I've found quickly that even if passthrough is perfect for PCM audio with ASIO (or WASAPI even), the foobar2000 keeps decoding my AC3 or DTS files, which is not filling my needs
  • VLC Media player : I tried with WASAPI and DirectX (since no ASIO was available), and I don't have any audio out of my DDC
  • Media Player Classic (MPC-HC) : with additions of  LAV Audio Decoder for bitstreaming, couldn't make it work neither
  • KODI : used an MKV with AC3 audio for this one, but I couldn't passthrough to my DDC, it had to be the default speaker
  • Winyl : can't load AC3 or DTS natively, I assumed any extensions would recreate the behavior of foobar2000 of decoding the compressed audio before doing a passthrough
  • JRiver : I've read here (https://www.head-fi.org/threads/jriver-media-center-21-ready-to-go.780652/page-6) that JRiver doesn't do passthrough so did not try too much with this one

Any advice or recommendations on media player software or alternative solutions that can accomplish this would be greatly appreciated.

Thank you for your help!

Re: Pass-Through of Compressed Audio to Yellowtec PUC Lite DDC without Decoding

Reply #1
To the best of my knowledge, USB audio, be is UAC1 oe UAC2 support only 2 modes.
One is of course linear PCM.
The other is RAW, mostly used for DSD.

A DAC (or its receivers) simply don't understand any PC audio format. You can't send FLAC, MP3, WAV, etc. to it as it simply don't have codec's onboard. All a DAC does understand is a couple of protocols e.g. SPDIF (linear PCM packed in a 32 bit word), UAC1 or 2 (PCM or DSD), etc.

The only thing that works to the best of my knowledge is decode any PC audio format to linear PCM, pack it in a protocol and send it to a protocol converter.
TheWellTemperedComputer.com

 

Re: Pass-Through of Compressed Audio to Yellowtec PUC Lite DDC without Decoding

Reply #2
foobar2000 started decoding DTS out-of-the-box by version 2. In 1.x it could not decode, so it would just pass it on.
2.1 though, did something to it. From changelog:
"Added an option to toggle additional decoding (DTS, HDCD, etc) during playback, so you can play DTS-WAV without decoding DTS."

Re: Pass-Through of Compressed Audio to Yellowtec PUC Lite DDC without Decoding

Reply #3
To the best of my knowledge, USB audio, be is UAC1 oe UAC2 support only 2 modes.
One is of course linear PCM.
The other is RAW, mostly used for DSD.

A DAC (or its receivers) simply don't understand any PC audio format. You can't send FLAC, MP3, WAV, etc. to it as it simply don't have codec's onboard. All a DAC does understand is a couple of protocols e.g. SPDIF (linear PCM packed in a 32 bit word), UAC1 or 2 (PCM or DSD), etc.

The only thing that works to the best of my knowledge is decode any PC audio format to linear PCM, pack it in a protocol and send it to a protocol converter.

That's quite a bummer, I assume that trying to send a compressed source from a computer wouldn't work, then ?

Can I ask you if you'd know by chance any hardware devices that could send a compressed audio source with an AES3, SPDIF or coax output (or anything not USB) ? I tried from an old DVD player with an SPDIF output, but the output stream seemed to be decoded by the DVD player

foobar2000 started decoding DTS out-of-the-box by version 2. In 1.x it could not decode, so it would just pass it on.
2.1 though, did something to it. From changelog:
"Added an option to toggle additional decoding (DTS, HDCD, etc) during playback, so you can play DTS-WAV without decoding DTS."


I tried also with foobar2000 1.6 too, but the issue I had here was that either it couldn't read my AC3 or DTS (because foo-input-dts wasn't installed), either it could read it with foo-input-dts, but would decode my dts stream. Do you know if an audio file can be read "raw" without having anything decoded ?
However based on Roseval answer I'm starting to doubt my whole setup : if the USB from a computer wouldn't allow to have a stream passed through to a DDC, using foobar or another software would give the same result, woudn't it ?

Re: Pass-Through of Compressed Audio to Yellowtec PUC Lite DDC without Decoding

Reply #4
Ah. I remember now, I only ever tried DTS-WAV. That is, DTS on audio CDs, zeroing out the top two bits and encoding the rest in 14 bits.
"Played back" without decoding it is a PCM stream of static at 12 dB below full volume.

Re: Pass-Through of Compressed Audio to Yellowtec PUC Lite DDC without Decoding

Reply #5
I don't understand the question.  I had a look at the Yellowtec data, and so far as I can see this is a 192ksps 24-bit USB sound card, with no capability to decode/encode compressed formats, so I can't see that passing compressed data to it is relevant.
It's your privilege to disagree, but that doesn't make you right and me wrong.

Re: Pass-Through of Compressed Audio to Yellowtec PUC Lite DDC without Decoding

Reply #6
The datasheet for the PUC2 Lite only lists support for PCM formats, so I don't think you'll be able to bitstream compressed audio.

Does your PC already have a digital audio output that supports compressed audio passthrough? What device are you trying to send that compressed audio to? You may have some different options available depending on exactly what it is you're trying to do.

Re: Pass-Through of Compressed Audio to Yellowtec PUC Lite DDC without Decoding

Reply #7
The datasheet for the PUC2 Lite only lists support for PCM formats, so I don't think you'll be able to bitstream compressed audio.

Does your PC already have a digital audio output that supports compressed audio passthrough? What device are you trying to send that compressed audio to? You may have some different options available depending on exactly what it is you're trying to do.

My computer indeed has HDMI and display port where my screens were plugged to ; the device I'm trying to send that compressed audio to (AC3 mostly) is actually a home made device that takes Coax IN. My goal is to find a proper source with compressed audio to send to this device

Re: Pass-Through of Compressed Audio to Yellowtec PUC Lite DDC without Decoding

Reply #8
If your homemade device will accept S/PDIF instead of AES3 (they have different voltages and slightly different data formats), you can try using an HDMI audio extractor. I've seen some that claim to support extracting compressed audio without decompressing it.

Re: Pass-Through of Compressed Audio to Yellowtec PUC Lite DDC without Decoding

Reply #9
the device I'm trying to send that compressed audio to (AC3 mostly) is actually a home made device that takes Coax IN. My goal is to find a proper source with compressed audio to send to this device
That's not what it says in the thread title nor your first post, so anybody replying has been wasting their time.
It's your privilege to disagree, but that doesn't make you right and me wrong.

Re: Pass-Through of Compressed Audio to Yellowtec PUC Lite DDC without Decoding

Reply #10
If your homemade device will accept S/PDIF instead of AES3 (they have different voltages and slightly different data formats), you can try using an HDMI audio extractor. I've seen some that claim to support extracting compressed audio without decompressing it.
Thank you a lot ! I will look into that !

the device I'm trying to send that compressed audio to (AC3 mostly) is actually a home made device that takes Coax IN. My goal is to find a proper source with compressed audio to send to this device
That's not what it says in the thread title nor your first post, so anybody replying has been wasting their time.

As Roseval indicated, A DAC (or its receivers) simply don't understand any PC audio format, thing I didn't know before posting here ; and hence my follow up question to check if  there were any hardware devices that could send a compressed audio source with an AES3, SPDIF or coax output (or anything not USB).
Thanks to Octocontrabass I now have another lead to investigate, I'll look into HDMI audio extractors

Thank you all for your time, it was really helpful !