Announce: Enhanced Digital Output app - USB Dac and 192k Digital Ouput

[lintweaker]

Short answer is - I don't know. That document seems to suggest a way of packing DSD into PCM frames. If there is a dac which supports this and a way of creating a flac file which when played over a normal usb interface from a PC without special software plays back with a compatible dac then it may also work with touch. Note however this assumes absolutely no DSD specific processing in the Touch or LMS - it needs to be in the creation of the flac file and the dac only.

I have been thinking about this for a while myself. With the touch now able to output the required 176400 Hz it should be possible to let it output DSD-over-PCM (DoP) coded files to a capable DAC. I did some testing and created a FLAC file with DSD-over-PCM data inside. My DAC is happy to play this as native DSD. I have not been able to test this via the LMS->Touch route as I still have not upgraded my LMS. Watch this space...

[mldb]

Have modified SBT and taken the I2S signal to the internal DAC and use it to connect external DAC. I tested version 0.5 which only support up to 24/96. Would this new version make it work for 24/192 sampling?

[adyc]

I have been thinking about this for a while myself. With the touch now able to output the required 176400 Hz it should be possible to let it output DSD-over-PCM (DoP) coded files to a capable DAC. I did some testing and created a FLAC file with DSD-over-PCM data inside. My DAC is happy to play this as native DSD. I have not been able to test this via the LMS->Touch route as I still have not upgraded my LMS. Watch this space...

I think it may require another plugin which it can recognized native dsd file and rearrange it to pcm format on the fly. It then can pass the file to EDO. There are going to be more DACs which can accept DSD-over-PCM in the very near future.

[lintweaker]

I think it may require another plugin which it can recognized native dsd file and rearrange it to pcm format on the fly. It then can pass the file to EDO. There are going to be more DACs which can accept DSD-over-PCM in the very near future.

You mean a plugin in LMS? I wrote some code to get MPD support DSD in DSF (sony) format and output it in DoP v1. I think we should let the touch just play 'PCM' and let any DSD to DSD-over-PCM code be handled on the server side. Putting DSD-over-PCM into a FLAC containter is just an easy way to get it going without LMS even knowing it and the ability to edit tags with the available tag editing software.

[rgro]

Hi Triode,

I've experimented with a number of different combinations, but the only one that seems to work when switching from a low bitrate radio stream to My Music is your "default" buffer settings. As soon as I go to the "large" buffer setting and switch from radio to My Music, I get the immediate lockup and the Touch disappears off the network. I tried stopping the stream prior to switching but that had no effect.

Quite odd...............

[Triode]

Have modified SBT and taken the I2S signal to the internal DAC and use it to connect external DAC. I tested version 0.5 which only support up to 24/96. Would this new version make it work for 24/192 sampling?

Sorry no.

[Triode]

I've experimented with a number of different combinations, but the only one that seems to work when switching from a low bitrate radio stream to My Music is your "default" buffer settings. As soon as I go to the "large" buffer setting and switch from radio to My Music, I get the immediate lockup and the Touch disappears off the network. I tried stopping the stream prior to switching but that had no effect.

Afraid I can't reproduce this. Can you try to capture some log from /var/log/messages with audio.output debugging enabled when you switch sample rates?

[adyc]

You mean a plugin in LMS? I wrote some code to get MPD support DSD in DSF (sony) format and output it in DoP v1. I think we should let the touch just play 'PCM' and let any DSD to DSD-over-PCM code be handled on the server side. Putting DSD-over-PCM into a FLAC containter is just an easy way to get it going without LMS even knowing it and the ability to edit tags with the available tag editing software.

Yes, a plugin in LMS. Do you have such plugin in LMS or some offline program with can place DSD into flac container?

[rgro]

Hi Triode,

Here is the debug from the last episode I just induced:

Debug.txt

I hope this attachment works----first time I've attempted.....

[rgro]

Afraid I can't reproduce this. Can you try to capture some log from /var/log/messages with audio.output debugging enabled when you switch sample rates?

Triode...

In order to rule out everything else, I started from scratch---all the way down to reinstalling 7.7.2 in the Touch. Then I installed EDO, only---absolutely nothing else. With the default buffer settings I was able to switch back and forth from low bitrate internet radio (tried this with several different stations) to My Music with no problem. With the "large" buffer settings, when I switched from low bitrate internet radio back to My Music, it caused everything to lock up and immediately precipitated an auto-reboot of the Touch. Higher bitrate radio streams cause no problems with either buffer setting. Very strange.................