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blu-ray audio

If I use an external dac with a blu-ray player, apparently I cannot get lossless audio for movies unless it is an HDMI dac. Per oppo:

"Due to bandwidth limitations, high resolution audio formats such as Dolby Digital Plus, Dolby TrueHD, DTS-HD High Resolution and DTS-HD Master Audio cannot be sent through the coaxial or optical digital audio output. A reduced resolution version of the same audio track will be output instead. To listen to high resolution audio formats in their best quality, please use the HDMI connection..."

My question is if I use my computer to play blu-rays or ripped bluray mkv  files and use a usb dac will I get lossless audio?  Using an ifi idsd.  thank you. 

 
majorc
16 responses Add your response
auxinput
2,920 posts
 

You might get 24/48 audio (which is what most blurays are produced at), but it will be 2-channel stereo.  This is most likely the 2-channel stereo audio track on the bluray that can be used for Dolby Pro Logic surround decoding.  Multi-channel audio cannot be sent across USB.  Per licensing, only HDMI can send multi-channel DTS-HD or TrueHD.

Even if the computer did send some form the DTS signal, the USB DAC would not be able to decode it.

majorc OP
76 posts
 
Thank you. The software (jriver) is decoding the lossless audio to pcm and that is being transmitted (downmixed to 2 channel) to the usb dac.  Q is whether licensing or bandwith limitations would prevent this - I would think not - it sure sounds like the dts master audio and dolby tru hd tracks to me. Just looking for audiophile quality for Blu-ray soundtracks without having to purchase an oppo (and perhaps better than an oppo).   
bigridge's avatar
bigridge
8 posts
 
I have an Oppo BluRay player. In order to send 24/96 sound to my DAC when playing a BluRay audio disc, I purchased an inexpensive device called a "de-embedder". The one that I bought was by Kanex and I got it from Amazon. The Oppo has two HDMI outputs that can be set-up so that one is for video and the other is audio. Connect the "video" to your TV, and the "audio" to the de- embedder. Then connect the de-embedder to your DAC by Toslink or coax. Works like a charm and costs $75. The BluRay audio discs that I have sound terrific.
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majorc OP
76 posts
 
Carlos, I don't understand "will despite everything I have the lossless blu ray files." Are you saying that you are feeding a dac with a spdif converter and are receiving lossless, or are you asking a question? 
jaybe
739 posts
 
Not sure why "lossless" is being tossed around. No where in the process or equipment mentioned is there any conversion to lossy files. And, PCM is lossless.
majorc OP
76 posts
 
Native PCM is lossless. The audio output from blu ray for movies is either native PCM or more frequently either a lossless or lossy codec decoded to PCM. A blu ray player will not output the lossless codec decoded to PCM via spdif - only via HDMI or analog.  the q is if one uses a computer to play a ripped blu ray can the lossless codec decoded to PCM can be passed through spdif. 
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