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problem decoding hdcd content from streaming WAV to av32r

Discussion in 'AV Pre-Amp/Processors & Power Amps' started by squadra, Oct 31, 2005.

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  1. squadra

    squadra
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    I have an av32r 192 sp (firmware version 3.75) and have a problem which I assume is caused by the av32r.
    Some time ago I bought a Roku soundbridge, and started to rip all my cd's to my harddisk.
    Files are stored as WAV files, created using eac.
    When I play non HDCD content via the roku and use the spdif input from the Tag everything is very good.
    However, when i play a wav with HDCD content the hdcd logo on the front of the Tag is constantly switching on/off, and the sound is distorted with some sort of rattling.
    This is both via optical and coax spdif connections.
    I also have a PS Audio Ultralink II dac, and when the Roku is connected to the PS Audio the hdcd content is decoded perfectly.
    The PS Audio has an spdif output and when I go from Roku -> PS Audio -> Tag the Tag doesn't 'lock' and keeps on switching hdcd on/off while the PS Audio detects and decodes the HDCD stream perfectly.
    Another thing I have tried is buying the audio files I tested (Dire Straits & Tool) from allofmp3.com in WAV and WMA losless format, but with the exact same results.

    Has anybody noticed (or can confirm) this behaviour from the av32r?
    And, even better, does anybody know of a solution (new firmware?)

    Thanks,

    Peter
     
  2. Teejoo

    Teejoo
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    Hi Peter,

    It's always a good plan to upgrade to the latest SW version that was made for the SP. (V3.80). However I really can't remember if there are changes to the HDCD part between these releases. Steve, can you log into your memory?(or files ;) )
     
  3. squadra

    squadra
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    Hoi Teejoo,

    Thanks for your reply.
    I have to find someone with a rs232 <-> tagtronic interface, but that shouldn't be too difficult :)
     
  4. Stevesky

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    Are you sure that the signal is not getting attenuated slightly (Windows volume control etc. in the way), hence mildly corrupting the LSB of the data. The AV32R has slower response times compared to a hardware implementation of HDCD and if there is HDCD data corruption it can sounds pretty lousy. Between 3.75 and 3.85 there wasn't any fixes to HDCD as to my knowledge it wasn't broke!

    If you have a sample of file that fails, do feel free to PM me and we can arrange for you to send me a sample file so I can try it out here.
     
  5. Stevesky

    Stevesky
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    One other thought - burn the wav back on to a CD and see if it fails when played via a CD player.
     
  6. squadra

    squadra
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    Hello Steve,

    I have tried your suggestion, and created a CD from the wav's.
    The CD is currently playing without flaws.

    The volume control is at 100%, and at this position the roku doesn't do any work on the stream.
    Other people are also using it to stream dts encoded cd's etc.

    I have sent you a message with a link to my pc at home, so you can download the sample, if you would like.
     
  7. Stevesky

    Stevesky
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    Hi,

    Just tried playing the test stream through an AV32R connected to my PC using SPDIF (card is a Midiman Audiophile 2494) and it locked fine on the HDCD without any issues.

    A few more thoughts:
    1. Does the AV32R show 44.1kHz in the top left hand corner when replaying the audio? If not then the Roku is upsampling the audio.

    2. I wonder if there is some sample rate conversion going on (eg. 44.1k->48kHz->44.1kHz) which is corrupting the stream?

    3. Try configuring your player not to use windows volume control or the windows mixer.
     
  8. squadra

    squadra
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    Hi Steve,

    1 + 2: The samplerate is 44.1 kHz and no resampling is done playing WAV (or AIFF) files.
    There is a new version out which does resample to 48 kHz, but I have the 'old' version which doesn't touch the stream.
    This is a link to the Roku forum, where people are complaining about the new 48kHz upsampling 'feature'.
    3: The file is retrieved using a http GET over wired ethernet and in my case is not served by Windows Media Connect, but by an Intel reference media server application.
    The Roku is a stand alone device, so windows settings have no influence at all.
     
  9. squadra

    squadra
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    Today I had the Tag upgraded to 3.80, and it didn't make a difference.
    One thing I still can try is using the wifi card i.o. the wired ethernet.
    Anyway, thanks Stevesky & Teejoo for your help so far.
     
  10. squadra

    squadra
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    Breaking news :)

    I unplugged the unit from AC and later reconnected it.
    99% of the time I use the unit as a DAC, via the tape out connectors.
    This can be done without taking the unit out of standby.
    When I do this the HDCD decoding is probably not activated and no noise is generated on playing back a hdcd stream.
    After taking the unit out of stand-by the hdcd decoding is (apparently) activated and then the unit will generate the switching noise.
    Going to stand-by again leaves the hdcd detection activated and thus the clicking noise is generated for hdcd streams.

    This is good enough for me, as I use the unit as a DAC only and almost never take it out of standby.
     
  11. Stevesky

    Stevesky
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    When the unit is in standby the control micro just lets the DSP do it's own thing, hence won't drive the HDCD initialisation. Still doesn't explain what is going on with the bitstream when it comes out of the soundbridge. They must be mildly corrupting the stream somewhere in their processing chain (internal floating point maths causing rounding errors on the LSB?).

    One thing you could do (if your soundcard has an SPDIF input) is capture the SPDIF out from the soundbridge back into your PC and save the resultant as a WAV. Then compare the original samples with the capture and see if they match up. Bet they don't!
     
  12. squadra

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    Hi Steve,

    I don't have a spdif input in my laptop, so I can't compare the streams.
    However, I guess you might be right about the altered streams.
    When I searched for HDCD on the roku forums I couldn't find anyone with problems, but some people are having similar problems with DTS encoded cd's.
    (i.e. http://www.rokulabs.com/forums/viewtopic.php?t=4775)

    btw, I have read that Martin can switch HDCD detection on/off via a remote.
    Do the same commands also work on my av32r 192bp?

    The HDCD detection is not switched of when the av32r goes into standby, I have to switch the device off and on to disable the detection.
     
  13. squadra

    squadra
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    I also posted this on the Roku forums, since they were beta testing a new firmware release.
    It was indeed a bug in the Roku, and it will be solved in the final release of the new firmware :thumbsup:
     

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