INTERACT FORUM

Please login or register.

Login with username, password and session length
Advanced search  
Pages: [1]   Go Down

Author Topic: Sample Rate Conversion: DSD256 downsample to DSD64 questions, issues  (Read 3567 times)

jeremya

  • Recent member
  • *
  • Posts: 5

Questions:
1. When using the 'Convert Format' tool to change the sample rate of a DSD (dsf) file (say, hypothetically, DSD256 -> DSD64), does the conversion engine use PCM as an intermediary format (DSD -> PCM -> DSD), or does it re-sample purely in the DSD domain?

2. Similar to #1, when selecting to output *everything* to DSD (1x, 2x, etc.) via DSP Studio, if a DSD source is played back does the data get converted to PCM as an intermediary on-the-fly, or does the re-sampling to the chosen DSD sample rate happen purely in the DSD domain?


Problem I'm having:
Scenario #2 results in stuttered playback. Given DSD256 and told to output DSD64 (via DoP), My DAC reports DSD, but it constantly judders/hiccups like an old Nintendo game being played with a slow-motion controller.

Re-sampling the same source to PCM (by specifying that everything >32/384 be converted to 32/352.8) works fine and sounds good, but I know my DAC has some DSD-related goodness that I'm skipping by going this route.

Salient System Details:
Media Center 20.0.131 on Windows 10
Light Harmonic Geek Out (plays 32/384 and DSD64 (via DoP))
Light Harmonic Lightspeed 10G cable


Logged

dtc

  • MC Beta Team
  • Citizen of the Universe
  • *****
  • Posts: 3019
Re: Sample Rate Conversion: DSD256 downsample to DSD64 questions, issues
« Reply #1 on: August 16, 2015, 08:29:00 am »

First, I presume a DSD 64 track plays without problem and the only problem is when doing real time conversion.

DSD to DSD conversions go through PCM.

http://yabb.jriver.com/interact/index.php?topic=94936.msg653851#msg653851

The PCM to DSD conversion is probably causing your stuttering. Converting from PCM to DSD takes a lot of compute power and you need a relatively fast system to do the conversion on the fly. If I remember correctly, a JMARK of 2500 or so is usually considered a minimum. If the system cannot keep up with the real time conversion then you get stuttering and buffering problems. Converting DSD to PCM is a much easier load on the computer. You can check your JMARK under the Help tab.

You may need to convert your 2x or 4x DSD to 1x DSD files if you computer is not up to the task of real time conversion. Unfortunately, you need a different conversion tool than MC is you want to avoid the PCM conversion.
Logged

jeremya

  • Recent member
  • *
  • Posts: 5
Re: Sample Rate Conversion: DSD256 downsample to DSD64 questions, issues
« Reply #2 on: August 17, 2015, 03:13:10 pm »

Thanks for the info on the DSD conversion route.

Just ran a benchmark and got JRMark (version 20.0.131): 4064... so I'm well over the minimum. (Math in particular, otoh, was just above 2400 at 2414 (See below), so that could be the culprit?)


=== Running Benchmarks (please do not interrupt) ===

Running 'Math' benchmark...
    Single-threaded integer math... 3.924 seconds
    Single-threaded floating point math... 2.597 seconds
    Multi-threaded integer math... 0.733 seconds
    Multi-threaded mixed math... 0.619 seconds
Score: 2414

Running 'Image' benchmark...
    Image creation / destruction... 0.637 seconds
    Flood filling... 0.516 seconds
    Direct copying... 0.295 seconds
    Small renders... 1.288 seconds
    Bilinear rendering... 0.896 seconds
    Bicubic rendering... 0.551 seconds
Score: 5259

Running 'Database' benchmark...
    Create database... 0.276 seconds
    Populate database... 1.281 seconds
    Save database... 0.332 seconds
    Reload database... 0.066 seconds
    Search database... 0.961 seconds
    Sort database... 1.156 seconds
    Group database... 0.683 seconds
Score: 4521

Logged

dtc

  • MC Beta Team
  • Citizen of the Universe
  • *****
  • Posts: 3019
Re: Sample Rate Conversion: DSD256 downsample to DSD64 questions, issues
« Reply #3 on: August 17, 2015, 04:10:04 pm »

No expert, but from what I have read, you machine should be OK. The 2500 is from memory and may be low, but I would think 4000 would be OK. How does re-sampling PCM to DSD on the fly do? Does straight 1x DSD play OK?
Logged
Pages: [1]   Go Up