Author Topic: Tip: options for bit-perfect playback  (Read 1317 times)


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Tip: options for bit-perfect playback
« on: 11 Jan '16 - 18:36 »
Since there is no single GUI button or options checkbox for bit-perfect playback, I wanted to document the exact options needed for bit-perfect playback in the "Options and stuff" menu for XMPlay v3.8.2.

Bit-perfect playback requires bypassing the Windows mixer.  This can be achieved with WASAPI and ASIO output plug-ins (and maybe others).  My external DAC driver supports both WASAPI and ASIO.  While playing a 24-bit WAV track in XMPlay, I switched back-and-forth between the two outputs in real time, and I found WASAPI (in exclusive mode) to sound better.  My ASIO driver may have a distorting mixer to support playback by multiple applications simultaneously.  ASIO may be bit-perfect for other DAC devices, but I am recommending WASAPI here since I confirmed it.  Install the WASAPI plug-in from here before proceeding:

DSP section:
uncheck Equalizer
uncheck Reverb
Amplification = +0.0 dB
Auto-amp = off
Replaygain = off
pre-amp = +0.0

Output section:
Device = WASAPI - device
Resolution = 24 bit (match your listening device)
uncheck Apply sample rate for all file formats
uncheck Downmix multi-channel
uncheck Dithering
uncheck Noise shaping

Output\WASAPI section:
check Enable (Exclusive mode)
check Use highest available resolution

I assume that "Sample rate" in the Output section is unused when "Use highest available resolution" is checked in the Output\WASAPI section.

Did I miss anything?

Some nice 24-bit WAV files for testing (especially the 192-kHz ones) are here:
« Last Edit: 11 Jan '16 - 19:03 by QuarterNote »

Ian @ un4seen

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Re: Tip: options for bit-perfect playback
« Reply #1 on: 12 Jan '16 - 15:20 »
That all looks correct. Basically, you want to avoid anything that will modify the data, which means no DSP and no resampling. "Resolution" doesn't really need to be set as it will be overridden when "Use highest available resolution" is enabled. The "Sample rate" setting is only used for file formats that don't have a defined sample rate (eg. MOD and MIDI) or when "Apply sample rate for all file formats" is enabled.

I guess it could useful to have a "bypass DSP" switch, to make it easier/quicker to get bit-perfect output when wanted. I'll look into that.