ShuriZma
/
BizHawk
mirror of https://github.com/TASEmulators/BizHawk.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

SoundOutputProvider: Small improvements to resampling (round instead of truncate and noise shaping) - probably inaudible.

This commit is contained in:
jdpurcell 2015-01-24 21:52:27 +00:00
parent 779d7c0cee
commit a04982bc84
1 changed files with 15 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
BizHawk.Client.EmuHawk/SoundOutputProvider.cs
View File

@ -163,8 +163,8 @@ namespace BizHawk.Client.EmuHawk
}
}
double newCountTarget = count * scaleFactor;
int newCount = (int)Math.Round(newCountTarget + _resampleLengthRoundingError);
double newCountExact = (count * scaleFactor) + _resampleLengthRoundingError;
int newCount = (int)Math.Round(newCountExact);
// Due to small inaccuracies and rounding errors, it's pointless to resample by
// just a sample or two because those may be fluctuations that will average out
// over time. So instead of immediately resampling to cover small differences, we
@ -179,7 +179,7 @@ namespace BizHawk.Client.EmuHawk
// time so we need to keep track of it. With NTSC @ 59.94 FPS, for example, if we
// were to always round to 736 samples per frame ignoring the rounding error, we
// would drift by ~22 milliseconds per minute.
_resampleLengthRoundingError += newCountTarget - count;
_resampleLengthRoundingError = newCountExact - count;
AddSamplesToBuffer(samples, count);
}
@ -236,6 +236,7 @@ namespace BizHawk.Client.EmuHawk
return output;
}
double roundingError = 0.0;
for (int iOutput = 0; iOutput < outputCount; iOutput++)
{
double iInput = ((double)iOutput / (outputCount - 1)) * (inputCount - 1);
@ -249,9 +250,17 @@ namespace BizHawk.Client.EmuHawk
for (int iChannel = 0; iChannel < ChannelCount; iChannel++)
{
output[iOutput * ChannelCount + iChannel] = (short)
(input[iInput0 * ChannelCount + iChannel] * input0Weight +
input[iInput1 * ChannelCount + iChannel] * input1Weight);
double valueExact =
input[iInput0 * ChannelCount + iChannel] * input0Weight +
input[iInput1 * ChannelCount + iChannel] * input1Weight +
roundingError;
if (valueExact < -32768.0) valueExact = -32768.0;
if (valueExact > 32767.0) valueExact = 32767.0;
short value = (short)((int)(valueExact + 32768.5) - 32768);
output[iOutput * ChannelCount + iChannel] = value;
roundingError = valueExact - value;
}
}