Add options to disable Pulse's and ALSA's resamplers

3 files changed, 22 insertions, 4 deletions

diff --git a/Alc/backends/alsa.c b/Alc/backends/alsa.c
index 97723cae..9a443c09 100644
--- a/Alc/backends/alsa.c
+++ b/Alc/backends/alsa.c
@@ -770,8 +770,11 @@ static ALCboolean ALCplaybackAlsa_reset(ALCplaybackAlsa *self)
     }
     CHECK(snd_pcm_hw_params_set_channels(self->pcmHandle, hp, ChannelsFromDevFmt(device->FmtChans)));
     /* set rate (implicitly constrains period/buffer parameters) */
-    if(snd_pcm_hw_params_set_rate_resample(self->pcmHandle, hp, 0) < 0)
-        ERR("Failed to disable ALSA resampler\n");
+    if(GetConfigValueBool(al_string_get_cstr(device->DeviceName), "alsa", "allow-resampler", 0))
+    {
+        if(snd_pcm_hw_params_set_rate_resample(self->pcmHandle, hp, 0) < 0)
+            ERR("Failed to disable ALSA resampler\n");
+    }
     CHECK(snd_pcm_hw_params_set_rate_near(self->pcmHandle, hp, &rate, NULL));
     /* set buffer time (implicitly constrains period/buffer parameters) */
     if((err=snd_pcm_hw_params_set_buffer_time_near(self->pcmHandle, hp, &bufferLen, NULL)) < 0)
diff --git a/Alc/backends/pulseaudio.c b/Alc/backends/pulseaudio.c
index ffbf04b2..9ad04a71 100644
--- a/Alc/backends/pulseaudio.c
+++ b/Alc/backends/pulseaudio.c
@@ -950,7 +950,8 @@ static ALCboolean ALCpulsePlayback_reset(ALCpulsePlayback *self)
                                          ALCpulsePlayback_sinkInfoCallback, self);
     wait_for_operation(o, self->loop);
 
-    if(!(device->Flags&DEVICE_FREQUENCY_REQUEST))
+    if(GetConfigValueBool(al_string_get_cstr(device->DeviceName), "pulse", "fix-rate", 0) ||
+       !(device->Flags&DEVICE_FREQUENCY_REQUEST))
         flags |= PA_STREAM_FIX_RATE;
     flags |= PA_STREAM_INTERPOLATE_TIMING | PA_STREAM_AUTO_TIMING_UPDATE;
     flags |= PA_STREAM_ADJUST_LATENCY;
diff --git a/alsoftrc.sample b/alsoftrc.sample
index 3e7494dd..d40e6c37 100644
--- a/alsoftrc.sample
+++ b/alsoftrc.sample
@@ -132,7 +132,7 @@
 #  sinc4 - extrapolates samples using a 4-point Sinc filter
 #  sinc8 - extrapolates samples using an 8-point Sinc filter
 #  bsinc - extrapolates samples using a band-limited Sinc filter (varying
-#          between 12 and 24 points)
+#          between 12 and 24 points, with anti-aliasing)
 #  Specifying other values will result in using the default (linear).
 #resampler = linear
 
@@ -227,6 +227,13 @@
 #  etc).
 #allow-moves = false
 
+## fix-rate:
+#  Specifies whether to match the playback device's sample rate to the hardware
+#  device's sample rate. Enabling this allows OpenAL Soft to resample sources
+#  directly to the actual output rate, avoiding a second resample pass by the
+#  PulseAudio server.
+#fix-rate = false
+
 ##
 ## ALSA backend stuff
 ##
@@ -273,6 +280,13 @@
 #  and anything else will force mmap off.
 #mmap = true
 
+## allow-resampler:
+#  Specifies whether to allow ALSA's built-in resampler. Enabling this will
+#  allow the playback device to be set to a different sample rate than the
+#  actual output, causing ALSA to apply its own resampling pass after OpenAL
+#  Soft resamples and mixes the sources and effects for output.
+#allow-resampler = false
+
 ##
 ## OSS backend stuff
 ##