coreaudio: correctly apply mute/volume adjustments

Author: warmenhoven

audio/audio_driver.c

@@ -492,7 +492,7 @@ static void audio_driver_flush(audio_driver_state_t *audio_st,
 
       /* Note: mute/volume is not applied here - driver must handle or ignore */
       audio_st->current_audio->write_raw(audio_st->context_audio_data,
-            data, frames, input_rate, rate_adjust);
+            data, frames, input_rate, rate_adjust, audio_volume_gain);
       return;
    }
 

audio/audio_driver.h

@@ -170,17 +170,19 @@ typedef struct audio_driver
     * Optional. Write raw int16 samples with resampling handled by driver.
     * If non-NULL, audio_driver will call this instead of doing software
     * resampling. The driver is responsible for resampling from input_rate
-    * to its output rate, applying the rate_adjust factor for A/V sync.
+    * to its output rate, applying the rate_adjust factor for A/V sync,
+    * and applying the volume gain to the output.
     *
     * @param data        Driver context
     * @param samples     Interleaved int16 stereo samples (LRLRLR...)
     * @param frames      Number of frames (pairs of samples)
     * @param input_rate  Source sample rate in Hz
     * @param rate_adjust Rate adjustment multiplier for A/V sync (1.0 = normal)
+    * @param volume      Volume gain to apply (0.0 = muted, 1.0 = full volume)
     * @return Number of frames written, or -1 on error
     */
    ssize_t (*write_raw)(void *data, const int16_t *samples, size_t frames,
-         unsigned input_rate, double rate_adjust);
+         unsigned input_rate, double rate_adjust, float volume);
 } audio_driver_t;
 
 typedef struct

audio/drivers/coreaudio.c

@@ -30,6 +30,11 @@
 #include <AudioUnit/AudioUnit.h>
 #include <AudioUnit/AUComponent.h>
 
+/* Nb is defined by AES code included earlier in griffin.c amalgamation.
+ * It conflicts with Sparse BLAS headers in Accelerate, so undefine it. */
+#undef Nb
+#include <Accelerate/Accelerate.h>
+
 #include <boolean.h>
 #include <retro_endianness.h>
 #include <string/stdstring.h>
@@ -591,7 +596,7 @@ static ssize_t coreaudio_write(void *data, const void *buf_, size_t len)
 
 /* Write raw int16 samples with hardware-accelerated resampling */
 static ssize_t coreaudio_write_raw(void *data, const int16_t *samples,
-      size_t frames, unsigned input_rate, double rate_adjust)
+      size_t frames, unsigned input_rate, double rate_adjust, float volume)
 {
    coreaudio_t *dev = (coreaudio_t*)data;
    double effective_rate;
@@ -639,6 +644,11 @@ static ssize_t coreaudio_write_raw(void *data, const int16_t *samples,
       if (output_frames == 0)
          break;
 
+      /* Apply volume to converted samples */
+      if (volume != 1.0f)
+         vDSP_vsmul(dev->conv_buffer, 1, &volume,
+               dev->conv_buffer, 1, (vDSP_Length)(output_frames * 2));
+
       /* Write converted samples to ring buffer */
       {
          float *out_ptr     = dev->conv_buffer;

audio/drivers/coreaudio3.m

@@ -16,6 +16,7 @@
 #import <Foundation/Foundation.h>
 #import <AudioToolbox/AudioToolbox.h>
 #import <AVFoundation/AVFoundation.h>
+#import <Accelerate/Accelerate.h>
 
 #include <stdio.h>
 #include <stdatomic.h>
@@ -197,7 +198,8 @@ - (ssize_t)writeFloat:(const float *)data samples:(size_t)samples;
 - (ssize_t)writeRawInt16:(const int16_t *)samples
                   frames:(size_t)frames
                inputRate:(unsigned)inputRate
-              rateAdjust:(double)rateAdjust;
+              rateAdjust:(double)rateAdjust
+                  volume:(float)volume;
 - (void)start;
 - (void)stop;
 
@@ -408,7 +410,8 @@ static OSStatus coreaudio3_converter_cb(
 - (ssize_t)writeRawInt16:(const int16_t *)samples
                   frames:(size_t)frames
                inputRate:(unsigned)inputRate
-              rateAdjust:(double)rateAdjust {
+              rateAdjust:(double)rateAdjust
+                  volume:(float)volume {
    OSStatus err;
    double effectiveRate;
    size_t framesWritten = 0;
@@ -500,8 +503,12 @@ - (ssize_t)writeRawInt16:(const int16_t *)samples
       if (outputFrames == 0)
          break;
 
-      /* Write resampled float data to ring buffer */
+      /* Apply volume to converted samples */
       outputSamples = outputFrames * 2;
+      if (volume != 1.0f)
+         vDSP_vsmul(_convBuffer, 1, &volume, _convBuffer, 1, (vDSP_Length)outputSamples);
+
+      /* Write resampled float data to ring buffer */
       written = [self writeFloat:_convBuffer samples:outputSamples];
 
       if (written > 0)
@@ -607,7 +614,7 @@ static size_t coreaudio3_buffer_size(void *data)
 }
 
 static ssize_t coreaudio3_write_raw(void *data, const int16_t *samples,
-      size_t frames, unsigned input_rate, double rate_adjust)
+      size_t frames, unsigned input_rate, double rate_adjust, float volume)
 {
    CoreAudio3 *dev = (__bridge CoreAudio3 *)data;
    if (dev == nil)
@@ -616,7 +623,8 @@ static ssize_t coreaudio3_write_raw(void *data, const int16_t *samples,
    return [dev writeRawInt16:samples
                       frames:frames
                    inputRate:input_rate
-                  rateAdjust:rate_adjust];
+                  rateAdjust:rate_adjust
+                      volume:volume];
 }
 
 audio_driver_t audio_coreaudio3 = {