Add microphone support via a new driver

AUTHORS.h

@@ -231,6 +231,7 @@ Jean-Sébastien Guay (Skylark13)
 Jeff (jeffbdavenport)
 Jeff Sousa (LordeIlluminati)
 jess (winneon)
+Jesse Talavera-Greenberg (JesseTG)
 Joan Coll Cerdán (johanbcn)
 Job Adrian Salinas Gonzalez (efylan)
 Joe Osborn (JoeOsborn)

CHANGES.md

@@ -1,4 +1,9 @@
 # Future
+- LIBRETRO/MICROPHONE: Add new API for microphone support.
+- MICROPHONE: Add support for microphones.
+- MICROPHONE/ALSA: Add `alsa` and `alsathread` microphone drivers.
+- MICROPHONE/SDL: Add `sdl2` microphone driver.
+- MICROPHONE/WASAPI: Add `wasapi` microphone driver.
 
 # 1.15.0
 - AI SERVICE: Fix NVDA switching to Powershell on speak
@@ -116,8 +121,9 @@ as well. Without this, sound files can not be opened from file browser with core
 - MENU/CHEATS: Fixed label capitalization in cheats (Add New After/Before This)
 - MENU/SOUNDS: Add scrolling sounds for RGUI, XMB, MaterialUI and Ozone.
 - MENU/SOUNDS: Better scrolling sound implementation, add new 'notice back' sound
-- MENU/SOUNDS: Scroll sound fixes. Correctly get list size in xmb.c for playing scrolling sound when switching categories, play the scrolling sound when pressing cancel in ozone, play the sound when scrolling with ZL and ZR, play the correct sound when scrolling with L- MIYOO: L3/R3 support for Dingux Gamepad controller device.
+- MENU/SOUNDS: Scroll sound fixes. Correctly get list size in xmb.c for playing scrolling sound when switching categories, play the scrolling sound when pressing cancel in ozone, play the sound when scrolling with ZL and ZR, play the correct sound when scrolling with L
 - MENU/WIDGETS: Show square sized widget on volume mute. Volume widget is currently fixed size always, and thus showing a lot of empty space when muting, therefore shorten the box to icon size only when muting.
+- MIYOO: L3/R3 support for Dingux Gamepad controller device.
 - NETWORKING: Call ssl_socket_close for SSL sockets
 - NETWORKING/CHEEVOS: net_http - Temporary fix for cheevos crash. Don't use new timeout/poll code for cheevos HTTP requests.
 - NETWORKING/MENU: Network information cleanup:

Makefile.common

@@ -327,6 +327,11 @@ OBJ += \
        cores/dynamic_dummy.o \
        $(LIBRETRO_COMM_DIR)/queues/message_queue.o
 
+ifeq ($(HAVE_MICROPHONE), 1)
+   DEFINES += -DHAVE_MICROPHONE
+   OBJ += audio/microphone_driver.o
+endif
+
 ifeq ($(HAVE_REWIND), 1)
 DEFINES += -DHAVE_REWIND
 OBJ     += state_manager.o
@@ -820,7 +825,12 @@ endif
 endif
 
 ifeq ($(HAVE_ALSA), 1)
-   OBJ += audio/drivers/alsa.o
+   OBJ += audio/drivers/alsa.o \
+          audio/common/alsa.o
+
+   ifeq ($(HAVE_MICROPHONE), 1)
+      OBJ += audio/drivers_microphone/alsa.o
+   endif
 
    ifneq ($(HAVE_HAKCHI), 1)
       ifneq ($(HAVE_SEGAM), 1)
@@ -832,7 +842,12 @@ ifeq ($(HAVE_ALSA), 1)
 
    ifneq ($(MIYOO), 1)
       ifeq ($(HAVE_THREADS), 1)
-         OBJ += audio/drivers/alsathread.o
+         OBJ += audio/drivers/alsathread.o \
+                audio/common/alsathread.o
+
+         ifeq ($(HAVE_MICROPHONE), 1)
+            OBJ += audio/drivers_microphone/alsathread.o
+         endif
       endif
    endif
 
@@ -895,9 +910,14 @@ endif
 
 ifeq ($(HAVE_WASAPI), 1)
 	HAVE_MMDEVAPI = 1
-   OBJ += audio/drivers/wasapi.o
+   OBJ += audio/drivers/wasapi.o \
+          audio/common/wasapi.o
    DEFINES += -DHAVE_WASAPI
    LIBS += -lole32 -lksuser
+
+   ifeq ($(HAVE_MICROPHONE), 1)
+      OBJ += audio/drivers_microphone/wasapi.o
+      endif
 endif
 
 ifeq ($(HAVE_XAUDIO), 1)
@@ -928,7 +948,9 @@ ifeq ($(HAVE_NEON),1)
 endif
 
 OBJ += $(LIBRETRO_COMM_DIR)/audio/conversion/s16_to_float.o \
-       $(LIBRETRO_COMM_DIR)/audio/conversion/float_to_s16.o
+       $(LIBRETRO_COMM_DIR)/audio/conversion/float_to_s16.o \
+       $(LIBRETRO_COMM_DIR)/audio/conversion/mono_to_stereo_float.o \
+       $(LIBRETRO_COMM_DIR)/audio/conversion/stereo_to_mono_float.o \
 
 ifeq ($(HAVE_RWAV), 1)
 DEFINES += -DHAVE_RWAV
@@ -1540,6 +1562,11 @@ ifeq ($(HAVE_SDL2), 1)
 			 gfx/common/sdl2_common.o
    DEF_FLAGS += $(SDL2_CFLAGS)
    LIBS += $(SDL2_LIBS)
+
+   ifeq ($(HAVE_MICROPHONE), 1)
+      OBJ += audio/drivers_microphone/sdl_microphone.o
+      # Microphones are not supported by SDL 1.x
+   endif
 else ifeq ($(HAVE_SDL), 1)
    HAVE_SDL_COMMON = 1
    OBJ += gfx/drivers/sdl_gfx.o

audio/audio_defines.h

@@ -83,17 +83,87 @@ enum audio_mixer_state
    AUDIO_STREAM_STATE_PLAYING_SEQUENTIAL
 };
 
+/**
+ * Bit flags that describe the current state of the audio driver.
+ */
 enum audio_driver_state_flags
 {
+   /**
+    * Indicates that the driver was successfully created
+    * and is currently valid.
+    * You may submit samples for output at any time.
+    *
+    * This flag does \em not mean that the player will hear anything;
+    * the driver might be suspended.
+    *
+    * @see AUDIO_FLAG_SUSPENDED
+    */
    AUDIO_FLAG_ACTIVE       = (1 << 0),
+
+   /**
+    * Indicates that the audio driver outputs floating-point samples,
+    * as opposed to integer samples.
+    *
+    * All audio is sent through the resampler,
+    * which operates on floating-point samples.
+    *
+    * If this flag is set, then the resampled output doesn't need
+    * to be converted back to \c int16_t format.
+    *
+    * This won't affect the audio that the core writes;
+    * either way, it's supposed to output \c int16_t samples.
+    *
+    * This flag won't be set if the selected audio driver
+    * doesn't support (or is configured to not use) \c float samples.
+    *
+    * @see audio_driver_t::use_float
+    */
    AUDIO_FLAG_USE_FLOAT    = (1 << 1),
+
+   /**
+    * Indicates that the audio driver is not currently rendering samples,
+    * although it's valid and can be resumed.
+    *
+    * Usually set when RetroArch needs to simulate audio output
+    * without actually rendering samples (e.g. runahead),
+    * or when reinitializing the driver.
+    *
+    * Samples will still be accepted, but they will be silently dropped.
+    */
    AUDIO_FLAG_SUSPENDED    = (1 << 2),
+
+   /**
+    * Indicates that the audio mixer is available
+    * and can mix one or more audio streams.
+    *
+    * Will not be set if RetroArch was built without \c HAVE_AUDIOMIXER.
+    */
    AUDIO_FLAG_MIXER_ACTIVE = (1 << 3),
+
+   /**
+    * Indicates that the frontend will never need audio from the core,
+    * usually when runahead is active.
+    *
+    * When set, any audio received by the core will not be processed.
+    *
+    * Will not be set if RetroArch was built without \c HAVE_RUNAHEAD.
+    *
+    * @see RETRO_ENVIRONMENT_GET_AUDIO_VIDEO_ENABLE
+    */
    AUDIO_FLAG_HARD_DISABLE = (1 << 4),
+
+   /**
+    * Indicates that audio rate control is enabled.
+    * This means that the audio system will adjust the rate at which
+    * it sends samples to the driver,
+    * minimizing the occurrences of buffer overrun or underrun.
+    *
+    * @see audio_driver_t::write_avail
+    * @see audio_driver_t::buffer_size
+    */
    AUDIO_FLAG_CONTROL      = (1 << 5)
 };
 
-
 typedef struct audio_statistics
 {
    unsigned samples;