gstreamer/sys/osxaudio/gstosxringbuffer.c

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/*
* GStreamer
* Copyright (C) 2006 Zaheer Abbas Merali <zaheerabbas at merali dot org>
* Copyright (C) 2008 Pioneers of the Inevitable <songbird@songbirdnest.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*
* Alternatively, the contents of this file may be used under the
* GNU Lesser General Public License Version 2.1 (the "LGPL"), in
* which case the following provisions apply instead of the ones
* mentioned above:
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include <CoreAudio/CoreAudio.h>
#include <CoreServices/CoreServices.h>
#include <gst/gst.h>
#include <gst/audio/multichannel.h>
#include "gstosxringbuffer.h"
#include "gstosxaudiosink.h"
#include "gstosxaudiosrc.h"
GST_DEBUG_CATEGORY_STATIC (osx_audio_debug);
#define GST_CAT_DEFAULT osx_audio_debug
static void gst_osx_ring_buffer_dispose (GObject * object);
static void gst_osx_ring_buffer_finalize (GObject * object);
static gboolean gst_osx_ring_buffer_open_device (GstRingBuffer * buf);
static gboolean gst_osx_ring_buffer_close_device (GstRingBuffer * buf);
static gboolean gst_osx_ring_buffer_acquire (GstRingBuffer * buf,
GstRingBufferSpec * spec);
static gboolean gst_osx_ring_buffer_release (GstRingBuffer * buf);
static gboolean gst_osx_ring_buffer_start (GstRingBuffer * buf);
static gboolean gst_osx_ring_buffer_pause (GstRingBuffer * buf);
static gboolean gst_osx_ring_buffer_stop (GstRingBuffer * buf);
static guint gst_osx_ring_buffer_delay (GstRingBuffer * buf);
static GstRingBufferClass *ring_parent_class = NULL;
static OSStatus gst_osx_ring_buffer_render_notify (GstOsxRingBuffer * osxbuf,
AudioUnitRenderActionFlags * ioActionFlags,
const AudioTimeStamp * inTimeStamp, unsigned int inBusNumber,
unsigned int inNumberFrames, AudioBufferList * ioData);
static AudioBufferList *buffer_list_alloc (int channels, int size);
static void buffer_list_free (AudioBufferList * list);
static void
gst_osx_ring_buffer_do_init (GType type)
{
GST_DEBUG_CATEGORY_INIT (osx_audio_debug, "osxaudio", 0,
"OSX Audio Elements");
}
GST_BOILERPLATE_FULL (GstOsxRingBuffer, gst_osx_ring_buffer, GstRingBuffer,
GST_TYPE_RING_BUFFER, gst_osx_ring_buffer_do_init);
static void
gst_osx_ring_buffer_base_init (gpointer g_class)
{
/* Nothing to do right now */
}
static void
gst_osx_ring_buffer_class_init (GstOsxRingBufferClass * klass)
{
GObjectClass *gobject_class;
GstObjectClass *gstobject_class;
GstRingBufferClass *gstringbuffer_class;
gobject_class = (GObjectClass *) klass;
gstobject_class = (GstObjectClass *) klass;
gstringbuffer_class = (GstRingBufferClass *) klass;
ring_parent_class = g_type_class_peek_parent (klass);
gobject_class->dispose = gst_osx_ring_buffer_dispose;
gobject_class->finalize = gst_osx_ring_buffer_finalize;
gstringbuffer_class->open_device =
GST_DEBUG_FUNCPTR (gst_osx_ring_buffer_open_device);
gstringbuffer_class->close_device =
GST_DEBUG_FUNCPTR (gst_osx_ring_buffer_close_device);
gstringbuffer_class->acquire =
GST_DEBUG_FUNCPTR (gst_osx_ring_buffer_acquire);
gstringbuffer_class->release =
GST_DEBUG_FUNCPTR (gst_osx_ring_buffer_release);
gstringbuffer_class->start = GST_DEBUG_FUNCPTR (gst_osx_ring_buffer_start);
gstringbuffer_class->pause = GST_DEBUG_FUNCPTR (gst_osx_ring_buffer_pause);
gstringbuffer_class->resume = GST_DEBUG_FUNCPTR (gst_osx_ring_buffer_start);
gstringbuffer_class->stop = GST_DEBUG_FUNCPTR (gst_osx_ring_buffer_stop);
gstringbuffer_class->delay = GST_DEBUG_FUNCPTR (gst_osx_ring_buffer_delay);
GST_DEBUG ("osx ring buffer class init");
}
static void
gst_osx_ring_buffer_init (GstOsxRingBuffer * ringbuffer,
GstOsxRingBufferClass * g_class)
{
/* Nothing to do right now */
}
static void
gst_osx_ring_buffer_dispose (GObject * object)
{
G_OBJECT_CLASS (ring_parent_class)->dispose (object);
}
static void
gst_osx_ring_buffer_finalize (GObject * object)
{
G_OBJECT_CLASS (ring_parent_class)->finalize (object);
}
static AudioUnit
gst_osx_ring_buffer_create_audio_unit (GstOsxRingBuffer * osxbuf,
gboolean input, AudioDeviceID device_id)
{
ComponentDescription desc;
Component comp;
OSStatus status;
AudioUnit unit;
UInt32 enableIO;
/* Create a HALOutput AudioUnit.
* This is the lowest-level output API that is actually sensibly usable
* (the lower level ones require that you do channel-remapping yourself,
* and the CoreAudio channel mapping is sufficiently complex that doing
* so would be very difficult)
*
* Note that for input we request an output unit even though we will do
* input with it: http://developer.apple.com/technotes/tn2002/tn2091.html
*/
desc.componentType = kAudioUnitType_Output;
desc.componentSubType = kAudioUnitSubType_HALOutput;
desc.componentManufacturer = kAudioUnitManufacturer_Apple;
desc.componentFlags = 0;
desc.componentFlagsMask = 0;
comp = FindNextComponent (NULL, &desc);
if (comp == NULL) {
GST_WARNING_OBJECT (osxbuf, "Couldn't find HALOutput component");
return NULL;
}
status = OpenAComponent (comp, &unit);
if (status) {
GST_WARNING_OBJECT (osxbuf, "Couldn't open HALOutput component");
return NULL;
}
if (input) {
/* enable input */
enableIO = 1;
status = AudioUnitSetProperty (unit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Input, 1, /* 1 = input element */
&enableIO, sizeof (enableIO));
if (status) {
CloseComponent (unit);
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GST_WARNING_OBJECT (osxbuf, "Failed to enable input: %lx",
(gulong) status);
return NULL;
}
/* disable output */
enableIO = 0;
status = AudioUnitSetProperty (unit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Output, 0, /* 0 = output element */
&enableIO, sizeof (enableIO));
if (status) {
CloseComponent (unit);
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GST_WARNING_OBJECT (osxbuf, "Failed to disable output: %lx",
(gulong) status);
return NULL;
}
}
/* Specify which device we're using. */
GST_DEBUG_OBJECT (osxbuf, "Setting device to %d", (int) device_id);
status = AudioUnitSetProperty (unit, kAudioOutputUnitProperty_CurrentDevice, kAudioUnitScope_Global, 0, /* N/A for global */
&device_id, sizeof (AudioDeviceID));
if (status) {
CloseComponent (unit);
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GST_WARNING_OBJECT (osxbuf, "Failed to set device: %lx", (gulong) status);
return NULL;
}
GST_DEBUG_OBJECT (osxbuf, "Create HALOutput AudioUnit: %p", unit);
return unit;
}
static gboolean
gst_osx_ring_buffer_open_device (GstRingBuffer * buf)
{
GstOsxRingBuffer *osxbuf;
GstOsxAudioSink *sink;
GstOsxAudioSrc *src;
AudioStreamBasicDescription asbd_in;
OSStatus status;
UInt32 propertySize;
osxbuf = GST_OSX_RING_BUFFER (buf);
sink = NULL;
src = NULL;
osxbuf->audiounit = gst_osx_ring_buffer_create_audio_unit (osxbuf,
osxbuf->is_src, osxbuf->device_id);
if (osxbuf->is_src) {
src = GST_OSX_AUDIO_SRC (GST_OBJECT_PARENT (buf));
propertySize = sizeof (asbd_in);
status = AudioUnitGetProperty (osxbuf->audiounit,
kAudioUnitProperty_StreamFormat,
kAudioUnitScope_Input, 1, &asbd_in, &propertySize);
if (status) {
CloseComponent (osxbuf->audiounit);
osxbuf->audiounit = NULL;
GST_WARNING_OBJECT (osxbuf, "Unable to obtain device properties: %lx",
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(gulong) status);
return FALSE;
}
src->deviceChannels = asbd_in.mChannelsPerFrame;
} else {
sink = GST_OSX_AUDIO_SINK (GST_OBJECT_PARENT (buf));
/* needed for the sink's volume control */
sink->audiounit = osxbuf->audiounit;
}
return TRUE;
}
static gboolean
gst_osx_ring_buffer_close_device (GstRingBuffer * buf)
{
GstOsxRingBuffer *osxbuf;
osxbuf = GST_OSX_RING_BUFFER (buf);
CloseComponent (osxbuf->audiounit);
osxbuf->audiounit = NULL;
return TRUE;
}
static AudioChannelLabel
gst_audio_channel_position_to_coreaudio_channel_label (GstAudioChannelPosition
position, int channel)
{
switch (position) {
case GST_AUDIO_CHANNEL_POSITION_NONE:
return kAudioChannelLabel_Discrete_0 | channel;
case GST_AUDIO_CHANNEL_POSITION_FRONT_MONO:
return kAudioChannelLabel_Mono;
case GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT:
return kAudioChannelLabel_Left;
case GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT:
return kAudioChannelLabel_Right;
case GST_AUDIO_CHANNEL_POSITION_REAR_CENTER:
return kAudioChannelLabel_CenterSurround;
case GST_AUDIO_CHANNEL_POSITION_REAR_LEFT:
return kAudioChannelLabel_LeftSurround;
case GST_AUDIO_CHANNEL_POSITION_REAR_RIGHT:
return kAudioChannelLabel_RightSurround;
case GST_AUDIO_CHANNEL_POSITION_LFE:
return kAudioChannelLabel_LFEScreen;
case GST_AUDIO_CHANNEL_POSITION_FRONT_CENTER:
return kAudioChannelLabel_Center;
case GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER:
return kAudioChannelLabel_Center; // ???
case GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER:
return kAudioChannelLabel_Center; // ???
case GST_AUDIO_CHANNEL_POSITION_SIDE_LEFT:
return kAudioChannelLabel_LeftSurroundDirect;
case GST_AUDIO_CHANNEL_POSITION_SIDE_RIGHT:
return kAudioChannelLabel_RightSurroundDirect;
default:
return kAudioChannelLabel_Unknown;
}
}
static gboolean
gst_osx_ring_buffer_acquire (GstRingBuffer * buf, GstRingBufferSpec * spec)
{
/* Configure the output stream and allocate ringbuffer memory */
GstOsxRingBuffer *osxbuf;
AudioStreamBasicDescription format;
AudioChannelLayout *layout = NULL;
OSStatus status;
UInt32 propertySize;
int layoutSize;
int element;
int i;
int width, depth;
AudioUnitScope scope;
gboolean ret = FALSE;
GstStructure *structure;
GstAudioChannelPosition *positions;
UInt32 frameSize;
osxbuf = GST_OSX_RING_BUFFER (buf);
/* Fill out the audio description we're going to be using */
format.mFormatID = kAudioFormatLinearPCM;
format.mSampleRate = (double) spec->rate;
format.mChannelsPerFrame = spec->channels;
if (spec->type == GST_BUFTYPE_FLOAT) {
format.mFormatFlags = kAudioFormatFlagsNativeFloatPacked;
width = depth = spec->width;
} else {
format.mFormatFlags = kAudioFormatFlagIsSignedInteger;
width = spec->width;
depth = spec->depth;
if (width == depth) {
format.mFormatFlags |= kAudioFormatFlagIsPacked;
} else {
format.mFormatFlags |= kAudioFormatFlagIsAlignedHigh;
}
if (spec->bigend) {
format.mFormatFlags |= kAudioFormatFlagIsBigEndian;
}
}
format.mBytesPerFrame = spec->channels * (width >> 3);
format.mBitsPerChannel = depth;
format.mBytesPerPacket = spec->channels * (width >> 3);
format.mFramesPerPacket = 1;
format.mReserved = 0;
/* Describe channels */
layoutSize = sizeof (AudioChannelLayout) +
spec->channels * sizeof (AudioChannelDescription);
layout = g_malloc (layoutSize);
structure = gst_caps_get_structure (spec->caps, 0);
positions = gst_audio_get_channel_positions (structure);
layout->mChannelLayoutTag = kAudioChannelLayoutTag_UseChannelDescriptions;
layout->mChannelBitmap = 0; /* Not used */
layout->mNumberChannelDescriptions = spec->channels;
for (i = 0; i < spec->channels; i++) {
if (positions) {
layout->mChannelDescriptions[i].mChannelLabel =
gst_audio_channel_position_to_coreaudio_channel_label (positions[i],
i);
} else {
/* Discrete channel numbers are ORed into this */
layout->mChannelDescriptions[i].mChannelLabel =
kAudioChannelLabel_Discrete_0 | i;
}
/* Others unused */
layout->mChannelDescriptions[i].mChannelFlags = 0;
layout->mChannelDescriptions[i].mCoordinates[0] = 0.f;
layout->mChannelDescriptions[i].mCoordinates[1] = 0.f;
layout->mChannelDescriptions[i].mCoordinates[2] = 0.f;
}
if (positions) {
g_free (positions);
positions = NULL;
}
GST_LOG_OBJECT (osxbuf, "Format: %x, %f, %u, %x, %d, %d, %d, %d, %d",
(unsigned int) format.mFormatID,
format.mSampleRate,
(unsigned int) format.mChannelsPerFrame,
(unsigned int) format.mFormatFlags,
(unsigned int) format.mBytesPerFrame,
(unsigned int) format.mBitsPerChannel,
(unsigned int) format.mBytesPerPacket,
(unsigned int) format.mFramesPerPacket, (unsigned int) format.mReserved);
GST_DEBUG_OBJECT (osxbuf, "Setting format for AudioUnit");
scope = osxbuf->is_src ? kAudioUnitScope_Output : kAudioUnitScope_Input;
element = osxbuf->is_src ? 1 : 0;
propertySize = sizeof (format);
status = AudioUnitSetProperty (osxbuf->audiounit,
kAudioUnitProperty_StreamFormat, scope, element, &format, propertySize);
if (status) {
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GST_WARNING_OBJECT (osxbuf, "Failed to set audio description: %lx",
(gulong) status);
goto done;
}
status = AudioUnitSetProperty (osxbuf->audiounit,
kAudioUnitProperty_AudioChannelLayout,
scope, element, layout, layoutSize);
if (status) {
GST_WARNING_OBJECT (osxbuf, "Failed to set output channel layout: %lx",
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(gulong) status);
goto done;
}
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spec->segsize =
(spec->latency_time * spec->rate / G_USEC_PER_SEC) *
spec->bytes_per_sample;
spec->segtotal = spec->buffer_time / spec->latency_time;
/* create AudioBufferList needed for recording */
if (osxbuf->is_src) {
propertySize = sizeof (frameSize);
status = AudioUnitGetProperty (osxbuf->audiounit, kAudioDevicePropertyBufferFrameSize, kAudioUnitScope_Global, 0, /* N/A for global */
&frameSize, &propertySize);
if (status) {
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GST_WARNING_OBJECT (osxbuf, "Failed to get frame size: %lx",
(gulong) status);
goto done;
}
osxbuf->recBufferList = buffer_list_alloc (format.mChannelsPerFrame,
frameSize * format.mBytesPerFrame);
}
buf->data = gst_buffer_new_and_alloc (spec->segtotal * spec->segsize);
memset (GST_BUFFER_DATA (buf->data), 0, GST_BUFFER_SIZE (buf->data));
osxbuf->segoffset = 0;
status = AudioUnitInitialize (osxbuf->audiounit);
if (status) {
gst_buffer_unref (buf->data);
buf->data = NULL;
if (osxbuf->recBufferList) {
buffer_list_free (osxbuf->recBufferList);
osxbuf->recBufferList = NULL;
}
GST_WARNING_OBJECT (osxbuf,
"Failed to initialise AudioUnit: %d", (int) status);
goto done;
}
GST_DEBUG_OBJECT (osxbuf, "osx ring buffer acquired");
ret = TRUE;
done:
g_free (layout);
return ret;
}
static gboolean
gst_osx_ring_buffer_release (GstRingBuffer * buf)
{
GstOsxRingBuffer *osxbuf;
osxbuf = GST_OSX_RING_BUFFER (buf);
AudioUnitUninitialize (osxbuf->audiounit);
gst_buffer_unref (buf->data);
buf->data = NULL;
if (osxbuf->recBufferList) {
buffer_list_free (osxbuf->recBufferList);
osxbuf->recBufferList = NULL;
}
return TRUE;
}
static void
gst_osx_ring_buffer_remove_render_callback (GstOsxRingBuffer * osxbuf)
{
AURenderCallbackStruct input;
OSStatus status;
/* Deactivate the render callback by calling SetRenderCallback with a NULL
* inputProc.
*/
input.inputProc = NULL;
input.inputProcRefCon = NULL;
status = AudioUnitSetProperty (osxbuf->audiounit, kAudioUnitProperty_SetRenderCallback, kAudioUnitScope_Global, 0, /* N/A for global */
&input, sizeof (input));
if (status) {
GST_WARNING_OBJECT (osxbuf, "Failed to remove render callback");
}
/* Remove the RenderNotify too */
status = AudioUnitRemoveRenderNotify (osxbuf->audiounit,
(AURenderCallback) gst_osx_ring_buffer_render_notify, osxbuf);
if (status) {
GST_WARNING_OBJECT (osxbuf, "Failed to remove render notify callback");
}
/* We're deactivated.. */
osxbuf->io_proc_needs_deactivation = FALSE;
osxbuf->io_proc_active = FALSE;
}
static OSStatus
gst_osx_ring_buffer_render_notify (GstOsxRingBuffer * osxbuf,
AudioUnitRenderActionFlags * ioActionFlags,
const AudioTimeStamp * inTimeStamp,
unsigned int inBusNumber,
unsigned int inNumberFrames, AudioBufferList * ioData)
{
/* Before rendering a frame, we get the PreRender notification.
* Here, we detach the RenderCallback if we've been paused.
*
* This is necessary (rather than just directly detaching it) to work
* around some thread-safety issues in CoreAudio
*/
if ((*ioActionFlags) & kAudioUnitRenderAction_PreRender) {
if (osxbuf->io_proc_needs_deactivation) {
gst_osx_ring_buffer_remove_render_callback (osxbuf);
}
}
return noErr;
}
static gboolean
gst_osx_ring_buffer_start (GstRingBuffer * buf)
{
OSStatus status;
GstOsxRingBuffer *osxbuf;
AURenderCallbackStruct input;
AudioUnitPropertyID callback_type;
osxbuf = GST_OSX_RING_BUFFER (buf);
GST_DEBUG ("osx ring buffer start ioproc: 0x%p device_id %lu",
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osxbuf->element->io_proc, (gulong) osxbuf->device_id);
if (!osxbuf->io_proc_active) {
callback_type = osxbuf->is_src ?
kAudioOutputUnitProperty_SetInputCallback :
kAudioUnitProperty_SetRenderCallback;
input.inputProc = (AURenderCallback) osxbuf->element->io_proc;
input.inputProcRefCon = osxbuf;
status = AudioUnitSetProperty (osxbuf->audiounit, callback_type, kAudioUnitScope_Global, 0, /* N/A for global */
&input, sizeof (input));
if (status) {
GST_WARNING ("AudioUnitSetProperty returned %d", (int) status);
return FALSE;
}
// ### does it make sense to do this notify stuff for input mode?
status = AudioUnitAddRenderNotify (osxbuf->audiounit,
(AURenderCallback) gst_osx_ring_buffer_render_notify, osxbuf);
if (status) {
GST_WARNING ("AudioUnitAddRenderNotify returned %d", (int) status);
return FALSE;
}
osxbuf->io_proc_active = TRUE;
}
osxbuf->io_proc_needs_deactivation = FALSE;
status = AudioOutputUnitStart (osxbuf->audiounit);
if (status) {
GST_WARNING ("AudioOutputUnitStart returned %d", (int) status);
return FALSE;
}
return TRUE;
}
// ###
static gboolean
gst_osx_ring_buffer_pause (GstRingBuffer * buf)
{
GstOsxRingBuffer *osxbuf = GST_OSX_RING_BUFFER (buf);
GST_DEBUG ("osx ring buffer pause ioproc: 0x%p device_id %lu",
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osxbuf->element->io_proc, (gulong) osxbuf->device_id);
if (osxbuf->io_proc_active) {
/* CoreAudio isn't threadsafe enough to do this here; we must deactivate
* the render callback elsewhere. See:
* http://lists.apple.com/archives/Coreaudio-api/2006/Mar/msg00010.html
*/
osxbuf->io_proc_needs_deactivation = TRUE;
}
return TRUE;
}
// ###
static gboolean
gst_osx_ring_buffer_stop (GstRingBuffer * buf)
{
OSErr status;
GstOsxRingBuffer *osxbuf;
osxbuf = GST_OSX_RING_BUFFER (buf);
GST_DEBUG ("osx ring buffer stop ioproc: 0x%p device_id %lu",
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osxbuf->element->io_proc, (gulong) osxbuf->device_id);
status = AudioOutputUnitStop (osxbuf->audiounit);
if (status)
GST_WARNING ("AudioOutputUnitStop returned %d", (int) status);
// ###: why is it okay to directly remove from here but not from pause() ?
if (osxbuf->io_proc_active) {
gst_osx_ring_buffer_remove_render_callback (osxbuf);
}
return TRUE;
}
static guint
gst_osx_ring_buffer_delay (GstRingBuffer * buf)
{
double latency;
UInt32 size = sizeof (double);
GstOsxRingBuffer *osxbuf;
OSStatus status;
guint samples;
osxbuf = GST_OSX_RING_BUFFER (buf);
status = AudioUnitGetProperty (osxbuf->audiounit, kAudioUnitProperty_Latency, kAudioUnitScope_Global, 0, /* N/A for global */
&latency, &size);
if (status) {
GST_WARNING_OBJECT (buf, "Failed to get latency: %d", (int) status);
return 0;
}
samples = latency * GST_RING_BUFFER (buf)->spec.rate;
GST_DEBUG_OBJECT (buf, "Got latency: %f seconds -> %d samples", latency,
samples);
return samples;
}
static AudioBufferList *
buffer_list_alloc (int channels, int size)
{
AudioBufferList *list;
int total_size;
int n;
total_size = sizeof (AudioBufferList) + 1 * sizeof (AudioBuffer);
list = (AudioBufferList *) g_malloc (total_size);
list->mNumberBuffers = 1;
for (n = 0; n < (int) list->mNumberBuffers; ++n) {
list->mBuffers[n].mNumberChannels = channels;
list->mBuffers[n].mDataByteSize = size;
list->mBuffers[n].mData = g_malloc (size);
}
return list;
}
static void
buffer_list_free (AudioBufferList * list)
{
int n;
for (n = 0; n < (int) list->mNumberBuffers; ++n) {
if (list->mBuffers[n].mData)
g_free (list->mBuffers[n].mData);
}
g_free (list);
}