audio_output_coreaudio.c

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/*
 * Copyright (c) 2006-2009 Ed Schouten <ed@80386.nl>
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
#include "stdinc.h"

#include <CoreAudio/AudioHardware.h>

#include "audio_file.h"
#include "audio_output.h"
#include "gui.h"

/*
 * A small problem with CoreAudio is that it doesn't actually have a
 * standard blocking push-interface such as OSS or ALSA. We have to
 * install a routine in the audio layer that gets called routinely to
 * pull data from buffers.
 *
 * According to a discussion on the CoreAudio mailing list, we can't use
 * stuff such as spinlocks from within this callback routine (probably
 * served through some kind of interrupt-driven context) we guarantee
 * buffer locking by using atomic operations on abufulen; the indicator
 * of the length of the buffer that is used.
 */

AudioDeviceID                   adid;
AudioStreamBasicDescription     afmt;
#ifdef MAC_OS_X_VERSION_10_5

AudioDeviceIOProcID             aprocid;
#else /* !MAC_OS_X_VERSION_10_5 */
#define aprocid                 audio_output_ioproc
#endif /* MAC_OS_X_VERSION_10_5 */

int16_t                         *abufnew;
int16_t                         *abufcur;
int                             abuflen;
int                             abufulen = 0;
GMutex                          *abuflock;
GCond                           *abufdrained;
#ifdef BUILD_VOLUME

UInt32                          achans[2] = { 0, 0 };
#endif /* BUILD_VOLUME */

static OSStatus
audio_output_ioproc(AudioDeviceID inDevice, const AudioTimeStamp *inNow,
    const AudioBufferList *inInputData, const AudioTimeStamp *inInputTime,
    AudioBufferList *outOutputData, const AudioTimeStamp *inOutputTime,
    void *inClientData)
{
        int i, len;
        float *ob = outOutputData->mBuffers[0].mData;

        /* Stop the IOProc handling if we're going idle */
        len = g_atomic_int_get(&abufulen);
        if (len == 0)
                AudioDeviceStop(adid, aprocid);

        /* Convert the data to floats */
        for (i = 0; i < len; i++)
                ob[i] = (float)abufcur[i] / SHRT_MAX;

        /* Empty the buffer and notify that we can receive new data */
        g_atomic_int_set(&abufulen, 0);
        g_cond_signal(abufdrained);

        /* Fill the trailer with zero's */
        for (; i < abuflen; i++)
                ob[i] = 0.0;
        
        return (0);
}

int
audio_output_open(void)
{
        UInt32 size;

        /* Obtain the audio device ID */
        size = sizeof adid;
        if (AudioHardwareGetProperty(
            kAudioHardwarePropertyDefaultOutputDevice, 
            &size, &adid) != 0 || adid == kAudioDeviceUnknown)
                goto error;

        /* Adjust the stream format */
        size = sizeof afmt;
        if (AudioDeviceGetProperty(adid, 0, false,
            kAudioDevicePropertyStreamFormat, &size, &afmt) != 0 ||
            afmt.mFormatID != kAudioFormatLinearPCM)
                goto error;

        /* To be set on the first run */
        afmt.mSampleRate = 0;
        afmt.mChannelsPerFrame = 0;
        afmt.mBytesPerFrame = afmt.mChannelsPerFrame * sizeof (float);
        afmt.mBytesPerPacket = afmt.mBytesPerFrame * afmt.mFramesPerPacket;

        /* Decide what buffer size to use */
        size = sizeof abuflen;
        abuflen = 32768;
        AudioDeviceSetProperty(adid, 0, 0, false,
            kAudioDevicePropertyBufferSize, size, &abuflen);
        if (AudioDeviceGetProperty(adid, 0, false,
            kAudioDevicePropertyBufferSize, &size, &abuflen) != 0)
                goto error;

#ifdef BUILD_VOLUME
        /* Store the audio channels */
        size = sizeof achans;
        AudioDeviceGetProperty(adid, 0, false,
            kAudioDevicePropertyPreferredChannelsForStereo, &size, &achans);
#endif /* BUILD_VOLUME */

        /* The buffer size reported is in floats */
        abuflen /= sizeof(float);
        abufnew = g_malloc(abuflen * sizeof(int16_t));
        abufcur = g_malloc(abuflen * sizeof(int16_t));

        /* Locking down the buffer length */
        abuflock = g_mutex_new();
        abufdrained = g_cond_new();

        /* Add our own I/O handling routine */
#ifdef MAC_OS_X_VERSION_10_5
        if (AudioDeviceCreateIOProcID(adid, audio_output_ioproc, NULL,
            &aprocid) != 0)
#else /* !MAC_OS_X_VERSION_10_5 */
        if (AudioDeviceAddIOProc(adid, audio_output_ioproc, NULL) != 0)
#endif /* MAC_OS_X_VERSION_10_5 */
                goto error;

        return (0);
error:
        g_printerr("%s\n", _("Cannot open the audio device."));
        return (-1);
}

int
audio_output_play(struct audio_file *fd)
{
        UInt32 len, size;
        int16_t *tmp;
        
        /* Read data in our temporary buffer */
        if ((len = audio_file_read(fd, abufnew, abuflen)) == 0)
                return (-1);

        if (fd->srate != afmt.mSampleRate ||
            fd->channels != afmt.mChannelsPerFrame) {
                /* Sample rate or the amount of channels has changed */
                afmt.mSampleRate = fd->srate;
                afmt.mChannelsPerFrame = fd->channels;

                if (AudioDeviceSetProperty(adid, 0, 0, 0,
                    kAudioDevicePropertyStreamFormat, sizeof afmt, &afmt) != 0) {
                        /* Get current settings back */
                        size = sizeof afmt;
                        AudioDeviceGetProperty(adid, 0, false,
                            kAudioDevicePropertyStreamFormat, &size, &afmt);

                        gui_msgbar_warn(_("Sample rate or amount of channels not supported."));
                        return (-1);
                }
        }

        /* XXX: Mutex not actually needed - only for the condvar */
        g_mutex_lock(abuflock);
        while (g_atomic_int_get(&abufulen) != 0)
                g_cond_wait(abufdrained, abuflock);
        g_mutex_unlock(abuflock);
        
        /* Toggle the buffers */
        tmp = abufcur;
        abufcur = abufnew;
        abufnew = tmp;

        /* Atomically set the usage length */
        g_atomic_int_set(&abufulen, len);

        /* Start processing of the data */
        AudioDeviceStart(adid, aprocid);

        return (0);
}

void
audio_output_close(void)
{
        AudioDeviceStop(adid, aprocid);
#ifdef MAC_OS_X_VERSION_10_5
        AudioDeviceDestroyIOProcID(adid, aprocid);
#else /* !MAC_OS_X_VERSION_10_5 */
        AudioDeviceRemoveIOProc(adid, aprocid);
#endif /* MAC_OS_X_VERSION_10_5 */

        g_free(abufnew);
        g_free(abufcur);
}

#ifdef BUILD_VOLUME

static int
audio_output_volume_adjust(Float32 n)
{
        Float32 vl, vr, vn;
        UInt32 size = sizeof vl;

        /*
         * Merge left and right. On Mac OS X, we want to do this. My
         * PowerBook has this odd bug that the built-in OS X volume
         * applet makes the sound card go unbalanced after a long amount
         * of time. We can prevent that over here...
         */
        if (AudioDeviceGetProperty(adid, achans[0], false,
            kAudioDevicePropertyVolumeScalar, &size, &vl) != 0 ||
            AudioDeviceGetProperty(adid, achans[1], false,
            kAudioDevicePropertyVolumeScalar, &size, &vr) != 0)
                return (-1);
        vn = CLAMP((vl + vr) / 2.0 + n, 0.0, 1.0);

        /* Set the new volume */
        if (AudioDeviceSetProperty(adid, 0, achans[0], false,
            kAudioDevicePropertyVolumeScalar, size, &vn) != 0 ||
            AudioDeviceSetProperty(adid, 0, achans[1], false,
            kAudioDevicePropertyVolumeScalar, size, &vn) != 0)
                return (-1);

        return (vn * 100.0);
}

int
audio_output_volume_up(void)
{
        return audio_output_volume_adjust(0.04);
}

int
audio_output_volume_down(void)
{
        return audio_output_volume_adjust(-0.04);
}
#endif /* BUILD_VOLUME */

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