mpv/audio/out/ao_coreaudio.c

/*
 * This file is part of mpv.
 *
 * mpv is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * mpv 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with mpv.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "config.h"
#include "ao.h"
#include "internal.h"
#include "audio/format.h"
#include "osdep/timer.h"
#include "options/m_option.h"
#include "misc/ring.h"
#include "common/msg.h"
#include "audio/out/ao_coreaudio_properties.h"
#include "audio/out/ao_coreaudio_utils.h"

struct priv {
    AudioDeviceID device;
    AudioUnit audio_unit;

    // options
    int opt_device_id;
    int opt_list;
};

static OSStatus render_cb_lpcm(void *ctx, AudioUnitRenderActionFlags *aflags,
                              const AudioTimeStamp *ts, UInt32 bus,
                              UInt32 frames, AudioBufferList *buffer_list)
{
    struct ao *ao   = ctx;
    AudioBuffer buf = buffer_list->mBuffers[0];
    ao_read_data(ao, &buf.mData, frames, ts->mSampleTime);
    return noErr;
}

static int get_volume(struct ao *ao, struct ao_control_vol *vol) {
    struct priv *p = ao->priv;
    float auvol;
    OSStatus err =
        AudioUnitGetParameter(p->audio_unit, kHALOutputParam_Volume,
                              kAudioUnitScope_Global, 0, &auvol);

    CHECK_CA_ERROR("could not get HAL output volume");
    vol->left = vol->right = auvol * 100.0;
    return CONTROL_TRUE;
coreaudio_error:
    return CONTROL_ERROR;
}

static int set_volume(struct ao *ao, struct ao_control_vol *vol) {
    struct priv *p = ao->priv;
    float auvol = (vol->left + vol->right) / 200.0;
    OSStatus err =
        AudioUnitSetParameter(p->audio_unit, kHALOutputParam_Volume,
                              kAudioUnitScope_Global, 0, auvol, 0);
    CHECK_CA_ERROR("could not set HAL output volume");
    return CONTROL_TRUE;
coreaudio_error:
    return CONTROL_ERROR;
}

static int control(struct ao *ao, enum aocontrol cmd, void *arg)
{
    switch (cmd) {
    case AOCONTROL_GET_VOLUME:
        return get_volume(ao, arg);
    case AOCONTROL_SET_VOLUME:
        return set_volume(ao, arg);
    }
    return CONTROL_UNKNOWN;
}

static bool init_chmap(struct ao *ao);
static bool init_audiounit(struct ao *ao, AudioStreamBasicDescription asbd);

static int init(struct ao *ao)
{
    struct priv *p = ao->priv;

    if (p->opt_list) ca_print_device_list(ao);

    ao->per_application_mixer = true;
    ao->no_persistent_volume  = true;

    OSStatus err = ca_select_device(ao, p->opt_device_id, &p->device);
    CHECK_CA_ERROR("failed to select device");

    if (!init_chmap(ao))
        goto coreaudio_error;

    ao->format = af_fmt_from_planar(ao->format);

    AudioStreamBasicDescription asbd;
    ca_fill_asbd(ao, &asbd);

    if (!init_audiounit(ao, asbd))
        goto coreaudio_error;

    return CONTROL_OK;

coreaudio_error:
    return CONTROL_ERROR;
}

static bool init_chmap(struct ao *ao)
{
    struct priv *p = ao->priv;
    OSStatus err;
    AudioChannelLayout *layouts;
    size_t n_layouts;

    err = CA_GET_ARY_O(p->device,
                       kAudioDevicePropertyPreferredChannelLayout,
                       &layouts, &n_layouts);
    CHECK_CA_ERROR("could not get audio device prefered layouts");

    struct mp_chmap_sel chmap_sel = {0};
    for (int i = 0; i < n_layouts; i++) {
        struct mp_chmap chmap = {0};
        if (ca_layout_to_mp_chmap(ao, &layouts[i], &chmap))
            mp_chmap_sel_add_map(&chmap_sel, &chmap);
    }

    talloc_free(layouts);

    if (ao->channels.num < 3) {
        struct mp_chmap chmap;
        mp_chmap_from_channels(&chmap, ao->channels.num);
        mp_chmap_sel_add_map(&chmap_sel, &chmap);
    }

    if (!ao_chmap_sel_adjust(ao, &chmap_sel, &ao->channels)) {
        MP_ERR(ao, "could not select a suitable channel map among the "
                   "hardware supported ones. Make sure to configure your "
                   "output device correctly in 'Audio MIDI Setup.app'\n");
        goto coreaudio_error;
    }

    return true;

coreaudio_error:
    return false;
}

static bool init_audiounit(struct ao *ao, AudioStreamBasicDescription asbd)
{
    OSStatus err;
    uint32_t size;
    struct priv *p = ao->priv;

    AudioComponentDescription desc = (AudioComponentDescription) {
        .componentType         = kAudioUnitType_Output,
        .componentSubType      = (p->opt_device_id < 0) ?
                                    kAudioUnitSubType_DefaultOutput :
                                    kAudioUnitSubType_HALOutput,
        .componentManufacturer = kAudioUnitManufacturer_Apple,
        .componentFlags        = 0,
        .componentFlagsMask    = 0,
    };

    AudioComponent comp = AudioComponentFindNext(NULL, &desc);
    if (comp == NULL) {
        MP_ERR(ao, "unable to find audio component\n");
        goto coreaudio_error;
    }

    err = AudioComponentInstanceNew(comp, &(p->audio_unit));
    CHECK_CA_ERROR("unable to open audio component");

    err = AudioUnitInitialize(p->audio_unit);
    CHECK_CA_ERROR_L(coreaudio_error_component,
                     "unable to initialize audio unit");

    size = sizeof(AudioStreamBasicDescription);
    err = AudioUnitSetProperty(p->audio_unit,
                               kAudioUnitProperty_StreamFormat,
                               kAudioUnitScope_Input, 0, &asbd, size);

    CHECK_CA_ERROR_L(coreaudio_error_audiounit,
                     "unable to set the input format on the audio unit");

    err = AudioUnitSetProperty(p->audio_unit,
                               kAudioOutputUnitProperty_CurrentDevice,
                               kAudioUnitScope_Global, 0, &p->device,
                               sizeof(p->device));
    CHECK_CA_ERROR_L(coreaudio_error_audiounit,
                     "can't link audio unit to selected device");

    AURenderCallbackStruct render_cb = (AURenderCallbackStruct) {
        .inputProc       = render_cb_lpcm,
        .inputProcRefCon = ao,
    };

    err = AudioUnitSetProperty(p->audio_unit,
                               kAudioUnitProperty_SetRenderCallback,
                               kAudioUnitScope_Input, 0, &render_cb,
                               sizeof(AURenderCallbackStruct));

    CHECK_CA_ERROR_L(coreaudio_error_audiounit,
                     "unable to set render callback on audio unit");

    return true;

coreaudio_error_audiounit:
    AudioUnitUninitialize(p->audio_unit);
coreaudio_error_component:
    AudioComponentInstanceDispose(p->audio_unit);
coreaudio_error:
    return false;
}

static void stop(struct ao *ao)
{
    struct priv *p = ao->priv;
    OSStatus err = AudioOutputUnitStop(p->audio_unit);
    CHECK_CA_WARN("can't stop audio unit");
}

static void start(struct ao *ao)
{
    struct priv *p = ao->priv;
    OSStatus err = AudioOutputUnitStart(p->audio_unit);
    CHECK_CA_WARN("can't start audio unit");
}


static void uninit(struct ao *ao)
{
    struct priv *p = ao->priv;
    AudioOutputUnitStop(p->audio_unit);
    AudioUnitUninitialize(p->audio_unit);
    AudioComponentInstanceDispose(p->audio_unit);
}

#define OPT_BASE_STRUCT struct priv

const struct ao_driver audio_out_coreaudio = {
    .description = "CoreAudio AudioUnit",
    .name      = "coreaudio",
    .uninit    = uninit,
    .init      = init,
    .control   = control,
    .pause     = stop,
    .resume    = start,
    .priv_size = sizeof(struct priv),
    .options = (const struct m_option[]) {
        OPT_INT("device_id", opt_device_id, 0, OPTDEF_INT(-1)),
        OPT_FLAG("list", opt_list, 0),
        {0}
    },
};