/*
* This file is part of mpv.
*
* mpv is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with mpv. If not, see .
*/
#include
#include "common/common.h"
#include "ao_coreaudio_utils.h"
#include "ao_coreaudio_chmap.h"
#include
static const int speaker_map[][2] = {
{ kAudioChannelLabel_Left, MP_SPEAKER_ID_FL },
{ kAudioChannelLabel_Right, MP_SPEAKER_ID_FR },
{ kAudioChannelLabel_Center, MP_SPEAKER_ID_FC },
{ kAudioChannelLabel_LFEScreen, MP_SPEAKER_ID_LFE },
{ kAudioChannelLabel_LeftSurround, MP_SPEAKER_ID_BL },
{ kAudioChannelLabel_RightSurround, MP_SPEAKER_ID_BR },
{ kAudioChannelLabel_LeftCenter, MP_SPEAKER_ID_FLC },
{ kAudioChannelLabel_RightCenter, MP_SPEAKER_ID_FRC },
{ kAudioChannelLabel_CenterSurround, MP_SPEAKER_ID_BC },
{ kAudioChannelLabel_LeftSurroundDirect, MP_SPEAKER_ID_SL },
{ kAudioChannelLabel_RightSurroundDirect, MP_SPEAKER_ID_SR },
{ kAudioChannelLabel_TopCenterSurround, MP_SPEAKER_ID_TC },
{ kAudioChannelLabel_VerticalHeightLeft, MP_SPEAKER_ID_TFL },
{ kAudioChannelLabel_VerticalHeightCenter, MP_SPEAKER_ID_TFC },
{ kAudioChannelLabel_VerticalHeightRight, MP_SPEAKER_ID_TFR },
{ kAudioChannelLabel_TopBackLeft, MP_SPEAKER_ID_TBL },
{ kAudioChannelLabel_TopBackCenter, MP_SPEAKER_ID_TBC },
{ kAudioChannelLabel_TopBackRight, MP_SPEAKER_ID_TBR },
// unofficial extensions
{ kAudioChannelLabel_RearSurroundLeft, MP_SPEAKER_ID_SDL },
{ kAudioChannelLabel_RearSurroundRight, MP_SPEAKER_ID_SDR },
{ kAudioChannelLabel_LeftWide, MP_SPEAKER_ID_WL },
{ kAudioChannelLabel_RightWide, MP_SPEAKER_ID_WR },
{ kAudioChannelLabel_LFE2, MP_SPEAKER_ID_LFE2 },
#if __MAC_OS_X_VERSION_MAX_ALLOWED >= 130000
{ kAudioChannelLabel_LeftTopSurround, MP_SPEAKER_ID_TSL },
{ kAudioChannelLabel_RightTopSurround, MP_SPEAKER_ID_TSR },
{ kAudioChannelLabel_CenterBottom, MP_SPEAKER_ID_BFC },
{ kAudioChannelLabel_LeftBottom, MP_SPEAKER_ID_BFL },
{ kAudioChannelLabel_RightBottom, MP_SPEAKER_ID_BFR },
#endif
{ kAudioChannelLabel_HeadphonesLeft, MP_SPEAKER_ID_DL },
{ kAudioChannelLabel_HeadphonesRight, MP_SPEAKER_ID_DR },
{ kAudioChannelLabel_Unknown, MP_SPEAKER_ID_NA },
{ 0, -1 },
};
static const AudioChannelLayoutTag std_layouts[] = {
(100U<<16) | 1, // kAudioChannelLayoutTag_Mono
(101U<<16) | 2, // kAudioChannelLayoutTag_Stereo
(102U<<16) | 2, // kAudioChannelLayoutTag_StereoHeadphones
(103U<<16) | 2, // kAudioChannelLayoutTag_MatrixStereo
(104U<<16) | 2, // kAudioChannelLayoutTag_MidSide
(105U<<16) | 2, // kAudioChannelLayoutTag_XY
(106U<<16) | 2, // kAudioChannelLayoutTag_Binaural
(107U<<16) | 4, // kAudioChannelLayoutTag_Ambisonic_B_Format
(108U<<16) | 4, // kAudioChannelLayoutTag_Quadraphonic
(109U<<16) | 5, // kAudioChannelLayoutTag_Pentagonal
(110U<<16) | 6, // kAudioChannelLayoutTag_Hexagonal
(111U<<16) | 8, // kAudioChannelLayoutTag_Octagonal
(112U<<16) | 8, // kAudioChannelLayoutTag_Cube
(113U<<16) | 3, // kAudioChannelLayoutTag_MPEG_3_0_A
(114U<<16) | 3, // kAudioChannelLayoutTag_MPEG_3_0_B
(115U<<16) | 4, // kAudioChannelLayoutTag_MPEG_4_0_A
(116U<<16) | 4, // kAudioChannelLayoutTag_MPEG_4_0_B
(117U<<16) | 5, // kAudioChannelLayoutTag_MPEG_5_0_A
(118U<<16) | 5, // kAudioChannelLayoutTag_MPEG_5_0_B
(119U<<16) | 5, // kAudioChannelLayoutTag_MPEG_5_0_C
(120U<<16) | 5, // kAudioChannelLayoutTag_MPEG_5_0_D
(121U<<16) | 6, // kAudioChannelLayoutTag_MPEG_5_1_A
(122U<<16) | 6, // kAudioChannelLayoutTag_MPEG_5_1_B
(123U<<16) | 6, // kAudioChannelLayoutTag_MPEG_5_1_C
(124U<<16) | 6, // kAudioChannelLayoutTag_MPEG_5_1_D
(125U<<16) | 7, // kAudioChannelLayoutTag_MPEG_6_1_A
(126U<<16) | 8, // kAudioChannelLayoutTag_MPEG_7_1_A
(127U<<16) | 8, // kAudioChannelLayoutTag_MPEG_7_1_B
(128U<<16) | 8, // kAudioChannelLayoutTag_MPEG_7_1_C
(129U<<16) | 8, // kAudioChannelLayoutTag_Emagic_Default_7_1
(130U<<16) | 8, // kAudioChannelLayoutTag_SMPTE_DTV
(131U<<16) | 3, // kAudioChannelLayoutTag_ITU_2_1
(132U<<16) | 4, // kAudioChannelLayoutTag_ITU_2_2
(133U<<16) | 3, // kAudioChannelLayoutTag_DVD_4
(134U<<16) | 4, // kAudioChannelLayoutTag_DVD_5
(135U<<16) | 5, // kAudioChannelLayoutTag_DVD_6
(136U<<16) | 4, // kAudioChannelLayoutTag_DVD_10
(137U<<16) | 5, // kAudioChannelLayoutTag_DVD_11
(138U<<16) | 5, // kAudioChannelLayoutTag_DVD_18
(139U<<16) | 6, // kAudioChannelLayoutTag_AudioUnit_6_0
(140U<<16) | 7, // kAudioChannelLayoutTag_AudioUnit_7_0
(148U<<16) | 7, // kAudioChannelLayoutTag_AudioUnit_7_0_Front
(141U<<16) | 6, // kAudioChannelLayoutTag_AAC_6_0
(142U<<16) | 7, // kAudioChannelLayoutTag_AAC_6_1
(143U<<16) | 7, // kAudioChannelLayoutTag_AAC_7_0
(183U<<16) | 8, // kAudioChannelLayoutTag_AAC_7_1_B
(184U<<16) | 8, // kAudioChannelLayoutTag_AAC_7_1_C
(144U<<16) | 8, // kAudioChannelLayoutTag_AAC_Octagonal
(145U<<16) | 16, // kAudioChannelLayoutTag_TMH_10_2_std
(146U<<16) | 21, // kAudioChannelLayoutTag_TMH_10_2_full
(149U<<16) | 2, // kAudioChannelLayoutTag_AC3_1_0_1
(150U<<16) | 3, // kAudioChannelLayoutTag_AC3_3_0
(151U<<16) | 4, // kAudioChannelLayoutTag_AC3_3_1
(152U<<16) | 4, // kAudioChannelLayoutTag_AC3_3_0_1
(153U<<16) | 4, // kAudioChannelLayoutTag_AC3_2_1_1
(154U<<16) | 5, // kAudioChannelLayoutTag_AC3_3_1_1
(155U<<16) | 6, // kAudioChannelLayoutTag_EAC_6_0_A
(156U<<16) | 7, // kAudioChannelLayoutTag_EAC_7_0_A
(157U<<16) | 7, // kAudioChannelLayoutTag_EAC3_6_1_A
(158U<<16) | 7, // kAudioChannelLayoutTag_EAC3_6_1_B
(159U<<16) | 7, // kAudioChannelLayoutTag_EAC3_6_1_C
(160U<<16) | 8, // kAudioChannelLayoutTag_EAC3_7_1_A
(161U<<16) | 8, // kAudioChannelLayoutTag_EAC3_7_1_B
(162U<<16) | 8, // kAudioChannelLayoutTag_EAC3_7_1_C
(163U<<16) | 8, // kAudioChannelLayoutTag_EAC3_7_1_D
(164U<<16) | 8, // kAudioChannelLayoutTag_EAC3_7_1_E
(165U<<16) | 8, // kAudioChannelLayoutTag_EAC3_7_1_F
(166U<<16) | 8, // kAudioChannelLayoutTag_EAC3_7_1_G
(167U<<16) | 8, // kAudioChannelLayoutTag_EAC3_7_1_H
(168U<<16) | 4, // kAudioChannelLayoutTag_DTS_3_1
(169U<<16) | 5, // kAudioChannelLayoutTag_DTS_4_1
(170U<<16) | 6, // kAudioChannelLayoutTag_DTS_6_0_A
(171U<<16) | 6, // kAudioChannelLayoutTag_DTS_6_0_B
(172U<<16) | 6, // kAudioChannelLayoutTag_DTS_6_0_C
(173U<<16) | 7, // kAudioChannelLayoutTag_DTS_6_1_A
(174U<<16) | 7, // kAudioChannelLayoutTag_DTS_6_1_B
(175U<<16) | 7, // kAudioChannelLayoutTag_DTS_6_1_C
(176U<<16) | 7, // kAudioChannelLayoutTag_DTS_7_0
(177U<<16) | 8, // kAudioChannelLayoutTag_DTS_7_1
(178U<<16) | 8, // kAudioChannelLayoutTag_DTS_8_0_A
(179U<<16) | 8, // kAudioChannelLayoutTag_DTS_8_0_B
(180U<<16) | 9, // kAudioChannelLayoutTag_DTS_8_1_A
(181U<<16) | 9, // kAudioChannelLayoutTag_DTS_8_1_B
(182U<<16) | 7, // kAudioChannelLayoutTag_DTS_6_1_D
(185U<<16) | 4, // kAudioChannelLayoutTag_WAVE_4_0_B
(186U<<16) | 5, // kAudioChannelLayoutTag_WAVE_5_0_B
(187U<<16) | 6, // kAudioChannelLayoutTag_WAVE_5_1_B
(188U<<16) | 7, // kAudioChannelLayoutTag_WAVE_6_1
(189U<<16) | 8, // kAudioChannelLayoutTag_WAVE_7_1
(194U<<16) | 8, // kAudioChannelLayoutTag_Atmos_5_1_2
(195U<<16) | 10, // kAudioChannelLayoutTag_Atmos_5_1_4
(196U<<16) | 10, // kAudioChannelLayoutTag_Atmos_7_1_2
(192U<<16) | 12, // kAudioChannelLayoutTag_Atmos_7_1_4
(193U<<16) | 16, // kAudioChannelLayoutTag_Atmos_9_1_6
(197U<<16) | 4, // kAudioChannelLayoutTag_Logic_4_0_C
(198U<<16) | 6, // kAudioChannelLayoutTag_Logic_6_0_B
(199U<<16) | 7, // kAudioChannelLayoutTag_Logic_6_1_B
(200U<<16) | 7, // kAudioChannelLayoutTag_Logic_6_1_D
(201U<<16) | 8, // kAudioChannelLayoutTag_Logic_7_1_B
(202U<<16) | 12, // kAudioChannelLayoutTag_Logic_Atmos_7_1_4_B
(203U<<16) | 14, // kAudioChannelLayoutTag_Logic_Atmos_7_1_6
(204U<<16) | 24, // kAudioChannelLayoutTag_CICP_13
(205U<<16) | 8, // kAudioChannelLayoutTag_CICP_14
(206U<<16) | 12, // kAudioChannelLayoutTag_CICP_15
(207U<<16) | 10, // kAudioChannelLayoutTag_CICP_16
(208U<<16) | 12, // kAudioChannelLayoutTag_CICP_17
(209U<<16) | 14, // kAudioChannelLayoutTag_CICP_18
(210U<<16) | 12, // kAudioChannelLayoutTag_CICP_19
(211U<<16) | 14, // kAudioChannelLayoutTag_CICP_20
kAudioChannelLayoutTag_Unknown
};
int ca_label_to_mp_speaker_id(AudioChannelLabel label)
{
for (int i = 0; speaker_map[i][1] >= 0; i++)
if (speaker_map[i][0] == label)
return speaker_map[i][1];
return -1;
}
AudioChannelLabel mp_speaker_id_to_ca_label(int speaker_id)
{
for (int i = 0; speaker_map[i][1] >= 0; i++)
if (speaker_map[i][1] == speaker_id)
return speaker_map[i][0];
return -1; // kAudioChannelLabel_Unknown
}
#if HAVE_COREAUDIO
void ca_log_layout(struct ao *ao, int l, AudioChannelLayout *layout)
{
if (!mp_msg_test(ao->log, l))
return;
AudioChannelLayoutTag tag = layout->mChannelLayoutTag;
mp_msg(ao->log, l, "audio channel layout: tag: <%u>", tag);
if (tag == kAudioChannelLayoutTag_UseChannelDescriptions) {
AudioChannelDescription *descs = layout->mChannelDescriptions;
mp_msg(ao->log, l, ", descriptions <%u>\n",
(unsigned) layout->mNumberChannelDescriptions);
for (int i = 0; i < layout->mNumberChannelDescriptions; i++) {
AudioChannelDescription d = descs[i];
mp_msg(ao->log, l, " - description %d: label <%u, %u>, flags: <%u>",
i,
(unsigned) d.mChannelLabel,
(unsigned) ca_label_to_mp_speaker_id(d.mChannelLabel),
(unsigned) d.mChannelFlags);
if (d.mChannelFlags != kAudioChannelFlags_AllOff) {
mp_msg(ao->log, l, ", coords: <%f, %f, %f>\n",
d.mCoordinates[0],
d.mCoordinates[1],
d.mCoordinates[2]);
} else {
mp_msg(ao->log, l, "\n");
}
}
} else if (tag == kAudioChannelLayoutTag_UseChannelBitmap) {
mp_msg(ao->log, l, ", bitmap <%u>\n", layout->mChannelBitmap);
} else {
mp_msg(ao->log, l, "\n");
}
}
static AudioChannelLayout *ca_layout_to_custom_layout(struct ao *ao,
void *talloc_ctx,
AudioChannelLayout *l)
{
AudioChannelLayoutTag tag = l->mChannelLayoutTag;
AudioChannelLayout *r;
OSStatus err;
if (tag == kAudioChannelLayoutTag_UseChannelDescriptions)
return l;
if (tag == kAudioChannelLayoutTag_UseChannelBitmap) {
uint32_t psize;
err = AudioFormatGetPropertyInfo(
kAudioFormatProperty_ChannelLayoutForBitmap,
sizeof(uint32_t), &l->mChannelBitmap, &psize);
CHECK_CA_ERROR("failed to convert channel bitmap to descriptions (info)");
r = talloc_size(talloc_ctx, psize);
err = AudioFormatGetProperty(
kAudioFormatProperty_ChannelLayoutForBitmap,
sizeof(uint32_t), &l->mChannelBitmap, &psize, r);
CHECK_CA_ERROR("failed to convert channel bitmap to descriptions (get)");
} else {
uint32_t psize;
err = AudioFormatGetPropertyInfo(
kAudioFormatProperty_ChannelLayoutForTag,
sizeof(AudioChannelLayoutTag), &l->mChannelLayoutTag, &psize);
r = talloc_size(talloc_ctx, psize);
CHECK_CA_ERROR("failed to convert channel tag to descriptions (info)");
err = AudioFormatGetProperty(
kAudioFormatProperty_ChannelLayoutForTag,
sizeof(AudioChannelLayoutTag), &l->mChannelLayoutTag, &psize, r);
CHECK_CA_ERROR("failed to convert channel tag to descriptions (get)");
}
if (ao) {
MP_VERBOSE(ao, "converted input channel layout:\n");
ca_log_layout(ao, MSGL_V, l);
}
return r;
coreaudio_error:
return NULL;
}
AudioChannelLayout *ca_find_standard_layout(void *talloc_ctx, AudioChannelLayout *l)
{
if (l->mChannelLayoutTag != kAudioChannelLayoutTag_UseChannelDescriptions)
return l;
AudioChannelLayout *s = talloc_size(talloc_ctx, sizeof(AudioChannelLayout));
for (int i = 0; ; ++i) {
if ((s->mChannelLayoutTag = std_layouts[i]) == kAudioChannelLayoutTag_Unknown) {
s = NULL;
break;
}
AudioChannelLayout *r = ca_layout_to_custom_layout(NULL, talloc_ctx, s);
if (!r)
goto mismatch;
if (l->mNumberChannelDescriptions != r->mNumberChannelDescriptions)
goto mismatch;
for (int i = 0; i < l->mNumberChannelDescriptions; ++i) {
AudioChannelDescription *ld = l->mChannelDescriptions + i;
AudioChannelDescription *rd = r->mChannelDescriptions + i;
if (ld->mChannelLabel == rd->mChannelLabel)
continue;
// XXX: we cannot handle channels with coordinates
goto mismatch;
}
break;
mismatch:;
}
return s ? s : l;
}
#define CHMAP(n, ...) &(struct mp_chmap) MP_CONCAT(MP_CHMAP, n) (__VA_ARGS__)
// Replace each channel in a with b (a->num == b->num)
static void replace_submap(struct mp_chmap *dst, struct mp_chmap *a,
struct mp_chmap *b)
{
struct mp_chmap t = *dst;
if (!mp_chmap_is_valid(&t) || mp_chmap_diffn(a, &t) != 0)
return;
assert(a->num == b->num);
for (int n = 0; n < t.num; n++) {
for (int i = 0; i < a->num; i++) {
if (t.speaker[n] == a->speaker[i]) {
t.speaker[n] = b->speaker[i];
break;
}
}
}
if (mp_chmap_is_valid(&t))
*dst = t;
}
static bool ca_layout_to_mp_chmap(struct ao *ao, AudioChannelLayout *layout,
struct mp_chmap *chmap)
{
void *talloc_ctx = talloc_new(NULL);
MP_VERBOSE(ao, "input channel layout:\n");
ca_log_layout(ao, MSGL_V, layout);
AudioChannelLayout *l = ca_layout_to_custom_layout(ao, talloc_ctx, layout);
if (!l)
goto coreaudio_error;
if (l->mNumberChannelDescriptions > MP_NUM_CHANNELS) {
MP_VERBOSE(ao, "layout has too many descriptions (%u, max: %d)\n",
(unsigned) l->mNumberChannelDescriptions, MP_NUM_CHANNELS);
return false;
}
chmap->num = l->mNumberChannelDescriptions;
for (int n = 0; n < l->mNumberChannelDescriptions; n++) {
AudioChannelLabel label = l->mChannelDescriptions[n].mChannelLabel;
int speaker = ca_label_to_mp_speaker_id(label);
if (speaker < 0) {
MP_VERBOSE(ao, "channel label=%u unusable to build channel "
"bitmap, skipping layout\n", (unsigned) label);
goto coreaudio_error;
}
chmap->speaker[n] = speaker;
}
// Remap weird 7.1(rear) layouts correctly.
replace_submap(chmap, CHMAP(6, FL, FR, BL, BR, SDL, SDR),
CHMAP(6, FL, FR, SL, SR, BL, BR));
talloc_free(talloc_ctx);
MP_VERBOSE(ao, "mp chmap: %s\n", mp_chmap_to_str(chmap));
return mp_chmap_is_valid(chmap) && !mp_chmap_is_unknown(chmap);
coreaudio_error:
MP_VERBOSE(ao, "converted input channel layout (failed):\n");
ca_log_layout(ao, MSGL_V, layout);
talloc_free(talloc_ctx);
return false;
}
static AudioChannelLayout* ca_query_layout(struct ao *ao,
AudioDeviceID device,
void *talloc_ctx)
{
OSStatus err;
uint32_t psize;
AudioChannelLayout *r = NULL;
AudioObjectPropertyAddress p_addr = (AudioObjectPropertyAddress) {
.mSelector = kAudioDevicePropertyPreferredChannelLayout,
.mScope = kAudioDevicePropertyScopeOutput,
.mElement = kAudioObjectPropertyElementWildcard,
};
err = AudioObjectGetPropertyDataSize(device, &p_addr, 0, NULL, &psize);
CHECK_CA_ERROR("could not get device preferred layout (size)");
r = talloc_size(talloc_ctx, psize);
err = AudioObjectGetPropertyData(device, &p_addr, 0, NULL, &psize, r);
CHECK_CA_ERROR("could not get device preferred layout (get)");
coreaudio_error:
return r;
}
static AudioChannelLayout* ca_query_stereo_layout(struct ao *ao,
AudioDeviceID device,
void *talloc_ctx)
{
OSStatus err;
uint32_t channels[2];
const int nch = MP_ARRAY_SIZE(channels);
AudioChannelLayout *r = NULL;
AudioObjectPropertyAddress p_addr = (AudioObjectPropertyAddress) {
.mSelector = kAudioDevicePropertyPreferredChannelsForStereo,
.mScope = kAudioDevicePropertyScopeOutput,
.mElement = kAudioObjectPropertyElementWildcard,
};
uint32_t psize = sizeof(channels);
err = AudioObjectGetPropertyData(device, &p_addr, 0, NULL, &psize, channels);
CHECK_CA_ERROR("could not get device preferred stereo layout");
psize = sizeof(AudioChannelLayout) + nch * sizeof(AudioChannelDescription);
r = talloc_zero_size(talloc_ctx, psize);
r->mChannelLayoutTag = kAudioChannelLayoutTag_UseChannelDescriptions;
r->mNumberChannelDescriptions = nch;
AudioChannelDescription desc = {0};
desc.mChannelFlags = kAudioChannelFlags_AllOff;
for(int i = 0; i < nch; i++) {
desc.mChannelLabel = channels[i];
r->mChannelDescriptions[i] = desc;
}
coreaudio_error:
return r;
}
static void ca_retrieve_layouts(struct ao *ao, struct mp_chmap_sel *s,
AudioDeviceID device)
{
void *ta_ctx = talloc_new(NULL);
struct mp_chmap chmap;
AudioChannelLayout *ml = ca_query_layout(ao, device, ta_ctx);
if (ml && ca_layout_to_mp_chmap(ao, ml, &chmap))
mp_chmap_sel_add_map(s, &chmap);
AudioChannelLayout *sl = ca_query_stereo_layout(ao, device, ta_ctx);
if (sl && ca_layout_to_mp_chmap(ao, sl, &chmap))
mp_chmap_sel_add_map(s, &chmap);
talloc_free(ta_ctx);
}
bool ca_init_chmap(struct ao *ao, AudioDeviceID device)
{
struct mp_chmap_sel chmap_sel = {0};
ca_retrieve_layouts(ao, &chmap_sel, device);
if (!chmap_sel.num_chmaps)
mp_chmap_sel_add_map(&chmap_sel, &(struct mp_chmap)MP_CHMAP_INIT_STEREO);
mp_chmap_sel_add_map(&chmap_sel, &(struct mp_chmap)MP_CHMAP_INIT_MONO);
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");
return false;
}
return true;
}
void ca_get_active_chmap(struct ao *ao, AudioDeviceID device, int channel_count,
struct mp_chmap *out_map)
{
// Apparently, we have to guess by looking back at the supported layouts,
// and I haven't found a property that retrieves the actual currently
// active channel layout.
struct mp_chmap_sel chmap_sel = {0};
ca_retrieve_layouts(ao, &chmap_sel, device);
// Use any exact match.
for (int n = 0; n < chmap_sel.num_chmaps; n++) {
if (chmap_sel.chmaps[n].num == channel_count) {
MP_VERBOSE(ao, "mismatching channels - fallback #%d\n", n);
*out_map = chmap_sel.chmaps[n];
return;
}
}
// Fall back to stereo or mono, and fill the rest with silence. (We don't
// know what the device expects. We could use a larger default layout here,
// but let's not.)
mp_chmap_from_channels(out_map, MPMIN(2, channel_count));
out_map->num = channel_count;
for (int n = 2; n < out_map->num; n++)
out_map->speaker[n] = MP_SPEAKER_ID_NA;
MP_WARN(ao, "mismatching channels - falling back to %s\n",
mp_chmap_to_str(out_map));
}
#endif