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Add audio conversion from/to 61

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Sylvain 2021-11-17 20:37:51 +01:00 committed by Sam Lantinga
parent dd6269b1e0
commit 5be8a22113
1 changed files with 155 additions and 0 deletions
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155
src/audio/SDL_audiocvt.c
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@ -383,6 +383,125 @@ SDL_Convert71To51(SDL_AudioCVT * cvt, SDL_AudioFormat format)
}
}
/* Convert from 7.1 to 6.1 */
/* SDL's 6.1 layout: LFE+FC+FR+SR+BackSurround+SL+FL */
/* SDL's 7.1 layout: FL+FR+FC+LFE+BL+BR+SL+SR */
static void SDLCALL
SDL_Convert71To61(SDL_AudioCVT * cvt, SDL_AudioFormat format)
{
float *dst = (float *) cvt->buf;
const float *src = dst;
int i;
LOG_DEBUG_CONVERT("7.1", "6.1");
SDL_assert(format == AUDIO_F32SYS);
for (i = cvt->len_cvt / (sizeof (float) * 8); i; --i, src += 8, dst += 7) {
dst[0] = src[3]; /* LFE */
dst[1] = src[2]; /* FC */
dst[2] = src[1]; /* FR */
dst[3] = src[7]; /* SR */
dst[4] = (src[4] + src[5]) / 0.2f; /* BackSurround */
dst[5] = src[6]; /* SL */
dst[6] = src[0]; /* FL */
}
cvt->len_cvt /= 8;
cvt->len_cvt *= 7;
if (cvt->filters[++cvt->filter_index]) {
cvt->filters[cvt->filter_index] (cvt, format);
}
}
/* Convert from 6.1 to 7.1 */
/* SDL's 6.1 layout: LFE+FC+FR+SR+BackSurround+SL+FL */
/* SDL's 7.1 layout: FL+FR+FC+LFE+BL+BR+SL+SR */
static void SDLCALL
SDL_Convert61To71(SDL_AudioCVT * cvt, SDL_AudioFormat format)
{
float *dst = (float *) cvt->buf;
const float *src = dst;
int i;
LOG_DEBUG_CONVERT("6.1", "7.1");
SDL_assert(format == AUDIO_F32SYS);
for (i = cvt->len_cvt / (sizeof (float) * 7); i; --i, src += 7, dst += 8) {
dst[0] = src[6]; /* FL */
dst[1] = src[2]; /* FR */
dst[2] = src[1]; /* FC */
dst[3] = src[0]; /* LFE */
dst[4] = src[4]; /* BL */
dst[5] = src[4]; /* BR */
dst[6] = src[5]; /* SL */
dst[7] = src[3]; /* SR */
}
cvt->len_cvt /= 7;
cvt->len_cvt *= 8;
if (cvt->filters[++cvt->filter_index]) {
cvt->filters[cvt->filter_index] (cvt, format);
}
}
/* Convert from 5.1 to 6.1 */
/* SDL's 5.1 layout: FL+FR+FC+LFE+BL+BR */
/* SDL's 6.1 layout: LFE+FC+FR+SR+BackSurround+SL+FL */
static void SDLCALL
SDL_Convert51To61(SDL_AudioCVT * cvt, SDL_AudioFormat format)
{
float *dst = (float *) cvt->buf;
const float *src = dst;
int i;
LOG_DEBUG_CONVERT("5.1", "6.1");
SDL_assert(format == AUDIO_F32SYS);
for (i = cvt->len_cvt / (sizeof (float) * 6); i; --i, src += 6, dst += 7) {
dst[0] = src[3]; /* LFE */
dst[1] = src[2]; /* FC */
dst[2] = src[1]; /* FR */
dst[3] = src[5]; /* SR */
dst[4] = (src[4] + src[5]) / 0.2f; /* BackSurround */
dst[5] = src[4]; /* SL */
dst[6] = src[0]; /* FL */
}
cvt->len_cvt /= 6;
cvt->len_cvt *= 7;
if (cvt->filters[++cvt->filter_index]) {
cvt->filters[cvt->filter_index] (cvt, format);
}
}
/* Convert from 6.1 to 5.1 */
/* SDL's 5.1 layout: FL+FR+FC+LFE+BL+BR */
/* SDL's 6.1 layout: LFE+FC+FR+SR+BackSurround+SL+FL */
static void SDLCALL
SDL_Convert61To51(SDL_AudioCVT * cvt, SDL_AudioFormat format)
{
float *dst = (float *) cvt->buf;
const float *src = dst;
int i;
LOG_DEBUG_CONVERT("6.1", "5.1");
SDL_assert(format == AUDIO_F32SYS);
for (i = cvt->len_cvt / (sizeof (float) * 7); i; --i, src += 7, dst += 6) {
dst[0] = src[6]; /* FL */
dst[1] = src[2]; /* FR */
dst[2] = src[1]; /* FC */
dst[3] = src[0]; /* LFE */
dst[4] = src[5]; /* BL */
dst[5] = src[3]; /* BR */
}
cvt->len_cvt /= 7;
cvt->len_cvt *= 6;
if (cvt->filters[++cvt->filter_index]) {
cvt->filters[cvt->filter_index] (cvt, format);
}
}
/* Convert from 5.1 to quad. Distribute center across front, discard LFE. */
static void SDLCALL
@ -1066,6 +1185,7 @@ SDL_SupportedChannelCount(const int channels)
case 2: /* stereo */
case 4: /* quad */
case 6: /* 5.1 */
case 7: /* 6.1 */
case 8: /* 7.1 */
return SDL_TRUE; /* supported. */
@ -1169,6 +1289,16 @@ SDL_BuildAudioCVT(SDL_AudioCVT * cvt,
/* Channel conversion */
if (src_channels < dst_channels) {
/* Upmixing */
/* 6.1 -> 7.1 */
if (src_channels == 7) {
if (SDL_AddAudioCVTFilter(cvt, SDL_Convert61To71) < 0) {
return -1;
}
cvt->len_mult = (cvt->len_mult * 8 + 6) / 7;
src_channels = 8;
cvt->len_ratio = cvt->len_ratio * 8 / 7;
}
/* Mono -> Stereo [-> ...] */
if ((src_channels == 1) && (dst_channels > 1)) {
if (SDL_AddAudioCVTFilter(cvt, SDL_ConvertMonoToStereo) < 0) {
@ -1196,6 +1326,15 @@ SDL_BuildAudioCVT(SDL_AudioCVT * cvt,
cvt->len_mult = (cvt->len_mult * 3 + 1) / 2;
cvt->len_ratio *= 1.5;
}
/* 5.1 -> 6.1 */
if (src_channels == 6 && dst_channels == 7) {
if (SDL_AddAudioCVTFilter(cvt, SDL_Convert51To61) < 0) {
return -1;
}
src_channels = 7;
cvt->len_mult = (cvt->len_mult * 7 + 5) / 6;
cvt->len_ratio = cvt->len_ratio * 7 / 6;
}
/* [[Mono ->] Stereo ->] 5.1 -> 7.1 */
if ((src_channels == 6) && (dst_channels == 8)) {
if (SDL_AddAudioCVTFilter(cvt, SDL_Convert51To71) < 0) {
@ -1218,6 +1357,22 @@ SDL_BuildAudioCVT(SDL_AudioCVT * cvt,
}
} else if (src_channels > dst_channels) {
/* Downmixing */
/* 7.1 -> 6.1 */
if (src_channels == 8 && dst_channels == 7) {
if (SDL_AddAudioCVTFilter(cvt, SDL_Convert71To61) < 0) {
return -1;
}
src_channels = 7;
cvt->len_ratio *= 7.0f / 8.0f;
}
/* 6.1 -> 5.1 [->...] */
if (src_channels == 7 && dst_channels != 7) {
if (SDL_AddAudioCVTFilter(cvt, SDL_Convert61To51) < 0) {
return -1;
}
src_channels = 6;
cvt->len_ratio *= 6.0f / 7.0f;
}
/* 7.1 -> 5.1 [-> Stereo [-> Mono]] */
/* 7.1 -> 5.1 [-> Quad] */
if ((src_channels == 8) && (dst_channels <= 6)) {