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Implement some basic audio mixing

master
jp9000 2014-02-17 16:41:47 -07:00
parent a6dbe1501d
commit 860a43c31f
1 changed files with 124 additions and 3 deletions
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127
libobs/media-io/audio-io.c
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@ -166,7 +166,128 @@ static inline size_t min_size(size_t a, size_t b)
return a < b ? a : b;
}
/* TODO: this just overwrites. handle actual mixing */
#ifndef CLAMP
#define CLAMP(val, minval, maxval) \
((val > maxval) ? maxval : ((val < minval) ? minval : val))
#endif
#define MIN_S8 -128
#define MAX_S8 127
#define MIN_S16 -32767
#define MAX_S16 32767
#define MIN_S32 -2147483647
#define MAX_S32 2147483647
#define MIX_BUFFER_SIZE 256
/* TODO: optimize mixing */
static void mix_u8(uint8_t *mix, struct circlebuf *buf, size_t size)
{
uint8_t vals[MIX_BUFFER_SIZE];
register int16_t mix_val;
while (size) {
size_t pop_count = min_size(size, sizeof(vals));
size -= pop_count;
circlebuf_pop_front(buf, vals, pop_count);
for (size_t i = 0; i < pop_count; i++) {
mix_val = (int16_t)*mix - 128;
mix_val += (int16_t)vals[i] - 128;
mix_val = CLAMP(mix_val, MIN_S8, MAX_S8) + 128;
*(mix++) = (uint8_t)mix_val;
}
}
}
static void mix_s16(uint8_t *mix_in, struct circlebuf *buf, size_t size)
{
int16_t *mix = (int16_t*)mix_in;
int16_t vals[MIX_BUFFER_SIZE];
register int32_t mix_val;
while (size) {
size_t pop_count = min_size(size, sizeof(vals));
size -= pop_count;
circlebuf_pop_front(buf, vals, pop_count);
pop_count /= sizeof(int16_t);
for (size_t i = 0; i < pop_count; i++) {
mix_val = (int32_t)*mix;
mix_val += (int32_t)vals[i];
*(mix++) = (int16_t)CLAMP(mix_val, MIN_S16, MAX_S16);
}
}
}
static void mix_s32(uint8_t *mix_in, struct circlebuf *buf, size_t size)
{
int32_t *mix = (int32_t*)mix_in;
int32_t vals[MIX_BUFFER_SIZE];
register int64_t mix_val;
while (size) {
size_t pop_count = min_size(size, sizeof(vals));
size -= pop_count;
circlebuf_pop_front(buf, vals, pop_count);
pop_count /= sizeof(int32_t);
for (size_t i = 0; i < pop_count; i++) {
mix_val = (int64_t)*mix;
mix_val += (int64_t)vals[i];
*(mix++) = (int32_t)CLAMP(mix_val, MIN_S32, MAX_S32);
}
}
}
static void mix_float(uint8_t *mix_in, struct circlebuf *buf, size_t size)
{
float *mix = (float*)mix_in;
float vals[MIX_BUFFER_SIZE];
register float mix_val;
while (size) {
size_t pop_count = min_size(size, sizeof(vals));
size -= pop_count;
circlebuf_pop_front(buf, vals, pop_count);
pop_count /= sizeof(float);
for (size_t i = 0; i < pop_count; i++) {
mix_val = *mix + vals[i];
*(mix++) = CLAMP(mix_val, -1.0f, 1.0f);
}
}
}
static inline void mix_audio(enum audio_format format,
uint8_t *mix, struct circlebuf *buf, size_t size)
{
switch (format) {
case AUDIO_FORMAT_UNKNOWN:
break;
case AUDIO_FORMAT_U8BIT:
case AUDIO_FORMAT_U8BIT_PLANAR:
mix_u8(mix, buf, size); break;
case AUDIO_FORMAT_16BIT:
case AUDIO_FORMAT_16BIT_PLANAR:
mix_s16(mix, buf, size); break;
case AUDIO_FORMAT_32BIT:
case AUDIO_FORMAT_32BIT_PLANAR:
mix_s32(mix, buf, size); break;
case AUDIO_FORMAT_FLOAT:
case AUDIO_FORMAT_FLOAT_PLANAR:
mix_float(mix, buf, size); break;
}
}
static inline bool mix_audio_line(struct audio_output *audio,
struct audio_line *line, size_t size, uint64_t timestamp)
{
@ -184,9 +305,9 @@ static inline bool mix_audio_line(struct audio_output *audio,
for (size_t i = 0; i < audio->planes; i++) {
size_t pop_size = min_size(size, line->buffers[i].size);
circlebuf_pop_front(&line->buffers[i],
mix_audio(audio->info.format,
audio->mix_buffers[i].array + time_offset,
pop_size);
&line->buffers[i], pop_size);
}
return true;