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mixer: add support for mixing 16 bit streams #1144

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Merged
lgirdwood merged 1 commit into from
Mar 19, 2019
Merged

mixer: add support for mixing 16 bit streams #1144

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44 changes: 38 additions & 6 deletions src/audio/mixer.c
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Original file line number Diff line number Diff line change
Expand Up @@ -52,10 +52,42 @@ struct mixer_data {
struct comp_buffer **sources, uint32_t count, uint32_t frames);
};

/* mix N PCM source streams to one sink stream */
static void mix_n(struct comp_dev *dev, struct comp_buffer *sink,
struct comp_buffer **sources, uint32_t num_sources,
uint32_t frames)
/* Mix n 16 bit PCM source streams to one sink stream */
static void mix_n_s16(struct comp_dev *dev, struct comp_buffer *sink,
struct comp_buffer **sources, uint32_t num_sources,
uint32_t frames)
{
int16_t *src;
int16_t *dest;
int32_t val;
int i;
int j;
int channel;
uint32_t frag = 0;

for (i = 0; i < frames; i++) {
for (channel = 0; channel < dev->params.channels; channel++) {
val = 0;

for (j = 0; j < num_sources; j++) {
src = buffer_read_frag_s16(sources[j], frag);
val += *src;
}

dest = buffer_write_frag_s16(sink, frag);

/* Saturate to 16 bits */
*dest = sat_int16(val);

frag++;
}
}
}

/* Mix n 32 bit PCM source streams to one sink stream */
static void mix_n_s32(struct comp_dev *dev, struct comp_buffer *sink,
struct comp_buffer **sources, uint32_t num_sources,
uint32_t frames)
{
int32_t *src;
int32_t *dest;
Expand Down Expand Up @@ -342,9 +374,9 @@ static int mixer_prepare(struct comp_dev *dev)

/* does mixer already have active source streams ? */
if (dev->state != COMP_STATE_ACTIVE) {

/* currently inactive so setup mixer */
md->mix_func = mix_n;
md->mix_func = dev->params.frame_fmt == SOF_IPC_FRAME_S16_LE ?
mix_n_s16 : mix_n_s32;

ret = comp_set_state(dev, COMP_TRIGGER_PREPARE);
if (ret < 0)
Expand Down