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Preparation for more rate conversion types

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This commit is contained in:
Jaroslav Kysela 2004-01-24 16:23:11 +00:00
parent 819a85fb2c
commit 0f88788f8b
1 changed files with 43 additions and 26 deletions
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69
src/pcm/pcm_rate.c
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@ -40,11 +40,21 @@ const char *_snd_module_pcm_rate = "";
#define DIV (1<<16)
enum rate_type {
RATE_TYPE_LINEAR, /* linear interpolation */
RATE_TYPE_BANDLIMIT, /* bandlimited interpolation */
RATE_TYPE_POLYPHASE, /* polyphase resampling */
};
typedef struct {
int init;
int16_t old_sample, new_sample;
int sum;
unsigned int pos;
union {
struct {
int init;
int16_t old_sample, new_sample;
int sum;
unsigned int pos;
} linear;
} u;
} snd_pcm_rate_state_t;
typedef snd_pcm_uframes_t (*rate_f)(const snd_pcm_channel_area_t *dst_areas,
@ -61,6 +71,7 @@ typedef snd_pcm_uframes_t (*rate_f)(const snd_pcm_channel_area_t *dst_areas,
typedef struct {
/* This field need to be the first */
snd_pcm_plugin_t plug;
enum rate_type type;
unsigned int get_idx;
unsigned int put_idx;
unsigned int pitch;
@ -117,24 +128,24 @@ static snd_pcm_uframes_t snd_pcm_rate_expand(const snd_pcm_channel_area_t *dst_a
const char *src;
char *dst;
int src_step, dst_step;
int16_t old_sample = states->old_sample;
int16_t new_sample = states->new_sample;
unsigned int pos = states->pos;
int16_t old_sample = states->u.linear.old_sample;
int16_t new_sample = states->u.linear.new_sample;
unsigned int pos = states->u.linear.pos;
src = snd_pcm_channel_area_addr(src_area, src_offset);
dst = snd_pcm_channel_area_addr(dst_area, dst_offset);
src_step = snd_pcm_channel_area_step(src_area);
dst_step = snd_pcm_channel_area_step(dst_area);
src_frames1 = 0;
dst_frames1 = 0;
if (! states->init) {
if (! states->u.linear.init) {
sample = initial_sample(src, getidx);
old_sample = new_sample = sample;
src += src_step;
src_frames1++;
states->init = 2; /* get a new sample */
states->u.linear.init = 2; /* get a new sample */
}
while (dst_frames1 < dst_frames) {
if (states->init == 2) {
if (states->u.linear.init == 2) {
old_sample = new_sample;
goto *get;
#define GET16_END after_get
@ -142,7 +153,7 @@ static snd_pcm_uframes_t snd_pcm_rate_expand(const snd_pcm_channel_area_t *dst_a
#undef GET16_END
after_get:
new_sample = sample;
states->init = 1;
states->u.linear.init = 1;
}
sample = (((int64_t)old_sample * (int64_t)(get_threshold - pos)) + ((int64_t)new_sample * pos)) / get_threshold;
goto *put;
@ -157,14 +168,14 @@ static snd_pcm_uframes_t snd_pcm_rate_expand(const snd_pcm_channel_area_t *dst_a
pos -= get_threshold;
src += src_step;
src_frames1++;
states->init = 2; /* get a new sample */
states->u.linear.init = 2; /* get a new sample */
if (src_frames1 >= src_frames)
break;
}
}
states->old_sample = old_sample;
states->new_sample = new_sample;
states->pos = pos;
states->u.linear.old_sample = old_sample;
states->u.linear.new_sample = new_sample;
states->u.linear.pos = pos;
states++;
}
*dst_framesp = dst_frames1;
@ -204,9 +215,9 @@ static snd_pcm_uframes_t snd_pcm_rate_shrink(const snd_pcm_channel_area_t *dst_a
const char *src;
char *dst;
int src_step, dst_step;
sum = states->sum;
pos = states->pos;
states->init = 0;
sum = states->u.linear.sum;
pos = states->u.linear.pos;
states->u.linear.init = 0;
src = snd_pcm_channel_area_addr(src_area, src_offset);
dst = snd_pcm_channel_area_addr(dst_area, dst_offset);
src_step = snd_pcm_channel_area_step(src_area);
@ -242,8 +253,8 @@ static snd_pcm_uframes_t snd_pcm_rate_shrink(const snd_pcm_channel_area_t *dst_a
} else
sum += sample * get_increment;
}
states->sum = sum;
states->pos = pos;
states->u.linear.sum = sum;
states->u.linear.pos = pos;
states++;
}
*dst_framesp = dst_frames1;
@ -488,12 +499,17 @@ static int snd_pcm_rate_init(snd_pcm_t *pcm)
{
snd_pcm_rate_t *rate = pcm->private_data;
unsigned int k;
for (k = 0; k < pcm->channels; ++k) {
rate->states[k].sum = 0;
rate->states[k].old_sample = 0;
rate->states[k].new_sample = 0;
rate->states[k].pos = 0;
rate->states[k].init = 0;
switch (rate->type) {
case RATE_TYPE_LINEAR:
for (k = 0; k < pcm->channels; ++k) {
rate->states[k].u.linear.sum = 0;
rate->states[k].u.linear.old_sample = 0;
rate->states[k].u.linear.new_sample = 0;
rate->states[k].u.linear.pos = 0;
rate->states[k].u.linear.init = 0;
}
default:
assert(0);
}
return 0;
}
@ -617,6 +633,7 @@ int snd_pcm_rate_open(snd_pcm_t **pcmp, const char *name, snd_pcm_format_t sform
return -ENOMEM;
}
snd_pcm_plugin_init(&rate->plug);
rate->type = RATE_TYPE_LINEAR;
rate->srate = srate;
rate->sformat = sformat;
rate->plug.read = snd_pcm_rate_read_areas;