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/*
* Rate converter plugin using libsamplerate
*
* Copyright (c) 2006 by Takashi Iwai <tiwai@suse.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
*/
#include <stdio.h>
#include <samplerate.h>
#include <alsa/asoundlib.h>
#include <alsa/pcm_rate.h>
struct rate_src {
double ratio;
int converter;
unsigned int channels;
float *src_buf;
float *dst_buf;
SRC_STATE *state;
SRC_DATA data;
};
static snd_pcm_uframes_t input_frames(void *obj, snd_pcm_uframes_t frames)
{
struct rate_src *rate = obj;
if (frames == 0)
return 0;
return (snd_pcm_uframes_t)(frames / rate->ratio);
}
static snd_pcm_uframes_t output_frames(void *obj, snd_pcm_uframes_t frames)
{
struct rate_src *rate = obj;
if (frames == 0)
return 0;
return (snd_pcm_uframes_t)(frames * rate->ratio);
}
static void pcm_src_free(void *obj)
{
struct rate_src *rate = obj;
free(rate->src_buf);
free(rate->dst_buf);
rate->src_buf = rate->dst_buf = NULL;
if (rate->state) {
src_delete(rate->state);
rate->state = NULL;
}
}
static int pcm_src_init(void *obj, snd_pcm_rate_info_t *info)
{
struct rate_src *rate = obj;
int err;
if (! rate->state || rate->channels != info->channels) {
if (rate->state)
src_delete(rate->state);
rate->channels = info->channels;
rate->state = src_new(rate->converter, rate->channels, &err);
if (! rate->state)
return -EINVAL;
}
rate->ratio = (double)info->out.rate / (double)info->in.rate;
free(rate->src_buf);
rate->src_buf = malloc(sizeof(float) * rate->channels * info->in.period_size);
free(rate->dst_buf);
rate->dst_buf = malloc(sizeof(float) * rate->channels * info->out.period_size);
if (! rate->src_buf || ! rate->dst_buf) {
pcm_src_free(rate);
return -ENOMEM;
}
rate->data.data_in = rate->src_buf;
rate->data.data_out = rate->dst_buf;
rate->data.src_ratio = rate->ratio;
rate->data.end_of_input = 0;
return 0;
}
static int pcm_src_adjust_pitch(void *obj, snd_pcm_rate_info_t *info)
{
struct rate_src *rate = obj;
rate->ratio = ((double)info->out.period_size / (double)info->in.period_size);
rate->data.src_ratio = rate->ratio;
return 0;
}
static void pcm_src_reset(void *obj)
{
struct rate_src *rate = obj;
src_reset(rate->state);
}
static void pcm_src_convert_s16(void *obj, int16_t *dst, unsigned int dst_frames,
const int16_t *src, unsigned int src_frames)
{
struct rate_src *rate = obj;
unsigned int ofs;
rate->data.input_frames = src_frames;
rate->data.output_frames = dst_frames;
rate->data.end_of_input = 0;
src_short_to_float_array(src, rate->src_buf, src_frames * rate->channels);
src_process(rate->state, &rate->data);
if (rate->data.output_frames_gen < dst_frames)
ofs = dst_frames - rate->data.output_frames_gen;
else
ofs = 0;
src_float_to_short_array(rate->dst_buf, dst + ofs * rate->channels,
rate->data.output_frames_gen * rate->channels);
}
static void pcm_src_close(void *obj)
{
free(obj);
}
static snd_pcm_rate_ops_t pcm_src_ops = {
.close = pcm_src_close,
.init = pcm_src_init,
.free = pcm_src_free,
.reset = pcm_src_reset,
.adjust_pitch = pcm_src_adjust_pitch,
.convert_s16 = pcm_src_convert_s16,
.input_frames = input_frames,
.output_frames = output_frames,
};
static int pcm_src_open(unsigned int version, void **objp,
snd_pcm_rate_ops_t *ops, int type)
{
struct rate_src *rate;
if (version != SND_PCM_RATE_PLUGIN_VERSION) {
fprintf(stderr, "Invalid rate plugin version %x\n", version);
return -EINVAL;
}
rate = calloc(1, sizeof(*rate));
if (! rate)
return -ENOMEM;
rate->converter = type;
*objp = rate;
*ops = pcm_src_ops;
return 0;
}
int SND_PCM_RATE_PLUGIN_ENTRY(samplerate) (unsigned int version, void **objp,
snd_pcm_rate_ops_t *ops)
{
return pcm_src_open(version, objp, ops, SRC_SINC_FASTEST);
}
int SND_PCM_RATE_PLUGIN_ENTRY(samplerate_best) (unsigned int version, void **objp,
snd_pcm_rate_ops_t *ops)
{
return pcm_src_open(version, objp, ops, SRC_SINC_BEST_QUALITY);
}
int SND_PCM_RATE_PLUGIN_ENTRY(samplerate_medium) (unsigned int version, void **objp,
snd_pcm_rate_ops_t *ops)
{
return pcm_src_open(version, objp, ops, SRC_SINC_MEDIUM_QUALITY);
}
int SND_PCM_RATE_PLUGIN_ENTRY(samplerate_order) (unsigned int version, void **objp,
snd_pcm_rate_ops_t *ops)
{
return pcm_src_open(version, objp, ops, SRC_ZERO_ORDER_HOLD);
}
int SND_PCM_RATE_PLUGIN_ENTRY(samplerate_linear) (unsigned int version, void **objp,
snd_pcm_rate_ops_t *ops)
{
return pcm_src_open(version, objp, ops, SRC_LINEAR);
}
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