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33d69ef33b
Created a new rate converter plugin SDK. A rate converter can be replaced as an extra plugin now. The default rate converter is a built-in linear converter. You can find a sample external converter in alsa-plugins package.
117 lines
3.2 KiB
C
117 lines
3.2 KiB
C
/**
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* \file include/pcm_rate.h
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* \brief External Rate-Converter-Plugin SDK
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* \author Takashi Iwai <tiwai@suse.de>
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* \date 2006
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*
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* External Rate-Converter-Plugin SDK
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*/
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/*
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* ALSA external PCM rate-converter plugin SDK (draft version)
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*
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* Copyright (c) 2006 Takashi Iwai <tiwai@suse.de>
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*
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* This library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as
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* published by the Free Software Foundation; either version 2.1 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#ifndef __ALSA_PCM_RATE_H
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#define __ALSA_PCM_RATE_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* Protocol version
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*/
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#define SND_PCM_RATE_PLUGIN_VERSION 0x010001
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/** hw_params information for a single side */
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typedef struct snd_pcm_rate_side_info {
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snd_pcm_format_t format;
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unsigned int rate;
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snd_pcm_uframes_t buffer_size;
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snd_pcm_uframes_t period_size;
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} snd_pcm_rate_side_info_t;
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/** hw_params information */
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typedef struct snd_pcm_rate_info {
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struct snd_pcm_rate_side_info in;
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struct snd_pcm_rate_side_info out;
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unsigned int channels;
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} snd_pcm_rate_info_t;
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/** Callback table of rate-converter */
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typedef struct snd_pcm_rate_ops {
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/**
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* close the converter; optional
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*/
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void (*close)(void *obj);
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/**
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* initialize the converter, called at hw_params
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*/
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int (*init)(void *obj, snd_pcm_rate_info_t *info);
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/**
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* free the converter; optional
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*/
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void (*free)(void *obj);
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/**
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* reset the converter, called at prepare; optional
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*/
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void (*reset)(void *obj);
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/**
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* adjust the pitch, called at sw_params; optional
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*/
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int (*adjust_pitch)(void *obj, snd_pcm_rate_info_t *info);
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/**
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* convert the data
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*/
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void (*convert)(void *obj,
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const snd_pcm_channel_area_t *dst_areas,
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snd_pcm_uframes_t dst_offset, unsigned int dst_frames,
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const snd_pcm_channel_area_t *src_areas,
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snd_pcm_uframes_t src_offset, unsigned int src_frames);
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/**
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* convert an s16 interleaved-data array; exclusive with convert
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*/
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void (*convert_s16)(void *obj, int16_t *dst, unsigned int dst_frames,
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const int16_t *src, unsigned int src_frames);
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/**
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* compute the frame size for input
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*/
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snd_pcm_uframes_t (*input_frames)(void *obj, snd_pcm_uframes_t frames);
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/**
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* compute the frame size for output
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*/
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snd_pcm_uframes_t (*output_frames)(void *obj, snd_pcm_uframes_t frames);
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} snd_pcm_rate_ops_t;
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/** open function type */
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typedef int (*snd_pcm_rate_open_func_t)(unsigned int version, void **objp,
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snd_pcm_rate_ops_t *opsp);
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/**
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* Define the object entry for external PCM rate-converter plugins
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*/
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#define SND_PCM_RATE_PLUGIN_ENTRY(name) _snd_pcm_rate_##name##_open
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#ifdef __cplusplus
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}
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#endif
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#endif /* __ALSA_PCM_RATE_H */
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