mirror of https://github.com/mpv-player/mpv
276 lines
7.5 KiB
C
276 lines
7.5 KiB
C
/*=============================================================================
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//
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// This software has been released under the terms of the GNU Public
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// license. See http://www.gnu.org/copyleft/gpl.html for details.
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//
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// Copyright 2001 Anders Johansson ajh@atri.curtin.edu.au
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//
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//=============================================================================
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*/
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/* This audio output plugin changes the sample rate. The output
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samplerate from this plugin is specified by using the switch
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`fout=F' where F is the desired output sample frequency
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*/
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#define PLUGIN
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <inttypes.h>
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#include "audio_out.h"
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#include "audio_plugin.h"
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#include "audio_plugin_internal.h"
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#include "afmt.h"
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// #include "../config.h"
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static ao_info_t info =
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{
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"Sample frequency conversion audio plugin",
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"resample",
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"Anders",
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""
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};
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LIBAO_PLUGIN_EXTERN(resample)
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#define min(a,b) (((a) < (b)) ? (a) : (b))
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#define max(a,b) (((a) > (b)) ? (a) : (b))
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/* Below definition selects the length of each poly phase component.
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Valid definitions are L4 and L8, where the number denotes the
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length of the filter. This definition affects the computational
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complexity (see play()), the performance (see filter.h) and the
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memory usage. For now the filterlenght is choosen to 4 and without
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assembly optimization if no SSE is present.
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*/
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// #ifdef HAVE_SSE
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#define L8 1 // Filter bank type
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#define W W8 // Filter bank parameters
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#define L 8 // Filter length
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// #else
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// #define L4 1
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// #define W W4
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// #define L 4
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// #endif
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#define CH 6 // Max number of channels
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#define UP 128 /* Up sampling factor. Increasing this value will
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improve frequency accuracy. Think about the L1
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cashing of filter parameters - how big can it be? */
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#include "fir.h"
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#include "filter.h"
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// local data
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typedef struct pl_resample_s
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{
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int16_t* data; // Data buffer
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int16_t* w; // Current filter weights
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uint16_t dn; // Down sampling factor
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uint16_t up; // Up sampling factor
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int channels; // Number of channels
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int len; // Lenght of buffer
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int16_t ws[UP*L]; // List of all available filters
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int16_t xs[CH][L*2]; // Circular buffers
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} pl_resample_t;
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static pl_resample_t pl_resample = {NULL,NULL,1,1,1,0,W};
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// to set/get/query special features/parameters
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static int control(int cmd,int arg){
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switch(cmd){
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case AOCONTROL_PLUGIN_SET_LEN:
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if(pl_resample.data)
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free(pl_resample.data);
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pl_resample.len = ao_plugin_data.len;
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pl_resample.data=(int16_t*)malloc(pl_resample.len);
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if(!pl_resample.data)
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return CONTROL_ERROR;
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ao_plugin_data.len = (int)((double)ao_plugin_data.len *
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((double)pl_resample.up)/
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((double)pl_resample.dn));
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return CONTROL_OK;
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}
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return -1;
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}
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// open & setup audio device
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// return: 1=success 0=fail
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static int init(){
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int fin=ao_plugin_data.rate;
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int fout=ao_plugin_cfg.pl_resample_fout;
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pl_resample.w=pl_resample.ws;
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pl_resample.up=UP;
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// Sheck input format
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if(ao_plugin_data.format != AFMT_S16_LE){
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fprintf(stderr,"[pl_resample] Input audio format not yet suported. \n");
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return 0;
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}
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// Sanity check and calculate down sampling factor
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if((float)max(fin,fout)/(float)min(fin,fout) > 10){
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fprintf(stderr,"[pl_resample] The difference between fin and fout is too large.\n");
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return 0;
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}
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pl_resample.dn=(int)(0.5+((float)(fin*pl_resample.up))/((float)fout));
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pl_resample.channels=ao_plugin_data.channels;
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if(ao_plugin_data.channels>CH){
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fprintf(stderr,"[pl_resample] Too many channels, max is 6.\n");
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return 0;
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}
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// Tell the world what we are up to
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printf("[pl_resample] Up=%i, Down=%i, True fout=%f\n",
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pl_resample.up,pl_resample.dn,
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((float)fin*pl_resample.up)/((float)pl_resample.dn));
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// This plugin changes buffersize and adds some delay
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ao_plugin_data.sz_mult/=((float)pl_resample.up)/((float)pl_resample.dn);
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ao_plugin_data.delay_fix-= ((float)L/2) * (1/fout);
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ao_plugin_data.rate=fout;
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return 1;
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}
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// close plugin
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static void uninit(){
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if(pl_resample.data)
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free(pl_resample.data);
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pl_resample.data=NULL;
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}
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// empty buffers
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static void reset(){
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}
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// processes 'ao_plugin_data.len' bytes of 'data'
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// called for every block of data
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// FIXME: this routine needs to be optimized (it is probably possible to do a lot here)
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static int play(){
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if(pl_resample.up==pl_resample.dn){
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register int16_t* in = ((int16_t*)ao_plugin_data.data);
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register int16_t* end = in+ao_plugin_data.len/2;
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while(in < end) *in=(*in++)>>1;
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return 1;
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}
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if(pl_resample.up>pl_resample.dn)
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return upsample();
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if(pl_resample.up<pl_resample.dn)
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return downsample();
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}
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int upsample(){
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static uint16_t pwi = 0; // Index for w
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static uint16_t pxi = 0; // Index for circular queue
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uint16_t ci = pl_resample.channels; // Index for channels
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uint16_t nch = pl_resample.channels; // Number of channels
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uint16_t len = 0; // Number of input samples
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uint16_t inc = pl_resample.up/pl_resample.dn;
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uint16_t level = pl_resample.up%pl_resample.dn;
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uint16_t up = pl_resample.up;
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uint16_t dn = pl_resample.dn;
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register int16_t* w = pl_resample.w;
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register uint16_t wi,xi; // Temporary indexes
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// Index current channel
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while(ci--){
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// Temporary pointers
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register int16_t* x = pl_resample.xs[ci];
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register int16_t* in = ((int16_t*)ao_plugin_data.data)+ci;
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register int16_t* out = pl_resample.data+ci;
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int16_t* end = in+ao_plugin_data.len/2; // Block loop end
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wi = pwi; xi = pxi;
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LOAD_QUE(x);
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while(in < end){
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register uint16_t i = inc;
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if(wi<level) i++;
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UPDATE_QUE(in);
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in+=nch;
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while(i--){
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// Run the FIR filter
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FIR((&x[xi]),(&w[wi*L]),out);
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len++; out+=nch;
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// Update wi to point at the correct polyphase component
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wi=(wi+dn)%up;
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}
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}
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SAVE_QUE(x);
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}
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// Save values that needs to be kept for next time
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pwi = wi;
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pxi = xi;
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// Set new data
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ao_plugin_data.len=len*2;
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ao_plugin_data.data=pl_resample.data;
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return 1;
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}
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int downsample(){
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static uint16_t pwi = 0; // Index for w
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static uint16_t pxi = 0; // Index for circular queue
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static uint16_t pi = 1; // Number of new samples to put in x queue
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uint16_t ci = pl_resample.channels; // Index for channels
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uint16_t len = 0; // Number of input samples
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uint16_t nch = pl_resample.channels; // Number of channels
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uint16_t inc = pl_resample.dn/pl_resample.up;
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uint16_t level = pl_resample.dn%pl_resample.up;
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uint16_t up = pl_resample.up;
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uint16_t dn = pl_resample.dn;
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register uint16_t i,wi,xi; // Temporary indexes
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// Index current channel
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while(ci--){
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// Temporary pointers
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register int16_t* x = pl_resample.xs[ci];
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register int16_t* in = ((int16_t*)ao_plugin_data.data)+ci;
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register int16_t* out = pl_resample.data+ci;
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// Block loop end
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register int16_t* end = in+ao_plugin_data.len/2;
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i = pi; wi = pwi; xi = pxi;
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LOAD_QUE(x);
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while(in < end){
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UPDATE_QUE(in);
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in+=nch;
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if(!--i){
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// Run the FIR filter
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FIR((&x[xi]),(&pl_resample.w[wi*L]),out);
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len++; out+=nch;
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// Update wi to point at the correct polyphase component
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wi=(wi+dn)%up;
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// Insert i number of new samples in queue
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i = inc;
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if(wi<level) i++;
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}
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}
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SAVE_QUE(x);
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}
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// Save values that needs to be kept for next time
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pwi = wi;
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pxi = xi;
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pi = i;
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// Set new data
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ao_plugin_data.len=len*2;
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ao_plugin_data.data=pl_resample.data;
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return 1;
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}
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