move mp3 stuff to /sys/src/cmd/audio, add ogg vorbis, add play

1 files changed, 200 insertions, 0 deletions

diff --git a/sys/src/cmd/audio/libvorbis/lpc.c b/sys/src/cmd/audio/libvorbis/lpc.c
new file mode 100644
index 000000000..4005c4f0f
--- /dev/null
+++ b/sys/src/cmd/audio/libvorbis/lpc.c
@@ -0,0 +1,200 @@
+/********************************************************************
+ *                                                                  *
+ * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
+ * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
+ * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
+ * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
+ *                                                                  *
+ * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2002             *
+ * by the XIPHOPHORUS Company http://www.xiph.org/                  *
+ *                                                                  *
+ ********************************************************************
+
+  function: LPC low level routines
+  last mod: $Id: lpc.c,v 1.35 2002/07/11 06:40:49 xiphmont Exp $
+
+ ********************************************************************/
+
+/* Some of these routines (autocorrelator, LPC coefficient estimator)
+   are derived from code written by Jutta Degener and Carsten Bormann;
+   thus we include their copyright below.  The entirety of this file
+   is freely redistributable on the condition that both of these
+   copyright notices are preserved without modification.  */
+
+/* Preserved Copyright: *********************************************/
+
+/* Copyright 1992, 1993, 1994 by Jutta Degener and Carsten Bormann,
+Technische Universita"t Berlin
+
+Any use of this software is permitted provided that this notice is not
+removed and that neither the authors nor the Technische Universita"t
+Berlin are deemed to have made any representations as to the
+suitability of this software for any purpose nor are held responsible
+for any defects of this software. THERE IS ABSOLUTELY NO WARRANTY FOR
+THIS SOFTWARE.
+
+As a matter of courtesy, the authors request to be informed about uses
+this software has found, about bugs in this software, and about any
+improvements that may be of general interest.
+
+Berlin, 28.11.1994
+Jutta Degener
+Carsten Bormann
+
+*********************************************************************/
+
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include "os.h"
+#include "smallft.h"
+#include "lpc.h"
+#include "scales.h"
+#include "misc.h"
+
+/* Autocorrelation LPC coeff generation algorithm invented by
+   N. Levinson in 1947, modified by J. Durbin in 1959. */
+
+/* Input : n elements of time doamin data
+   Output: m lpc coefficients, excitation energy */
+
+float vorbis_lpc_from_data(float *data,float *lpc,int n,int m){
+  float *aut=malloc(sizeof(*aut)*(m+1));
+  float error;
+  int i,j;
+
+  /* autocorrelation, p+1 lag coefficients */
+
+  j=m+1;
+  while(j--){
+    double d=0; /* double needed for accumulator depth */
+    for(i=j;i<n;i++)d+=data[i]*data[i-j];
+    aut[j]=d;
+  }
+  
+  /* Generate lpc coefficients from autocorr values */
+
+  error=aut[0];
+  
+  for(i=0;i<m;i++){
+    float r= -aut[i+1];
+
+    if(error==0){
+      memset(lpc,0,m*sizeof(*lpc));
+      free(aut);
+      return 0;
+    }
+
+    /* Sum up this iteration's reflection coefficient; note that in
+       Vorbis we don't save it.  If anyone wants to recycle this code
+       and needs reflection coefficients, save the results of 'r' from
+       each iteration. */
+
+    for(j=0;j<i;j++)r-=lpc[j]*aut[i-j];
+    r/=error; 
+
+    /* Update LPC coefficients and total error */
+    
+    lpc[i]=r;
+    for(j=0;j<i/2;j++){
+      float tmp=lpc[j];
+      lpc[j]+=r*lpc[i-1-j];
+      lpc[i-1-j]+=r*tmp;
+    }
+    if(i%2)lpc[j]+=lpc[j]*r;
+    
+    error*=1.f-r*r;
+  }
+  
+  /* we need the error value to know how big an impulse to hit the
+     filter with later */
+  free(aut);
+  return error;
+}
+
+/* Input : n element envelope spectral curve
+   Output: m lpc coefficients, excitation energy */
+
+float vorbis_lpc_from_curve(float *curve,float *lpc,lpc_lookup *l){
+  int n=l->ln;
+  int m=l->m;
+  float *work=malloc(sizeof(*work)*(n+n));
+  float fscale=.5f/n;
+  float tmp;
+  int i,j;
+  
+  /* input is a real curve. make it complex-real */
+  /* This mixes phase, but the LPC generation doesn't care. */
+  for(i=0;i<n;i++){
+    work[i*2]=curve[i]*fscale;
+    work[i*2+1]=0;
+  }
+  work[n*2-1]=curve[n-1]*fscale;
+  
+  n*=2;
+  drft_backward(&l->fft,work);
+
+  /* The autocorrelation will not be circular.  Shift, else we lose
+     most of the power in the edges. */
+  
+  for(i=0,j=n/2;i<n/2;){
+    float temp=work[i];
+    work[i++]=work[j];
+    work[j++]=temp;
+  }
+  
+  /* we *could* shave speed here by skimping on the edges (thus
+     speeding up the autocorrelation in vorbis_lpc_from_data) but we
+     don't right now. */
+  tmp = vorbis_lpc_from_data(work,lpc,n,m);
+  free(work);
+  return(tmp);
+}
+
+void lpc_init(lpc_lookup *l,long mapped, int m){
+  memset(l,0,sizeof(*l));
+
+  l->ln=mapped;
+  l->m=m;
+
+  /* we cheat decoding the LPC spectrum via FFTs */  
+  drft_init(&l->fft,mapped*2);
+
+}
+
+void lpc_clear(lpc_lookup *l){
+  if(l){
+    drft_clear(&l->fft);
+  }
+}
+
+void vorbis_lpc_predict(float *coeff,float *prime,int m,
+                     float *data,long n){
+
+  /* in: coeff[0...m-1] LPC coefficients 
+         prime[0...m-1] initial values (allocated size of n+m-1)
+    out: data[0...n-1] data samples */
+
+  long i,j,o,p;
+  float y;
+  float *work=malloc(sizeof(*work)*(m+n));
+
+  if(!prime)
+    for(i=0;i<m;i++)
+      work[i]=0.f;
+  else
+    for(i=0;i<m;i++)
+      work[i]=prime[i];
+
+  for(i=0;i<n;i++){
+    y=0;
+    o=i;
+    p=m;
+    for(j=0;j<m;j++)
+      y-=work[o++]*coeff[--p];
+    
+    data[i]=work[o]=y;
+  }
+  free(work);
+  return;
+}