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diff decoders/libmpg123/layer1.c @ 562:7e08477b0fc1

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MP3 decoder upgrade work. Ripped out SMPEG and mpglib support, replaced it with "mpg123.c" and libmpg123. libmpg123 is a much better version of mpglib, so it should solve all the problems about MP3's not seeking, or most modern MP3's not playing at all, etc. Since you no longer have to make a tradeoff with SMPEG for features, and SMPEG is basically rotting, I removed it from the project. There is still work to be done with libmpg123...there are MMX, 3DNow, SSE, Altivec, etc decoders which we don't have enabled at the moment, and the build system could use some work to make this compile more cleanly, etc. Still: huge win.
author Ryan C. Gordon <icculus@icculus.org>
date Fri, 30 Jan 2009 02:44:47 -0500
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/decoders/libmpg123/layer1.c	Fri Jan 30 02:44:47 2009 -0500
@@ -0,0 +1,153 @@
+/*
+	layer1.c: the layer 1 decoder
+
+	copyright 1995-2007 by the mpg123 project - free software under the terms of the LGPL 2.1
+	see COPYING and AUTHORS files in distribution or http://mpg123.org
+	initially written by Michael Hipp
+
+	may have a few bugs after last optimization ... 
+*/
+
+#include "mpg123lib_intern.h"
+#include "getbits.h"
+
+void I_step_one(unsigned int balloc[], unsigned int scale_index[2][SBLIMIT],mpg123_handle *fr)
+{
+  unsigned int *ba=balloc;
+  unsigned int *sca = (unsigned int *) scale_index;
+
+  if(fr->stereo == 2) {
+    int i;
+    int jsbound = fr->jsbound;
+    for (i=0;i<jsbound;i++) { 
+      *ba++ = getbits(fr, 4);
+      *ba++ = getbits(fr, 4);
+    }
+    for (i=jsbound;i<SBLIMIT;i++)
+      *ba++ = getbits(fr, 4);
+
+    ba = balloc;
+
+    for (i=0;i<jsbound;i++) {
+      if ((*ba++))
+        *sca++ = getbits(fr, 6);
+      if ((*ba++))
+        *sca++ = getbits(fr, 6);
+    }
+    for (i=jsbound;i<SBLIMIT;i++)
+      if ((*ba++)) {
+        *sca++ =  getbits(fr, 6);
+        *sca++ =  getbits(fr, 6);
+      }
+  }
+  else {
+    int i;
+    for (i=0;i<SBLIMIT;i++)
+      *ba++ = getbits(fr, 4);
+    ba = balloc;
+    for (i=0;i<SBLIMIT;i++)
+      if ((*ba++))
+        *sca++ = getbits(fr, 6);
+  }
+}
+
+void I_step_two(real fraction[2][SBLIMIT],unsigned int balloc[2*SBLIMIT],
+	unsigned int scale_index[2][SBLIMIT],mpg123_handle *fr)
+{
+  int i,n;
+  int smpb[2*SBLIMIT]; /* values: 0-65535 */
+  int *sample;
+  register unsigned int *ba;
+  register unsigned int *sca = (unsigned int *) scale_index;
+
+  if(fr->stereo == 2) {
+    int jsbound = fr->jsbound;
+    register real *f0 = fraction[0];
+    register real *f1 = fraction[1];
+    ba = balloc;
+    for (sample=smpb,i=0;i<jsbound;i++)  {
+      if ((n = *ba++))
+        *sample++ = getbits(fr, n+1);
+      if ((n = *ba++))
+        *sample++ = getbits(fr, n+1);
+    }
+    for (i=jsbound;i<SBLIMIT;i++) 
+      if ((n = *ba++))
+        *sample++ = getbits(fr, n+1);
+
+    ba = balloc;
+    for (sample=smpb,i=0;i<jsbound;i++) {
+      if((n=*ba++))
+        *f0++ = (real) ( ((-1)<<n) + (*sample++) + 1) * fr->muls[n+1][*sca++];
+      else
+        *f0++ = 0.0;
+      if((n=*ba++))
+        *f1++ = (real) ( ((-1)<<n) + (*sample++) + 1) * fr->muls[n+1][*sca++];
+      else
+        *f1++ = 0.0;
+    }
+    for (i=jsbound;i<SBLIMIT;i++) {
+      if ((n=*ba++)) {
+        real samp = ( ((-1)<<n) + (*sample++) + 1);
+        *f0++ = samp * fr->muls[n+1][*sca++];
+        *f1++ = samp * fr->muls[n+1][*sca++];
+      }
+      else
+        *f0++ = *f1++ = 0.0;
+    }
+    for(i=fr->down_sample_sblimit;i<32;i++)
+      fraction[0][i] = fraction[1][i] = 0.0;
+  }
+  else {
+    register real *f0 = fraction[0];
+    ba = balloc;
+    for (sample=smpb,i=0;i<SBLIMIT;i++)
+      if ((n = *ba++))
+        *sample++ = getbits(fr, n+1);
+    ba = balloc;
+    for (sample=smpb,i=0;i<SBLIMIT;i++) {
+      if((n=*ba++))
+        *f0++ = (real) ( ((-1)<<n) + (*sample++) + 1) * fr->muls[n+1][*sca++];
+      else
+        *f0++ = 0.0;
+    }
+    for(i=fr->down_sample_sblimit;i<32;i++)
+      fraction[0][i] = 0.0;
+  }
+}
+
+int do_layer1(mpg123_handle *fr)
+{
+  int clip=0;
+  int i,stereo = fr->stereo;
+  unsigned int balloc[2*SBLIMIT];
+  unsigned int scale_index[2][SBLIMIT];
+  ALIGNED(16) real fraction[2][SBLIMIT];
+  int single = fr->single;
+
+  fr->jsbound = (fr->mode == MPG_MD_JOINT_STEREO) ? (fr->mode_ext<<2)+4 : 32;
+
+  if(stereo == 1 || single == SINGLE_MIX) /* I don't see mixing handled here */
+    single = SINGLE_LEFT;
+
+  I_step_one(balloc,scale_index,fr);
+
+  for (i=0;i<SCALE_BLOCK;i++)
+  {
+    I_step_two(fraction,balloc,scale_index,fr);
+
+    if(single != SINGLE_STEREO)
+    {
+      clip += (fr->synth_mono)( (real *) fraction[single], fr);
+    }
+    else
+    {
+      clip += (fr->synth)( (real *) fraction[0], 0, fr, 0);
+      clip += (fr->synth)( (real *) fraction[1], 1, fr, 1);
+    }
+  }
+
+  return clip;
+}
+
+