1 files changed, 109 insertions, 0 deletions
diff --git a/mpeglib/lib/splay/mpeglayer1.cpp b/mpeglib/lib/splay/mpeglayer1.cpp
new file mode 100644
index 00000000..a32951c4
--- /dev/null
+++ b/mpeglib/lib/splay/mpeglayer1.cpp
@@ -0,0 +1,109 @@
+/* MPEG/WAVE Sound library
+
+   (C) 1997 by Jung woo-jae */
+
+// Mpeglayer1.cc
+// It's for MPEG Layer 1
+
+ 
+
+#include "mpegsound.h"
+#include "synthesis.h"
+
+// Tables for layer 1
+static const REAL factortable[15] = 
+{
+  0.0, 
+  (1.0/2.0)    * (4.0/3.0),         (1.0/4.0)     * (8.0/7.0),
+  (1.0/8.0)    * (16.0/15.0),       (1.0/16.0)    * (32.0/31.0),
+  (1.0/32.0)   * (64.0/63.0),       (1.0/64.0)    * (128.0/127.0),
+  (1.0/128.0)  * (256.0/255.0),     (1.0/256.0)   * (512.0/511.0),
+  (1.0/512.0)  * (1024.0/1023.0),   (1.0/1024.0)  * (2048.0/2047.0),
+  (1.0/2048.0) * (4096.0/4095.0),   (1.0/4096.0)  * (8192.0/8191.0),
+  (1.0/8192.0) * (16384.0/16383.0), (1.0/16384.0) * (32768.0/32767.0)
+};
+
+static const REAL offsettable[15] = 
+{
+  0.0, 
+  ((1.0/2.0)-1.0)    * (4.0/3.0),         ((1.0/4.0)-1.0)     * (8.0/7.0), 
+  ((1.0/8.0)-1.0)    * (16.0/15.0),       ((1.0/16.0)-1.0)    * (32.0/31.0),
+  ((1.0/32.0)-1.0)   * (64.0/63.0),       ((1.0/64.0)-1.0)    * (128.0/127.0),
+  ((1.0/128.0)-1.0)  * (256.0/255.0),     ((1.0/256.0)-1.0)   * (512.0/511.0),
+  ((1.0/512.0)-1.0)  * (1024.0/1023.0),   ((1.0/1024.0)-1.0)  * (2048.0/2047.0),
+  ((1.0/2048.0)-1.0) * (4096.0/4095.0),   ((1.0/4096.0)-1.0)  * (8192.0/8191.0),
+  ((1.0/8192.0)-1.0) * (16384.0/16383.0), ((1.0/16384.0)-1.0) * (32768.0/32767.0)
+};
+
+// Mpeg layer 1
+void Mpegtoraw::extractlayer1(void)
+{
+  int inputstereo=mpegAudioHeader->getInputstereo();
+  int stereobound=mpegAudioHeader->getStereobound();
+  REAL fraction[MAXCHANNEL][MAXSUBBAND];
+  REAL scalefactor[MAXCHANNEL][MAXSUBBAND];
+
+  int bitalloc[MAXCHANNEL][MAXSUBBAND],
+      sample[MAXCHANNEL][MAXSUBBAND];
+
+  register int i,j;
+  int s=stereobound,l;
+
+
+// Bitalloc
+  for(i=0;i<s;i++)
+  {
+    bitalloc[LS][i]=getbits(4);
+    bitalloc[RS][i]=getbits(4);
+  }
+  for(;i<MAXSUBBAND;i++)
+    bitalloc[LS][i]=
+    bitalloc[RS][i]=getbits(4);
+
+// Scale index
+  if(inputstereo)
+    for(i=0;i<MAXSUBBAND;i++)
+    {
+      if(bitalloc[LS][i])scalefactor[LS][i]=scalefactorstable[getbits(6)];
+      if(bitalloc[RS][i])scalefactor[RS][i]=scalefactorstable[getbits(6)];
+    }
+  else
+    for(i=0;i<MAXSUBBAND;i++)
+      if(bitalloc[LS][i])scalefactor[LS][i]=scalefactorstable[getbits(6)];
+
+  for(l=0;l<SCALEBLOCK;l++)
+  {
+    // Sample
+    for(i=0;i<s;i++)
+    {
+      if((j=bitalloc[LS][i]))sample[LS][i]=getbits(j+1);
+      if((j=bitalloc[RS][i]))sample[RS][i]=getbits(j+1);
+    }
+    for(;i<MAXSUBBAND;i++)
+      if((j=bitalloc[LS][i]))sample[LS][i]=sample[RS][i]=getbits(j+1);
+
+
+    // Fraction
+    if(lOutputStereo)
+      for(i=0;i<MAXSUBBAND;i++)
+      {
+	if((j=bitalloc[LS][i]))
+	  fraction[LS][i]=(REAL(sample[LS][i])*factortable[j]+offsettable[j])
+			  *scalefactor[LS][i];
+	else fraction[LS][i]=0.0;
+	if((j=bitalloc[RS][i]))
+	  fraction[RS][i]=(REAL(sample[RS][i])*factortable[j]+offsettable[j])
+			  *scalefactor[RS][i];
+	else fraction[RS][i]=0.0;
+      }
+    else
+      for(i=0;i<MAXSUBBAND;i++)
+	if((j=bitalloc[LS][i]))
+	  fraction[LS][i]=(REAL(sample[LS][i])*factortable[j]+offsettable[j])
+			  *scalefactor[LS][i];
+	else fraction[LS][i]=0.0;
+
+    synthesis->doSynth(lDownSample,lOutputStereo,
+		       fraction[LS],fraction[RS]);
+  }
+}