[xiph-commits] r13453 - trunk/ghost/libghost

[jm at svn.xiph.org]

Author: jm
Date: 2007-08-05 17:12:36 -0700 (Sun, 05 Aug 2007)
New Revision: 13453

Added:
   trunk/ghost/libghost/adpcm.c
Modified:
   trunk/ghost/libghost/Makefile.am
Log:
Simple ADPCM-like code (doesn't work)


Modified: trunk/ghost/libghost/Makefile.am
===================================================================
--- trunk/ghost/libghost/Makefile.am	2007-08-05 19:28:34 UTC (rev 13452)
+++ trunk/ghost/libghost/Makefile.am	2007-08-06 00:12:36 UTC (rev 13453)
@@ -9,8 +9,8 @@
 lib_LTLIBRARIES = libghost.la
 
 # Sources for compilation in the library
-libghost_la_SOURCES = ghost.c sinusoids.c pitch.c lifting.c \
-	smallft.c fftwrap.c misc.c vorbis_psy.c lpc.c
+libghost_la_SOURCES = adpcm.c fftwrap.c ghost.c lifting.c lpc.c misc.c pitch.c \
+	sinusoids.c smallft.c vorbis_psy.c
 
 #noinst_HEADERS =
 

Added: trunk/ghost/libghost/adpcm.c
===================================================================
--- trunk/ghost/libghost/adpcm.c	                        (rev 0)
+++ trunk/ghost/libghost/adpcm.c	2007-08-06 00:12:36 UTC (rev 13453)
@@ -0,0 +1,51 @@
+/**
+   @file adpcm.c
+   @brief ADPCM-like code
+ */
+
+/* Copyright (C) 2007
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with this library; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#include <math.h>
+
+void adpcm_quant(float *x, float *a, int *q, int N, int len)
+{
+   int i,j;
+   for (i=0;i<len;i++)
+   {
+      float p = 0;
+      /* Prediction: conceptual code, this will segfault (or worse) */
+      for (j=0;j<N;j++)
+         p += a[j]*q[i-j-1];
+      /* Difference */
+      q[i] = rint(x[i]-p);
+      /* Adaptation: conceptual code, this will segfault (or worse) */
+      for (j=0;j<N;j++)
+         a[j] += q[i]*q[i-j-1]/(q[i]*q[i]); 
+   }
+}
+
+void adpcm_unquant(int *q, float *a, float *x, int len)
+{
+   int i;
+   for (i=0;i<len;i++)
+   {
+      float p = 0;
+      x[i] = q[i]+p;
+   }
+}
+