[FFmpeg-cvslog] r19571 - in trunk/libavcodec: Makefile lsp.c lsp.h qcelp_lsp.c qcelpdec.c

[superdump]

Author: superdump
Date: Mon Aug  3 10:37:02 2009
New Revision: 19571

Log:
Expose QCELP's floating-point LSP-to-LPC function
qcelp_lsp exported a single function, ff_acelp_lspd2lpc, which was not
specific to qcelp. It can be kept with its fixed-point version
ff_acelp_lsp2lpc in lpc.c.

Patch by Colin McQuillan ( m.niloc googlemail com )

Deleted:
   trunk/libavcodec/qcelp_lsp.c
Modified:
   trunk/libavcodec/Makefile
   trunk/libavcodec/lsp.c
   trunk/libavcodec/lsp.h
   trunk/libavcodec/qcelpdec.c

Modified: trunk/libavcodec/Makefile
==============================================================================
--- trunk/libavcodec/Makefile	Mon Aug  3 10:31:20 2009	(r19570)
+++ trunk/libavcodec/Makefile	Mon Aug  3 10:37:02 2009	(r19571)
@@ -177,7 +177,7 @@ OBJS-$(CONFIG_PNG_ENCODER)             +
 OBJS-$(CONFIG_PPM_DECODER)             += pnmenc.o pnm.o
 OBJS-$(CONFIG_PPM_ENCODER)             += pnmenc.o
 OBJS-$(CONFIG_PTX_DECODER)             += ptx.o
-OBJS-$(CONFIG_QCELP_DECODER)           += qcelpdec.o qcelp_lsp.o celp_math.o celp_filters.o acelp_vectors.o
+OBJS-$(CONFIG_QCELP_DECODER)           += qcelpdec.o lsp.o celp_math.o celp_filters.o acelp_vectors.o
 OBJS-$(CONFIG_QDM2_DECODER)            += qdm2.o mpegaudiodec.o mpegaudiodecheader.o mpegaudio.o mpegaudiodata.o
 OBJS-$(CONFIG_QDRAW_DECODER)           += qdrw.o
 OBJS-$(CONFIG_QPEG_DECODER)            += qpeg.o

Modified: trunk/libavcodec/lsp.c
==============================================================================
--- trunk/libavcodec/lsp.c	Mon Aug  3 10:31:20 2009	(r19570)
+++ trunk/libavcodec/lsp.c	Mon Aug  3 10:37:02 2009	(r19571)
@@ -1,6 +1,7 @@
 /*
  * LSP routines for ACELP-based codecs
  *
+ * Copyright (c) 2007 Reynaldo H. Verdejo Pinochet (QCELP decoder)
  * Copyright (c) 2008 Vladimir Voroshilov
  *
  * This file is part of FFmpeg.
@@ -118,3 +119,48 @@ void ff_acelp_lp_decode(int16_t* lp_1st,
     /* LSP values for second subframe (3.2.5 of G.729)*/
     ff_acelp_lsp2lpc(lp_2nd, lsp_2nd, lp_order >> 1);
 }
+
+/**
+ * Computes the Pa / (1 + z(-1)) or Qa / (1 - z(-1)) coefficients
+ * needed for LSP to LPC conversion.
+ * We only need to calculate the 6 first elements of the polynomial.
+ *
+ * @param lsp line spectral pairs in cosine domain
+ * @param f [out] polynomial input/output as a vector
+ *
+ * TIA/EIA/IS-733 2.4.3.3.5-1/2
+ */
+static void lsp2polyf(const double *lsp, double *f, int lp_half_order)
+{
+    int i, j;
+
+    f[0] = 1.0;
+    f[1] = -2 * lsp[0];
+    lsp -= 2;
+    for(i=2; i<=lp_half_order; i++)
+    {
+        double val = -2 * lsp[2*i];
+        f[i] = val * f[i-1] + 2*f[i-2];
+        for(j=i-1; j>1; j--)
+            f[j] += f[j-1] * val + f[j-2];
+        f[1] += val;
+    }
+}
+
+void ff_acelp_lspd2lpc(const double *lsp, float *lpc)
+{
+    double pa[6], qa[6];
+    int   i;
+
+    lsp2polyf(lsp,     pa, 5);
+    lsp2polyf(lsp + 1, qa, 5);
+
+    for (i=4; i>=0; i--)
+    {
+        double paf = pa[i+1] + pa[i];
+        double qaf = qa[i+1] - qa[i];
+
+        lpc[i  ] = 0.5*(paf+qaf);
+        lpc[9-i] = 0.5*(paf-qaf);
+    }
+}

Modified: trunk/libavcodec/lsp.h
==============================================================================
--- trunk/libavcodec/lsp.h	Mon Aug  3 10:31:20 2009	(r19570)
+++ trunk/libavcodec/lsp.h	Mon Aug  3 10:37:02 2009	(r19571)
@@ -67,4 +67,14 @@ void ff_acelp_lsp2lpc(int16_t* lp, const
  */
 void ff_acelp_lp_decode(int16_t* lp_1st, int16_t* lp_2nd, const int16_t* lsp_2nd, const int16_t* lsp_prev, int lp_order);
 
+/**
+ * Reconstructs LPC coefficients from the line spectral pair frequencies.
+ *
+ * @param lsp line spectral pairs in cosine domain
+ * @param lpc linear predictive coding coefficients
+ *
+ * TIA/EIA/IS-733 2.4.3.3.5
+ */
+void ff_acelp_lspd2lpc(const double *lsp, float *lpc);
+
 #endif /* AVCODEC_LSP_H */

Modified: trunk/libavcodec/qcelpdec.c
==============================================================================
--- trunk/libavcodec/qcelpdec.c	Mon Aug  3 10:31:20 2009	(r19570)
+++ trunk/libavcodec/qcelpdec.c	Mon Aug  3 10:37:02 2009	(r19571)
@@ -38,6 +38,7 @@
 #include "celp_math.h"
 #include "celp_filters.h"
 #include "acelp_vectors.h"
+#include "lsp.h"
 
 #undef NDEBUG
 #include <assert.h>
@@ -76,13 +77,6 @@ typedef struct
 } QCELPContext;
 
 /**
- * Reconstructs LPC coefficients from the line spectral pair frequencies.
- *
- * TIA/EIA/IS-733 2.4.3.3.5
- */
-void ff_acelp_lspd2lpc(const double *lsp, float *lpc);
-
-/**
  * Initialize the speech codec according to the specification.
  *
  * TIA/EIA/IS-733 2.4.9