X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Flpc.h;h=659060869369d45939f1e6431117e5e033451b1b;hb=9a07c1332cfe092b57b5758f22b686ca58806c60;hp=d3754f04d284153a4d4cc7f367e168458e50b527;hpb=3da1180409ba7d553f40a74bb61b2f7952bc84d5;p=ffmpeg

diff --git a/libavcodec/lpc.h b/libavcodec/lpc.h
index d3754f04d28..65906086936 100644
--- a/libavcodec/lpc.h
+++ b/libavcodec/lpc.h
@@ -1,21 +1,21 @@
-/**
+/*
  * LPC utility code
  * Copyright (c) 2006  Justin Ruggles <justin.ruggles@gmail.com>
  *
- * This file is part of FFmpeg.
+ * This file is part of Libav.
  *
- * FFmpeg is free software; you can redistribute it and/or
+ * Libav 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.
  *
- * FFmpeg is distributed in the hope that it will be useful,
+ * Libav 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 FFmpeg; if not, write to the Free Software
+ * License along with Libav; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
@@ -35,18 +35,77 @@
 #define MIN_LPC_ORDER        1
 #define MAX_LPC_ORDER       32
 
+/**
+ * LPC analysis type
+ */
+enum FFLPCType {
+    FF_LPC_TYPE_DEFAULT     = -1, ///< use the codec default LPC type
+    FF_LPC_TYPE_NONE        =  0, ///< do not use LPC prediction or use all zero coefficients
+    FF_LPC_TYPE_FIXED       =  1, ///< fixed LPC coefficients
+    FF_LPC_TYPE_LEVINSON    =  2, ///< Levinson-Durbin recursion
+    FF_LPC_TYPE_CHOLESKY    =  3, ///< Cholesky factorization
+    FF_LPC_TYPE_NB              , ///< Not part of ABI
+};
+
+typedef struct LPCContext {
+    int blocksize;
+    int max_order;
+    enum FFLPCType lpc_type;
+    double *windowed_buffer;
+    double *windowed_samples;
+
+    /**
+     * Apply a Welch window to an array of input samples.
+     * The output samples have the same scale as the input, but are in double
+     * sample format.
+     * @param data    input samples
+     * @param len     number of input samples
+     * @param w_data  output samples
+     */
+    void (*lpc_apply_welch_window)(const int32_t *data, int len,
+                                   double *w_data);
+    /**
+     * Perform autocorrelation on input samples with delay of 0 to lag.
+     * @param data  input samples.
+     *              constraints: no alignment needed, but must have have at
+     *              least lag*sizeof(double) valid bytes preceding it, and
+     *              size must be at least (len+1)*sizeof(double) if data is
+     *              16-byte aligned or (len+2)*sizeof(double) if data is
+     *              unaligned.
+     * @param len   number of input samples to process
+     * @param lag   maximum delay to calculate
+     * @param autoc output autocorrelation coefficients.
+     *              constraints: array size must be at least lag+1.
+     */
+    void (*lpc_compute_autocorr)(const double *data, int len, int lag,
+                                 double *autoc);
+} LPCContext;
+
 
 /**
  * Calculate LPC coefficients for multiple orders
  */
-int ff_lpc_calc_coefs(DSPContext *s,
+int ff_lpc_calc_coefs(LPCContext *s,
                       const int32_t *samples, int blocksize, int min_order,
                       int max_order, int precision,
-                      int32_t coefs[][MAX_LPC_ORDER], int *shift, int use_lpc,
+                      int32_t coefs[][MAX_LPC_ORDER], int *shift,
+                      enum FFLPCType lpc_type, int lpc_passes,
                       int omethod, int max_shift, int zero_shift);
 
-void ff_lpc_compute_autocorr(const int32_t *data, int len, int lag,
-                             double *autoc);
+int ff_lpc_calc_ref_coefs(LPCContext *s,
+                          const int32_t *samples, int order, double *ref);
+
+/**
+ * Initialize LPCContext.
+ */
+int ff_lpc_init(LPCContext *s, int blocksize, int max_order,
+                enum FFLPCType lpc_type);
+void ff_lpc_init_x86(LPCContext *s);
+
+/**
+ * Uninitialize LPCContext.
+ */
+void ff_lpc_end(LPCContext *s);
 
 #ifdef LPC_USE_DOUBLE
 #define LPC_TYPE double
@@ -54,9 +113,40 @@ void ff_lpc_compute_autocorr(const int32_t *data, int len, int lag,
 #define LPC_TYPE float
 #endif
 
+/**
+ * Schur recursion.
+ * Produces reflection coefficients from autocorrelation data.
+ */
+static inline void compute_ref_coefs(const LPC_TYPE *autoc, int max_order,
+                                     LPC_TYPE *ref, LPC_TYPE *error)
+{
+    int i, j;
+    LPC_TYPE err;
+    LPC_TYPE gen0[MAX_LPC_ORDER], gen1[MAX_LPC_ORDER];
+
+    for (i = 0; i < max_order; i++)
+        gen0[i] = gen1[i] = autoc[i + 1];
+
+    err    = autoc[0];
+    ref[0] = -gen1[0] / err;
+    err   +=  gen1[0] * ref[0];
+    if (error)
+        error[0] = err;
+    for (i = 1; i < max_order; i++) {
+        for (j = 0; j < max_order - i; j++) {
+            gen1[j] = gen1[j + 1] + ref[i - 1] * gen0[j];
+            gen0[j] = gen1[j + 1] * ref[i - 1] + gen0[j];
+        }
+        ref[i] = -gen1[0] / err;
+        err   +=  gen1[0] * ref[i];
+        if (error)
+            error[i] = err;
+    }
+}
+
 /**
  * Levinson-Durbin recursion.
- * Produces LPC coefficients from autocorrelation data.
+ * Produce LPC coefficients from autocorrelation data.
  */
 static inline int compute_lpc_coefs(const LPC_TYPE *autoc, int max_order,
                                     LPC_TYPE *lpc, int lpc_stride, int fail,