G.729 postfilter

libavcodec/Makefile

@@ -159,7 +159,7 @@ OBJS-$(CONFIG_FLIC_DECODER)            += flicvideo.o
 OBJS-$(CONFIG_FOURXM_DECODER)          += 4xm.o
 OBJS-$(CONFIG_FRAPS_DECODER)           += fraps.o
 OBJS-$(CONFIG_FRWU_DECODER)            += frwu.o
-OBJS-$(CONFIG_G729_DECODER)            += g729dec.o lsp.o celp_math.o acelp_filters.o acelp_pitch_delay.o acelp_vectors.o
+OBJS-$(CONFIG_G729_DECODER)            += g729dec.o lsp.o celp_math.o acelp_filters.o acelp_pitch_delay.o acelp_vectors.o g729postfilter.o
 OBJS-$(CONFIG_GIF_DECODER)             += gifdec.o lzw.o
 OBJS-$(CONFIG_GIF_ENCODER)             += gif.o lzwenc.o
 OBJS-$(CONFIG_GSM_DECODER)             += gsmdec.o gsmdec_data.o msgsmdec.o

libavcodec/g729dec.c

@@ -39,6 +39,7 @@
 #include "acelp_pitch_delay.h"
 #include "acelp_vectors.h"
 #include "g729data.h"
+#include "g729postfilter.h"
 
 /**
  * minimum quantized LSF value (3.2.4)
@@ -122,6 +123,16 @@ typedef struct {
     /// previous speech data for LP synthesis filter
     int16_t syn_filter_data[10];
 
+
+    /// residual signal buffer (used in long-term postfilter)
+    int16_t residual[SUBFRAME_SIZE + RES_PREV_DATA_SIZE];
+
+    /// previous speech data for residual calculation filter
+    int16_t res_filter_data[SUBFRAME_SIZE+10];
+
+    /// previous speech data for short-term postfilter
+    int16_t pos_filter_data[SUBFRAME_SIZE+10];
+
     /// (1.14) pitch gain of current and five previous subframes
     int16_t past_gain_pitch[6];
 
@@ -133,6 +144,7 @@ typedef struct {
 
     int16_t onset;              ///< detected onset level (0-2)
     int16_t was_periodic;       ///< whether previous frame was declared as periodic or not (4.4)
+    int16_t ht_prev_data;       ///< previous data for 4.2.3, equation 86
     uint16_t rand_value;        ///< random number generator value (4.4.4)
     int ma_predictor_prev;      ///< switched MA predictor of LSP quantizer from last good frame
 
@@ -625,6 +637,19 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
         /* Save data (without postfilter) for use in next subframe. */
         memcpy(ctx->syn_filter_data, synth+SUBFRAME_SIZE, 10 * sizeof(int16_t));
 
+        /* Call postfilter and also update voicing decision for use in next frame. */
+        g729_postfilter(
+                &ctx->dsp,
+                &ctx->ht_prev_data,
+                &is_periodic,
+                &lp[i][0],
+                pitch_delay_int[0],
+                ctx->residual,
+                ctx->res_filter_data,
+                ctx->pos_filter_data,
+                synth+10,
+                SUBFRAME_SIZE);
+
         if (frame_erasure)
             ctx->pitch_delay_int_prev = FFMIN(ctx->pitch_delay_int_prev + 1, PITCH_DELAY_MAX);
         else

libavcodec/g729postfilter.h

+/*
+ * G.729, G729 Annex D postfilter
+ * Copyright (c) 2008 Vladimir Voroshilov
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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,
+ * 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
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#ifndef FFMPEG_G729POSTFILTER_H
+#define FFMPEG_G729POSTFILTER_H
+
+#include <stdint.h>
+
+/**
+ * tilt compensation factor (G.729, k1>0)
+ * 0.2 in Q15
+ */
+#define G729_TILT_FACTOR_PLUS       6554
+
+/**
+ * tilt compensation factor (G.729, k1<0)
+ * 0.9 in Q15
+ */
+#define G729_TILT_FACTOR_MINUS     29491
+
+/* 4.2.2 */
+#define FORMANT_PP_FACTOR_NUM  18022             //0.55 in Q15
+#define FORMANT_PP_FACTOR_DEN  22938             //0.70 in Q15
+
+/**
+ * 1.0 / (1.0 + 0.5) in Q15
+ * where 0.5 is the minimum value of
+ * weight factor, controlling amount of long-term postfiltering
+ */
+#define MIN_LT_FILT_FACTOR_A       21845
+
+/**
+ * Short interpolation filter length
+ */
+#define SHORT_INT_FILT_LEN         2
+
+/**
+ * Long interpolation filter length
+ */
+#define LONG_INT_FILT_LEN          8
+
+/**
+ * Number of analyzed fractional pitch delays in second stage of long-term
+ * postfilter
+ */
+#define ANALYZED_FRAC_DELAYS       7
+
+/**
+ * Amount of past residual signal data stored in buffer
+ */
+#define RES_PREV_DATA_SIZE (PITCH_DELAY_MAX + LONG_INT_FILT_LEN + 1)
+
+/**
+ * \brief Signal postfiltering (4.2)
+ * \param dsp initialized DSP context
+ * \param ht_prev_data [in/out] (Q12) pointer to variable receiving tilt
+ *                     compensation filter data from previous subframe
+ * \param voicing [in/out] (Q0) pointer to variable receiving voicing decision
+ * \param lp_filter_coeffs (Q12) LP filter coefficients
+ * \param pitch_delay_int integer part of the pitch delay
+ * \param residual [in/out] (Q0) residual signal buffer (used in long-term postfilter)
+ * \param res_filter_data [in/out] (Q0) speech data of previous subframe
+ * \param pos_filter_data [in/out] (Q0) previous speech data for short-term postfilter
+ * \param speech [in/out] (Q0) signal buffer
+ * \param subframe_size size of subframe
+ *
+ * Filtering has the following  stages:
+ *   Long-term postfilter (4.2.1)
+ *   Short-term postfilter (4.2.2).
+ *   Tilt-compensation (4.2.3)
+ */
+void g729_postfilter(DSPContext *dsp, int16_t* ht_prev_data, int16_t* voicing,
+                     const int16_t *lp_filter_coeffs, int pitch_delay_int,
+                     int16_t* residual, int16_t* res_filter_data,
+                     int16_t* pos_filter_data, int16_t *speech,
+                     int subframe_size);
+
+#endif // FFMPEG_G729POSTFILTER_H