opus_celt: move quantization and band decoding to opus_pvq.c

A huge amount can be reused by the encoder, as the only thing
which needs to be done would be to add a 10 line celt_icwrsi,
a wrapper around it (celt_alg_quant) and templating the
ff_celt_decode_band to replace entropy decoding functions
with entropy encoding.

There is no performance loss but in fact a performance gain of
around 6% which is caused by the compiler being able to optimize
the decoding more efficiently.

Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>

1 files changed, 133 insertions, 0 deletions

diff --git a/libavcodec/opus_celt.h b/libavcodec/opus_celt.h
new file mode 100644
index 0000000000..e9b5946642
--- /dev/null
+++ b/libavcodec/opus_celt.h
@@ -0,0 +1,133 @@
+/*
+ * Opus decoder/demuxer common functions
+ * Copyright (c) 2012 Andrew D'Addesio
+ * Copyright (c) 2013-2014 Mozilla Corporation
+ * Copyright (c) 2016 Rostislav Pehlivanov <atomnuker@gmail.com>
+ *
+ * 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 AVCODEC_OPUS_CELT_H
+#define AVCODEC_OPUS_CELT_H
+
+#include "opus.h"
+
+#include "mdct15.h"
+#include "libavutil/float_dsp.h"
+#include "libavutil/libm.h"
+
+#define CELT_VECTORS                 11
+#define CELT_ALLOC_STEPS             6
+#define CELT_FINE_OFFSET             21
+#define CELT_MAX_FINE_BITS           8
+#define CELT_NORM_SCALE              16384
+#define CELT_QTHETA_OFFSET           4
+#define CELT_QTHETA_OFFSET_TWOPHASE  16
+#define CELT_DEEMPH_COEFF            0.85000610f
+#define CELT_POSTFILTER_MINPERIOD    15
+#define CELT_ENERGY_SILENCE          (-28.0f)
+
+enum CeltSpread {
+    CELT_SPREAD_NONE,
+    CELT_SPREAD_LIGHT,
+    CELT_SPREAD_NORMAL,
+    CELT_SPREAD_AGGRESSIVE
+};
+
+typedef struct CeltFrame {
+    float energy[CELT_MAX_BANDS];
+    float prev_energy[2][CELT_MAX_BANDS];
+
+    uint8_t collapse_masks[CELT_MAX_BANDS];
+
+    /* buffer for mdct output + postfilter */
+    DECLARE_ALIGNED(32, float, buf)[2048];
+
+    /* postfilter parameters */
+    int pf_period_new;
+    float pf_gains_new[3];
+    int pf_period;
+    float pf_gains[3];
+    int pf_period_old;
+    float pf_gains_old[3];
+
+    float deemph_coeff;
+} CeltFrame;
+
+struct CeltContext {
+    // constant values that do not change during context lifetime
+    AVCodecContext    *avctx;
+    MDCT15Context     *imdct[4];
+    AVFloatDSPContext  *dsp;
+    int output_channels;
+
+    // values that have inter-frame effect and must be reset on flush
+    CeltFrame frame[2];
+    uint32_t seed;
+    int flushed;
+
+    // values that only affect a single frame
+    int coded_channels;
+    int framebits;
+    int duration;
+
+    /* number of iMDCT blocks in the frame */
+    int blocks;
+    /* size of each block */
+    int blocksize;
+
+    int startband;
+    int endband;
+    int codedbands;
+
+    int anticollapse_bit;
+
+    int intensitystereo;
+    int dualstereo;
+    enum CeltSpread spread;
+
+    int remaining;
+    int remaining2;
+    int fine_bits    [CELT_MAX_BANDS];
+    int fine_priority[CELT_MAX_BANDS];
+    int pulses       [CELT_MAX_BANDS];
+    int tf_change    [CELT_MAX_BANDS];
+
+    DECLARE_ALIGNED(32, float, coeffs)[2][CELT_MAX_FRAME_SIZE];
+    DECLARE_ALIGNED(32, float, scratch)[22 * 8]; // MAX(ff_celt_freq_range) * 1<<CELT_MAX_LOG_BLOCKS
+};
+
+/* LCG for noise generation */
+static av_always_inline uint32_t celt_rng(CeltContext *s)
+{
+    s->seed = 1664525 * s->seed + 1013904223;
+    return s->seed;
+}
+
+static av_always_inline void celt_renormalize_vector(float *X, int N, float gain)
+{
+    int i;
+    float g = 1e-15f;
+    for (i = 0; i < N; i++)
+        g += X[i] * X[i];
+    g = gain / sqrtf(g);
+
+    for (i = 0; i < N; i++)
+        X[i] *= g;
+}
+
+#endif /* AVCODEC_OPUS_CELT_H */