ac3enc: split templated float vs. fixed functions into a separate file.

Function pointers are used for templated functions instead of needlessly
duplicating many functions.

1 files changed, 377 insertions, 0 deletions

diff --git a/libavcodec/ac3enc_template.c b/libavcodec/ac3enc_template.c
new file mode 100644
index 0000000000..d88fa225a1
--- /dev/null
+++ b/libavcodec/ac3enc_template.c
@@ -0,0 +1,377 @@
+/*
+ * AC-3 encoder float/fixed template
+ * Copyright (c) 2000 Fabrice Bellard
+ * Copyright (c) 2006-2011 Justin Ruggles <justin.ruggles@gmail.com>
+ * Copyright (c) 2006-2010 Prakash Punnoor <prakash@punnoor.de>
+ *
+ * This file is part of Libav.
+ *
+ * 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.
+ *
+ * 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * AC-3 encoder float/fixed template
+ */
+
+#include <stdint.h>
+
+#include "ac3enc.h"
+
+
+/**
+ * Deinterleave input samples.
+ * Channels are reordered from Libav's default order to AC-3 order.
+ */
+void AC3_NAME(deinterleave_input_samples)(AC3EncodeContext *s,
+                                          const SampleType *samples)
+{
+    int ch, i;
+
+    /* deinterleave and remap input samples */
+    for (ch = 0; ch < s->channels; ch++) {
+        const SampleType *sptr;
+        int sinc;
+
+        /* copy last 256 samples of previous frame to the start of the current frame */
+        memcpy(&s->planar_samples[ch][0], &s->planar_samples[ch][AC3_FRAME_SIZE],
+               AC3_BLOCK_SIZE * sizeof(s->planar_samples[0][0]));
+
+        /* deinterleave */
+        sinc = s->channels;
+        sptr = samples + s->channel_map[ch];
+        for (i = AC3_BLOCK_SIZE; i < AC3_FRAME_SIZE+AC3_BLOCK_SIZE; i++) {
+            s->planar_samples[ch][i] = *sptr;
+            sptr += sinc;
+        }
+    }
+}
+
+
+/**
+ * Apply the MDCT to input samples to generate frequency coefficients.
+ * This applies the KBD window and normalizes the input to reduce precision
+ * loss due to fixed-point calculations.
+ */
+void AC3_NAME(apply_mdct)(AC3EncodeContext *s)
+{
+    int blk, ch;
+
+    for (ch = 0; ch < s->channels; ch++) {
+        for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
+            AC3Block *block = &s->blocks[blk];
+            const SampleType *input_samples = &s->planar_samples[ch][blk * AC3_BLOCK_SIZE];
+
+            s->apply_window(&s->dsp, s->windowed_samples, input_samples,
+                            s->mdct->window, AC3_WINDOW_SIZE);
+
+            if (s->fixed_point)
+                block->coeff_shift[ch+1] = s->normalize_samples(s);
+
+            s->mdct->fft.mdct_calcw(&s->mdct->fft, block->mdct_coef[ch+1],
+                                    s->windowed_samples);
+        }
+    }
+}
+
+
+/**
+ * Calculate a single coupling coordinate.
+ */
+static inline float calc_cpl_coord(float energy_ch, float energy_cpl)
+{
+    float coord = 0.125;
+    if (energy_cpl > 0)
+        coord *= sqrtf(energy_ch / energy_cpl);
+    return coord;
+}
+
+
+/**
+ * Calculate coupling channel and coupling coordinates.
+ * TODO: Currently this is only used for the floating-point encoder. I was
+ *       able to make it work for the fixed-point encoder, but quality was
+ *       generally lower in most cases than not using coupling. If a more
+ *       adaptive coupling strategy were to be implemented it might be useful
+ *       at that time to use coupling for the fixed-point encoder as well.
+ */
+void AC3_NAME(apply_channel_coupling)(AC3EncodeContext *s)
+{
+#if CONFIG_AC3ENC_FLOAT
+    LOCAL_ALIGNED_16(float,   cpl_coords,       [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]);
+    LOCAL_ALIGNED_16(int32_t, fixed_cpl_coords, [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]);
+    int blk, ch, bnd, i, j;
+    CoefSumType energy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][16] = {{{0}}};
+    int num_cpl_coefs = s->num_cpl_subbands * 12;
+
+    memset(cpl_coords,       0, AC3_MAX_BLOCKS * sizeof(*cpl_coords));
+    memset(fixed_cpl_coords, 0, AC3_MAX_BLOCKS * sizeof(*fixed_cpl_coords));
+
+    /* calculate coupling channel from fbw channels */
+    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
+        AC3Block *block = &s->blocks[blk];
+        CoefType *cpl_coef = &block->mdct_coef[CPL_CH][s->start_freq[CPL_CH]];
+        if (!block->cpl_in_use)
+            continue;
+        memset(cpl_coef-1, 0, (num_cpl_coefs+4) * sizeof(*cpl_coef));
+        for (ch = 1; ch <= s->fbw_channels; ch++) {
+            CoefType *ch_coef = &block->mdct_coef[ch][s->start_freq[CPL_CH]];
+            if (!block->channel_in_cpl[ch])
+                continue;
+            for (i = 0; i < num_cpl_coefs; i++)
+                cpl_coef[i] += ch_coef[i];
+        }
+        /* note: coupling start bin % 4 will always be 1 and num_cpl_coefs
+                 will always be a multiple of 12, so we need to subtract 1 from
+                 the start and add 4 to the length when using optimized
+                 functions which require 16-byte alignment. */
+
+        /* coefficients must be clipped to +/- 1.0 in order to be encoded */
+        s->dsp.vector_clipf(cpl_coef-1, cpl_coef-1, -1.0f, 1.0f, num_cpl_coefs+4);
+
+        /* scale coupling coefficients from float to 24-bit fixed-point */
+        s->ac3dsp.float_to_fixed24(&block->fixed_coef[CPL_CH][s->start_freq[CPL_CH]-1],
+                                   cpl_coef-1, num_cpl_coefs+4);
+    }
+
+    /* calculate energy in each band in coupling channel and each fbw channel */
+    /* TODO: possibly use SIMD to speed up energy calculation */
+    bnd = 0;
+    i = s->start_freq[CPL_CH];
+    while (i < s->cpl_end_freq) {
+        int band_size = s->cpl_band_sizes[bnd];
+        for (ch = CPL_CH; ch <= s->fbw_channels; ch++) {
+            for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
+                AC3Block *block = &s->blocks[blk];
+                if (!block->cpl_in_use || (ch > CPL_CH && !block->channel_in_cpl[ch]))
+                    continue;
+                for (j = 0; j < band_size; j++) {
+                    CoefType v = block->mdct_coef[ch][i+j];
+                    MAC_COEF(energy[blk][ch][bnd], v, v);
+                }
+            }
+        }
+        i += band_size;
+        bnd++;
+    }
+
+    /* determine which blocks to send new coupling coordinates for */
+    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
+        AC3Block *block  = &s->blocks[blk];
+        AC3Block *block0 = blk ? &s->blocks[blk-1] : NULL;
+        int new_coords = 0;
+        CoefSumType coord_diff[AC3_MAX_CHANNELS] = {0,};
+
+        if (block->cpl_in_use) {
+            /* calculate coupling coordinates for all blocks and calculate the
+               average difference between coordinates in successive blocks */
+            for (ch = 1; ch <= s->fbw_channels; ch++) {
+                if (!block->channel_in_cpl[ch])
+                    continue;
+
+                for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
+                    cpl_coords[blk][ch][bnd] = calc_cpl_coord(energy[blk][ch][bnd],
+                                                              energy[blk][CPL_CH][bnd]);
+                    if (blk > 0 && block0->cpl_in_use &&
+                        block0->channel_in_cpl[ch]) {
+                        coord_diff[ch] += fabs(cpl_coords[blk-1][ch][bnd] -
+                                               cpl_coords[blk  ][ch][bnd]);
+                    }
+                }
+                coord_diff[ch] /= s->num_cpl_bands;
+            }
+
+            /* send new coordinates if this is the first block, if previous
+             * block did not use coupling but this block does, the channels
+             * using coupling has changed from the previous block, or the
+             * coordinate difference from the last block for any channel is
+             * greater than a threshold value. */
+            if (blk == 0) {
+                new_coords = 1;
+            } else if (!block0->cpl_in_use) {
+                new_coords = 1;
+            } else {
+                for (ch = 1; ch <= s->fbw_channels; ch++) {
+                    if (block->channel_in_cpl[ch] && !block0->channel_in_cpl[ch]) {
+                        new_coords = 1;
+                        break;
+                    }
+                }
+                if (!new_coords) {
+                    for (ch = 1; ch <= s->fbw_channels; ch++) {
+                        if (block->channel_in_cpl[ch] && coord_diff[ch] > 0.04) {
+                            new_coords = 1;
+                            break;
+                        }
+                    }
+                }
+            }
+        }
+        block->new_cpl_coords = new_coords;
+    }
+
+    /* calculate final coupling coordinates, taking into account reusing of
+       coordinates in successive blocks */
+    for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
+        blk = 0;
+        while (blk < AC3_MAX_BLOCKS) {
+            int blk1;
+            CoefSumType energy_cpl;
+            AC3Block *block  = &s->blocks[blk];
+
+            if (!block->cpl_in_use) {
+                blk++;
+                continue;
+            }
+
+            energy_cpl = energy[blk][CPL_CH][bnd];
+            blk1 = blk+1;
+            while (!s->blocks[blk1].new_cpl_coords && blk1 < AC3_MAX_BLOCKS) {
+                if (s->blocks[blk1].cpl_in_use)
+                    energy_cpl += energy[blk1][CPL_CH][bnd];
+                blk1++;
+            }
+
+            for (ch = 1; ch <= s->fbw_channels; ch++) {
+                CoefType energy_ch;
+                if (!block->channel_in_cpl[ch])
+                    continue;
+                energy_ch = energy[blk][ch][bnd];
+                blk1 = blk+1;
+                while (!s->blocks[blk1].new_cpl_coords && blk1 < AC3_MAX_BLOCKS) {
+                    if (s->blocks[blk1].cpl_in_use)
+                        energy_ch += energy[blk1][ch][bnd];
+                    blk1++;
+                }
+                cpl_coords[blk][ch][bnd] = calc_cpl_coord(energy_ch, energy_cpl);
+            }
+            blk = blk1;
+        }
+    }
+
+    /* calculate exponents/mantissas for coupling coordinates */
+    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
+        AC3Block *block = &s->blocks[blk];
+        if (!block->cpl_in_use || !block->new_cpl_coords)
+            continue;
+
+        s->ac3dsp.float_to_fixed24(fixed_cpl_coords[blk][1],
+                                   cpl_coords[blk][1],
+                                   s->fbw_channels * 16);
+        s->ac3dsp.extract_exponents(block->cpl_coord_exp[1],
+                                    fixed_cpl_coords[blk][1],
+                                    s->fbw_channels * 16);
+
+        for (ch = 1; ch <= s->fbw_channels; ch++) {
+            int bnd, min_exp, max_exp, master_exp;
+
+            /* determine master exponent */
+            min_exp = max_exp = block->cpl_coord_exp[ch][0];
+            for (bnd = 1; bnd < s->num_cpl_bands; bnd++) {
+                int exp = block->cpl_coord_exp[ch][bnd];
+                min_exp = FFMIN(exp, min_exp);
+                max_exp = FFMAX(exp, max_exp);
+            }
+            master_exp = ((max_exp - 15) + 2) / 3;
+            master_exp = FFMAX(master_exp, 0);
+            while (min_exp < master_exp * 3)
+                master_exp--;
+            for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
+                block->cpl_coord_exp[ch][bnd] = av_clip(block->cpl_coord_exp[ch][bnd] -
+                                                        master_exp * 3, 0, 15);
+            }
+            block->cpl_master_exp[ch] = master_exp;
+
+            /* quantize mantissas */
+            for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
+                int cpl_exp  = block->cpl_coord_exp[ch][bnd];
+                int cpl_mant = (fixed_cpl_coords[blk][ch][bnd] << (5 + cpl_exp + master_exp * 3)) >> 24;
+                if (cpl_exp == 15)
+                    cpl_mant >>= 1;
+                else
+                    cpl_mant -= 16;
+
+                block->cpl_coord_mant[ch][bnd] = cpl_mant;
+            }
+        }
+    }
+
+    if (CONFIG_EAC3_ENCODER && s->eac3)
+        ff_eac3_set_cpl_states(s);
+#endif /* CONFIG_AC3ENC_FLOAT */
+}
+
+
+/**
+ * Determine rematrixing flags for each block and band.
+ */
+void AC3_NAME(compute_rematrixing_strategy)(AC3EncodeContext *s)
+{
+    int nb_coefs;
+    int blk, bnd, i;
+    AC3Block *block, *av_uninit(block0);
+
+    if (s->channel_mode != AC3_CHMODE_STEREO)
+        return;
+
+    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
+        block = &s->blocks[blk];
+        block->new_rematrixing_strategy = !blk;
+
+        if (!s->rematrixing_enabled) {
+            block0 = block;
+            continue;
+        }
+
+        block->num_rematrixing_bands = 4;
+        if (block->cpl_in_use) {
+            block->num_rematrixing_bands -= (s->start_freq[CPL_CH] <= 61);
+            block->num_rematrixing_bands -= (s->start_freq[CPL_CH] == 37);
+            if (blk && block->num_rematrixing_bands != block0->num_rematrixing_bands)
+                block->new_rematrixing_strategy = 1;
+        }
+        nb_coefs = FFMIN(block->end_freq[1], block->end_freq[2]);
+
+        for (bnd = 0; bnd < block->num_rematrixing_bands; bnd++) {
+            /* calculate calculate sum of squared coeffs for one band in one block */
+            int start = ff_ac3_rematrix_band_tab[bnd];
+            int end   = FFMIN(nb_coefs, ff_ac3_rematrix_band_tab[bnd+1]);
+            CoefSumType sum[4] = {0,};
+            for (i = start; i < end; i++) {
+                CoefType lt = block->mdct_coef[1][i];
+                CoefType rt = block->mdct_coef[2][i];
+                CoefType md = lt + rt;
+                CoefType sd = lt - rt;
+                MAC_COEF(sum[0], lt, lt);
+                MAC_COEF(sum[1], rt, rt);
+                MAC_COEF(sum[2], md, md);
+                MAC_COEF(sum[3], sd, sd);
+            }
+
+            /* compare sums to determine if rematrixing will be used for this band */
+            if (FFMIN(sum[2], sum[3]) < FFMIN(sum[0], sum[1]))
+                block->rematrixing_flags[bnd] = 1;
+            else
+                block->rematrixing_flags[bnd] = 0;
+
+            /* determine if new rematrixing flags will be sent */
+            if (blk &&
+                block->rematrixing_flags[bnd] != block0->rematrixing_flags[bnd]) {
+                block->new_rematrixing_strategy = 1;
+            }
+        }
+        block0 = block;
+    }
+}