making act segmenter

1 files changed, 447 insertions, 0 deletions

diff --git a/ffmpeg/libavcodec/ac3enc_template.c b/ffmpeg/libavcodec/ac3enc_template.c
new file mode 100644
index 0000000..0389c2e
--- /dev/null
+++ b/ffmpeg/libavcodec/ac3enc_template.c
@@ -0,0 +1,447 @@
+/*
+ * 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 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
+ */
+
+/**
+ * @file
+ * AC-3 encoder float/fixed template
+ */
+
+#include <stdint.h>
+
+#include "libavutil/internal.h"
+
+/* prototypes for static functions in ac3enc_fixed.c and ac3enc_float.c */
+
+static void scale_coefficients(AC3EncodeContext *s);
+
+static void apply_window(void *dsp, SampleType *output,
+                         const SampleType *input, const SampleType *window,
+                         unsigned int len);
+
+static int normalize_samples(AC3EncodeContext *s);
+
+static void clip_coefficients(DSPContext *dsp, CoefType *coef, unsigned int len);
+
+static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl);
+
+static void sum_square_butterfly(AC3EncodeContext *s, CoefSumType sum[4],
+                                 const CoefType *coef0, const CoefType *coef1,
+                                 int len);
+
+int AC3_NAME(allocate_sample_buffers)(AC3EncodeContext *s)
+{
+    int ch;
+
+    FF_ALLOC_OR_GOTO(s->avctx, s->windowed_samples, AC3_WINDOW_SIZE *
+                     sizeof(*s->windowed_samples), alloc_fail);
+    FF_ALLOC_OR_GOTO(s->avctx, s->planar_samples, s->channels * sizeof(*s->planar_samples),
+                     alloc_fail);
+    for (ch = 0; ch < s->channels; ch++) {
+        FF_ALLOCZ_OR_GOTO(s->avctx, s->planar_samples[ch],
+                          (AC3_FRAME_SIZE+AC3_BLOCK_SIZE) * sizeof(**s->planar_samples),
+                          alloc_fail);
+    }
+
+    return 0;
+alloc_fail:
+    return AVERROR(ENOMEM);
+}
+
+
+/*
+ * Copy input samples.
+ * Channels are reordered from FFmpeg's default order to AC-3 order.
+ */
+static void copy_input_samples(AC3EncodeContext *s, SampleType **samples)
+{
+    int ch;
+
+    /* copy and remap input samples */
+    for (ch = 0; ch < s->channels; ch++) {
+        /* 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_BLOCK_SIZE * s->num_blocks],
+               AC3_BLOCK_SIZE * sizeof(s->planar_samples[0][0]));
+
+        /* copy new samples for current frame */
+        memcpy(&s->planar_samples[ch][AC3_BLOCK_SIZE],
+               samples[s->channel_map[ch]],
+               AC3_BLOCK_SIZE * s->num_blocks * sizeof(s->planar_samples[0][0]));
+    }
+}
+
+
+/*
+ * 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.
+ */
+static void apply_mdct(AC3EncodeContext *s)
+{
+    int blk, ch;
+
+    for (ch = 0; ch < s->channels; ch++) {
+        for (blk = 0; blk < s->num_blocks; blk++) {
+            AC3Block *block = &s->blocks[blk];
+            const SampleType *input_samples = &s->planar_samples[ch][blk * AC3_BLOCK_SIZE];
+
+#if CONFIG_AC3ENC_FLOAT
+            apply_window(&s->fdsp, s->windowed_samples, input_samples,
+                         s->mdct_window, AC3_WINDOW_SIZE);
+#else
+            apply_window(&s->dsp, s->windowed_samples, input_samples,
+                         s->mdct_window, AC3_WINDOW_SIZE);
+#endif
+
+            if (s->fixed_point)
+                block->coeff_shift[ch+1] = normalize_samples(s);
+
+            s->mdct.mdct_calcw(&s->mdct, block->mdct_coef[ch+1],
+                               s->windowed_samples);
+        }
+    }
+}
+
+
+/*
+ * Calculate coupling channel and coupling coordinates.
+ */
+static void apply_channel_coupling(AC3EncodeContext *s)
+{
+    LOCAL_ALIGNED_16(CoefType, cpl_coords,      [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]);
+#if CONFIG_AC3ENC_FLOAT
+    LOCAL_ALIGNED_16(int32_t, fixed_cpl_coords, [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]);
+#else
+    int32_t (*fixed_cpl_coords)[AC3_MAX_CHANNELS][16] = cpl_coords;
+#endif
+    int av_uninit(blk), ch, bnd, i, j;
+    CoefSumType energy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][16] = {{{0}}};
+    int cpl_start, num_cpl_coefs;
+
+    memset(cpl_coords,       0, AC3_MAX_BLOCKS * sizeof(*cpl_coords));
+#if CONFIG_AC3ENC_FLOAT
+    memset(fixed_cpl_coords, 0, AC3_MAX_BLOCKS * sizeof(*cpl_coords));
+#endif
+
+    /* align start to 16-byte boundary. align length to multiple of 32.
+        note: coupling start bin % 4 will always be 1 */
+    cpl_start     = s->start_freq[CPL_CH] - 1;
+    num_cpl_coefs = FFALIGN(s->num_cpl_subbands * 12 + 1, 32);
+    cpl_start     = FFMIN(256, cpl_start + num_cpl_coefs) - num_cpl_coefs;
+
+    /* calculate coupling channel from fbw channels */
+    for (blk = 0; blk < s->num_blocks; blk++) {
+        AC3Block *block = &s->blocks[blk];
+        CoefType *cpl_coef = &block->mdct_coef[CPL_CH][cpl_start];
+        if (!block->cpl_in_use)
+            continue;
+        memset(cpl_coef, 0, num_cpl_coefs * sizeof(*cpl_coef));
+        for (ch = 1; ch <= s->fbw_channels; ch++) {
+            CoefType *ch_coef = &block->mdct_coef[ch][cpl_start];
+            if (!block->channel_in_cpl[ch])
+                continue;
+            for (i = 0; i < num_cpl_coefs; i++)
+                cpl_coef[i] += ch_coef[i];
+        }
+
+        /* coefficients must be clipped in order to be encoded */
+        clip_coefficients(&s->dsp, cpl_coef, num_cpl_coefs);
+    }
+
+    /* 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 < s->num_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++;
+    }
+
+    /* calculate coupling coordinates for all blocks for all channels */
+    for (blk = 0; blk < s->num_blocks; blk++) {
+        AC3Block *block  = &s->blocks[blk];
+        if (!block->cpl_in_use)
+            continue;
+        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]);
+            }
+        }
+    }
+
+    /* determine which blocks to send new coupling coordinates for */
+    for (blk = 0; blk < s->num_blocks; blk++) {
+        AC3Block *block  = &s->blocks[blk];
+        AC3Block *block0 = blk ? &s->blocks[blk-1] : NULL;
+
+        memset(block->new_cpl_coords, 0, sizeof(block->new_cpl_coords));
+
+        if (block->cpl_in_use) {
+            /* 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 || !block0->cpl_in_use) {
+                for (ch = 1; ch <= s->fbw_channels; ch++)
+                    block->new_cpl_coords[ch] = 1;
+            } else {
+                for (ch = 1; ch <= s->fbw_channels; ch++) {
+                    if (!block->channel_in_cpl[ch])
+                        continue;
+                    if (!block0->channel_in_cpl[ch]) {
+                        block->new_cpl_coords[ch] = 1;
+                    } else {
+                        CoefSumType coord_diff = 0;
+                        for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
+                            coord_diff += FFABS(cpl_coords[blk-1][ch][bnd] -
+                                                cpl_coords[blk  ][ch][bnd]);
+                        }
+                        coord_diff /= s->num_cpl_bands;
+                        if (coord_diff > NEW_CPL_COORD_THRESHOLD)
+                            block->new_cpl_coords[ch] = 1;
+                    }
+                }
+            }
+        }
+    }
+
+    /* 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 < s->num_blocks) {
+            int av_uninit(blk1);
+            AC3Block *block  = &s->blocks[blk];
+
+            if (!block->cpl_in_use) {
+                blk++;
+                continue;
+            }
+
+            for (ch = 1; ch <= s->fbw_channels; ch++) {
+                CoefSumType energy_ch, energy_cpl;
+                if (!block->channel_in_cpl[ch])
+                    continue;
+                energy_cpl = energy[blk][CPL_CH][bnd];
+                energy_ch = energy[blk][ch][bnd];
+                blk1 = blk+1;
+                while (!s->blocks[blk1].new_cpl_coords[ch] && blk1 < s->num_blocks) {
+                    if (s->blocks[blk1].cpl_in_use) {
+                        energy_cpl += energy[blk1][CPL_CH][bnd];
+                        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 < s->num_blocks; blk++) {
+        AC3Block *block = &s->blocks[blk];
+        if (!block->cpl_in_use)
+            continue;
+
+#if CONFIG_AC3ENC_FLOAT
+        s->ac3dsp.float_to_fixed24(fixed_cpl_coords[blk][1],
+                                   cpl_coords[blk][1],
+                                   s->fbw_channels * 16);
+#endif
+        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;
+
+            if (!block->new_cpl_coords[ch])
+                continue;
+
+            /* 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);
+}
+
+
+/*
+ * Determine rematrixing flags for each block and band.
+ */
+static void compute_rematrixing_strategy(AC3EncodeContext *s)
+{
+    int nb_coefs;
+    int blk, bnd;
+    AC3Block *block, *block0 = NULL;
+
+    if (s->channel_mode != AC3_CHMODE_STEREO)
+        return;
+
+    for (blk = 0; blk < s->num_blocks; blk++) {
+        block = &s->blocks[blk];
+        block->new_rematrixing_strategy = !blk;
+
+        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]);
+
+        if (!s->rematrixing_enabled) {
+            block0 = block;
+            continue;
+        }
+
+        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];
+            sum_square_butterfly(s, sum, block->mdct_coef[1] + start,
+                                 block->mdct_coef[2] + start, end - start);
+
+            /* 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;
+    }
+}
+
+
+int AC3_NAME(encode_frame)(AVCodecContext *avctx, AVPacket *avpkt,
+                           const AVFrame *frame, int *got_packet_ptr)
+{
+    AC3EncodeContext *s = avctx->priv_data;
+    int ret;
+
+    if (s->options.allow_per_frame_metadata) {
+        ret = ff_ac3_validate_metadata(s);
+        if (ret)
+            return ret;
+    }
+
+    if (s->bit_alloc.sr_code == 1 || s->eac3)
+        ff_ac3_adjust_frame_size(s);
+
+    copy_input_samples(s, (SampleType **)frame->extended_data);
+
+    apply_mdct(s);
+
+    if (s->fixed_point)
+        scale_coefficients(s);
+
+    clip_coefficients(&s->dsp, s->blocks[0].mdct_coef[1],
+                      AC3_MAX_COEFS * s->num_blocks * s->channels);
+
+    s->cpl_on = s->cpl_enabled;
+    ff_ac3_compute_coupling_strategy(s);
+
+    if (s->cpl_on)
+        apply_channel_coupling(s);
+
+    compute_rematrixing_strategy(s);
+
+    if (!s->fixed_point)
+        scale_coefficients(s);
+
+    ff_ac3_apply_rematrixing(s);
+
+    ff_ac3_process_exponents(s);
+
+    ret = ff_ac3_compute_bit_allocation(s);
+    if (ret) {
+        av_log(avctx, AV_LOG_ERROR, "Bit allocation failed. Try increasing the bitrate.\n");
+        return ret;
+    }
+
+    ff_ac3_group_exponents(s);
+
+    ff_ac3_quantize_mantissas(s);
+
+    if ((ret = ff_alloc_packet2(avctx, avpkt, s->frame_size)) < 0)
+        return ret;
+    ff_ac3_output_frame(s, avpkt->data);
+
+    if (frame->pts != AV_NOPTS_VALUE)
+        avpkt->pts = frame->pts - ff_samples_to_time_base(avctx, avctx->delay);
+
+    *got_packet_ptr = 1;
+    return 0;
+}