making act segmenter

1 files changed, 181 insertions, 0 deletions

diff --git a/ffmpeg/libavcodec/ac3.h b/ffmpeg/libavcodec/ac3.h
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+++ b/ffmpeg/libavcodec/ac3.h
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+/*
+ * Common code between the AC-3 encoder and decoder
+ * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
+ *
+ * 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
+ * Common code between the AC-3 encoder and decoder.
+ */
+
+#ifndef AVCODEC_AC3_H
+#define AVCODEC_AC3_H
+
+#define AC3_MAX_CODED_FRAME_SIZE 3840 /* in bytes */
+#define AC3_MAX_CHANNELS 7            /**< maximum number of channels, including coupling channel */
+#define CPL_CH 0                      /**< coupling channel index */
+
+#define AC3_MAX_COEFS   256
+#define AC3_BLOCK_SIZE  256
+#define AC3_MAX_BLOCKS    6
+#define AC3_FRAME_SIZE (AC3_MAX_BLOCKS * 256)
+#define AC3_WINDOW_SIZE (AC3_BLOCK_SIZE * 2)
+#define AC3_CRITICAL_BANDS 50
+#define AC3_MAX_CPL_BANDS  18
+
+#include "libavutil/opt.h"
+#include "avcodec.h"
+#include "ac3tab.h"
+
+/* exponent encoding strategy */
+#define EXP_REUSE 0
+#define EXP_NEW   1
+
+#define EXP_D15   1
+#define EXP_D25   2
+#define EXP_D45   3
+
+/* pre-defined gain values */
+#define LEVEL_PLUS_3DB          1.4142135623730950
+#define LEVEL_PLUS_1POINT5DB    1.1892071150027209
+#define LEVEL_MINUS_1POINT5DB   0.8408964152537145
+#define LEVEL_MINUS_3DB         0.7071067811865476
+#define LEVEL_MINUS_4POINT5DB   0.5946035575013605
+#define LEVEL_MINUS_6DB         0.5000000000000000
+#define LEVEL_MINUS_9DB         0.3535533905932738
+#define LEVEL_ZERO              0.0000000000000000
+#define LEVEL_ONE               1.0000000000000000
+
+/** Delta bit allocation strategy */
+typedef enum {
+    DBA_REUSE = 0,
+    DBA_NEW,
+    DBA_NONE,
+    DBA_RESERVED
+} AC3DeltaStrategy;
+
+/** Channel mode (audio coding mode) */
+typedef enum {
+    AC3_CHMODE_DUALMONO = 0,
+    AC3_CHMODE_MONO,
+    AC3_CHMODE_STEREO,
+    AC3_CHMODE_3F,
+    AC3_CHMODE_2F1R,
+    AC3_CHMODE_3F1R,
+    AC3_CHMODE_2F2R,
+    AC3_CHMODE_3F2R
+} AC3ChannelMode;
+
+typedef struct AC3BitAllocParameters {
+    int sr_code;
+    int sr_shift;
+    int slow_gain, slow_decay, fast_decay, db_per_bit, floor;
+    int cpl_fast_leak, cpl_slow_leak;
+} AC3BitAllocParameters;
+
+/**
+ * @struct AC3HeaderInfo
+ * Coded AC-3 header values up to the lfeon element, plus derived values.
+ */
+typedef struct AC3HeaderInfo {
+    /** @name Coded elements
+     * @{
+     */
+    uint16_t sync_word;
+    uint16_t crc1;
+    uint8_t sr_code;
+    uint8_t bitstream_id;
+    uint8_t bitstream_mode;
+    uint8_t channel_mode;
+    uint8_t lfe_on;
+    uint8_t frame_type;
+    int substreamid;                        ///< substream identification
+    int center_mix_level;                   ///< Center mix level index
+    int surround_mix_level;                 ///< Surround mix level index
+    uint16_t channel_map;
+    int num_blocks;                         ///< number of audio blocks
+    /** @} */
+
+    /** @name Derived values
+     * @{
+     */
+    uint8_t sr_shift;
+    uint16_t sample_rate;
+    uint32_t bit_rate;
+    uint8_t channels;
+    uint16_t frame_size;
+    uint64_t channel_layout;
+    /** @} */
+} AC3HeaderInfo;
+
+typedef enum {
+    EAC3_FRAME_TYPE_INDEPENDENT = 0,
+    EAC3_FRAME_TYPE_DEPENDENT,
+    EAC3_FRAME_TYPE_AC3_CONVERT,
+    EAC3_FRAME_TYPE_RESERVED
+} EAC3FrameType;
+
+void ff_ac3_common_init(void);
+
+/**
+ * Calculate the log power-spectral density of the input signal.
+ * This gives a rough estimate of signal power in the frequency domain by using
+ * the spectral envelope (exponents).  The psd is also separately grouped
+ * into critical bands for use in the calculating the masking curve.
+ * 128 units in psd = -6 dB.  The dbknee parameter in AC3BitAllocParameters
+ * determines the reference level.
+ *
+ * @param[in]  exp        frequency coefficient exponents
+ * @param[in]  start      starting bin location
+ * @param[in]  end        ending bin location
+ * @param[out] psd        signal power for each frequency bin
+ * @param[out] band_psd   signal power for each critical band
+ */
+void ff_ac3_bit_alloc_calc_psd(int8_t *exp, int start, int end, int16_t *psd,
+                               int16_t *band_psd);
+
+/**
+ * Calculate the masking curve.
+ * First, the excitation is calculated using parameters in s and the signal
+ * power in each critical band.  The excitation is compared with a predefined
+ * hearing threshold table to produce the masking curve.  If delta bit
+ * allocation information is provided, it is used for adjusting the masking
+ * curve, usually to give a closer match to a better psychoacoustic model.
+ *
+ * @param[in]  s            adjustable bit allocation parameters
+ * @param[in]  band_psd     signal power for each critical band
+ * @param[in]  start        starting bin location
+ * @param[in]  end          ending bin location
+ * @param[in]  fast_gain    fast gain (estimated signal-to-mask ratio)
+ * @param[in]  is_lfe       whether or not the channel being processed is the LFE
+ * @param[in]  dba_mode     delta bit allocation mode (none, reuse, or new)
+ * @param[in]  dba_nsegs    number of delta segments
+ * @param[in]  dba_offsets  location offsets for each segment
+ * @param[in]  dba_lengths  length of each segment
+ * @param[in]  dba_values   delta bit allocation for each segment
+ * @param[out] mask         calculated masking curve
+ * @return returns 0 for success, non-zero for error
+ */
+int ff_ac3_bit_alloc_calc_mask(AC3BitAllocParameters *s, int16_t *band_psd,
+                               int start, int end, int fast_gain, int is_lfe,
+                               int dba_mode, int dba_nsegs, uint8_t *dba_offsets,
+                               uint8_t *dba_lengths, uint8_t *dba_values,
+                               int16_t *mask);
+
+#endif /* AVCODEC_AC3_H */