/*
- * Common code between AC3 encoder and decoder
- * Copyright (c) 2000, 2001, 2002 Fabrice Bellard.
+ * Common code between the AC-3 encoder and decoder
+ * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
*
- * This file is part of FFmpeg.
+ * This file is part of Libav.
*
- * FFmpeg is free software; you can redistribute it and/or
+ * 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.
*
- * FFmpeg is distributed in the hope that it will be useful,
+ * 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 FFmpeg; if not, write to the Free Software
+ * License along with Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
- * @file ac3.h
- * Common code between AC3 encoder and decoder.
+ * @file
+ * Common code between the AC-3 encoder and decoder.
*/
-#ifndef FFMPEG_AC3_H
-#define FFMPEG_AC3_H
-
-#include "ac3tab.h"
+#ifndef AVCODEC_AC3_H
+#define AVCODEC_AC3_H
#define AC3_MAX_CODED_FRAME_SIZE 3840 /* in bytes */
#define AC3_MAX_CHANNELS 6 /* including LFE channel */
-#define NB_BLOCKS 6 /* number of PCM blocks inside an AC3 frame */
-#define AC3_FRAME_SIZE (NB_BLOCKS * 256)
+#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 "ac3tab.h"
/* exponent encoding strategy */
#define EXP_REUSE 0
#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,
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
/** @} */
/** @defgroup derived Derived values
uint32_t bit_rate;
uint8_t channels;
uint16_t frame_size;
+ int64_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 ac3_common_init(void);
+void ff_ac3_common_init(void);
/**
- * Calculates the log power-spectral density of the input signal.
+ * 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.
int16_t *band_psd);
/**
- * Calculates the masking curve.
- * First, the excitation is calculated using parameters in \p s and the signal
+ * 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
* @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
*/
-void 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);
+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);
/**
- * Calculates bit allocation pointers.
+ * Calculate bit allocation pointers.
* The SNR is the difference between the masking curve and the signal. AC-3
- * uses this value for each frequency bin to allocate bits. The \p snroffset
+ * uses this value for each frequency bin to allocate bits. The snroffset
* parameter is a global adjustment to the SNR for all bins.
*
* @param[in] mask masking curve
* @param[in] end ending bin location
* @param[in] snr_offset SNR adjustment
* @param[in] floor noise floor
+ * @param[in] bap_tab look-up table for bit allocation pointers
* @param[out] bap bit allocation pointers
*/
void ff_ac3_bit_alloc_calc_bap(int16_t *mask, int16_t *psd, int start, int end,
- int snr_offset, int floor, uint8_t *bap);
-
-void ac3_parametric_bit_allocation(AC3BitAllocParameters *s, uint8_t *bap,
- int8_t *exp, int start, int end,
- int snr_offset, int fast_gain, int is_lfe,
- int dba_mode, int dba_nsegs,
- uint8_t *dba_offsets, uint8_t *dba_lengths,
- uint8_t *dba_values);
+ int snr_offset, int floor,
+ const uint8_t *bap_tab, uint8_t *bap);
-#endif /* FFMPEG_AC3_H */
+#endif /* AVCODEC_AC3_H */
projects / ffmpeg / blobdiff