/* * AC-3 DSP functions * Copyright (c) 2011 Justin Ruggles * * 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_AC3DSP_H#define AVCODEC_AC3DSP_H #include <stdint.h> /** * Number of mantissa bits written for each bap value. * bap values with fractional bits are set to 0 and are calculated separately. */extern const uint16_t ff_ac3_bap_bits[16]; typedef struct AC3DSPContext {    /**     * Set each encoded exponent in a block to the minimum of itself and the     * exponents in the same frequency bin of up to 5 following blocks.     * @param exp   pointer to the start of the current block of exponents.     *              constraints: align 16     * @param num_reuse_blocks  number of blocks that will reuse exponents from the current block.     *                          constraints: range 0 to 5     * @param nb_coefs  number of frequency coefficients.     */    void (*ac3_exponent_min)(uint8_t *exp, int num_reuse_blocks, int nb_coefs);     /**     * Calculate the maximum MSB of the absolute value of each element in an     * array of int16_t.     * @param src input array     *            constraints: align 16. values must be in range [-32767,32767]     * @param len number of values in the array     *            constraints: multiple of 16 greater than 0     * @return    a value with the same MSB as max(abs(src[]))     */    int (*ac3_max_msb_abs_int16)(const int16_t *src, int len);     /**     * Left-shift each value in an array of int16_t by a specified amount.     * @param src    input array     *               constraints: align 16     * @param len    number of values in the array     *               constraints: multiple of 32 greater than 0     * @param shift  left shift amount     *               constraints: range [0,15]     */    void (*ac3_lshift_int16)(int16_t *src, unsigned int len, unsigned int shift);     /**     * Right-shift each value in an array of int32_t by a specified amount.     * @param src    input array     *               constraints: align 16     * @param len    number of values in the array     *               constraints: multiple of 16 greater than 0     * @param shift  right shift amount     *               constraints: range [0,31]     */    void (*ac3_rshift_int32)(int32_t *src, unsigned int len, unsigned int shift);     /**     * Convert an array of float in range [-1.0,1.0] to int32_t with range     * [-(1<<24),(1<<24)]     *     * @param dst destination array of int32_t.     *            constraints: 16-byte aligned     * @param src source array of float.     *            constraints: 16-byte aligned     * @param len number of elements to convert.     *            constraints: multiple of 32 greater than zero     */    void (*float_to_fixed24)(int32_t *dst, const float *src, unsigned int len);     /**     * 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 snroffset     * parameter is a global adjustment to the SNR for all bins.     *     * @param[in]  mask       masking curve     * @param[in]  psd        signal power for each frequency bin     * @param[in]  start      starting bin location     * @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 (*bit_alloc_calc_bap)(int16_t *mask, int16_t *psd, int start, int end,                               int snr_offset, int floor,                               const uint8_t *bap_tab, uint8_t *bap);     /**     * Update bap counts using the supplied array of bap.     *     * @param[out] mant_cnt   bap counts for 1 block     * @param[in]  bap        array of bap, pointing to start coef bin     * @param[in]  len        number of elements to process     */    void (*update_bap_counts)(uint16_t mant_cnt[16], uint8_t *bap, int len);     /**     * Calculate the number of bits needed to encode a set of mantissas.     *     * @param[in] mant_cnt    bap counts for all blocks     * @return                mantissa bit count     */    int (*compute_mantissa_size)(uint16_t mant_cnt[6][16]);     void (*extract_exponents)(uint8_t *exp, int32_t *coef, int nb_coefs);     void (*sum_square_butterfly_int32)(int64_t sum[4], const int32_t *coef0,                                       const int32_t *coef1, int len);     void (*sum_square_butterfly_float)(float sum[4], const float *coef0,                                       const float *coef1, int len);     int out_channels;    int in_channels;    void (*downmix)(float **samples, float **matrix, int len);    void (*downmix_fixed)(int32_t **samples, int16_t **matrix, int len);     /**     * Apply symmetric window in 16-bit fixed-point.     * @param output destination array     *               constraints: 16-byte aligned     * @param input  source array     *               constraints: 16-byte aligned     * @param window window array     *               constraints: 16-byte aligned, at least len/2 elements     * @param len    full window length     *               constraints: multiple of ? greater than zero     */    void (*apply_window_int16)(int16_t *output, const int16_t *input,                               const int16_t *window, unsigned int len);} AC3DSPContext; void ff_ac3dsp_init    (AC3DSPContext *c, int bit_exact);void ff_ac3dsp_init_arm(AC3DSPContext *c, int bit_exact);void ff_ac3dsp_init_x86(AC3DSPContext *c, int bit_exact);void ff_ac3dsp_init_mips(AC3DSPContext *c, int bit_exact); void ff_ac3dsp_downmix(AC3DSPContext *c, float **samples, float **matrix,                       int out_ch, int in_ch, int len);void ff_ac3dsp_downmix_fixed(AC3DSPContext *c, int32_t **samples, int16_t **matrix,                             int out_ch, int in_ch, int len); void ff_ac3dsp_set_downmix_x86(AC3DSPContext *c); #endif /* AVCODEC_AC3DSP_H */