*/
/**
- * @file libavcodec/ac3.h
+ * @file
* Common code between the AC-3 and E-AC-3 decoders.
+ *
+ * Summary of MDCT Coefficient Grouping:
+ * The individual MDCT coefficient indices are often referred to in the
+ * (E-)AC-3 specification as frequency bins. These bins are grouped together
+ * into subbands of 12 coefficients each. The subbands are grouped together
+ * into bands as defined in the bitstream by the band structures, which
+ * determine the number of bands and the size of each band. The full spectrum
+ * of 256 frequency bins is divided into 1 DC bin + 21 subbands = 253 bins.
+ * This system of grouping coefficients is used for channel bandwidth, stereo
+ * rematrixing, channel coupling, enhanced coupling, and spectral extension.
+ *
+ * +-+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+-+
+ * |1| |12| | [12|12|12|12] | | | | | | | | | | | | |3|
+ * +-+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+-+
+ * ~~~ ~~~~ ~~~~~~~~~~~~~ ~~~
+ * | | | |
+ * | | | 3 unused frequency bins--+
+ * | | |
+ * | | +--1 band containing 4 subbands
+ * | |
+ * | +--1 subband of 12 frequency bins
+ * |
+ * +--DC frequency bin
*/
#ifndef AVCODEC_AC3DEC_H
#include "ac3.h"
#include "get_bits.h"
#include "dsputil.h"
+#include "fft.h"
+#include "fmtconvert.h"
/* override ac3.h to include coupling channel */
#undef AC3_MAX_CHANNELS
#define AC3_OUTPUT_LFEON 8
-#define AC3_MAX_COEFS 256
-#define AC3_BLOCK_SIZE 256
-#define MAX_BLOCKS 6
+#define SPX_MAX_BANDS 17
typedef struct {
AVCodecContext *avctx; ///< parent context
///@}
///@defgroup cpl standard coupling
- int cpl_in_use[MAX_BLOCKS]; ///< coupling in use (cplinu)
- int cpl_strategy_exists[MAX_BLOCKS]; ///< coupling strategy exists (cplstre)
+ int cpl_in_use[AC3_MAX_BLOCKS]; ///< coupling in use (cplinu)
+ int cpl_strategy_exists[AC3_MAX_BLOCKS];///< coupling strategy exists (cplstre)
int channel_in_cpl[AC3_MAX_CHANNELS]; ///< channel in coupling (chincpl)
int phase_flags_in_use; ///< phase flags in use (phsflginu)
int phase_flags[18]; ///< phase flags (phsflg)
int cpl_coords[AC3_MAX_CHANNELS][18]; ///< coupling coordinates (cplco)
///@}
+///@defgroup spx spectral extension
+///@{
+ int spx_in_use; ///< spectral extension in use (spxinu)
+ uint8_t channel_uses_spx[AC3_MAX_CHANNELS]; ///< channel uses spectral extension (chinspx)
+ int8_t spx_atten_code[AC3_MAX_CHANNELS]; ///< spx attenuation code (spxattencod)
+ int spx_src_start_freq; ///< spx start frequency bin
+ int spx_dst_end_freq; ///< spx end frequency bin
+ int spx_dst_start_freq; ///< spx starting frequency bin for copying (copystartmant)
+ ///< the copy region ends at the start of the spx region.
+ int num_spx_bands; ///< number of spx bands (nspxbnds)
+ uint8_t spx_band_sizes[SPX_MAX_BANDS]; ///< number of bins in each spx band
+ uint8_t first_spx_coords[AC3_MAX_CHANNELS]; ///< first spx coordinates states (firstspxcos)
+ float spx_noise_blend[AC3_MAX_CHANNELS][SPX_MAX_BANDS]; ///< spx noise blending factor (nblendfact)
+ float spx_signal_blend[AC3_MAX_CHANNELS][SPX_MAX_BANDS];///< spx signal blending factor (sblendfact)
+///@}
+
///@defgroup aht adaptive hybrid transform
int channel_uses_aht[AC3_MAX_CHANNELS]; ///< channel AHT in use (chahtinu)
- int pre_mantissa[AC3_MAX_CHANNELS][AC3_MAX_COEFS][MAX_BLOCKS]; ///< pre-IDCT mantissas
+ int pre_mantissa[AC3_MAX_CHANNELS][AC3_MAX_COEFS][AC3_MAX_BLOCKS]; ///< pre-IDCT mantissas
///@}
///@defgroup channel channel
///@defgroup exponents exponents
int num_exp_groups[AC3_MAX_CHANNELS]; ///< Number of exponent groups (nexpgrp)
int8_t dexps[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< decoded exponents
- int exp_strategy[MAX_BLOCKS][AC3_MAX_CHANNELS]; ///< exponent strategies (expstr)
+ int exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS]; ///< exponent strategies (expstr)
///@}
///@defgroup bitalloc bit allocation
int fast_gain[AC3_MAX_CHANNELS]; ///< fast gain values/SMR's (fgain)
uint8_t bap[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< bit allocation pointers
int16_t psd[AC3_MAX_CHANNELS][AC3_MAX_COEFS]; ///< scaled exponents
- int16_t band_psd[AC3_MAX_CHANNELS][50]; ///< interpolated exponents
- int16_t mask[AC3_MAX_CHANNELS][50]; ///< masking curve values
+ int16_t band_psd[AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS]; ///< interpolated exponents
+ int16_t mask[AC3_MAX_CHANNELS][AC3_CRITICAL_BANDS]; ///< masking curve values
int dba_mode[AC3_MAX_CHANNELS]; ///< delta bit allocation mode
int dba_nsegs[AC3_MAX_CHANNELS]; ///< number of delta segments
uint8_t dba_offsets[AC3_MAX_CHANNELS][8]; ///< delta segment offsets
///@defgroup opt optimization
DSPContext dsp; ///< for optimization
- float add_bias; ///< offset for float_to_int16 conversion
+ FmtConvertContext fmt_conv; ///< optimized conversion functions
float mul_bias; ///< scaling for float_to_int16 conversion
///@}
*/
void ff_eac3_decode_transform_coeffs_aht_ch(AC3DecodeContext *s, int ch);
+void ff_ac3_downmix_c(float (*samples)[256], float (*matrix)[2],
+ int out_ch, int in_ch, int len);
+
+/**
+ * Apply spectral extension to each channel by copying lower frequency
+ * coefficients to higher frequency bins and applying side information to
+ * approximate the original high frequency signal.
+ */
+void ff_eac3_apply_spectral_extension(AC3DecodeContext *s);
+
#endif /* AVCODEC_AC3DEC_H */
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