/*****************************************************************************
- * ac3_decoder.h : ac3 decoder thread interface
- * (c)1999 VideoLAN
+ * ac3_decoder.h : ac3 decoder interface
+ *****************************************************************************
+ * Copyright (C) 1999, 2000 VideoLAN
+ *
+ * Authors:
+ * Michel Kaempf <maxx@via.ecp.fr>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
*****************************************************************************/
-#define AC3DEC_FRAME_SIZE (2*256)
+/**** ac3 decoder API - public ac3 decoder structures */
-/*****************************************************************************
- * ac3dec_frame_t
- *****************************************************************************/
-typedef s16 ac3dec_frame_t[ AC3DEC_FRAME_SIZE ];
+typedef struct ac3dec_s ac3dec_t;
-/*****************************************************************************
- * ac3dec_thread_t : ac3 decoder thread descriptor
- *****************************************************************************/
-typedef struct ac3dec_thread_s
-{
- /*
- * Thread properties
- */
- vlc_thread_t thread_id; /* id for thread functions */
- boolean_t b_die; /* `die' flag */
- boolean_t b_error; /* `error' flag */
+typedef struct ac3_sync_info_s {
+ int sample_rate; /* sample rate in Hz */
+ int frame_size; /* frame size in bytes */
+ int bit_rate; /* nominal bit rate in kbps */
+} ac3_sync_info_t;
+
+typedef struct ac3_byte_stream_s {
+ u8 * p_byte;
+ u8 * p_end;
+ void * info;
+} ac3_byte_stream_t;
+
+/**** ac3 decoder API - functions publically provided by the ac3 decoder ****/
+
+int ac3_init (ac3dec_t * p_ac3dec);
+int ac3_sync_frame (ac3dec_t * p_ac3dec, ac3_sync_info_t * p_sync_info);
+int ac3_decode_frame (ac3dec_t * p_ac3dec, s16 * buffer);
+static ac3_byte_stream_t * ac3_byte_stream (ac3dec_t * p_ac3dec);
+
+/**** ac3 decoder API - user functions to be provided to the ac3 decoder ****/
+
+void ac3_byte_stream_next (ac3_byte_stream_t * p_byte_stream);
+
+/**** EVERYTHING AFTER THIS POINT IS PRIVATE ! DO NOT USE DIRECTLY ****/
+
+/**** ac3 decoder internal structures ****/
+
+/* The following structures are filled in by their corresponding parse_*
+ * functions. See http://www.atsc.org/Standards/A52/a_52.pdf for
+ * full details on each field. Indented fields are used to denote
+ * conditional fields.
+ */
+
+typedef struct syncinfo_s {
+ /* Sync word == 0x0B77 */
+ /* u16 syncword; */
+ /* crc for the first 5/8 of the sync block */
+ /* u16 crc1; */
+ /* Stream Sampling Rate (kHz) 0 = 48, 1 = 44.1, 2 = 32, 3 = reserved */
+ u16 fscod;
+ /* Frame size code */
+ u16 frmsizecod;
+
+ /* Information not in the AC-3 bitstream, but derived */
+ /* Frame size in 16 bit words */
+ u16 frame_size;
+ /* Bit rate in kilobits */
+ //u16 bit_rate;
+} syncinfo_t;
+
+typedef struct bsi_s {
+ /* Bit stream identification == 0x8 */
+ u16 bsid;
+ /* Bit stream mode */
+ u16 bsmod;
+ /* Audio coding mode */
+ u16 acmod;
+ /* If we're using the centre channel then */
+ /* centre mix level */
+ u16 cmixlev;
+ /* If we're using the surround channel then */
+ /* surround mix level */
+ u16 surmixlev;
+ /* If we're in 2/0 mode then */
+ /* Dolby surround mix level - NOT USED - */
+ u16 dsurmod;
+ /* Low frequency effects on */
+ u16 lfeon;
+ /* Dialogue Normalization level */
+ u16 dialnorm;
+ /* Compression exists */
+ u16 compre;
+ /* Compression level */
+ u16 compr;
+ /* Language code exists */
+ u16 langcode;
+ /* Language code */
+ u16 langcod;
+ /* Audio production info exists*/
+ u16 audprodie;
+ u16 mixlevel;
+ u16 roomtyp;
+ /* If we're in dual mono mode (acmod == 0) then extra stuff */
+ u16 dialnorm2;
+ u16 compr2e;
+ u16 compr2;
+ u16 langcod2e;
+ u16 langcod2;
+ u16 audprodi2e;
+ u16 mixlevel2;
+ u16 roomtyp2;
+ /* Copyright bit */
+ u16 copyrightb;
+ /* Original bit */
+ u16 origbs;
+ /* Timecode 1 exists */
+ u16 timecod1e;
+ /* Timecode 1 */
+ u16 timecod1;
+ /* Timecode 2 exists */
+ u16 timecod2e;
+ /* Timecode 2 */
+ u16 timecod2;
+ /* Additional bit stream info exists */
+ u16 addbsie;
+ /* Additional bit stream length - 1 (in bytes) */
+ u16 addbsil;
+ /* Additional bit stream information (max 64 bytes) */
+ u8 addbsi[64];
+
+ /* Information not in the AC-3 bitstream, but derived */
+ /* Number of channels (excluding LFE)
+ * Derived from acmod */
+ u16 nfchans;
+} bsi_t;
+
+/* more pain */
+typedef struct audblk_s {
+ /* block switch bit indexed by channel num */
+ u16 blksw[5];
+ /* dither enable bit indexed by channel num */
+ u16 dithflag[5];
+ /* dynamic range gain exists */
+ u16 dynrnge;
+ /* dynamic range gain */
+ u16 dynrng;
+ /* if acmod==0 then */
+ /* dynamic range 2 gain exists */
+ u16 dynrng2e;
+ /* dynamic range 2 gain */
+ u16 dynrng2;
+ /* coupling strategy exists */
+ u16 cplstre;
+ /* coupling in use */
+ u16 cplinu;
+ /* channel coupled */
+ u16 chincpl[5];
+ /* if acmod==2 then */
+ /* Phase flags in use */
+ u16 phsflginu;
+ /* coupling begin frequency code */
+ u16 cplbegf;
+ /* coupling end frequency code */
+ u16 cplendf;
+ /* coupling band structure bits */
+ u16 cplbndstrc[18];
+ /* Do coupling co-ords exist for this channel? */
+ u16 cplcoe[5];
+ /* Master coupling co-ordinate */
+ u16 mstrcplco[5];
+ /* Per coupling band coupling co-ordinates */
+ u16 cplcoexp[5][18];
+ u16 cplcomant[5][18];
+ /* Phase flags for dual mono */
+ u16 phsflg[18];
+ /* Is there a rematrixing strategy */
+ u16 rematstr;
+ /* Rematrixing bits */
+ u16 rematflg[4];
+ /* Coupling exponent strategy */
+ u16 cplexpstr;
+ /* Exponent strategy for full bandwidth channels */
+ u16 chexpstr[5];
+ /* Exponent strategy for lfe channel */
+ u16 lfeexpstr;
+ /* Channel bandwidth for independent channels */
+ u16 chbwcod[5];
+ /* The absolute coupling exponent */
+ u16 cplabsexp;
+ /* Coupling channel exponents (D15 mode gives 18 * 12 /3 encoded exponents */
+ u16 cplexps[18 * 12 / 3];
+ /* Sanity checking constant */
+ u32 magic2;
+ /* fbw channel exponents */
+ u16 exps[5][252 / 3];
+ /* channel gain range */
+ u16 gainrng[5];
+ /* low frequency exponents */
+ u16 lfeexps[3];
+
+ /* Bit allocation info */
+ u16 baie;
+ /* Slow decay code */
+ u16 sdcycod;
+ /* Fast decay code */
+ u16 fdcycod;
+ /* Slow gain code */
+ u16 sgaincod;
+ /* dB per bit code */
+ u16 dbpbcod;
+ /* masking floor code */
+ u16 floorcod;
+
+ /* SNR offset info */
+ u16 snroffste;
+ /* coarse SNR offset */
+ u16 csnroffst;
+ /* coupling fine SNR offset */
+ u16 cplfsnroffst;
+ /* coupling fast gain code */
+ u16 cplfgaincod;
+ /* fbw fine SNR offset */
+ u16 fsnroffst[5];
+ /* fbw fast gain code */
+ u16 fgaincod[5];
+ /* lfe fine SNR offset */
+ u16 lfefsnroffst;
+ /* lfe fast gain code */
+ u16 lfefgaincod;
+
+ /* Coupling leak info */
+ u16 cplleake;
+ /* coupling fast leak initialization */
+ u16 cplfleak;
+ /* coupling slow leak initialization */
+ u16 cplsleak;
+
+ /* delta bit allocation info */
+ u16 deltbaie;
+ /* coupling delta bit allocation exists */
+ u16 cpldeltbae;
+ /* fbw delta bit allocation exists */
+ u16 deltbae[5];
+ /* number of cpl delta bit segments */
+ u16 cpldeltnseg;
+ /* coupling delta bit allocation offset */
+ u16 cpldeltoffst[8];
+ /* coupling delta bit allocation length */
+ u16 cpldeltlen[8];
+ /* coupling delta bit allocation length */
+ u16 cpldeltba[8];
+ /* number of delta bit segments */
+ u16 deltnseg[5];
+ /* fbw delta bit allocation offset */
+ u16 deltoffst[5][8];
+ /* fbw delta bit allocation length */
+ u16 deltlen[5][8];
+ /* fbw delta bit allocation length */
+ u16 deltba[5][8];
+ /* skip length exists */
+ u16 skiple;
+ /* skip length */
+ u16 skipl;
+
+ /* channel mantissas */
+// u16 chmant[5][256];
+
+ /* coupling mantissas */
+ float cplfbw[ 256 ];
+// u16 cplmant[256];
+
+ /* coupling mantissas */
+// u16 lfemant[7];
+
+ /* -- Information not in the bitstream, but derived thereof -- */
+
+ /* Number of coupling sub-bands */
+ u16 ncplsubnd;
+
+ /* Number of combined coupling sub-bands
+ * Derived from ncplsubnd and cplbndstrc */
+ u16 ncplbnd;
+
+ /* Number of exponent groups by channel
+ * Derived from strmant, endmant */
+ u16 nchgrps[5];
+
+ /* Number of coupling exponent groups
+ * Derived from cplbegf, cplendf, cplexpstr */
+ u16 ncplgrps;
+
+ /* End mantissa numbers of fbw channels */
+ u16 endmant[5];
+
+ /* Start and end mantissa numbers for the coupling channel */
+ u16 cplstrtmant;
+ u16 cplendmant;
+
+ /* Decoded exponent info */
+ u16 fbw_exp[5][256];
+ u16 cpl_exp[256];
+ u16 lfe_exp[7];
+
+ /* Bit allocation pointer results */
+ u16 fbw_bap[5][256];
+ /* FIXME?? figure out exactly how many entries there should be (253-37?) */
+ u16 cpl_bap[256];
+ u16 lfe_bap[7];
+} audblk_t;
+
+/* Everything you wanted to know about band structure */
+/*
+ * The entire frequency domain is represented by 256 real
+ * floating point fourier coefficients. Only the lower 253
+ * coefficients are actually utilized however. We use arrays
+ * of 256 to be efficient in some cases.
+ *
+ * The 5 full bandwidth channels (fbw) can have their higher
+ * frequencies coupled together. These coupled channels then
+ * share their high frequency components.
+ *
+ * This coupling band is broken up into 18 sub-bands starting
+ * at mantissa number 37. Each sub-band is 12 bins wide.
+ *
+ * There are 50 bit allocation sub-bands which cover the entire
+ * frequency range. The sub-bands are of non-uniform width, and
+ * approximate a 1/6 octave scale.
+ */
+
+typedef struct stream_coeffs_s {
+ float fbw[5][256];
+ float lfe[256];
+} stream_coeffs_t;
+
+typedef struct stream_samples_s {
+ float channel[6][256];
+} stream_samples_t;
+
+typedef struct ac3_bit_stream_s {
+ u32 buffer;
+ int i_available;
+ ac3_byte_stream_t byte_stream;
+
+ unsigned int total_bits_read; /* temporary */
+} ac3_bit_stream_t;
+
+struct ac3dec_s {
/*
* Input properties
*/
- decoder_fifo_t fifo; /* stores the PES stream data */
+
/* The bit stream structure handles the PES stream at the bit level */
- bit_stream_t bit_stream;
+ ac3_bit_stream_t bit_stream;
/*
* Decoder properties
*/
- unsigned int total_bits_read;
+ syncinfo_t syncinfo;
+ bsi_t bsi;
+ audblk_t audblk;
- /*
- * Output properties
- */
- aout_fifo_t * p_aout_fifo; /* stores the decompressed audio frames */
- aout_thread_t * p_aout; /* needed to create the audio fifo */
+ stream_coeffs_t coeffs;
+ stream_samples_t samples;
+};
-} ac3dec_thread_t;
+/**** ac3 decoder inline functions ****/
-/*****************************************************************************
- * Prototypes
- *****************************************************************************/
-ac3dec_thread_t * ac3dec_CreateThread( input_thread_t * p_input );
-void ac3dec_DestroyThread( ac3dec_thread_t * p_ac3dec );
+static ac3_byte_stream_t * ac3_byte_stream (ac3dec_t * p_ac3dec)
+{
+ return &(p_ac3dec->bit_stream.byte_stream);
+}