vc9.c

ffmpeg源码分析

/*
 * VC-9 and WMV3 decoder
 * Copyright (c) 2005 Anonymous
 * Copyright (c) 2005 Alex Beregszaszi
 * Copyright (c) 2005 Michael Niedermayer
 *
 * This library 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 of the License, or (at your option) any later version.
 *
 * This library 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 this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *
 */

/**
 * @file vc9.c
 * VC-9 and WMV3 decoder
 *
 * TODO: most AP stuff, optimize, most of MB layer, transform, filtering and motion compensation, etc
 * TODO: use MPV_ !!
 */
#include "common.h"
#include "dsputil.h"
#include "avcodec.h"
#include "mpegvideo.h"
#include "vc9data.h"

#undef NDEBUG
#include <assert.h>

extern const uint32_t ff_table0_dc_lum[120][2], ff_table1_dc_lum[120][2];
extern const uint32_t ff_table0_dc_chroma[120][2], ff_table1_dc_chroma[120][2];
extern VLC ff_msmp4_dc_luma_vlc[2], ff_msmp4_dc_chroma_vlc[2];
#define MB_INTRA_VLC_BITS 9
extern VLC ff_msmp4_mb_i_vlc;
#define DC_VLC_BITS 9
static const uint16_t table_mb_intra[64][2];

/* Some inhibiting stuff */
#define HAS_ADVANCED_PROFILE   0
#define TRACE                  1

#if TRACE
#  define INIT_VLC(vlc, nb_bits, nb_codes, bits, bits_wrap, bits_size, \
                   codes, codes_wrap, codes_size, use_static)          \
  if (init_vlc(vlc, nb_bits, nb_codes, bits, bits_wrap, bits_size,     \
               codes, codes_wrap, codes_size, use_static) < 0)         \
  {                                                                    \
    av_log(v->s.avctx, AV_LOG_ERROR, "Error for " # vlc " (%i)\n", i);   \
    return -1;                                                         \
  }
#else
#  define INIT_VLC(vlc, nb_bits, nb_codes, bits, bits_wrap, bits_size, \
                   codes, codes_wrap, codes_size, use_static)          \
  init_vlc(vlc, nb_bits, nb_codes, bits, bits_wrap, bits_size,         \
           codes, codes_wrap, codes_size, use_static)
#endif

/** Available Profiles */
//@{
#define PROFILE_SIMPLE   0
#define PROFILE_MAIN     1
#define PROFILE_COMPLEX  2 ///< TODO: WMV9 specific
#define PROFILE_ADVANCED 3
//@}

/** Sequence quantizer mode */
//@{
#define QUANT_FRAME_IMPLICIT   0 ///< Implicitly specified at frame level
#define QUANT_FRAME_EXPLICIT   1 ///< Explicitly specified at frame level
#define QUANT_NON_UNIFORM      2 ///< Non-uniform quant used for all frames
#define QUANT_UNIFORM          3 ///< Uniform quant used for all frames
//@}

/** Where quant can be changed */
//@{
#define DQPROFILE_FOUR_EDGES   0
#define DQPROFILE_DOUBLE_EDGES 1
#define DQPROFILE_SINGLE_EDGE  2
#define DQPROFILE_ALL_MBS      3
//@}

/** @name Where quant can be changed
 */
//@{
#define DQPROFILE_FOUR_EDGES   0
#define DQSINGLE_BEDGE_LEFT   0
#define DQSINGLE_BEDGE_TOP    1
#define DQSINGLE_BEDGE_RIGHT  2
#define DQSINGLE_BEDGE_BOTTOM 3
//@}

/** Which pair of edges is quantized with ALTPQUANT */
//@{
#define DQDOUBLE_BEDGE_TOPLEFT     0
#define DQDOUBLE_BEDGE_TOPRIGHT    1
#define DQDOUBLE_BEDGE_BOTTOMRIGHT 2
#define DQDOUBLE_BEDGE_BOTTOMLEFT  3
//@}

/** MV modes for P frames */
//@{
#define MV_PMODE_1MV_HPEL_BILIN   0
#define MV_PMODE_1MV              1
#define MV_PMODE_1MV_HPEL         2
#define MV_PMODE_MIXED_MV         3
#define MV_PMODE_INTENSITY_COMP   4
//@}

/** @name MV types for B frames */
//@{
#define BMV_TYPE_BACKWARD          0
#define BMV_TYPE_BACKWARD          0
#define BMV_TYPE_FORWARD           1
#define BMV_TYPE_INTERPOLATED      3
//@}

/** MV P mode - the 5th element is only used for mode 1 */
static const uint8_t mv_pmode_table[2][5] = {
  { MV_PMODE_1MV_HPEL_BILIN, MV_PMODE_1MV, MV_PMODE_1MV_HPEL, MV_PMODE_MIXED_MV, MV_PMODE_INTENSITY_COMP },
  { MV_PMODE_1MV, MV_PMODE_MIXED_MV, MV_PMODE_1MV_HPEL, MV_PMODE_1MV_HPEL_BILIN, MV_PMODE_INTENSITY_COMP }
};

/** One more frame type */
#define BI_TYPE 7

static const int fps_nr[5] = { 24, 25, 30, 50, 60 },
  fps_dr[2] = { 1000, 1001 };
static const uint8_t pquant_table[3][32] = {
  {  /* Implicit quantizer */
     0,  1,  2,  3,  4,  5,  6,  7,  8,  6,  7,  8,  9, 10, 11, 12,
    13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 27, 29, 31
  },
  {  /* Explicit quantizer, pquantizer uniform */
     0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15,
    16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31
  },
  {  /* Explicit quantizer, pquantizer non-uniform */
     0,  1,  1,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13,
    14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 29, 31
  }
};

/** @name VC-9 VLC tables and defines
 *  @todo TODO move this into the context
 */
//@{
#define VC9_BFRACTION_VLC_BITS 7
static VLC vc9_bfraction_vlc;
#define VC9_IMODE_VLC_BITS 4
static VLC vc9_imode_vlc;
#define VC9_NORM2_VLC_BITS 3
static VLC vc9_norm2_vlc;
#define VC9_NORM6_VLC_BITS 9
static VLC vc9_norm6_vlc;
/* Could be optimized, one table only needs 8 bits */
#define VC9_TTMB_VLC_BITS 9 //12
static VLC vc9_ttmb_vlc[3];
#define VC9_MV_DIFF_VLC_BITS 9 //15
static VLC vc9_mv_diff_vlc[4];
#define VC9_CBPCY_P_VLC_BITS 9 //14
static VLC vc9_cbpcy_p_vlc[4];
#define VC9_4MV_BLOCK_PATTERN_VLC_BITS 6
static VLC vc9_4mv_block_pattern_vlc[4];
#define VC9_TTBLK_VLC_BITS 5
static VLC vc9_ttblk_vlc[3];
#define VC9_SUBBLKPAT_VLC_BITS 6
static VLC vc9_subblkpat_vlc[3];
//@}

/** Bitplane struct
 * We mainly need data and is_raw, so this struct could be avoided
 * to save a level of indirection; feel free to modify
 * @fixme For now, stride=width
 * @warning Data are bits, either 1 or 0
 */
typedef struct BitPlane {
    uint8_t *data;      ///< Data buffer
    int width;          ///< Width of the buffer
    int stride;         ///< Stride of the buffer
    int height;         ///< Plane height
    uint8_t is_raw;     ///< Bit values must be read at MB level
} BitPlane;

/** The VC9 Context
 * @fixme Change size wherever another size is more efficient
 * Many members are only used for Advanced Profile
 */
typedef struct VC9Context{
    MpegEncContext s;

    /** Simple/Main Profile sequence header */
    //@{
    int res_sm;           ///< reserved, 2b
    int res_x8;           ///< reserved
    int multires;         ///< frame-level RESPIC syntax element present
    int res_fasttx;       ///< reserved, always 1
    int res_transtab;     ///< reserved, always 0
    int rangered;         ///< RANGEREDFRM (range reduction) syntax element present
                          ///< at frame level
    int res_rtm_flag;     ///< reserved, set to 1
    int reserved;         ///< reserved
    //@}

#if HAS_ADVANCED_PROFILE
    /** Advanced Profile */
    //@{
    int level;            ///< 3bits, for Advanced/Simple Profile, provided by TS layer
    int chromaformat;     ///< 2bits, 2=4:2:0, only defined
    int postprocflag;     ///< Per-frame processing suggestion flag present
    int broadcast;        ///< TFF/RFF present
    int interlace;        ///< Progressive/interlaced (RPTFTM syntax element)
    int tfcntrflag;       ///< TFCNTR present
    int panscanflag;      ///< NUMPANSCANWIN, TOPLEFT{X,Y}, BOTRIGHT{X,Y} present
    int extended_dmv;     ///< Additional extended dmv range at P/B frame-level
    int color_prim;       ///< 8bits, chroma coordinates of the color primaries
    int transfer_char;    ///< 8bits, Opto-electronic transfer characteristics
    int matrix_coef;      ///< 8bits, Color primaries->YCbCr transform matrix
    int hrd_param_flag;   ///< Presence of Hypothetical Reference
                          ///< Decoder parameters
    //@}
#endif


    /** Sequence header data for all Profiles
     * TODO: choose between ints, uint8_ts and monobit flags
     */
    //@{
    int profile;          ///< 2bits, Profile
    int frmrtq_postproc;  ///< 3bits,
    int bitrtq_postproc;  ///< 5bits, quantized framerate-based postprocessing strength
    int fastuvmc;         ///< Rounding of qpel vector to hpel ? (not in Simple)
    int extended_mv;      ///< Ext MV in P/B (not in Simple)
    int dquant;           ///< How qscale varies with MBs, 2bits (not in Simple)
    int vstransform;      ///< variable-size [48]x[48] transform type + info
    int overlap;          ///< overlapped transforms in use
    int quantizer_mode;   ///< 2bits, quantizer mode used for sequence, see QUANT_*
    int finterpflag;      ///< INTERPFRM present
    //@}

    /** Frame decoding info for all profiles */
    //@{
    uint8_t mv_mode;      ///< MV coding monde
    uint8_t mv_mode2;     ///< Secondary MV coding mode (B frames)
    int k_x;              ///< Number of bits for MVs (depends on MV range)
    int k_y;              ///< Number of bits for MVs (depends on MV range)
    uint8_t pq, altpq;    ///< Current/alternate frame quantizer scale
    /** pquant parameters */
    //@{
    uint8_t dquantfrm;
    uint8_t dqprofile;
    uint8_t dqsbedge;
    uint8_t dqbilevel;
    //@}
    /** AC coding set indexes
     * @see 8.1.1.10, p(1)10
     */
    //@{
    int c_ac_table_index; ///< Chroma index from ACFRM element
    int y_ac_table_index; ///< Luma index from AC2FRM element
    //@}
    int ttfrm;            ///< Transform type info present at frame level
    uint8_t ttmbf;        ///< Transform type flag
    int ttmb;             ///< Transform type
    uint8_t ttblk4x4;     ///< Value of ttblk which indicates a 4x4 transform
    /** Luma compensation parameters */
    //@{
    uint8_t lumscale;
    uint8_t lumshift;
    //@}
    int16_t bfraction;    ///< Relative position % anchors=> how to scale MVs
    uint8_t halfpq;       ///< Uniform quant over image and qp+.5
    uint8_t respic;       ///< Frame-level flag for resized images
    int buffer_fullness;  ///< HRD info
    /** Ranges:
     * -# 0 -> [-64n 63.f] x [-32, 31.f]
     * -# 1 -> [-128, 127.f] x [-64, 63.f]
     * -# 2 -> [-512, 511.f] x [-128, 127.f]
     * -# 3 -> [-1024, 1023.f] x [-256, 255.f]
     */
    uint8_t mvrange;
    uint8_t pquantizer;           ///< Uniform (over sequence) quantizer in use
    uint8_t *previous_line_cbpcy; ///< To use for predicted CBPCY
    VLC *cbpcy_vlc;               ///< CBPCY VLC table
    int tt_index;                 ///< Index for Transform Type tables
    BitPlane mv_type_mb_plane;    ///< bitplane for mv_type == (4MV)
    BitPlane skip_mb_plane;       ///< bitplane for skipped MBs
    BitPlane direct_mb_plane;     ///< bitplane for "direct" MBs

    /** Frame decoding info for S/M profiles only */
    //@{
    uint8_t rangeredfrm; ///< out_sample = CLIP((in_sample-128)*2+128)
    uint8_t interpfrm;
    //@}

#if HAS_ADVANCED_PROFILE
    /** Frame decoding info for Advanced profile */
    //@{
    uint8_t fcm; ///< 0->Progressive, 2->Frame-Interlace, 3->Field-Interlace
    uint8_t numpanscanwin;
    uint8_t tfcntr;
    uint8_t rptfrm, tff, rff;
    uint16_t topleftx;
    uint16_t toplefty;
    uint16_t bottomrightx;
    uint16_t bottomrighty;
    uint8_t uvsamp;
    uint8_t postproc;
    int hrd_num_leaky_buckets;
    uint8_t bit_rate_exponent;
    uint8_t buffer_size_exponent;
    BitPlane ac_pred_plane;       ///< AC prediction flags bitplane
    BitPlane over_flags_plane;    ///< Overflags bitplane
    uint8_t condover;
    uint16_t *hrd_rate, *hrd_buffer;
    uint8_t *hrd_fullness;
    uint8_t range_mapy_flag;
    uint8_t range_mapuv_flag;
    uint8_t range_mapy;
    uint8_t range_mapuv;
    //@}
#endif
} VC9Context;

/**
 * Get unary code of limited length
 * @fixme FIXME Slow and ugly
 * @param gb GetBitContext
 * @param[in] stop The bitstop value (unary code of 1's or 0's)
 * @param[in] len Maximum length
 * @return Unary length/index
 */
static int get_prefix(GetBitContext *gb, int stop, int len)
{
#if 1
  int i = 0, tmp = !stop;

  while (i != len && tmp != stop)
  {
    tmp = get_bits(gb, 1);
    i++;
  }
  if (i == len && tmp != stop) return len+1;
  return i;
#else
  unsigned int buf;
  int log;

  OPEN_READER(re, gb);
  UPDATE_CACHE(re, gb);
  buf=GET_CACHE(re, gb); //Still not sure
  if (stop) buf = ~buf;

  log= av_log2(-buf); //FIXME: -?
  if (log < limit){
    LAST_SKIP_BITS(re, gb, log+1);
    CLOSE_READER(re, gb);
    return log;
  }

  LAST_SKIP_BITS(re, gb, limit);
  CLOSE_READER(re, gb);
  return limit;
#endif
}

/**
 * Init VC-9 specific tables and VC9Context members
 * @param v The VC9Context to initialize
 * @return Status
 */
static int vc9_init_common(VC9Context *v)
{
    static int done = 0;
    int i = 0;

    /* Set the bit planes */
    v->mv_type_mb_plane = (struct BitPlane) { NULL, 0, 0, 0 };
    v->direct_mb_plane = (struct BitPlane) { NULL, 0, 0, 0 };
    v->skip_mb_plane = (struct BitPlane) { NULL, 0, 0, 0 };
#if HAS_ADVANCED_PROFILE
    v->ac_pred_plane = v->over_flags_plane = (struct BitPlane) { NULL, 0, 0, 0 };
    v->hrd_rate = v->hrd_buffer = NULL;
#endif

    /* VLC tables */
#if 0 // spec -> actual tables converter
    for(i=0; i<64; i++){
        int code= (vc9_norm6_spec[i][1] << vc9_norm6_spec[i][4]) + vc9_norm6_spec[i][3];
        av_log(NULL, AV_LOG_DEBUG, "0x%03X, ", code);
        if(i%16==15) av_log(NULL, AV_LOG_DEBUG, "\n");
    }
    for(i=0; i<64; i++){
        int code= vc9_norm6_spec[i][2] + vc9_norm6_spec[i][4];
        av_log(NULL, AV_LOG_DEBUG, "%2d, ", code);
        if(i%16==15) av_log(NULL, AV_LOG_DEBUG, "\n");
    }
#endif
    if(!done)
    {
        done = 1;
        INIT_VLC(&vc9_bfraction_vlc, VC9_BFRACTION_VLC_BITS, 23,
                 vc9_bfraction_bits, 1, 1,
                 vc9_bfraction_codes, 1, 1, 1);
        INIT_VLC(&vc9_norm2_vlc, VC9_NORM2_VLC_BITS, 4,