FFmpeg/libavcodec/h264.h

/*
 * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder
 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
 *
 * 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
 */

/**
 * @file libavcodec/h264.h
 * H.264 / AVC / MPEG4 part10 codec.
 * @author Michael Niedermayer <michaelni@gmx.at>
 */

#ifndef AVCODEC_H264_H
#define AVCODEC_H264_H

#include "libavutil/intreadwrite.h"
#include "dsputil.h"
#include "cabac.h"
#include "mpegvideo.h"
#include "h264pred.h"
#include "rectangle.h"

#define interlaced_dct interlaced_dct_is_a_bad_name
#define mb_intra mb_intra_is_not_initialized_see_mb_type

#define LUMA_DC_BLOCK_INDEX   25
#define CHROMA_DC_BLOCK_INDEX 26

#define CHROMA_DC_COEFF_TOKEN_VLC_BITS 8
#define COEFF_TOKEN_VLC_BITS           8
#define TOTAL_ZEROS_VLC_BITS           9
#define CHROMA_DC_TOTAL_ZEROS_VLC_BITS 3
#define RUN_VLC_BITS                   3
#define RUN7_VLC_BITS                  6

#define MAX_SPS_COUNT 32
#define MAX_PPS_COUNT 256

#define MAX_MMCO_COUNT 66

#define MAX_DELAYED_PIC_COUNT 16

/* Compiling in interlaced support reduces the speed
 * of progressive decoding by about 2%. */
#define ALLOW_INTERLACE

#define ALLOW_NOCHROMA

/**
 * The maximum number of slices supported by the decoder.
 * must be a power of 2
 */
#define MAX_SLICES 16

#ifdef ALLOW_INTERLACE
#define MB_MBAFF h->mb_mbaff
#define MB_FIELD h->mb_field_decoding_flag
#define FRAME_MBAFF h->mb_aff_frame
#define FIELD_PICTURE (s->picture_structure != PICT_FRAME)
#else
#define MB_MBAFF 0
#define MB_FIELD 0
#define FRAME_MBAFF 0
#define FIELD_PICTURE 0
#undef  IS_INTERLACED
#define IS_INTERLACED(mb_type) 0
#endif
#define FIELD_OR_MBAFF_PICTURE (FRAME_MBAFF || FIELD_PICTURE)

#ifdef ALLOW_NOCHROMA
#define CHROMA h->sps.chroma_format_idc
#else
#define CHROMA 1
#endif

#ifndef CABAC
#define CABAC h->pps.cabac
#endif

#define EXTENDED_SAR          255

#define MB_TYPE_REF0       MB_TYPE_ACPRED //dirty but it fits in 16 bit
#define MB_TYPE_8x8DCT     0x01000000
#define IS_REF0(a)         ((a) & MB_TYPE_REF0)
#define IS_8x8DCT(a)       ((a) & MB_TYPE_8x8DCT)

/**
 * Value of Picture.reference when Picture is not a reference picture, but
 * is held for delayed output.
 */
#define DELAYED_PIC_REF 4


/* NAL unit types */
enum {
    NAL_SLICE=1,
    NAL_DPA,
    NAL_DPB,
    NAL_DPC,
    NAL_IDR_SLICE,
    NAL_SEI,
    NAL_SPS,
    NAL_PPS,
    NAL_AUD,
    NAL_END_SEQUENCE,
    NAL_END_STREAM,
    NAL_FILLER_DATA,
    NAL_SPS_EXT,
    NAL_AUXILIARY_SLICE=19
};

/**
 * SEI message types
 */
typedef enum {
    SEI_BUFFERING_PERIOD             =  0, ///< buffering period (H.264, D.1.1)
    SEI_TYPE_PIC_TIMING              =  1, ///< picture timing
    SEI_TYPE_USER_DATA_UNREGISTERED  =  5, ///< unregistered user data
    SEI_TYPE_RECOVERY_POINT          =  6  ///< recovery point (frame # to decoder sync)
} SEI_Type;

/**
 * pic_struct in picture timing SEI message
 */
typedef enum {
    SEI_PIC_STRUCT_FRAME             = 0, ///<  0: %frame
    SEI_PIC_STRUCT_TOP_FIELD         = 1, ///<  1: top field
    SEI_PIC_STRUCT_BOTTOM_FIELD      = 2, ///<  2: bottom field
    SEI_PIC_STRUCT_TOP_BOTTOM        = 3, ///<  3: top field, bottom field, in that order
    SEI_PIC_STRUCT_BOTTOM_TOP        = 4, ///<  4: bottom field, top field, in that order
    SEI_PIC_STRUCT_TOP_BOTTOM_TOP    = 5, ///<  5: top field, bottom field, top field repeated, in that order
    SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM = 6, ///<  6: bottom field, top field, bottom field repeated, in that order
    SEI_PIC_STRUCT_FRAME_DOUBLING    = 7, ///<  7: %frame doubling
    SEI_PIC_STRUCT_FRAME_TRIPLING    = 8  ///<  8: %frame tripling
} SEI_PicStructType;

/**
 * Sequence parameter set
 */
typedef struct SPS{

    int profile_idc;
    int level_idc;
    int chroma_format_idc;
    int transform_bypass;              ///< qpprime_y_zero_transform_bypass_flag
    int log2_max_frame_num;            ///< log2_max_frame_num_minus4 + 4
    int poc_type;                      ///< pic_order_cnt_type
    int log2_max_poc_lsb;              ///< log2_max_pic_order_cnt_lsb_minus4
    int delta_pic_order_always_zero_flag;
    int offset_for_non_ref_pic;
    int offset_for_top_to_bottom_field;
    int poc_cycle_length;              ///< num_ref_frames_in_pic_order_cnt_cycle
    int ref_frame_count;               ///< num_ref_frames
    int gaps_in_frame_num_allowed_flag;
    int mb_width;                      ///< pic_width_in_mbs_minus1 + 1
    int mb_height;                     ///< pic_height_in_map_units_minus1 + 1
    int frame_mbs_only_flag;
    int mb_aff;                        ///<mb_adaptive_frame_field_flag
    int direct_8x8_inference_flag;
    int crop;                   ///< frame_cropping_flag
    unsigned int crop_left;            ///< frame_cropping_rect_left_offset
    unsigned int crop_right;           ///< frame_cropping_rect_right_offset
    unsigned int crop_top;             ///< frame_cropping_rect_top_offset
    unsigned int crop_bottom;          ///< frame_cropping_rect_bottom_offset
    int vui_parameters_present_flag;
    AVRational sar;
    int video_signal_type_present_flag;
    int full_range;
    int colour_description_present_flag;
    enum AVColorPrimaries color_primaries;
    enum AVColorTransferCharacteristic color_trc;
    enum AVColorSpace colorspace;
    int timing_info_present_flag;
    uint32_t num_units_in_tick;
    uint32_t time_scale;
    int fixed_frame_rate_flag;
    short offset_for_ref_frame[256]; //FIXME dyn aloc?
    int bitstream_restriction_flag;
    int num_reorder_frames;
    int scaling_matrix_present;
    uint8_t scaling_matrix4[6][16];
    uint8_t scaling_matrix8[2][64];
    int nal_hrd_parameters_present_flag;
    int vcl_hrd_parameters_present_flag;
    int pic_struct_present_flag;
    int time_offset_length;
    int cpb_cnt;                       ///< See H.264 E.1.2
    int initial_cpb_removal_delay_length; ///< initial_cpb_removal_delay_length_minus1 +1
    int cpb_removal_delay_length;      ///< cpb_removal_delay_length_minus1 + 1
    int dpb_output_delay_length;       ///< dpb_output_delay_length_minus1 + 1
    int bit_depth_luma;                ///< bit_depth_luma_minus8 + 8
    int bit_depth_chroma;              ///< bit_depth_chroma_minus8 + 8
    int residual_color_transform_flag; ///< residual_colour_transform_flag
}SPS;

/**
 * Picture parameter set
 */
typedef struct PPS{
    unsigned int sps_id;
    int cabac;                  ///< entropy_coding_mode_flag
    int pic_order_present;      ///< pic_order_present_flag
    int slice_group_count;      ///< num_slice_groups_minus1 + 1
    int mb_slice_group_map_type;
    unsigned int ref_count[2];  ///< num_ref_idx_l0/1_active_minus1 + 1
    int weighted_pred;          ///< weighted_pred_flag
    int weighted_bipred_idc;
    int init_qp;                ///< pic_init_qp_minus26 + 26
    int init_qs;                ///< pic_init_qs_minus26 + 26
    int chroma_qp_index_offset[2];
    int deblocking_filter_parameters_present; ///< deblocking_filter_parameters_present_flag
    int constrained_intra_pred; ///< constrained_intra_pred_flag
    int redundant_pic_cnt_present; ///< redundant_pic_cnt_present_flag
    int transform_8x8_mode;     ///< transform_8x8_mode_flag
    uint8_t scaling_matrix4[6][16];
    uint8_t scaling_matrix8[2][64];
    uint8_t chroma_qp_table[2][64];  ///< pre-scaled (with chroma_qp_index_offset) version of qp_table
    int chroma_qp_diff;
}PPS;

/**
 * Memory management control operation opcode.
 */
typedef enum MMCOOpcode{
    MMCO_END=0,
    MMCO_SHORT2UNUSED,
    MMCO_LONG2UNUSED,
    MMCO_SHORT2LONG,
    MMCO_SET_MAX_LONG,
    MMCO_RESET,
    MMCO_LONG,
} MMCOOpcode;

/**
 * Memory management control operation.
 */
typedef struct MMCO{
    MMCOOpcode opcode;
    int short_pic_num;  ///< pic_num without wrapping (pic_num & max_pic_num)
    int long_arg;       ///< index, pic_num, or num long refs depending on opcode
} MMCO;

/**
 * H264Context
 */
typedef struct H264Context{
    MpegEncContext s;
    int nal_ref_idc;
    int nal_unit_type;
    uint8_t *rbsp_buffer[2];
    unsigned int rbsp_buffer_size[2];

    /**
      * Used to parse AVC variant of h264
      */
    int is_avc; ///< this flag is != 0 if codec is avc1
    int got_avcC; ///< flag used to parse avcC data only once
    int nal_length_size; ///< Number of bytes used for nal length (1, 2 or 4)

    int chroma_qp[2]; //QPc

    int qp_thresh;      ///< QP threshold to skip loopfilter

    int prev_mb_skipped;
    int next_mb_skipped;

    //prediction stuff
    int chroma_pred_mode;
    int intra16x16_pred_mode;

    int topleft_mb_xy;
    int top_mb_xy;
    int topright_mb_xy;
    int left_mb_xy[2];

    int topleft_type;
    int top_type;
    int topright_type;
    int left_type[2];

    const uint8_t * left_block;
    int topleft_partition;

    int8_t intra4x4_pred_mode_cache[5*8];
    int8_t (*intra4x4_pred_mode)[8];
    H264PredContext hpc;
    unsigned int topleft_samples_available;
    unsigned int top_samples_available;
    unsigned int topright_samples_available;
    unsigned int left_samples_available;
    uint8_t (*top_borders[2])[16+2*8];
    uint8_t left_border[2*(17+2*9)];

    /**
     * non zero coeff count cache.
     * is 64 if not available.
     */
    DECLARE_ALIGNED_8(uint8_t, non_zero_count_cache)[6*8];

    /*
    .UU.YYYY
    .UU.YYYY
    .vv.YYYY
    .VV.YYYY
    */
    uint8_t (*non_zero_count)[32];

    /**
     * Motion vector cache.
     */
    DECLARE_ALIGNED_16(int16_t, mv_cache)[2][5*8][2];
    DECLARE_ALIGNED_8(int8_t, ref_cache)[2][5*8];
#define LIST_NOT_USED -1 //FIXME rename?
#define PART_NOT_AVAILABLE -2

    /**
     * is 1 if the specific list MV&references are set to 0,0,-2.
     */
    int mv_cache_clean[2];

    /**
     * number of neighbors (top and/or left) that used 8x8 dct
     */
    int neighbor_transform_size;

    /**
     * block_offset[ 0..23] for frame macroblocks
     * block_offset[24..47] for field macroblocks
     */
    int block_offset[2*(16+8)];

    uint32_t *mb2b_xy; //FIXME are these 4 a good idea?
    uint32_t *mb2b8_xy;
    int b_stride; //FIXME use s->b4_stride
    int b8_stride;

    int mb_linesize;   ///< may be equal to s->linesize or s->linesize*2, for mbaff
    int mb_uvlinesize;

    int emu_edge_width;
    int emu_edge_height;

    int halfpel_flag;
    int thirdpel_flag;

    int unknown_svq3_flag;
    int next_slice_index;

    SPS *sps_buffers[MAX_SPS_COUNT];
    SPS sps; ///< current sps

    PPS *pps_buffers[MAX_PPS_COUNT];
    /**
     * current pps
     */
    PPS pps; //FIXME move to Picture perhaps? (->no) do we need that?

    uint32_t dequant4_buffer[6][52][16];
    uint32_t dequant8_buffer[2][52][64];
    uint32_t (*dequant4_coeff[6])[16];
    uint32_t (*dequant8_coeff[2])[64];
    int dequant_coeff_pps;     ///< reinit tables when pps changes

    int slice_num;
    uint16_t *slice_table_base;
    uint16_t *slice_table;     ///< slice_table_base + 2*mb_stride + 1
    int slice_type;
    int slice_type_nos;        ///< S free slice type (SI/SP are remapped to I/P)
    int slice_type_fixed;

    //interlacing specific flags
    int mb_aff_frame;
    int mb_field_decoding_flag;
    int mb_mbaff;              ///< mb_aff_frame && mb_field_decoding_flag

    DECLARE_ALIGNED_8(uint16_t, sub_mb_type)[4];

    //POC stuff
    int poc_lsb;
    int poc_msb;
    int delta_poc_bottom;
    int delta_poc[2];
    int frame_num;
    int prev_poc_msb;             ///< poc_msb of the last reference pic for POC type 0
    int prev_poc_lsb;             ///< poc_lsb of the last reference pic for POC type 0
    int frame_num_offset;         ///< for POC type 2
    int prev_frame_num_offset;    ///< for POC type 2
    int prev_frame_num;           ///< frame_num of the last pic for POC type 1/2

    /**
     * frame_num for frames or 2*frame_num+1 for field pics.
     */
    int curr_pic_num;

    /**
     * max_frame_num or 2*max_frame_num for field pics.
     */
    int max_pic_num;

    //Weighted pred stuff
    int use_weight;
    int use_weight_chroma;
    int luma_log2_weight_denom;
    int chroma_log2_weight_denom;
    int luma_weight[2][48];
    int luma_offset[2][48];
    int chroma_weight[2][48][2];
    int chroma_offset[2][48][2];
    int implicit_weight[48][48];

    //deblock
    int deblocking_filter;         ///< disable_deblocking_filter_idc with 1<->0
    int slice_alpha_c0_offset;
    int slice_beta_offset;

    int redundant_pic_count;

    int direct_spatial_mv_pred;
    int col_parity;
    int col_fieldoff;
    int dist_scale_factor[16];
    int dist_scale_factor_field[2][32];
    int map_col_to_list0[2][16+32];
    int map_col_to_list0_field[2][2][16+32];

    /**
     * num_ref_idx_l0/1_active_minus1 + 1
     */
    unsigned int ref_count[2];   ///< counts frames or fields, depending on current mb mode
    unsigned int list_count;
    uint8_t *list_counts;            ///< Array of list_count per MB specifying the slice type
    Picture *short_ref[32];
    Picture *long_ref[32];
    Picture default_ref_list[2][32]; ///< base reference list for all slices of a coded picture
    Picture ref_list[2][48];         /**< 0..15: frame refs, 16..47: mbaff field refs.
                                          Reordered version of default_ref_list
                                          according to picture reordering in slice header */
    int ref2frm[MAX_SLICES][2][64];  ///< reference to frame number lists, used in the loop filter, the first 2 are for -2,-1
    Picture *delayed_pic[MAX_DELAYED_PIC_COUNT+2]; //FIXME size?
    int outputed_poc;

    /**
     * memory management control operations buffer.
     */
    MMCO mmco[MAX_MMCO_COUNT];
    int mmco_index;

    int long_ref_count;  ///< number of actual long term references
    int short_ref_count; ///< number of actual short term references

    //data partitioning
    GetBitContext intra_gb;
    GetBitContext inter_gb;
    GetBitContext *intra_gb_ptr;
    GetBitContext *inter_gb_ptr;

    DECLARE_ALIGNED_16(DCTELEM, mb)[16*24];
    DCTELEM mb_padding[256];        ///< as mb is addressed by scantable[i] and scantable is uint8_t we can either check that i is not too large or ensure that there is some unused stuff after mb

    /**
     * Cabac
     */
    CABACContext cabac;
    uint8_t      cabac_state[460];
    int          cabac_init_idc;

    /* 0x100 -> non null luma_dc, 0x80/0x40 -> non null chroma_dc (cb/cr), 0x?0 -> chroma_cbp(0,1,2), 0x0? luma_cbp */
    uint16_t     *cbp_table;
    int cbp;
    int top_cbp;
    int left_cbp;
    /* chroma_pred_mode for i4x4 or i16x16, else 0 */
    uint8_t     *chroma_pred_mode_table;
    int         last_qscale_diff;
    int16_t     (*mvd_table[2])[2];
    DECLARE_ALIGNED_16(int16_t, mvd_cache)[2][5*8][2];
    uint8_t     *direct_table;
    uint8_t     direct_cache[5*8];

    uint8_t zigzag_scan[16];
    uint8_t zigzag_scan8x8[64];
    uint8_t zigzag_scan8x8_cavlc[64];
    uint8_t field_scan[16];
    uint8_t field_scan8x8[64];
    uint8_t field_scan8x8_cavlc[64];
    const uint8_t *zigzag_scan_q0;
    const uint8_t *zigzag_scan8x8_q0;
    const uint8_t *zigzag_scan8x8_cavlc_q0;
    const uint8_t *field_scan_q0;
    const uint8_t *field_scan8x8_q0;
    const uint8_t *field_scan8x8_cavlc_q0;

    int x264_build;

    /**
     * @defgroup multithreading Members for slice based multithreading
     * @{
     */
    struct H264Context *thread_context[MAX_THREADS];

    /**
     * current slice number, used to initalize slice_num of each thread/context
     */
    int current_slice;

    /**
     * Max number of threads / contexts.
     * This is equal to AVCodecContext.thread_count unless
     * multithreaded decoding is impossible, in which case it is
     * reduced to 1.
     */
    int max_contexts;

    /**
     *  1 if the single thread fallback warning has already been
     *  displayed, 0 otherwise.
     */
    int single_decode_warning;

    int last_slice_type;
    /** @} */

    int mb_xy;

    uint32_t svq3_watermark_key;

    /**
     * pic_struct in picture timing SEI message
     */
    SEI_PicStructType sei_pic_struct;

    /**
     * Complement sei_pic_struct
     * SEI_PIC_STRUCT_TOP_BOTTOM and SEI_PIC_STRUCT_BOTTOM_TOP indicate interlaced frames.
     * However, soft telecined frames may have these values.
     * This is used in an attempt to flag soft telecine progressive.
     */
    int prev_interlaced_frame;

    /**
     * Bit set of clock types for fields/frames in picture timing SEI message.
     * For each found ct_type, appropriate bit is set (e.g., bit 1 for
     * interlaced).
     */
    int sei_ct_type;

    /**
     * dpb_output_delay in picture timing SEI message, see H.264 C.2.2
     */
    int sei_dpb_output_delay;

    /**
     * cpb_removal_delay in picture timing SEI message, see H.264 C.1.2
     */
    int sei_cpb_removal_delay;

    /**
     * recovery_frame_cnt from SEI message
     *
     * Set to -1 if no recovery point SEI message found or to number of frames
     * before playback synchronizes. Frames having recovery point are key
     * frames.
     */
    int sei_recovery_frame_cnt;

    int is_complex;

    int luma_weight_flag[2];   ///< 7.4.3.2 luma_weight_lX_flag
    int chroma_weight_flag[2]; ///< 7.4.3.2 chroma_weight_lX_flag

    // Timestamp stuff
    int sei_buffering_period_present;  ///< Buffering period SEI flag
    int initial_cpb_removal_delay[32]; ///< Initial timestamps for CPBs
}H264Context;


extern const uint8_t ff_h264_chroma_qp[52];

void ff_svq3_luma_dc_dequant_idct_c(DCTELEM *block, int qp);

void ff_svq3_add_idct_c(uint8_t *dst, DCTELEM *block, int stride, int qp, int dc);

/**
 * Decode SEI
 */
int ff_h264_decode_sei(H264Context *h);

/**
 * Decode SPS
 */
int ff_h264_decode_seq_parameter_set(H264Context *h);

/**
 * Decode PPS
 */
int ff_h264_decode_picture_parameter_set(H264Context *h, int bit_length);

/**
 * Decodes a network abstraction layer unit.
 * @param consumed is the number of bytes used as input
 * @param length is the length of the array
 * @param dst_length is the number of decoded bytes FIXME here or a decode rbsp tailing?
 * @returns decoded bytes, might be src+1 if no escapes
 */
const uint8_t *ff_h264_decode_nal(H264Context *h, const uint8_t *src, int *dst_length, int *consumed, int length);

/**
 * identifies the exact end of the bitstream
 * @return the length of the trailing, or 0 if damaged
 */
int ff_h264_decode_rbsp_trailing(H264Context *h, const uint8_t *src);

/**
 * frees any data that may have been allocated in the H264 context like SPS, PPS etc.
 */
av_cold void ff_h264_free_context(H264Context *h);

/**
 * reconstructs bitstream slice_type.
 */
int ff_h264_get_slice_type(const H264Context *h);

/**
 * allocates tables.
 * needs width/height
 */
int ff_h264_alloc_tables(H264Context *h);

/**
 * fills the default_ref_list.
 */
int ff_h264_fill_default_ref_list(H264Context *h);

int ff_h264_decode_ref_pic_list_reordering(H264Context *h);
void ff_h264_fill_mbaff_ref_list(H264Context *h);
void ff_h264_remove_all_refs(H264Context *h);

/**
 * Executes the reference picture marking (memory management control operations).
 */
int ff_h264_execute_ref_pic_marking(H264Context *h, MMCO *mmco, int mmco_count);

int ff_h264_decode_ref_pic_marking(H264Context *h, GetBitContext *gb);


/**
 * checks if the top & left blocks are available if needed & changes the dc mode so it only uses the available blocks.
 */
int ff_h264_check_intra4x4_pred_mode(H264Context *h);

/**
 * checks if the top & left blocks are available if needed & changes the dc mode so it only uses the available blocks.
 */
int ff_h264_check_intra_pred_mode(H264Context *h, int mode);

void ff_h264_write_back_intra_pred_mode(H264Context *h);
void ff_h264_hl_decode_mb(H264Context *h);
int ff_h264_frame_start(H264Context *h);
av_cold int ff_h264_decode_init(AVCodecContext *avctx);
av_cold int ff_h264_decode_end(AVCodecContext *avctx);
av_cold void ff_h264_decode_init_vlc(void);

/**
 * decodes a macroblock
 * @returns 0 if OK, AC_ERROR / DC_ERROR / MV_ERROR if an error is noticed
 */
int ff_h264_decode_mb_cavlc(H264Context *h);

/**
 * decodes a CABAC coded macroblock
 * @returns 0 if OK, AC_ERROR / DC_ERROR / MV_ERROR if an error is noticed
 */
int ff_h264_decode_mb_cabac(H264Context *h);

void ff_h264_init_cabac_states(H264Context *h);

void ff_h264_direct_dist_scale_factor(H264Context * const h);
void ff_h264_direct_ref_list_init(H264Context * const h);
void ff_h264_pred_direct_motion(H264Context * const h, int *mb_type);

void ff_h264_filter_mb_fast( H264Context *h, int mb_x, int mb_y, uint8_t *img_y, uint8_t *img_cb, uint8_t *img_cr, unsigned int linesize, unsigned int uvlinesize);
void ff_h264_filter_mb( H264Context *h, int mb_x, int mb_y, uint8_t *img_y, uint8_t *img_cb, uint8_t *img_cr, unsigned int linesize, unsigned int uvlinesize);

/**
 * Reset SEI values at the beginning of the frame.
 *
 * @param h H.264 context.
 */
void ff_h264_reset_sei(H264Context *h);


/*
o-o o-o
 / / /
o-o o-o
 ,---'
o-o o-o
 / / /
o-o o-o
*/
//This table must be here because scan8[constant] must be known at compiletime
static const uint8_t scan8[16 + 2*4]={
 4+1*8, 5+1*8, 4+2*8, 5+2*8,
 6+1*8, 7+1*8, 6+2*8, 7+2*8,
 4+3*8, 5+3*8, 4+4*8, 5+4*8,
 6+3*8, 7+3*8, 6+4*8, 7+4*8,
 1+1*8, 2+1*8,
 1+2*8, 2+2*8,
 1+4*8, 2+4*8,
 1+5*8, 2+5*8,
};

static av_always_inline uint32_t pack16to32(int a, int b){
#if HAVE_BIGENDIAN
   return (b&0xFFFF) + (a<<16);
#else
   return (a&0xFFFF) + (b<<16);
#endif
}

/**
 * gets the chroma qp.
 */
static inline int get_chroma_qp(H264Context *h, int t, int qscale){
    return h->pps.chroma_qp_table[t][qscale];
}

static inline void pred_pskip_motion(H264Context * const h, int * const mx, int * const my);

static void fill_decode_neighbors(H264Context *h, int mb_type){
    MpegEncContext * const s = &h->s;
    const int mb_xy= h->mb_xy;
    int topleft_xy, top_xy, topright_xy, left_xy[2];
    static const uint8_t left_block_options[4][16]={
        {0,1,2,3,7,10,8,11,7+0*8, 7+1*8, 7+2*8, 7+3*8, 2+0*8, 2+3*8, 2+1*8, 2+2*8},
        {2,2,3,3,8,11,8,11,7+2*8, 7+2*8, 7+3*8, 7+3*8, 2+1*8, 2+2*8, 2+1*8, 2+2*8},
        {0,0,1,1,7,10,7,10,7+0*8, 7+0*8, 7+1*8, 7+1*8, 2+0*8, 2+3*8, 2+0*8, 2+3*8},
        {0,2,0,2,7,10,7,10,7+0*8, 7+2*8, 7+0*8, 7+2*8, 2+0*8, 2+3*8, 2+0*8, 2+3*8}
    };

    h->topleft_partition= -1;

    top_xy     = mb_xy  - (s->mb_stride << MB_FIELD);

    /* Wow, what a mess, why didn't they simplify the interlacing & intra
     * stuff, I can't imagine that these complex rules are worth it. */

    topleft_xy = top_xy - 1;
    topright_xy= top_xy + 1;
    left_xy[1] = left_xy[0] = mb_xy-1;
    h->left_block = left_block_options[0];
    if(FRAME_MBAFF){
        const int left_mb_field_flag     = IS_INTERLACED(s->current_picture.mb_type[mb_xy-1]);
        const int curr_mb_field_flag     = IS_INTERLACED(mb_type);
        if(s->mb_y&1){
            if (left_mb_field_flag != curr_mb_field_flag) {
                left_xy[1] = left_xy[0] = mb_xy - s->mb_stride - 1;
                if (curr_mb_field_flag) {
                    left_xy[1] += s->mb_stride;
                    h->left_block = left_block_options[3];
                } else {
                    topleft_xy += s->mb_stride;
                    // take top left mv from the middle of the mb, as opposed to all other modes which use the bottom right partition
                    h->topleft_partition = 0;
                    h->left_block = left_block_options[1];
                }
            }
        }else{
            if(curr_mb_field_flag){
                topleft_xy  += s->mb_stride & (((s->current_picture.mb_type[top_xy - 1]>>7)&1)-1);
                topright_xy += s->mb_stride & (((s->current_picture.mb_type[top_xy + 1]>>7)&1)-1);
                top_xy      += s->mb_stride & (((s->current_picture.mb_type[top_xy    ]>>7)&1)-1);
            }
            if (left_mb_field_flag != curr_mb_field_flag) {
                left_xy[1] = left_xy[0] = mb_xy - 1;
                if (curr_mb_field_flag) {
                    left_xy[1] += s->mb_stride;
                    h->left_block = left_block_options[3];
                } else {
                    h->left_block = left_block_options[2];
                }
            }
        }
    }

    h->topleft_mb_xy = topleft_xy;
    h->top_mb_xy     = top_xy;
    h->topright_mb_xy= topright_xy;
    h->left_mb_xy[0] = left_xy[0];
    h->left_mb_xy[1] = left_xy[1];
    //FIXME do we need all in the context?
    h->topleft_type = h->slice_table[topleft_xy ] == h->slice_num ? s->current_picture.mb_type[topleft_xy] : 0;
    h->top_type     = h->slice_table[top_xy     ] == h->slice_num ? s->current_picture.mb_type[top_xy]     : 0;
    h->topright_type= h->slice_table[topright_xy] == h->slice_num ? s->current_picture.mb_type[topright_xy]: 0;
    h->left_type[0] = h->slice_table[left_xy[0] ] == h->slice_num ? s->current_picture.mb_type[left_xy[0]] : 0;
    h->left_type[1] = h->slice_table[left_xy[1] ] == h->slice_num ? s->current_picture.mb_type[left_xy[1]] : 0;
}

static void fill_decode_caches(H264Context *h, int mb_type){
    MpegEncContext * const s = &h->s;
    int topleft_xy, top_xy, topright_xy, left_xy[2];
    int topleft_type, top_type, topright_type, left_type[2];
    const uint8_t * left_block= h->left_block;
    int i;

    topleft_xy   = h->topleft_mb_xy ;
    top_xy       = h->top_mb_xy     ;
    topright_xy  = h->topright_mb_xy;
    left_xy[0]   = h->left_mb_xy[0] ;
    left_xy[1]   = h->left_mb_xy[1] ;
    topleft_type = h->topleft_type  ;
    top_type     = h->top_type      ;
    topright_type= h->topright_type ;
    left_type[0] = h->left_type[0]  ;
    left_type[1] = h->left_type[1]  ;

    if(!IS_SKIP(mb_type)){
        if(IS_INTRA(mb_type)){
            int type_mask= h->pps.constrained_intra_pred ? IS_INTRA(-1) : -1;
            h->topleft_samples_available=
            h->top_samples_available=
            h->left_samples_available= 0xFFFF;
            h->topright_samples_available= 0xEEEA;

            if(!(top_type & type_mask)){
                h->topleft_samples_available= 0xB3FF;
                h->top_samples_available= 0x33FF;
                h->topright_samples_available= 0x26EA;
            }
            if(IS_INTERLACED(mb_type) != IS_INTERLACED(left_type[0])){
                if(IS_INTERLACED(mb_type)){
                    if(!(left_type[0] & type_mask)){
                        h->topleft_samples_available&= 0xDFFF;
                        h->left_samples_available&= 0x5FFF;
                    }
                    if(!(left_type[1] & type_mask)){
                        h->topleft_samples_available&= 0xFF5F;
                        h->left_samples_available&= 0xFF5F;
                    }
                }else{
                    int left_typei = h->slice_table[left_xy[0] + s->mb_stride ] == h->slice_num
                                    ? s->current_picture.mb_type[left_xy[0] + s->mb_stride] : 0;
                    assert(left_xy[0] == left_xy[1]);
                    if(!((left_typei & type_mask) && (left_type[0] & type_mask))){
                        h->topleft_samples_available&= 0xDF5F;
                        h->left_samples_available&= 0x5F5F;
                    }
                }
            }else{
                if(!(left_type[0] & type_mask)){
                    h->topleft_samples_available&= 0xDF5F;
                    h->left_samples_available&= 0x5F5F;
                }
            }

            if(!(topleft_type & type_mask))
                h->topleft_samples_available&= 0x7FFF;

            if(!(topright_type & type_mask))
                h->topright_samples_available&= 0xFBFF;

            if(IS_INTRA4x4(mb_type)){
                if(IS_INTRA4x4(top_type)){
                    h->intra4x4_pred_mode_cache[4+8*0]= h->intra4x4_pred_mode[top_xy][4];
                    h->intra4x4_pred_mode_cache[5+8*0]= h->intra4x4_pred_mode[top_xy][5];
                    h->intra4x4_pred_mode_cache[6+8*0]= h->intra4x4_pred_mode[top_xy][6];
                    h->intra4x4_pred_mode_cache[7+8*0]= h->intra4x4_pred_mode[top_xy][3];
                }else{
                    int pred;
                    if(!(top_type & type_mask))
                        pred= -1;
                    else{
                        pred= 2;
                    }
                    h->intra4x4_pred_mode_cache[4+8*0]=
                    h->intra4x4_pred_mode_cache[5+8*0]=
                    h->intra4x4_pred_mode_cache[6+8*0]=
                    h->intra4x4_pred_mode_cache[7+8*0]= pred;
                }
                for(i=0; i<2; i++){
                    if(IS_INTRA4x4(left_type[i])){
                        h->intra4x4_pred_mode_cache[3+8*1 + 2*8*i]= h->intra4x4_pred_mode[left_xy[i]][left_block[0+2*i]];
                        h->intra4x4_pred_mode_cache[3+8*2 + 2*8*i]= h->intra4x4_pred_mode[left_xy[i]][left_block[1+2*i]];
                    }else{
                        int pred;
                        if(!(left_type[i] & type_mask))
                            pred= -1;
                        else{
                            pred= 2;
                        }
                        h->intra4x4_pred_mode_cache[3+8*1 + 2*8*i]=
                        h->intra4x4_pred_mode_cache[3+8*2 + 2*8*i]= pred;
                    }
                }
            }
        }


/*
0 . T T. T T T T
1 L . .L . . . .
2 L . .L . . . .
3 . T TL . . . .
4 L . .L . . . .
5 L . .. . . . .
*/
//FIXME constraint_intra_pred & partitioning & nnz (let us hope this is just a typo in the spec)
    if(top_type){
        AV_COPY32(&h->non_zero_count_cache[4+8*0], &h->non_zero_count[top_xy][4+3*8]);
            h->non_zero_count_cache[1+8*0]= h->non_zero_count[top_xy][1+1*8];
            h->non_zero_count_cache[2+8*0]= h->non_zero_count[top_xy][2+1*8];

            h->non_zero_count_cache[1+8*3]= h->non_zero_count[top_xy][1+2*8];
            h->non_zero_count_cache[2+8*3]= h->non_zero_count[top_xy][2+2*8];
    }else {
            h->non_zero_count_cache[1+8*0]=
            h->non_zero_count_cache[2+8*0]=

            h->non_zero_count_cache[1+8*3]=
            h->non_zero_count_cache[2+8*3]=
            AV_WN32A(&h->non_zero_count_cache[4+8*0], CABAC && !IS_INTRA(mb_type) ? 0 : 0x40404040);
    }

    for (i=0; i<2; i++) {
        if(left_type[i]){
            h->non_zero_count_cache[3+8*1 + 2*8*i]= h->non_zero_count[left_xy[i]][left_block[8+0+2*i]];
            h->non_zero_count_cache[3+8*2 + 2*8*i]= h->non_zero_count[left_xy[i]][left_block[8+1+2*i]];
                h->non_zero_count_cache[0+8*1 +   8*i]= h->non_zero_count[left_xy[i]][left_block[8+4+2*i]];
                h->non_zero_count_cache[0+8*4 +   8*i]= h->non_zero_count[left_xy[i]][left_block[8+5+2*i]];
        }else{
                h->non_zero_count_cache[3+8*1 + 2*8*i]=
                h->non_zero_count_cache[3+8*2 + 2*8*i]=
                h->non_zero_count_cache[0+8*1 +   8*i]=
                h->non_zero_count_cache[0+8*4 +   8*i]= CABAC && !IS_INTRA(mb_type) ? 0 : 64;
        }
    }

    if( CABAC ) {
        // top_cbp
        if(top_type) {
            h->top_cbp = h->cbp_table[top_xy];
        } else if(IS_INTRA(mb_type)) {
            h->top_cbp = 0x1CF;
        } else {
            h->top_cbp = 0x00F;
        }
        // left_cbp
        if (left_type[0]) {
            h->left_cbp = h->cbp_table[left_xy[0]] & 0x1f0;
        } else if(IS_INTRA(mb_type)) {
            h->left_cbp = 0x1CF;
        } else {
            h->left_cbp = 0x00F;
        }
        if (left_type[0]) {
            h->left_cbp |= ((h->cbp_table[left_xy[0]]>>((left_block[0]&(~1))+1))&0x1) << 1;
        }
        if (left_type[1]) {
            h->left_cbp |= ((h->cbp_table[left_xy[1]]>>((left_block[2]&(~1))+1))&0x1) << 3;
        }
    }
    }

#if 1
    if(IS_INTER(mb_type) || (IS_DIRECT(mb_type) && h->direct_spatial_mv_pred)){
        int list;
        for(list=0; list<h->list_count; list++){
            if(!USES_LIST(mb_type, list)){
                /*if(!h->mv_cache_clean[list]){
                    memset(h->mv_cache [list],  0, 8*5*2*sizeof(int16_t)); //FIXME clean only input? clean at all?
                    memset(h->ref_cache[list], PART_NOT_AVAILABLE, 8*5*sizeof(int8_t));
                    h->mv_cache_clean[list]= 1;
                }*/
                continue;
            }
            assert(!(IS_DIRECT(mb_type) && !h->direct_spatial_mv_pred));

            h->mv_cache_clean[list]= 0;

            if(USES_LIST(top_type, list)){
                const int b_xy= h->mb2b_xy[top_xy] + 3*h->b_stride;
                const int b8_xy= h->mb2b8_xy[top_xy] + h->b8_stride;
                AV_COPY128(h->mv_cache[list][scan8[0] + 0 - 1*8], s->current_picture.motion_val[list][b_xy + 0]);
                    h->ref_cache[list][scan8[0] + 0 - 1*8]=
                    h->ref_cache[list][scan8[0] + 1 - 1*8]= s->current_picture.ref_index[list][b8_xy + 0];
                    h->ref_cache[list][scan8[0] + 2 - 1*8]=
                    h->ref_cache[list][scan8[0] + 3 - 1*8]= s->current_picture.ref_index[list][b8_xy + 1];
            }else{
                AV_ZERO128(h->mv_cache[list][scan8[0] + 0 - 1*8]);
                AV_WN32A(&h->ref_cache[list][scan8[0] + 0 - 1*8], ((top_type ? LIST_NOT_USED : PART_NOT_AVAILABLE)&0xFF)*0x01010101);
            }

            for(i=0; i<2; i++){
                int cache_idx = scan8[0] - 1 + i*2*8;
                if(USES_LIST(left_type[i], list)){
                    const int b_xy= h->mb2b_xy[left_xy[i]] + 3;
                    const int b8_xy= h->mb2b8_xy[left_xy[i]] + 1;
                    AV_COPY32(h->mv_cache[list][cache_idx  ], s->current_picture.motion_val[list][b_xy + h->b_stride*left_block[0+i*2]]);
                    AV_COPY32(h->mv_cache[list][cache_idx+8], s->current_picture.motion_val[list][b_xy + h->b_stride*left_block[1+i*2]]);
                        h->ref_cache[list][cache_idx  ]= s->current_picture.ref_index[list][b8_xy + h->b8_stride*(left_block[0+i*2]>>1)];
                        h->ref_cache[list][cache_idx+8]= s->current_picture.ref_index[list][b8_xy + h->b8_stride*(left_block[1+i*2]>>1)];
                }else{
                    AV_ZERO32(h->mv_cache [list][cache_idx  ]);
                    AV_ZERO32(h->mv_cache [list][cache_idx+8]);
                    h->ref_cache[list][cache_idx  ]=
                    h->ref_cache[list][cache_idx+8]= (left_type[i]) ? LIST_NOT_USED : PART_NOT_AVAILABLE;
                }
            }

            if(USES_LIST(topleft_type, list)){
                const int b_xy = h->mb2b_xy [topleft_xy] + 3 + h->b_stride + (h->topleft_partition & 2*h->b_stride);
                const int b8_xy= h->mb2b8_xy[topleft_xy] + 1 + (h->topleft_partition & h->b8_stride);
                AV_COPY32(h->mv_cache[list][scan8[0] - 1 - 1*8], s->current_picture.motion_val[list][b_xy]);
                h->ref_cache[list][scan8[0] - 1 - 1*8]= s->current_picture.ref_index[list][b8_xy];
            }else{
                AV_ZERO32(h->mv_cache[list][scan8[0] - 1 - 1*8]);
                h->ref_cache[list][scan8[0] - 1 - 1*8]= topleft_type ? LIST_NOT_USED : PART_NOT_AVAILABLE;
            }

            if(USES_LIST(topright_type, list)){
                const int b_xy= h->mb2b_xy[topright_xy] + 3*h->b_stride;
                const int b8_xy= h->mb2b8_xy[topright_xy] + h->b8_stride;
                AV_COPY32(h->mv_cache[list][scan8[0] + 4 - 1*8], s->current_picture.motion_val[list][b_xy]);
                h->ref_cache[list][scan8[0] + 4 - 1*8]= s->current_picture.ref_index[list][b8_xy];
            }else{
                AV_ZERO32(h->mv_cache [list][scan8[0] + 4 - 1*8]);
                h->ref_cache[list][scan8[0] + 4 - 1*8]= topright_type ? LIST_NOT_USED : PART_NOT_AVAILABLE;
            }

            if((mb_type&(MB_TYPE_SKIP|MB_TYPE_DIRECT2)) && !FRAME_MBAFF)
                continue;

            if(!(mb_type&(MB_TYPE_SKIP|MB_TYPE_DIRECT2))) {
            h->ref_cache[list][scan8[5 ]+1] =
            h->ref_cache[list][scan8[7 ]+1] =
            h->ref_cache[list][scan8[13]+1] =  //FIXME remove past 3 (init somewhere else)
            h->ref_cache[list][scan8[4 ]] =
            h->ref_cache[list][scan8[12]] = PART_NOT_AVAILABLE;
            AV_ZERO32(h->mv_cache [list][scan8[5 ]+1]);
            AV_ZERO32(h->mv_cache [list][scan8[7 ]+1]);
            AV_ZERO32(h->mv_cache [list][scan8[13]+1]); //FIXME remove past 3 (init somewhere else)
            AV_ZERO32(h->mv_cache [list][scan8[4 ]]);
            AV_ZERO32(h->mv_cache [list][scan8[12]]);

            if( CABAC ) {
                /* XXX beurk, Load mvd */
                if(USES_LIST(top_type, list)){
                    const int b_xy= h->mb2b_xy[top_xy] + 3*h->b_stride;
                    AV_COPY128(h->mvd_cache[list][scan8[0] + 0 - 1*8], h->mvd_table[list][b_xy + 0]);
                }else{
                    AV_ZERO128(h->mvd_cache[list][scan8[0] + 0 - 1*8]);
                }
                if(USES_LIST(left_type[0], list)){
                    const int b_xy= h->mb2b_xy[left_xy[0]] + 3;
                    AV_COPY32(h->mvd_cache[list][scan8[0] - 1 + 0*8], h->mvd_table[list][b_xy + h->b_stride*left_block[0]]);
                    AV_COPY32(h->mvd_cache[list][scan8[0] - 1 + 1*8], h->mvd_table[list][b_xy + h->b_stride*left_block[1]]);
                }else{
                    AV_ZERO32(h->mvd_cache [list][scan8[0] - 1 + 0*8]);
                    AV_ZERO32(h->mvd_cache [list][scan8[0] - 1 + 1*8]);
                }
                if(USES_LIST(left_type[1], list)){
                    const int b_xy= h->mb2b_xy[left_xy[1]] + 3;
                    AV_COPY32(h->mvd_cache[list][scan8[0] - 1 + 2*8], h->mvd_table[list][b_xy + h->b_stride*left_block[2]]);
                    AV_COPY32(h->mvd_cache[list][scan8[0] - 1 + 3*8], h->mvd_table[list][b_xy + h->b_stride*left_block[3]]);
                }else{
                    AV_ZERO32(h->mvd_cache [list][scan8[0] - 1 + 2*8]);
                    AV_ZERO32(h->mvd_cache [list][scan8[0] - 1 + 3*8]);
                }
                AV_ZERO32(h->mvd_cache [list][scan8[5 ]+1]);
                AV_ZERO32(h->mvd_cache [list][scan8[7 ]+1]);
                AV_ZERO32(h->mvd_cache [list][scan8[13]+1]); //FIXME remove past 3 (init somewhere else)
                AV_ZERO32(h->mvd_cache [list][scan8[4 ]]);
                AV_ZERO32(h->mvd_cache [list][scan8[12]]);

                if(h->slice_type_nos == FF_B_TYPE){
                    fill_rectangle(&h->direct_cache[scan8[0]], 4, 4, 8, MB_TYPE_16x16>>1, 1);

                    if(IS_DIRECT(top_type)){
                        AV_WN32A(&h->direct_cache[scan8[0] - 1*8], 0x01010101*(MB_TYPE_DIRECT2>>1));
                    }else if(IS_8X8(top_type)){
                        int b8_xy = h->mb2b8_xy[top_xy] + h->b8_stride;
                        h->direct_cache[scan8[0] + 0 - 1*8]= h->direct_table[b8_xy];
                        h->direct_cache[scan8[0] + 2 - 1*8]= h->direct_table[b8_xy + 1];
                    }else{
                        AV_WN32A(&h->direct_cache[scan8[0] - 1*8], 0x01010101*(MB_TYPE_16x16>>1));
                    }

                    if(IS_DIRECT(left_type[0]))
                        h->direct_cache[scan8[0] - 1 + 0*8]= MB_TYPE_DIRECT2>>1;
                    else if(IS_8X8(left_type[0]))
                        h->direct_cache[scan8[0] - 1 + 0*8]= h->direct_table[h->mb2b8_xy[left_xy[0]] + 1 + h->b8_stride*(left_block[0]>>1)];
                    else
                        h->direct_cache[scan8[0] - 1 + 0*8]= MB_TYPE_16x16>>1;

                    if(IS_DIRECT(left_type[1]))
                        h->direct_cache[scan8[0] - 1 + 2*8]= MB_TYPE_DIRECT2>>1;
                    else if(IS_8X8(left_type[1]))
                        h->direct_cache[scan8[0] - 1 + 2*8]= h->direct_table[h->mb2b8_xy[left_xy[1]] + 1 + h->b8_stride*(left_block[2]>>1)];
                    else
                        h->direct_cache[scan8[0] - 1 + 2*8]= MB_TYPE_16x16>>1;
                }
            }
            }
            if(FRAME_MBAFF){
#define MAP_MVS\
                    MAP_F2F(scan8[0] - 1 - 1*8, topleft_type)\
                    MAP_F2F(scan8[0] + 0 - 1*8, top_type)\
                    MAP_F2F(scan8[0] + 1 - 1*8, top_type)\
                    MAP_F2F(scan8[0] + 2 - 1*8, top_type)\
                    MAP_F2F(scan8[0] + 3 - 1*8, top_type)\
                    MAP_F2F(scan8[0] + 4 - 1*8, topright_type)\
                    MAP_F2F(scan8[0] - 1 + 0*8, left_type[0])\
                    MAP_F2F(scan8[0] - 1 + 1*8, left_type[0])\
                    MAP_F2F(scan8[0] - 1 + 2*8, left_type[1])\
                    MAP_F2F(scan8[0] - 1 + 3*8, left_type[1])
                if(MB_FIELD){
#define MAP_F2F(idx, mb_type)\
                    if(!IS_INTERLACED(mb_type) && h->ref_cache[list][idx] >= 0){\
                        h->ref_cache[list][idx] <<= 1;\
                        h->mv_cache[list][idx][1] /= 2;\
                        h->mvd_cache[list][idx][1] /= 2;\
                    }
                    MAP_MVS
#undef MAP_F2F
                }else{
#define MAP_F2F(idx, mb_type)\
                    if(IS_INTERLACED(mb_type) && h->ref_cache[list][idx] >= 0){\
                        h->ref_cache[list][idx] >>= 1;\
                        h->mv_cache[list][idx][1] <<= 1;\
                        h->mvd_cache[list][idx][1] <<= 1;\
                    }
                    MAP_MVS
#undef MAP_F2F
                }
            }
        }
    }
#endif

        h->neighbor_transform_size= !!IS_8x8DCT(top_type) + !!IS_8x8DCT(left_type[0]);
}

/**
 *
 * @returns non zero if the loop filter can be skiped
 */
static int fill_filter_caches(H264Context *h, int mb_type){
    MpegEncContext * const s = &h->s;
    const int mb_xy= h->mb_xy;
    int top_xy, left_xy[2];
    int top_type, left_type[2];

    top_xy     = mb_xy  - (s->mb_stride << MB_FIELD);

    //FIXME deblocking could skip the intra and nnz parts.

    /* Wow, what a mess, why didn't they simplify the interlacing & intra
     * stuff, I can't imagine that these complex rules are worth it. */

    left_xy[1] = left_xy[0] = mb_xy-1;
    if(FRAME_MBAFF){
        const int left_mb_field_flag     = IS_INTERLACED(s->current_picture.mb_type[mb_xy-1]);
        const int curr_mb_field_flag     = IS_INTERLACED(mb_type);
        if(s->mb_y&1){
            if (left_mb_field_flag != curr_mb_field_flag) {
                left_xy[0] -= s->mb_stride;
            }
        }else{
            if(curr_mb_field_flag){
                top_xy      += s->mb_stride & (((s->current_picture.mb_type[top_xy    ]>>7)&1)-1);
            }
            if (left_mb_field_flag != curr_mb_field_flag) {
                left_xy[1] += s->mb_stride;
            }
        }
    }

    h->top_mb_xy = top_xy;
    h->left_mb_xy[0] = left_xy[0];
    h->left_mb_xy[1] = left_xy[1];
    {
        //for sufficiently low qp, filtering wouldn't do anything
        //this is a conservative estimate: could also check beta_offset and more accurate chroma_qp
        int qp_thresh = h->qp_thresh; //FIXME strictly we should store qp_thresh for each mb of a slice
        int qp = s->current_picture.qscale_table[mb_xy];
        if(qp <= qp_thresh
           && (left_xy[0]<0 || ((qp + s->current_picture.qscale_table[left_xy[0]] + 1)>>1) <= qp_thresh)
           && (top_xy   < 0 || ((qp + s->current_picture.qscale_table[top_xy    ] + 1)>>1) <= qp_thresh)){
            if(!FRAME_MBAFF)
                return 1;
            if(   (left_xy[0]< 0            || ((qp + s->current_picture.qscale_table[left_xy[1]             ] + 1)>>1) <= qp_thresh)
               && (top_xy    < s->mb_stride || ((qp + s->current_picture.qscale_table[top_xy    -s->mb_stride] + 1)>>1) <= qp_thresh))
                return 1;
        }
    }

    if(h->deblocking_filter == 2){
        h->top_type    = top_type     = h->slice_table[top_xy     ] == h->slice_num ? s->current_picture.mb_type[top_xy]     : 0;
        h->left_type[0]= left_type[0] = h->slice_table[left_xy[0] ] == h->slice_num ? s->current_picture.mb_type[left_xy[0]] : 0;
        h->left_type[1]= left_type[1] = h->slice_table[left_xy[1] ] == h->slice_num ? s->current_picture.mb_type[left_xy[1]] : 0;
    }else{
        h->top_type    = top_type     = h->slice_table[top_xy     ] < 0xFFFF ? s->current_picture.mb_type[top_xy]     : 0;
        h->left_type[0]= left_type[0] = h->slice_table[left_xy[0] ] < 0xFFFF ? s->current_picture.mb_type[left_xy[0]] : 0;
        h->left_type[1]= left_type[1] = h->slice_table[left_xy[1] ] < 0xFFFF ? s->current_picture.mb_type[left_xy[1]] : 0;
    }
    if(IS_INTRA(mb_type))
        return 0;

    AV_COPY64(&h->non_zero_count_cache[0+8*1], &h->non_zero_count[mb_xy][ 0]);
    AV_COPY64(&h->non_zero_count_cache[0+8*2], &h->non_zero_count[mb_xy][ 8]);
    AV_COPY32(&h->non_zero_count_cache[0+8*5], &h->non_zero_count[mb_xy][16]);
    AV_COPY32(&h->non_zero_count_cache[4+8*3], &h->non_zero_count[mb_xy][20]);
    AV_COPY64(&h->non_zero_count_cache[0+8*4], &h->non_zero_count[mb_xy][24]);

    h->cbp= h->cbp_table[mb_xy];

    {
        int list;
        for(list=0; list<h->list_count; list++){
            int8_t *ref;
            int y, b_stride;
            int16_t (*mv_dst)[2];
            int16_t (*mv_src)[2];

            if(!USES_LIST(mb_type, list)){
                fill_rectangle(  h->mv_cache[list][scan8[0]], 4, 4, 8, pack16to32(0,0), 4);
                AV_WN32A(&h->ref_cache[list][scan8[ 0]], ((LIST_NOT_USED)&0xFF)*0x01010101u);
                AV_WN32A(&h->ref_cache[list][scan8[ 2]], ((LIST_NOT_USED)&0xFF)*0x01010101u);
                AV_WN32A(&h->ref_cache[list][scan8[ 8]], ((LIST_NOT_USED)&0xFF)*0x01010101u);
                AV_WN32A(&h->ref_cache[list][scan8[10]], ((LIST_NOT_USED)&0xFF)*0x01010101u);
                continue;
            }

            ref = &s->current_picture.ref_index[list][h->mb2b8_xy[mb_xy]];
            {
                int (*ref2frm)[64] = h->ref2frm[ h->slice_num&(MAX_SLICES-1) ][0] + (MB_MBAFF ? 20 : 2);
                AV_WN32A(&h->ref_cache[list][scan8[ 0]], (pack16to32(ref2frm[list][ref[0]],ref2frm[list][ref[1]])&0x00FF00FF)*0x0101);
                AV_WN32A(&h->ref_cache[list][scan8[ 2]], (pack16to32(ref2frm[list][ref[0]],ref2frm[list][ref[1]])&0x00FF00FF)*0x0101);
                ref += h->b8_stride;
                AV_WN32A(&h->ref_cache[list][scan8[ 8]], (pack16to32(ref2frm[list][ref[0]],ref2frm[list][ref[1]])&0x00FF00FF)*0x0101);
                AV_WN32A(&h->ref_cache[list][scan8[10]], (pack16to32(ref2frm[list][ref[0]],ref2frm[list][ref[1]])&0x00FF00FF)*0x0101);
            }

            b_stride = h->b_stride;
            mv_dst   = &h->mv_cache[list][scan8[0]];
            mv_src   = &s->current_picture.motion_val[list][4*s->mb_x + 4*s->mb_y*b_stride];
            for(y=0; y<4; y++){
                AV_COPY128(mv_dst + 8*y, mv_src + y*b_stride);
            }

        }
    }


/*
0 . T T. T T T T
1 L . .L . . . .
2 L . .L . . . .
3 . T TL . . . .
4 L . .L . . . .
5 L . .. . . . .
*/
//FIXME constraint_intra_pred & partitioning & nnz (let us hope this is just a typo in the spec)
    if(top_type){
        AV_COPY32(&h->non_zero_count_cache[4+8*0], &h->non_zero_count[top_xy][4+3*8]);
    }

    if(left_type[0]){
        h->non_zero_count_cache[3+8*1]= h->non_zero_count[left_xy[0]][7+0*8];
        h->non_zero_count_cache[3+8*2]= h->non_zero_count[left_xy[0]][7+1*8];
        h->non_zero_count_cache[3+8*3]= h->non_zero_count[left_xy[0]][7+2*8];
        h->non_zero_count_cache[3+8*4]= h->non_zero_count[left_xy[0]][7+3*8];
    }

    // CAVLC 8x8dct requires NNZ values for residual decoding that differ from what the loop filter needs
    if(!CABAC && h->pps.transform_8x8_mode){
        if(IS_8x8DCT(top_type)){
            h->non_zero_count_cache[4+8*0]=
            h->non_zero_count_cache[5+8*0]= h->cbp_table[top_xy] & 4;
            h->non_zero_count_cache[6+8*0]=
            h->non_zero_count_cache[7+8*0]= h->cbp_table[top_xy] & 8;
        }
        if(IS_8x8DCT(left_type[0])){
            h->non_zero_count_cache[3+8*1]=
            h->non_zero_count_cache[3+8*2]= h->cbp_table[left_xy[0]]&2; //FIXME check MBAFF
        }
        if(IS_8x8DCT(left_type[1])){
            h->non_zero_count_cache[3+8*3]=
            h->non_zero_count_cache[3+8*4]= h->cbp_table[left_xy[1]]&8; //FIXME check MBAFF
        }

        if(IS_8x8DCT(mb_type)){
            h->non_zero_count_cache[scan8[0   ]]= h->non_zero_count_cache[scan8[1   ]]=
            h->non_zero_count_cache[scan8[2   ]]= h->non_zero_count_cache[scan8[3   ]]= h->cbp & 1;

            h->non_zero_count_cache[scan8[0+ 4]]= h->non_zero_count_cache[scan8[1+ 4]]=
            h->non_zero_count_cache[scan8[2+ 4]]= h->non_zero_count_cache[scan8[3+ 4]]= h->cbp & 2;

            h->non_zero_count_cache[scan8[0+ 8]]= h->non_zero_count_cache[scan8[1+ 8]]=
            h->non_zero_count_cache[scan8[2+ 8]]= h->non_zero_count_cache[scan8[3+ 8]]= h->cbp & 4;

            h->non_zero_count_cache[scan8[0+12]]= h->non_zero_count_cache[scan8[1+12]]=
            h->non_zero_count_cache[scan8[2+12]]= h->non_zero_count_cache[scan8[3+12]]= h->cbp & 8;
        }
    }

    if(IS_INTER(mb_type) || IS_DIRECT(mb_type)){
        int list;
        for(list=0; list<h->list_count; list++){
            if(USES_LIST(top_type, list)){
                const int b_xy= h->mb2b_xy[top_xy] + 3*h->b_stride;
                const int b8_xy= h->mb2b8_xy[top_xy] + h->b8_stride;
                int (*ref2frm)[64] = h->ref2frm[ h->slice_table[top_xy]&(MAX_SLICES-1) ][0] + (MB_MBAFF ? 20 : 2);
                AV_COPY128(h->mv_cache[list][scan8[0] + 0 - 1*8], s->current_picture.motion_val[list][b_xy + 0]);
                h->ref_cache[list][scan8[0] + 0 - 1*8]=
                h->ref_cache[list][scan8[0] + 1 - 1*8]= ref2frm[list][s->current_picture.ref_index[list][b8_xy + 0]];
                h->ref_cache[list][scan8[0] + 2 - 1*8]=
                h->ref_cache[list][scan8[0] + 3 - 1*8]= ref2frm[list][s->current_picture.ref_index[list][b8_xy + 1]];
            }else{
                AV_ZERO128(h->mv_cache[list][scan8[0] + 0 - 1*8]);
                AV_WN32A(&h->ref_cache[list][scan8[0] + 0 - 1*8], ((LIST_NOT_USED)&0xFF)*0x01010101u);
            }

            if(!IS_INTERLACED(mb_type^left_type[0])){
                if(USES_LIST(left_type[0], list)){
                    const int b_xy= h->mb2b_xy[left_xy[0]] + 3;
                    const int b8_xy= h->mb2b8_xy[left_xy[0]] + 1;
                    int (*ref2frm)[64] = h->ref2frm[ h->slice_table[left_xy[0]]&(MAX_SLICES-1) ][0] + (MB_MBAFF ? 20 : 2);
                    AV_COPY32(h->mv_cache[list][scan8[0] - 1 + 0 ], s->current_picture.motion_val[list][b_xy + h->b_stride*0]);
                    AV_COPY32(h->mv_cache[list][scan8[0] - 1 + 8 ], s->current_picture.motion_val[list][b_xy + h->b_stride*1]);
                    AV_COPY32(h->mv_cache[list][scan8[0] - 1 +16 ], s->current_picture.motion_val[list][b_xy + h->b_stride*2]);
                    AV_COPY32(h->mv_cache[list][scan8[0] - 1 +24 ], s->current_picture.motion_val[list][b_xy + h->b_stride*3]);
                    h->ref_cache[list][scan8[0] - 1 + 0 ]=
                    h->ref_cache[list][scan8[0] - 1 + 8 ]= ref2frm[list][s->current_picture.ref_index[list][b8_xy + h->b8_stride*0]];
                    h->ref_cache[list][scan8[0] - 1 +16 ]=
                    h->ref_cache[list][scan8[0] - 1 +24 ]= ref2frm[list][s->current_picture.ref_index[list][b8_xy + h->b8_stride*1]];
                }else{
                    AV_ZERO32(h->mv_cache [list][scan8[0] - 1 + 0 ]);
                    AV_ZERO32(h->mv_cache [list][scan8[0] - 1 + 8 ]);
                    AV_ZERO32(h->mv_cache [list][scan8[0] - 1 +16 ]);
                    AV_ZERO32(h->mv_cache [list][scan8[0] - 1 +24 ]);
                    h->ref_cache[list][scan8[0] - 1 + 0  ]=
                    h->ref_cache[list][scan8[0] - 1 + 8  ]=
                    h->ref_cache[list][scan8[0] - 1 + 16 ]=
                    h->ref_cache[list][scan8[0] - 1 + 24 ]= LIST_NOT_USED;
                }
            }
        }
    }

    return 0;
}

/**
 * gets the predicted intra4x4 prediction mode.
 */
static inline int pred_intra_mode(H264Context *h, int n){
    const int index8= scan8[n];
    const int left= h->intra4x4_pred_mode_cache[index8 - 1];
    const int top = h->intra4x4_pred_mode_cache[index8 - 8];
    const int min= FFMIN(left, top);

    tprintf(h->s.avctx, "mode:%d %d min:%d\n", left ,top, min);

    if(min<0) return DC_PRED;
    else      return min;
}

static inline void write_back_non_zero_count(H264Context *h){
    const int mb_xy= h->mb_xy;

    AV_COPY64(&h->non_zero_count[mb_xy][ 0], &h->non_zero_count_cache[0+8*1]);
    AV_COPY64(&h->non_zero_count[mb_xy][ 8], &h->non_zero_count_cache[0+8*2]);
    AV_COPY32(&h->non_zero_count[mb_xy][16], &h->non_zero_count_cache[0+8*5]);
    AV_COPY32(&h->non_zero_count[mb_xy][20], &h->non_zero_count_cache[4+8*3]);
    AV_COPY64(&h->non_zero_count[mb_xy][24], &h->non_zero_count_cache[0+8*4]);
}

static inline void write_back_motion(H264Context *h, int mb_type){
    MpegEncContext * const s = &h->s;
    const int b_xy = 4*s->mb_x + 4*s->mb_y*h->b_stride;
    const int b8_xy= 2*s->mb_x + 2*s->mb_y*h->b8_stride;
    int list;

    if(!USES_LIST(mb_type, 0))
        fill_rectangle(&s->current_picture.ref_index[0][b8_xy], 2, 2, h->b8_stride, (uint8_t)LIST_NOT_USED, 1);

    for(list=0; list<h->list_count; list++){
        int y, b_stride;
        int16_t (*mv_dst)[2];
        int16_t (*mv_src)[2];

        if(!USES_LIST(mb_type, list))
            continue;

        b_stride = h->b_stride;
        mv_dst   = &s->current_picture.motion_val[list][b_xy];
        mv_src   = &h->mv_cache[list][scan8[0]];
        for(y=0; y<4; y++){
            AV_COPY128(mv_dst + y*b_stride, mv_src + 8*y);
        }
        if( CABAC ) {
            int16_t (*mvd_dst)[2] = &h->mvd_table[list][b_xy];
            int16_t (*mvd_src)[2] = &h->mvd_cache[list][scan8[0]];
            if(IS_SKIP(mb_type))
                fill_rectangle(mvd_dst, 4, 4, h->b_stride, 0, 4);
            else
            for(y=0; y<4; y++){
                AV_COPY128(mvd_dst + y*b_stride, mvd_src + 8*y);
            }
        }

        {
            int8_t *ref_index = &s->current_picture.ref_index[list][b8_xy];
            ref_index[0+0*h->b8_stride]= h->ref_cache[list][scan8[0]];
            ref_index[1+0*h->b8_stride]= h->ref_cache[list][scan8[4]];
            ref_index[0+1*h->b8_stride]= h->ref_cache[list][scan8[8]];
            ref_index[1+1*h->b8_stride]= h->ref_cache[list][scan8[12]];
        }
    }

    if(h->slice_type_nos == FF_B_TYPE && CABAC){
        if(IS_8X8(mb_type)){
            uint8_t *direct_table = &h->direct_table[b8_xy];
            direct_table[1+0*h->b8_stride] = h->sub_mb_type[1]>>1;
            direct_table[0+1*h->b8_stride] = h->sub_mb_type[2]>>1;
            direct_table[1+1*h->b8_stride] = h->sub_mb_type[3]>>1;
        }
    }
}

static inline int get_dct8x8_allowed(H264Context *h){
    if(h->sps.direct_8x8_inference_flag)
        return !(AV_RN64A(h->sub_mb_type) & ((MB_TYPE_16x8|MB_TYPE_8x16|MB_TYPE_8x8                )*0x0001000100010001ULL));
    else
        return !(AV_RN64A(h->sub_mb_type) & ((MB_TYPE_16x8|MB_TYPE_8x16|MB_TYPE_8x8|MB_TYPE_DIRECT2)*0x0001000100010001ULL));
}

/**
 * decodes a P_SKIP or B_SKIP macroblock
 */
static void decode_mb_skip(H264Context *h){
    MpegEncContext * const s = &h->s;
    const int mb_xy= h->mb_xy;
    int mb_type=0;

    memset(h->non_zero_count[mb_xy], 0, 32);
    memset(h->non_zero_count_cache + 8, 0, 8*5); //FIXME ugly, remove pfui

    if(MB_FIELD)
        mb_type|= MB_TYPE_INTERLACED;

    if( h->slice_type_nos == FF_B_TYPE )
    {
        // just for fill_caches. pred_direct_motion will set the real mb_type
        mb_type|= MB_TYPE_L0L1|MB_TYPE_DIRECT2|MB_TYPE_SKIP;
        if(h->direct_spatial_mv_pred){
            fill_decode_neighbors(h, mb_type);
        fill_decode_caches(h, mb_type); //FIXME check what is needed and what not ...
        }
        ff_h264_pred_direct_motion(h, &mb_type);
        mb_type|= MB_TYPE_SKIP;
    }
    else
    {
        int mx, my;
        mb_type|= MB_TYPE_16x16|MB_TYPE_P0L0|MB_TYPE_P1L0|MB_TYPE_SKIP;

        fill_decode_neighbors(h, mb_type);
        fill_decode_caches(h, mb_type); //FIXME check what is needed and what not ...
        pred_pskip_motion(h, &mx, &my);
        fill_rectangle(&h->ref_cache[0][scan8[0]], 4, 4, 8, 0, 1);
        fill_rectangle(  h->mv_cache[0][scan8[0]], 4, 4, 8, pack16to32(mx,my), 4);
    }

    write_back_motion(h, mb_type);
    s->current_picture.mb_type[mb_xy]= mb_type;
    s->current_picture.qscale_table[mb_xy]= s->qscale;
    h->slice_table[ mb_xy ]= h->slice_num;
    h->prev_mb_skipped= 1;
}

#include "h264_mvpred.h" //For pred_pskip_motion()

#endif /* AVCODEC_H264_H */