FFmpeg/libavcodec/mpeg4video.h

/*
 * MPEG4 encoder/decoder internal header.
 * Copyright (c) 2000,2001 Fabrice Bellard
 * Copyright (c) 2002-2010 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
 */

#ifndef AVCODEC_MPEG4VIDEO_H
#define AVCODEC_MPEG4VIDEO_H

#include <stdint.h>

#include "get_bits.h"
#include "mpegvideo.h"
#include "rl.h"

// shapes
#define RECT_SHAPE       0
#define BIN_SHAPE        1
#define BIN_ONLY_SHAPE   2
#define GRAY_SHAPE       3

#define SIMPLE_VO_TYPE           1
#define CORE_VO_TYPE             3
#define MAIN_VO_TYPE             4
#define NBIT_VO_TYPE             5
#define ARTS_VO_TYPE            10
#define ACE_VO_TYPE             12
#define ADV_SIMPLE_VO_TYPE      17

// aspect_ratio_info
#define EXTENDED_PAR 15

//vol_sprite_usage / sprite_enable
#define STATIC_SPRITE 1
#define GMC_SPRITE 2

#define MOTION_MARKER 0x1F001
#define DC_MARKER     0x6B001

#define VOS_STARTCODE        0x1B0
#define USER_DATA_STARTCODE  0x1B2
#define GOP_STARTCODE        0x1B3
#define VISUAL_OBJ_STARTCODE 0x1B5
#define VOP_STARTCODE        0x1B6

/* smaller packets likely don't contain a real frame */
#define MAX_NVOP_SIZE 19

typedef struct Mpeg4DecContext {
    MpegEncContext m;

    /// number of bits to represent the fractional part of time
    int time_increment_bits;
    int shape;
    int vol_sprite_usage;
    int sprite_brightness_change;
    int num_sprite_warping_points;
    /// sprite trajectory points
    uint16_t sprite_traj[4][2];
    /// sprite shift [isChroma]
    int sprite_shift[2];

    // reversible vlc
    int rvlc;
    /// could this stream contain resync markers
    int resync_marker;
    /// time distance of first I -> B, used for interlaced B-frames
    int t_frame;

    int new_pred;
    int enhancement_type;
    int scalability;
    int use_intra_dc_vlc;

    /// QP above which the ac VLC should be used for intra dc
    int intra_dc_threshold;

    /* bug workarounds */
    int divx_version;
    int divx_build;
    int xvid_build;
    int lavc_build;

    /// flag for having shown the warning about invalid Divx B-frames
    int showed_packed_warning;
    /** does the stream contain the low_delay flag,
     *  used to work around buggy encoders. */
    int vol_control_parameters;
    int cplx_estimation_trash_i;
    int cplx_estimation_trash_p;
    int cplx_estimation_trash_b;
} Mpeg4DecContext;

/* dc encoding for mpeg4 */
extern const uint8_t ff_mpeg4_DCtab_lum[13][2];
extern const uint8_t ff_mpeg4_DCtab_chrom[13][2];

extern const uint16_t ff_mpeg4_intra_vlc[103][2];
extern const int8_t ff_mpeg4_intra_level[102];
extern const int8_t ff_mpeg4_intra_run[102];

extern RLTable ff_mpeg4_rl_intra;

/* Note this is identical to the intra rvlc except that it is reordered. */
extern RLTable ff_rvlc_rl_inter;
extern RLTable ff_rvlc_rl_intra;

extern const uint16_t ff_sprite_trajectory_tab[15][2];
extern const uint8_t ff_mb_type_b_tab[4][2];

/* these matrixes will be permuted for the idct */
extern const int16_t ff_mpeg4_default_intra_matrix[64];
extern const int16_t ff_mpeg4_default_non_intra_matrix[64];

extern const uint8_t ff_mpeg4_y_dc_scale_table[32];
extern const uint8_t ff_mpeg4_c_dc_scale_table[32];
extern const uint16_t ff_mpeg4_resync_prefix[8];

extern const uint8_t ff_mpeg4_dc_threshold[8];

void ff_mpeg4_encode_mb(MpegEncContext *s,
                        int16_t block[6][64],
                        int motion_x, int motion_y);
void ff_mpeg4_pred_ac(MpegEncContext *s, int16_t *block, int n,
                      int dir);
void ff_set_mpeg4_time(MpegEncContext *s);
void ff_mpeg4_encode_picture_header(MpegEncContext *s, int picture_number);

int ff_mpeg4_decode_picture_header(Mpeg4DecContext *ctx, GetBitContext *gb);
void ff_mpeg4_encode_video_packet_header(MpegEncContext *s);
void ff_mpeg4_clean_buffers(MpegEncContext *s);
void ff_mpeg4_stuffing(PutBitContext *pbc);
void ff_mpeg4_init_partitions(MpegEncContext *s);
void ff_mpeg4_merge_partitions(MpegEncContext *s);
void ff_clean_mpeg4_qscales(MpegEncContext *s);
int ff_mpeg4_decode_partitions(Mpeg4DecContext *ctx);
int ff_mpeg4_get_video_packet_prefix_length(MpegEncContext *s);
int ff_mpeg4_decode_video_packet_header(Mpeg4DecContext *ctx);
void ff_mpeg4_init_direct_mv(MpegEncContext *s);
void ff_mpeg4videodec_static_init(void);
int ff_mpeg4_workaround_bugs(AVCodecContext *avctx);
int ff_mpeg4_frame_end(AVCodecContext *avctx, const uint8_t *buf, int buf_size);

/**
 *
 * @return the mb_type
 */
int ff_mpeg4_set_direct_mv(MpegEncContext *s, int mx, int my);

extern uint8_t ff_mpeg4_static_rl_table_store[3][2][2 * MAX_RUN + MAX_LEVEL + 3];

#if 0 //3IV1 is quite rare and it slows things down a tiny bit
#define IS_3IV1 s->codec_tag == AV_RL32("3IV1")
#else
#define IS_3IV1 0
#endif

/**
 * Predict the dc.
 * encoding quantized level -> quantized diff
 * decoding quantized diff -> quantized level
 * @param n block index (0-3 are luma, 4-5 are chroma)
 * @param dir_ptr pointer to an integer where the prediction direction will be stored
 */
static inline int ff_mpeg4_pred_dc(MpegEncContext *s, int n, int level,
                                   int *dir_ptr, int encoding)
{
    int a, b, c, wrap, pred, scale, ret;
    int16_t *dc_val;

    /* find prediction */
    if (n < 4)
        scale = s->y_dc_scale;
    else
        scale = s->c_dc_scale;
    if (IS_3IV1)
        scale = 8;

    wrap   = s->block_wrap[n];
    dc_val = s->dc_val[0] + s->block_index[n];

    /* B C
     * A X
     */
    a = dc_val[-1];
    b = dc_val[-1 - wrap];
    c = dc_val[-wrap];

    /* outside slice handling (we can't do that by memset as we need the
     * dc for error resilience) */
    if (s->first_slice_line && n != 3) {
        if (n != 2)
            b = c = 1024;
        if (n != 1 && s->mb_x == s->resync_mb_x)
            b = a = 1024;
    }
    if (s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y + 1) {
        if (n == 0 || n == 4 || n == 5)
            b = 1024;
    }

    if (abs(a - b) < abs(b - c)) {
        pred     = c;
        *dir_ptr = 1; /* top */
    } else {
        pred     = a;
        *dir_ptr = 0; /* left */
    }
    /* we assume pred is positive */
    pred = FASTDIV((pred + (scale >> 1)), scale);

    if (encoding) {
        ret = level - pred;
    } else {
        level += pred;
        ret    = level;
        if (s->err_recognition & (AV_EF_BITSTREAM | AV_EF_AGGRESSIVE)) {
            if (level < 0) {
                av_log(s->avctx, AV_LOG_ERROR,
                       "dc<0 at %dx%d\n", s->mb_x, s->mb_y);
                return -1;
            }
            if (level * scale > 2048 + scale) {
                av_log(s->avctx, AV_LOG_ERROR,
                       "dc overflow at %dx%d\n", s->mb_x, s->mb_y);
                return -1;
            }
        }
    }
    level *= scale;
    if (level & (~2047)) {
        if (level < 0)
            level = 0;
        else if (!(s->workaround_bugs & FF_BUG_DC_CLIP))
            level = 2047;
    }
    dc_val[0] = level;

    return ret;
}

#endif /* AVCODEC_MPEG4VIDEO_H */