mpeg12.c

Trolltech公司发布的图形界面操作系统。可在qt-embedded-2.3.7平台上编译为嵌入式图形界面操作系统。

/*
 * MPEG1 encoder / MPEG2 decoder
 * Copyright (c) 2000,2001 Fabrice Bellard.
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
//#define DEBUG
#include "avcodec.h"
#include "dsputil.h"
#include "mpegvideo.h"

#include "mpeg12data.h"

#if 1
#define PRINT_QP(a, b) {}
#else
#define PRINT_QP(a, b) printf(a, b)
#endif

/* Start codes. */
#define SEQ_END_CODE		0x000001b7
#define SEQ_START_CODE		0x000001b3
#define GOP_START_CODE		0x000001b8
#define PICTURE_START_CODE	0x00000100
#define SLICE_MIN_START_CODE	0x00000101
#define SLICE_MAX_START_CODE	0x000001af
#define EXT_START_CODE		0x000001b5
#define USER_START_CODE		0x000001b2

#define DC_VLC_BITS 9
#define MV_VLC_BITS 9
#define MBINCR_VLC_BITS 9
#define MB_PAT_VLC_BITS 9
#define MB_PTYPE_VLC_BITS 6
#define MB_BTYPE_VLC_BITS 6
#define TEX_VLC_BITS 9

static void mpeg1_encode_block(MpegEncContext *s, 
                         DCTELEM *block, 
                         int component);
static void mpeg1_encode_motion(MpegEncContext *s, int val);
static void mpeg1_skip_picture(MpegEncContext *s, int pict_num);
static inline int mpeg1_decode_block_inter(MpegEncContext *s, 
                              DCTELEM *block, 
                              int n);
static inline int mpeg1_decode_block_intra(MpegEncContext *s, 
                              DCTELEM *block, 
                              int n);
static inline int mpeg2_decode_block_non_intra(MpegEncContext *s, 
                                        DCTELEM *block, 
                                        int n);
static inline int mpeg2_decode_block_intra(MpegEncContext *s, 
                                    DCTELEM *block, 
                                    int n);
static int mpeg_decode_motion(MpegEncContext *s, int fcode, int pred);

static UINT16 mv_penalty[MAX_FCODE+1][MAX_MV*2+1];
static UINT8 fcode_tab[MAX_MV*2+1];

static inline int get_bits_diff(MpegEncContext *s){
    int bits,ret;
    
    bits= get_bit_count(&s->pb);
    ret= bits - s->last_bits;
    s->last_bits=bits;
    
    return ret;
}

static void init_2d_vlc_rl(RLTable *rl)
{
    int i;
    
    init_vlc(&rl->vlc, TEX_VLC_BITS, rl->n + 2, 
             &rl->table_vlc[0][1], 4, 2,
             &rl->table_vlc[0][0], 4, 2);

    
    rl->rl_vlc[0]= av_malloc(rl->vlc.table_size*sizeof(RL_VLC_ELEM));
    for(i=0; i<rl->vlc.table_size; i++){
        int code= rl->vlc.table[i][0];
        int len = rl->vlc.table[i][1];
        int level, run;
    
        if(len==0){ // illegal code
            run= 65;
            level= MAX_LEVEL;
        }else if(len<0){ //more bits needed
            run= 0;
            level= code;
        }else{
            if(code==rl->n){ //esc
                run= 65;
                level= 0;
            }else if(code==rl->n+1){ //eob
                run= 0;
                level= 127;
            }else{
                run=   rl->table_run  [code] + 1;
                level= rl->table_level[code];
            }
        }
        rl->rl_vlc[0][i].len= len;
        rl->rl_vlc[0][i].level= level;
        rl->rl_vlc[0][i].run= run;
    }
}


static void put_header(MpegEncContext *s, int header)
{
    align_put_bits(&s->pb);
    put_bits(&s->pb, 16, header>>16);
    put_bits(&s->pb, 16, header&0xFFFF);
}

/* put sequence header if needed */
static void mpeg1_encode_sequence_header(MpegEncContext *s)
{
        unsigned int vbv_buffer_size;
        unsigned int fps, v;
        int n;
        UINT64 time_code;
        
        if (s->picture_in_gop_number == 0) {
            /* mpeg1 header repeated every gop */
            put_header(s, SEQ_START_CODE);
            
            /* search closest frame rate */
            {
                int i, dmin, d;
                s->frame_rate_index = 0;
                dmin = 0x7fffffff;
                for(i=1;i<9;i++) {
                    d = abs(s->frame_rate - frame_rate_tab[i]);
                    if (d < dmin) {
                        dmin = d;
                        s->frame_rate_index = i;
                    }
                }
            }
 
            put_bits(&s->pb, 12, s->width);
            put_bits(&s->pb, 12, s->height);
            put_bits(&s->pb, 4, 1); /* 1/1 aspect ratio */
            put_bits(&s->pb, 4, s->frame_rate_index);
            v = s->bit_rate / 400;
            if (v > 0x3ffff)
                v = 0x3ffff;
            put_bits(&s->pb, 18, v);
            put_bits(&s->pb, 1, 1); /* marker */

            if(s->avctx->rc_buffer_size)
                vbv_buffer_size = s->avctx->rc_buffer_size;
            else
                /* VBV calculation: Scaled so that a VCD has the proper VBV size of 40 kilobytes */
                vbv_buffer_size = (( 20 * s->bit_rate) / (1151929 / 2)) * 8 * 1024;	 
            put_bits(&s->pb, 10, (vbv_buffer_size + 16383) / 16384); 
            put_bits(&s->pb, 1, 1); /* constrained parameter flag */
            put_bits(&s->pb, 1, 0); /* no custom intra matrix */
            put_bits(&s->pb, 1, 0); /* no custom non intra matrix */

            put_header(s, GOP_START_CODE);
            put_bits(&s->pb, 1, 0); /* do drop frame */
            /* time code : we must convert from the real frame rate to a
               fake mpeg frame rate in case of low frame rate */
            fps = frame_rate_tab[s->frame_rate_index];
            time_code = (INT64)s->fake_picture_number * FRAME_RATE_BASE;
            s->gop_picture_number = s->fake_picture_number;
            put_bits(&s->pb, 5, (UINT32)((time_code / (fps * 3600)) % 24));
            put_bits(&s->pb, 6, (UINT32)((time_code / (fps * 60)) % 60));
            put_bits(&s->pb, 1, 1);
            put_bits(&s->pb, 6, (UINT32)((time_code / fps) % 60));
            put_bits(&s->pb, 6, (UINT32)((time_code % fps) / FRAME_RATE_BASE));
            put_bits(&s->pb, 1, 1); /* closed gop */
            put_bits(&s->pb, 1, 0); /* broken link */
        }

        if (s->frame_rate < (24 * FRAME_RATE_BASE) && s->picture_number > 0) {
            /* insert empty P pictures to slow down to the desired
               frame rate. Each fake pictures takes about 20 bytes */
            fps = frame_rate_tab[s->frame_rate_index];
            n = (((INT64)s->picture_number * fps) / s->frame_rate) - 1;
            while (s->fake_picture_number < n) {
                mpeg1_skip_picture(s, s->fake_picture_number - 
                                   s->gop_picture_number); 
                s->fake_picture_number++;
            }

        }
}


/* insert a fake P picture */
static void mpeg1_skip_picture(MpegEncContext *s, int pict_num)
{
    unsigned int mb_incr;

    /* mpeg1 picture header */
    put_header(s, PICTURE_START_CODE);
    /* temporal reference */
    put_bits(&s->pb, 10, pict_num & 0x3ff); 
    
    put_bits(&s->pb, 3, P_TYPE);
    put_bits(&s->pb, 16, 0xffff); /* non constant bit rate */
    
    put_bits(&s->pb, 1, 1); /* integer coordinates */
    put_bits(&s->pb, 3, 1); /* forward_f_code */
    
    put_bits(&s->pb, 1, 0); /* extra bit picture */
    
    /* only one slice */
    put_header(s, SLICE_MIN_START_CODE);
    put_bits(&s->pb, 5, 1); /* quantizer scale */
    put_bits(&s->pb, 1, 0); /* slice extra information */
    
    mb_incr = 1;
    put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1], 
             mbAddrIncrTable[mb_incr - 1][0]);
    
    /* empty macroblock */
    put_bits(&s->pb, 3, 1); /* motion only */
    
    /* zero motion x & y */
    put_bits(&s->pb, 1, 1); 
    put_bits(&s->pb, 1, 1); 

    /* output a number of empty slice */
    mb_incr = s->mb_width * s->mb_height - 1;
    while (mb_incr > 33) {
        put_bits(&s->pb, 11, 0x008);
        mb_incr -= 33;
    }
    put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1], 
             mbAddrIncrTable[mb_incr - 1][0]);
    
    /* empty macroblock */
    put_bits(&s->pb, 3, 1); /* motion only */
    
    /* zero motion x & y */
    put_bits(&s->pb, 1, 1); 
    put_bits(&s->pb, 1, 1); 
}

static void common_init(MpegEncContext *s)
{
    s->y_dc_scale_table=
    s->c_dc_scale_table= ff_mpeg1_dc_scale_table;
}

void mpeg1_encode_picture_header(MpegEncContext *s, int picture_number)
{
    mpeg1_encode_sequence_header(s);

    /* mpeg1 picture header */
    put_header(s, PICTURE_START_CODE);
    /* temporal reference */
    put_bits(&s->pb, 10, (s->fake_picture_number - 
                          s->gop_picture_number) & 0x3ff); 
    s->fake_picture_number++;
    
    put_bits(&s->pb, 3, s->pict_type);
    put_bits(&s->pb, 16, 0xffff); /* non constant bit rate */
    
    if (s->pict_type == P_TYPE) {
        put_bits(&s->pb, 1, 0); /* half pel coordinates */
        put_bits(&s->pb, 3, s->f_code); /* forward_f_code */
    }
    
    put_bits(&s->pb, 1, 0); /* extra bit picture */
    
    /* only one slice */
    put_header(s, SLICE_MIN_START_CODE);
    put_bits(&s->pb, 5, s->qscale); /* quantizer scale */
    put_bits(&s->pb, 1, 0); /* slice extra information */
}

void mpeg1_encode_mb(MpegEncContext *s,
                     DCTELEM block[6][64],
                     int motion_x, int motion_y)
{
    int mb_incr, i, cbp, mb_x, mb_y;

    mb_x = s->mb_x;
    mb_y = s->mb_y;

    /* compute cbp */
    cbp = 0;
    for(i=0;i<6;i++) {
        if (s->block_last_index[i] >= 0)
            cbp |= 1 << (5 - i);
    }

    /* skip macroblock, except if first or last macroblock of a slice */
    if ((cbp | motion_x | motion_y) == 0 &&
        (!((mb_x | mb_y) == 0 ||
           (mb_x == s->mb_width - 1 && mb_y == s->mb_height - 1)))) {
        s->mb_incr++;
        s->qscale -= s->dquant;
        s->skip_count++;
        s->misc_bits++;
        s->last_bits++;
    } else {
        /* output mb incr */
        mb_incr = s->mb_incr;

        while (mb_incr > 33) {
            put_bits(&s->pb, 11, 0x008);
            mb_incr -= 33;
        }
        put_bits(&s->pb, mbAddrIncrTable[mb_incr - 1][1], 
                 mbAddrIncrTable[mb_incr - 1][0]);
        
        if (s->pict_type == I_TYPE) {
            if(s->dquant && cbp){
                put_bits(&s->pb, 2, 1); /* macroblock_type : macroblock_quant = 1 */
                put_bits(&s->pb, 5, s->qscale);
            }else{
                put_bits(&s->pb, 1, 1); /* macroblock_type : macroblock_quant = 0 */
                s->qscale -= s->dquant;
            }
            s->misc_bits+= get_bits_diff(s);
            s->i_count++;
        } else {
            if (s->mb_intra) {
                if(s->dquant && cbp){
                    put_bits(&s->pb, 6, 0x01);
                    put_bits(&s->pb, 5, s->qscale);
                }else{
                    put_bits(&s->pb, 5, 0x03);
                    s->qscale -= s->dquant;
                }
                s->misc_bits+= get_bits_diff(s);
                s->i_count++;
            } else {
                if (cbp != 0) {
                    if (motion_x == 0 && motion_y == 0) {
                        if(s->dquant){
                            put_bits(&s->pb, 5, 1); /* macroblock_pattern & quant */
                            put_bits(&s->pb, 5, s->qscale);
                        }else{
                            put_bits(&s->pb, 2, 1); /* macroblock_pattern only */
                        }
                        s->misc_bits+= get_bits_diff(s);
                        put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
                    } else {
                        if(s->dquant){
                            put_bits(&s->pb, 5, 2); /* motion + cbp */
                            put_bits(&s->pb, 5, s->qscale);
                        }else{
                            put_bits(&s->pb, 1, 1); /* motion + cbp */
                        }
                        s->misc_bits+= get_bits_diff(s);
                        mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0]); 
                        mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1]); 
                        s->mv_bits+= get_bits_diff(s);
                        put_bits(&s->pb, mbPatTable[cbp - 1][1], mbPatTable[cbp - 1][0]);
                    }
                } else {
                    put_bits(&s->pb, 3, 1); /* motion only */
                    mpeg1_encode_motion(s, motion_x - s->last_mv[0][0][0]); 
                    mpeg1_encode_motion(s, motion_y - s->last_mv[0][0][1]); 
                    s->qscale -= s->dquant;
                    s->mv_bits+= get_bits_diff(s);
                }
                s->f_count++;
            }
        }
        for(i=0;i<6;i++) {
            if (cbp & (1 << (5 - i))) {
                mpeg1_encode_block(s, block[i], i);
            }
        }
        s->mb_incr = 1;
        if(s->mb_intra)
            s->i_tex_bits+= get_bits_diff(s);
        else
            s->p_tex_bits+= get_bits_diff(s);
    }
    s->last_mv[0][0][0] = motion_x;
    s->last_mv[0][0][1] = motion_y;
}

static void mpeg1_encode_motion(MpegEncContext *s, int val)
{