mpeg12.c

Trolltech公司发布的图形界面操作系统。可在qt-embedded-2.3.10平台上编译为嵌入式图形界面操作系统。

/*
 * MPEG1 codec / 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
 */
 
/**
 * @file mpeg12.c
 * MPEG1/2 codec
 */
 
//#define DEBUG
#include "avcodec.h"
#include "dsputil.h"
#include "mpegvideo.h"

#include "mpeg12data.h"


/* 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

#ifdef CONFIG_ENCODERS
static void mpeg1_encode_block(MpegEncContext *s, 
                         DCTELEM *block, 
                         int component);
static void mpeg1_encode_motion(MpegEncContext *s, int val, int f_or_b_code);    // RAL: f_code parameter added
#endif //CONFIG_ENCODERS
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);

#ifdef HAVE_XVMC
extern int XVMC_field_start(MpegEncContext *s, AVCodecContext *avctx);
extern int XVMC_field_end(MpegEncContext *s);
extern void XVMC_pack_pblocks(MpegEncContext *s,int cbp);
extern void XVMC_init_block(s);//set s->block
#endif

#ifdef CONFIG_ENCODERS
static uint8_t (*mv_penalty)[MAX_MV*2+1]= NULL;
static uint8_t fcode_tab[MAX_MV*2+1];

static uint32_t uni_mpeg1_ac_vlc_bits[64*64*2];
static uint8_t  uni_mpeg1_ac_vlc_len [64*64*2];

/* simple include everything table for dc, first byte is bits number next 3 are code*/
static uint32_t mpeg1_lum_dc_uni[512];
static uint32_t mpeg1_chr_dc_uni[512];

static uint8_t mpeg1_index_run[2][64];
static int8_t mpeg1_max_level[2][64];
#endif //CONFIG_ENCODERS

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;
    }
}

#ifdef CONFIG_ENCODERS
static void init_uni_ac_vlc(RLTable *rl, uint32_t *uni_ac_vlc_bits, uint8_t *uni_ac_vlc_len){
    int i;

    for(i=0; i<128; i++){
        int level= i-64;
        int run;
        for(run=0; run<64; run++){
            int len, bits, code;
            
            int alevel= ABS(level);
            int sign= (level>>31)&1;

            if (alevel > rl->max_level[0][run])
                code= 111; /*rl->n*/
            else
                code= rl->index_run[0][run] + alevel - 1;

            if (code < 111 /* rl->n */) {
	    	/* store the vlc & sign at once */
                len=   mpeg1_vlc[code][1]+1;
                bits= (mpeg1_vlc[code][0]<<1) + sign;
            } else {
                len=  mpeg1_vlc[111/*rl->n*/][1]+6;
                bits= mpeg1_vlc[111/*rl->n*/][0]<<6;

                bits|= run;
                if (alevel < 128) {
                    bits<<=8; len+=8;
                    bits|= level & 0xff;
                } else {
                    bits<<=16; len+=16;
                    bits|= level & 0xff;
                    if (level < 0) {
                        bits|= 0x8001 + level + 255;
                    } else {
                        bits|= level & 0xffff;
                    }
                }
            }

            uni_ac_vlc_bits[UNI_AC_ENC_INDEX(run, i)]= bits;
            uni_ac_vlc_len [UNI_AC_ENC_INDEX(run, i)]= len;
        }
    }
}

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, i;
        uint64_t time_code;
        float best_aspect_error= 1E10;
        float aspect_ratio= av_q2d(s->avctx->sample_aspect_ratio);
        int constraint_parameter_flag;
        
        if(aspect_ratio==0.0) aspect_ratio= 1.0; //pixel aspect 1:1 (VGA)
        
        if (s->current_picture.key_frame) {
            /* 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<14;i++) {
                    if(s->avctx->strict_std_compliance >= 0 && i>=9) break;
                     
                    d = abs(MPEG1_FRAME_RATE_BASE*(int64_t)s->avctx->frame_rate/s->avctx->frame_rate_base - 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);
            
            for(i=1; i<15; i++){
                float error= aspect_ratio;
                if(s->codec_id == CODEC_ID_MPEG1VIDEO || i <=1)
                    error-= 1.0/mpeg1_aspect[i];
                else
                    error-= av_q2d(mpeg2_aspect[i])*s->height/s->width;
             
                error= ABS(error);
                
                if(error < best_aspect_error){
                    best_aspect_error= error;
                    s->aspect_ratio_info= i;
                }
            }
            
            put_bits(&s->pb, 4, s->aspect_ratio_info);
            put_bits(&s->pb, 4, s->frame_rate_index);
            
            if(s->avctx->rc_max_rate){
                v = (s->avctx->rc_max_rate + 399) / 400;
                if (v > 0x3ffff && s->codec_id == CODEC_ID_MPEG1VIDEO)
                    v = 0x3ffff;
            }else{
                v= 0x3FFFF;
            }

            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;
            vbv_buffer_size= (vbv_buffer_size + 16383) / 16384;

            put_bits(&s->pb, 18, v & 0x3FFFF);
            put_bits(&s->pb, 1, 1); /* marker */
            put_bits(&s->pb, 10, vbv_buffer_size & 0x3FF);

            constraint_parameter_flag= 
                s->width <= 768 && s->height <= 576 && 
                s->mb_width * s->mb_height <= 396 &&
                s->mb_width * s->mb_height * frame_rate_tab[s->frame_rate_index] <= MPEG1_FRAME_RATE_BASE*396*25 &&
                frame_rate_tab[s->frame_rate_index] <= MPEG1_FRAME_RATE_BASE*30 &&
                vbv_buffer_size <= 20 &&
                v <= 1856000/400 &&
                s->codec_id == CODEC_ID_MPEG1VIDEO;
                
            put_bits(&s->pb, 1, constraint_parameter_flag);
            
            ff_write_quant_matrix(&s->pb, s->avctx->intra_matrix);
            ff_write_quant_matrix(&s->pb, s->avctx->inter_matrix);

            if(s->codec_id == CODEC_ID_MPEG2VIDEO){
                put_header(s, EXT_START_CODE);
                put_bits(&s->pb, 4, 1); //seq ext
                put_bits(&s->pb, 1, 0); //esc
                put_bits(&s->pb, 3, 4); //profile
                put_bits(&s->pb, 4, 8); //level
                put_bits(&s->pb, 1, s->progressive_sequence=1);
                put_bits(&s->pb, 2, 1); //chroma format 4:2:0
                put_bits(&s->pb, 2, 0); //horizontal size ext
                put_bits(&s->pb, 2, 0); //vertical size ext
                put_bits(&s->pb, 12, v>>18); //bitrate ext
                put_bits(&s->pb, 1, 1); //marker
                put_bits(&s->pb, 8, vbv_buffer_size >>10); //vbv buffer ext
                put_bits(&s->pb, 1, s->low_delay);
                put_bits(&s->pb, 2, 0); // frame_rate_ext_n
                put_bits(&s->pb, 5, 0); // frame_rate_ext_d
            }
            
            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_t)s->fake_picture_number * MPEG1_FRAME_RATE_BASE;
            s->gop_picture_number = s->fake_picture_number;
            put_bits(&s->pb, 5, (uint32_t)((time_code / (fps * 3600)) % 24));
            put_bits(&s->pb, 6, (uint32_t)((time_code / (fps * 60)) % 60));
            put_bits(&s->pb, 1, 1);
            put_bits(&s->pb, 6, (uint32_t)((time_code / fps) % 60));
            put_bits(&s->pb, 6, (uint32_t)((time_code % fps) / MPEG1_FRAME_RATE_BASE));
            put_bits(&s->pb, 1, 0); /* closed gop */
            put_bits(&s->pb, 1, 0); /* broken link */
        }

        if (s->avctx->frame_rate < (24 * s->avctx->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 = av_rescale((int64_t)s->picture_number * s->avctx->frame_rate_base, fps, s->avctx->frame_rate) / MPEG1_FRAME_RATE_BASE - 1;
            while (s->fake_picture_number < n) {
                mpeg1_skip_picture(s, s->fake_picture_number - 
                                   s->gop_picture_number); 
                s->fake_picture_number++;
            }

        }
}

static inline void encode_mb_skip_run(MpegEncContext *s, int run){
    while (run >= 33) {
        put_bits(&s->pb, 11, 0x008);
        run -= 33;
    }
    put_bits(&s->pb, mbAddrIncrTable[run][1], 
             mbAddrIncrTable[run][0]);
}

/* insert a fake P picture */
static void mpeg1_skip_picture(MpegEncContext *s, int pict_num)
{
    assert(s->codec_id == CODEC_ID_MPEG1VIDEO); // mpeg2 can do these repeat things

    /* 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 */
    
    encode_mb_skip_run(s, 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 */
    encode_mb_skip_run(s, s->mb_width * s->mb_height - 2);
    
    /* 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); 
}
#endif //CONFIG_ENCODERS