dv.c

tcpmp播放器的flv插件

/*
 * DV decoder
 * Copyright (c) 2002 Fabrice Bellard.
 * Copyright (c) 2004 Roman Shaposhnik.
 *
 * DV encoder 
 * Copyright (c) 2003 Roman Shaposhnik.
 *
 * Many thanks to Dan Dennedy <[e-mail]> for providing wealth
 * of DV technical info.
 *
 * 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 dv.c
 * DV codec.
 */
#include "avcodec.h"
#include "dsputil.h"
#include "mpegvideo.h"
#include "simple_idct.h"
#include "dvdata.h"

//#undef NDEBUG
//#include <assert.h>

typedef struct DVVideoContext {
    const DVprofile* sys;
    AVFrame picture;
    AVCodecContext *avctx;
    uint8_t *buf;
    
    uint8_t dv_zigzag[2][64];
    uint8_t dv_idct_shift[2][2][22][64];
  
    void (*get_pixels)(DCTELEM *block, const uint8_t *pixels, int line_size);
    void (*fdct[2])(DCTELEM *block);
    void (*idct_put[2])(uint8_t *dest, int line_size, DCTELEM *block);
} DVVideoContext;

#define TEX_VLC_BITS 9

#ifdef DV_CODEC_TINY_TARGET
#define DV_VLC_MAP_RUN_SIZE 15
#define DV_VLC_MAP_LEV_SIZE 23
#else
#define DV_VLC_MAP_RUN_SIZE  64 
#define DV_VLC_MAP_LEV_SIZE 512 //FIXME sign was removed so this should be /2 but needs check
#endif

/* MultiThreading */
static uint8_t** dv_anchor;

/* XXX: also include quantization */
static RL_VLC_ELEM *dv_rl_vlc;
/* VLC encoding lookup table */
static struct dv_vlc_pair {
   uint32_t vlc;
   uint8_t  size;
} (*dv_vlc_map)[DV_VLC_MAP_LEV_SIZE] = NULL;

static void dv_build_unquantize_tables(DVVideoContext *s, uint8_t* perm)
{
    int i, q, j;

    /* NOTE: max left shift is 6 */
    for(q = 0; q < 22; q++) {
        /* 88DCT */
        for(i = 1; i < 64; i++) {
            /* 88 table */
            j = perm[i];
            s->dv_idct_shift[0][0][q][j] =
                dv_quant_shifts[q][dv_88_areas[i]] + 1;
	    s->dv_idct_shift[1][0][q][j] = s->dv_idct_shift[0][0][q][j] + 1;
        }
        
        /* 248DCT */
        for(i = 1; i < 64; i++) {
            /* 248 table */
            s->dv_idct_shift[0][1][q][i] =  
                dv_quant_shifts[q][dv_248_areas[i]] + 1;
	    s->dv_idct_shift[1][1][q][i] = s->dv_idct_shift[0][1][q][i] + 1;
        }
    }
}

static int dvvideo_init(AVCodecContext *avctx)
{
    DVVideoContext *s = avctx->priv_data;
    DSPContext dsp;
    static int done=0;
    int i, j;

    if (!done) {
        VLC dv_vlc;
        uint16_t new_dv_vlc_bits[NB_DV_VLC*2];
        uint8_t new_dv_vlc_len[NB_DV_VLC*2];
        uint8_t new_dv_vlc_run[NB_DV_VLC*2];
        int16_t new_dv_vlc_level[NB_DV_VLC*2];

        done = 1;

        dv_vlc_map = av_mallocz_static(DV_VLC_MAP_LEV_SIZE*DV_VLC_MAP_RUN_SIZE*sizeof(struct dv_vlc_pair));
	if (!dv_vlc_map)
	    return -ENOMEM;

	/* dv_anchor lets each thread know its Id */
	dv_anchor = av_malloc(12*27*sizeof(void*));
	if (!dv_anchor) {
	    return -ENOMEM;
	}
	for (i=0; i<12*27; i++)
	    dv_anchor[i] = (void*)(size_t)i;

	/* it's faster to include sign bit in a generic VLC parsing scheme */
	for (i=0, j=0; i<NB_DV_VLC; i++, j++) {
	    new_dv_vlc_bits[j] = dv_vlc_bits[i];
	    new_dv_vlc_len[j] = dv_vlc_len[i];
	    new_dv_vlc_run[j] = dv_vlc_run[i];
	    new_dv_vlc_level[j] = dv_vlc_level[i];
	    
	    if (dv_vlc_level[i]) {
	        new_dv_vlc_bits[j] <<= 1;
		new_dv_vlc_len[j]++;

		j++;
		new_dv_vlc_bits[j] = (dv_vlc_bits[i] << 1) | 1;
		new_dv_vlc_len[j] = dv_vlc_len[i] + 1;
		new_dv_vlc_run[j] = dv_vlc_run[i];
		new_dv_vlc_level[j] = -dv_vlc_level[i];
	    }
	}
             
        /* NOTE: as a trick, we use the fact the no codes are unused
           to accelerate the parsing of partial codes */
        init_vlc(&dv_vlc, TEX_VLC_BITS, j, 
                 new_dv_vlc_len, 1, 1, new_dv_vlc_bits, 2, 2, 0);

        dv_rl_vlc = av_malloc(dv_vlc.table_size * sizeof(RL_VLC_ELEM));
	if (!dv_rl_vlc) {
	    av_free(dv_anchor);
	    return -ENOMEM;
	}
        for(i = 0; i < dv_vlc.table_size; i++){
            int code= dv_vlc.table[i][0];
            int len = dv_vlc.table[i][1];
            int level, run;
        
            if(len<0){ //more bits needed
                run= 0;
                level= code;
            } else {
                run=   new_dv_vlc_run[code] + 1;
                level= new_dv_vlc_level[code];
            }
            dv_rl_vlc[i].len = len;
            dv_rl_vlc[i].level = level;
            dv_rl_vlc[i].run = run;
        }
	free_vlc(&dv_vlc);

	for (i = 0; i < NB_DV_VLC - 1; i++) {
           if (dv_vlc_run[i] >= DV_VLC_MAP_RUN_SIZE)
	       continue;
#ifdef DV_CODEC_TINY_TARGET
           if (dv_vlc_level[i] >= DV_VLC_MAP_LEV_SIZE)
	       continue;
#endif
	   
	   if (dv_vlc_map[dv_vlc_run[i]][dv_vlc_level[i]].size != 0)
	       continue;
	       
	   dv_vlc_map[dv_vlc_run[i]][dv_vlc_level[i]].vlc = dv_vlc_bits[i] << 
	                                                    (!!dv_vlc_level[i]);
	   dv_vlc_map[dv_vlc_run[i]][dv_vlc_level[i]].size = dv_vlc_len[i] + 
	                                                     (!!dv_vlc_level[i]);
	}
	for (i = 0; i < DV_VLC_MAP_RUN_SIZE; i++) {
#ifdef DV_CODEC_TINY_TARGET
	   for (j = 1; j < DV_VLC_MAP_LEV_SIZE; j++) {
	      if (dv_vlc_map[i][j].size == 0) {
	          dv_vlc_map[i][j].vlc = dv_vlc_map[0][j].vlc |
		            (dv_vlc_map[i-1][0].vlc << (dv_vlc_map[0][j].size));
	          dv_vlc_map[i][j].size = dv_vlc_map[i-1][0].size + 
		                          dv_vlc_map[0][j].size;
	      }
	   }
#else
	   for (j = 1; j < DV_VLC_MAP_LEV_SIZE/2; j++) {
	      if (dv_vlc_map[i][j].size == 0) {
	          dv_vlc_map[i][j].vlc = dv_vlc_map[0][j].vlc |
		            (dv_vlc_map[i-1][0].vlc << (dv_vlc_map[0][j].size));
	          dv_vlc_map[i][j].size = dv_vlc_map[i-1][0].size + 
		                          dv_vlc_map[0][j].size;
	      }
	      dv_vlc_map[i][((uint16_t)(-j))&0x1ff].vlc = 
	                                    dv_vlc_map[i][j].vlc | 1;
	      dv_vlc_map[i][((uint16_t)(-j))&0x1ff].size = 
	                                    dv_vlc_map[i][j].size;
	   }
#endif
	}
    }

    /* Generic DSP setup */
    dsputil_init(&dsp, avctx);
    s->get_pixels = dsp.get_pixels;

    /* 88DCT setup */
    s->fdct[0] = dsp.fdct;
    s->idct_put[0] = dsp.idct_put;
    for (i=0; i<64; i++)
       s->dv_zigzag[0][i] = dsp.idct_permutation[ff_zigzag_direct[i]];

    /* 248DCT setup */
    s->fdct[1] = dsp.fdct248;
    s->idct_put[1] = simple_idct248_put;  // FIXME: need to add it to DSP
    if(avctx->lowres){
        for (i=0; i<64; i++){
            int j= ff_zigzag248_direct[i];
            s->dv_zigzag[1][i] = dsp.idct_permutation[(j&7) + (j&8)*4 + (j&48)/2];
        }
    }else
        memcpy(s->dv_zigzag[1], ff_zigzag248_direct, 64);

    /* XXX: do it only for constant case */
    dv_build_unquantize_tables(s, dsp.idct_permutation);

    /* FIXME: I really don't think this should be here */
    if (dv_codec_profile(avctx))
	avctx->pix_fmt = dv_codec_profile(avctx)->pix_fmt; 
    avctx->coded_frame = &s->picture;
    s->avctx= avctx;
    
    return 0;
}

// #define VLC_DEBUG
// #define printf(...) av_log(NULL, AV_LOG_ERROR, __VA_ARGS__)

typedef struct BlockInfo {
    const uint8_t *shift_table;
    const uint8_t *scan_table;
    uint8_t pos; /* position in block */
    uint8_t dct_mode;
    uint8_t partial_bit_count;
    uint16_t partial_bit_buffer;
    int shift_offset;
} BlockInfo;

/* block size in bits */
static const uint16_t block_sizes[6] = {
    112, 112, 112, 112, 80, 80
};
/* bit budget for AC only in 5 MBs */
static const int vs_total_ac_bits = (100 * 4 + 68*2) * 5;
/* see dv_88_areas and dv_248_areas for details */
static const int mb_area_start[5] = { 1, 6, 21, 43, 64 }; 

#ifndef ALT_BITSTREAM_READER
#warning only works with ALT_BITSTREAM_READER
static int re_index; //Hack to make it compile
#endif

static inline int get_bits_left(GetBitContext *s)
{
    return s->size_in_bits - get_bits_count(s);
}

static inline int get_bits_size(GetBitContext *s)
{
    return s->size_in_bits;
}

static inline int put_bits_left(PutBitContext* s)
{
    return (s->buf_end - s->buf) * 8 - put_bits_count(s);
}

/* decode ac coefs */
static void dv_decode_ac(GetBitContext *gb, BlockInfo *mb, DCTELEM *block)
{
    int last_index = get_bits_size(gb);
    const uint8_t *scan_table = mb->scan_table;
    const uint8_t *shift_table = mb->shift_table;
    int pos = mb->pos;
    int partial_bit_count = mb->partial_bit_count;
    int level, pos1, run, vlc_len, index;
    
    OPEN_READER(re, gb);
    UPDATE_CACHE(re, gb);
    
    /* if we must parse a partial vlc, we do it here */
    if (partial_bit_count > 0) {
        re_cache = ((unsigned)re_cache >> partial_bit_count) |
	           (mb->partial_bit_buffer << (sizeof(re_cache)*8 - partial_bit_count));
	re_index -= partial_bit_count;
	mb->partial_bit_count = 0;
    }

    /* get the AC coefficients until last_index is reached */
    for(;;) {
#ifdef VLC_DEBUG
        printf("%2d: bits=%04x index=%d\n", pos, SHOW_UBITS(re, gb, 16), re_index);
#endif
        /* our own optimized GET_RL_VLC */
        index = NEG_USR32(re_cache, TEX_VLC_BITS);
	vlc_len = dv_rl_vlc[index].len;
        if (vlc_len < 0) {
            index = NEG_USR32((unsigned)re_cache << TEX_VLC_BITS, -vlc_len) + dv_rl_vlc[index].level;
            vlc_len = TEX_VLC_BITS - vlc_len;
        }
        level = dv_rl_vlc[index].level;
	run = dv_rl_vlc[index].run;
	
	/* gotta check if we're still within gb boundaries */
	if (re_index + vlc_len > last_index) {
	    /* should be < 16 bits otherwise a codeword could have been parsed */
	    mb->partial_bit_count = last_index - re_index;
	    mb->partial_bit_buffer = NEG_USR32(re_cache, mb->partial_bit_count);
	    re_index = last_index;
	    break;