dv.c

arm平台下的H264编码和解码源代码

/*
 * 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"

typedef struct DVVideoContext {
    const DVprofile* sys;
    AVFrame picture;
    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
#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(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) {
	    av_free(dv_vlc_map);
	    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);

        dv_rl_vlc = av_malloc(dv_vlc.table_size * sizeof(RL_VLC_ELEM));
	if (!dv_rl_vlc) {
	    av_free(dv_anchor);
	    av_free(dv_vlc_map);
	    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 || dv_vlc_level[i] >= DV_VLC_MAP_LEV_SIZE)
	       continue;
	   
	   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
    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;
    
    return 0;
}

static int dvvideo_end(AVCodecContext *avctx)
{
    avcodec_default_free_buffers(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
#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;
	}
	re_index += vlc_len;

#ifdef VLC_DEBUG
	printf("run=%d level=%d\n", run, level);
#endif
	pos += run; 	
	if (pos >= 64)
	    break;
        
	if (level) {
            pos1 = scan_table[pos];
            block[pos1] = level << shift_table[pos1];
        } 

        UPDATE_CACHE(re, gb);
    }
    CLOSE_READER(re, gb);
    mb->pos = pos;
}

static inline void bit_copy(PutBitContext *pb, GetBitContext *gb)
{
    int bits_left = get_bits_left(gb);
    while (bits_left >= 16) {
        put_bits(pb, 16, get_bits(gb, 16));
        bits_left -= 16;
    }
    if (bits_left > 0) {
        put_bits(pb, bits_left, get_bits(gb, bits_left));
    }
}

/* mb_x and mb_y are in units of 8 pixels */
static inline void dv_decode_video_segment(DVVideoContext *s, 
                                           uint8_t *buf_ptr1, 
                                           const uint16_t *mb_pos_ptr)
{
    int quant, dc, dct_mode, class1, j;
    int mb_index, mb_x, mb_y, v, last_index;
    DCTELEM *block, *block1;
    int c_offset;
    uint8_t *y_ptr;
    void (*idct_put)(uint8_t *dest, int line_size, DCTELEM *block);
    uint8_t *buf_ptr;
    PutBitContext pb, vs_pb;
    GetBitContext gb;
    BlockInfo mb_data[5 * 6], *mb, *mb1;
    DCTELEM sblock[5*6][64] __align8;
    uint8_t mb_bit_buffer[80 + 4]; /* allow some slack */
    uint8_t vs_bit_buffer[5 * 80 + 4]; /* allow some slack */
	    
    memset(sblock, 0, sizeof(sblock));

    /* pass 1 : read DC and AC coefficients in blocks */
    buf_ptr = buf_ptr1;
    block1 = &sblock[0][0];
    mb1 = mb_data;
    init_put_bits(&vs_pb, vs_bit_buffer, 5 * 80);
    for(mb_index = 0; mb_index < 5; mb_index++, mb1 += 6, block1 += 6 * 64) {
        /* skip header */
        quant = buf_ptr[3] & 0x0f;
        buf_ptr += 4;
        init_put_bits(&pb, mb_bit_buffer, 80);
        mb = mb1;
        block = block1;
        for(j = 0;j < 6; j++) {
            last_index = block_sizes[j];
	    init_get_bits(&gb, buf_ptr, last_index);
            
            /* get the dc */
            dc = get_bits(&gb, 9);
            dc = (dc << (32 - 9)) >> (32 - 9);
            dct_mode = get_bits1(&gb);
            mb->dct_mode = dct_mode;
            mb->scan_table = s->dv_zigzag[dct_mode];
            class1 = get_bits(&gb, 2);
            mb->shift_table = s->dv_idct_shift[class1 == 3][dct_mode]
                [quant + dv_quant_offset[class1]];
            dc = dc << 2;
            /* convert to unsigned because 128 is not added in the
               standard IDCT */
            dc += 1024;
            block[0] = dc;
            buf_ptr += last_index >> 3;
            mb->pos = 0;
            mb->partial_bit_count = 0;

#ifdef VLC_DEBUG
            printf("MB block: %d, %d ", mb_index, j);
#endif
            dv_decode_ac(&gb, mb, block);

            /* write the remaining bits  in a new buffer only if the
               block is finished */
            if (mb->pos >= 64)
                bit_copy(&pb, &gb);
            
            block += 64;
            mb++;
        }
        
        /* pass 2 : we can do it just after */
#ifdef VLC_DEBUG
        printf("***pass 2 size=%d MB#=%d\n", put_bits_count(&pb), mb_index);
#endif
        block = block1;
        mb = mb1;
        init_get_bits(&gb, mb_bit_buffer, put_bits_count(&pb));
	flush_put_bits(&pb);
        for(j = 0;j < 6; j++, block += 64, mb++) {
            if (mb->pos < 64 && get_bits_left(&gb) > 0) {
                dv_decode_ac(&gb, mb, block);
                /* if still not finished, no need to parse other blocks */
                if (mb->pos < 64)
                    break;
            }
        }
        /* all blocks are finished, so the extra bytes can be used at
           the video segment level */
        if (j >= 6)
	    bit_copy(&vs_pb, &gb);
    }

    /* we need a pass other the whole video segment */
#ifdef VLC_DEBUG
    printf("***pass 3 size=%d\n", put_bits_count(&vs_pb));
#endif
    block = &sblock[0][0];
    mb = mb_data;
    init_get_bits(&gb, vs_bit_buffer, put_bits_count(&vs_pb));
    flush_put_bits(&vs_pb);
    for(mb_index = 0; mb_index < 5; mb_index++) {
        for(j = 0;j < 6; j++) {
            if (mb->pos < 64) {
#ifdef VLC_DEBUG
                printf("start %d:%d\n", mb_index, j);
#endif
                dv_decode_ac(&gb, mb, block);
            }
	    if (mb->pos >= 64 && mb->pos < 127)
		av_log(NULL, AV_LOG_ERROR, "AC EOB marker is absent pos=%d\n", mb->pos);
            block += 64;
            mb++;
        }
    }
    
    /* compute idct and place blocks */
    block = &sblock[0][0];
    mb = mb_data;
    for(mb_index = 0; mb_index < 5; mb_index++) {
        v = *mb_pos_ptr++;
        mb_x = v & 0xff;
        mb_y = v >> 8;
        y_ptr = s->picture.data[0] + (mb_y * s->picture.linesize[0] * 8) + (mb_x * 8);
        if (s->sys->pix_fmt == PIX_FMT_YUV411P)
            c_offset = (mb_y * s->picture.linesize[1] * 8) + ((mb_x >> 2) * 8);
        else
            c_offset = ((mb_y >> 1) * s->picture.linesize[1] * 8) + ((mb_x >> 1) * 8);
        for(j = 0;j < 6; j++) {
            idct_put = s->idct_put[mb->dct_mode];