dv.c

来自「Trolltech公司发布的图形界面操作系统。可在qt-embedded-2.3」· C语言 代码 · 共 958 行 · 第 1/2 页

                if (s->sys->pix_fmt == PIX_FMT_YUV411P && mb_x < (704 / 8)) {
                    /* NOTE: at end of line, the macroblock is handled as 420 */
                    idct_put(y_ptr + (j * 8), s->picture.linesize[0], block);
                } else {
                    idct_put(y_ptr + ((j & 1) * 8) + ((j >> 1) * 8 * s->picture.linesize[0]),
                             s->picture.linesize[0], block);
                }
            } else {
                if (s->sys->pix_fmt == PIX_FMT_YUV411P && mb_x >= (704 / 8)) {
                    uint64_t aligned_pixels[64/8];
                    uint8_t *pixels= (uint8_t*)aligned_pixels;
		    uint8_t *c_ptr, *c_ptr1, *ptr;
                    int y, linesize;
                    /* NOTE: at end of line, the macroblock is handled as 420 */
                    idct_put(pixels, 8, block);
                    linesize = s->picture.linesize[6 - j];
                    c_ptr = s->picture.data[6 - j] + c_offset;
                    ptr = pixels;
                    for(y = 0;y < 8; y++) {
                        /* convert to 411P */
                        c_ptr1 = c_ptr + 8*linesize;
                        c_ptr[0]= ptr[0]; c_ptr1[0]= ptr[4];
                        c_ptr[1]= ptr[1]; c_ptr1[1]= ptr[5];
                        c_ptr[2]= ptr[2]; c_ptr1[2]= ptr[6];
                        c_ptr[3]= ptr[3]; c_ptr1[3]= ptr[7];
                        c_ptr += linesize;
                        ptr += 8;
                    }
                } else {
                    /* don't ask me why they inverted Cb and Cr ! */
                    idct_put(s->picture.data[6 - j] + c_offset, 
                             s->picture.linesize[6 - j], block);
                }
            }
            block += 64;
            mb++;
        }
    }
}

/* Converts run and level (where level != 0) pair into vlc, returning bit size */
static inline int dv_rl2vlc(int run, int l, uint32_t* vlc)
{
    int sign = l >> 8;
    int level = (l ^ sign) - sign;
    int size;
    
    sign = (sign & 1);

    if (run < 15 && level < 23 && dv_vlc_codes[run][level] != -1) {
        *vlc = (dv_vlc_bits[dv_vlc_codes[run][level]] << 1) | sign; 
	size = dv_vlc_len[dv_vlc_codes[run][level]] + 1;
    }
    else { 
	if (level < 23) {
	    *vlc = (dv_vlc_bits[dv_vlc_codes[0][level]] << 1) | sign; 
	    size = dv_vlc_len[dv_vlc_codes[0][level]] + 1;
	} else {
	    *vlc = 0xfe00 | (level << 1) | sign;
	    size = 16;
	}

	switch(run) {
	case 0:
	    break;
	case 1:
	case 2:
	    *vlc |= ((0x7ce | (run - 1)) << size);
	    size += 11;
	    break;
	case 3:
	case 4:
	case 5:
	case 6:
	    *vlc |= ((0xfac | (run - 3)) << size);
	    size += 12;
	    break;
	default:
	    *vlc |= ((0x1f80 | (run - 1)) << size);
	    size += 13;
	    break;
	}
    }
    
    return size;
}

typedef struct EncBlockInfo {
    int qno;
    int cno;
    int dct_mode;
    int block_size;
    DCTELEM *mb;
    PutBitContext pb;
    const uint8_t* zigzag_scan;
    uint8_t *dv_shift;
} EncBlockInfo;

static inline int dv_bits_left(EncBlockInfo* bi)
{
    return (bi->block_size - get_bit_count(&bi->pb));
}

static inline void dv_encode_ac(EncBlockInfo* bi, PutBitContext* heap)
{
    int i, level, size, run = 0;
    uint32_t vlc;
    PutBitContext* cpb = &bi->pb;
    int bias = (bi->cno == 3);
    
    for (i=1; i<64; i++) {
       level = bi->mb[bi->zigzag_scan[i]] / (1<<(bi->dv_shift[i] + bias));
       if (level != 0) {
	   size = dv_rl2vlc(run, level, &vlc);
put_vlc:

#ifdef VLC_DEBUG
           printf(" %3d:%3d", run, level);
#endif
	   if (cpb == &bi->pb && size > dv_bits_left(bi)) {
	       size -= dv_bits_left(bi);
	       put_bits(cpb, dv_bits_left(bi), vlc >> size);
	       vlc = vlc & ((1<<size)-1);
	       cpb = heap;
	   }
	   put_bits(cpb, size, vlc);
	   run = 0;
       } else
	   run++;
    }
   
    if (i == 64) {
        size = 4; vlc = 6; /* End Of Block stamp */
	goto put_vlc;
    }
}

static inline void dv_redistr_bits(EncBlockInfo* bi, int count, uint8_t* extra_data, int extra_bits, PutBitContext* heap)
{
    int i;
    GetBitContext gb;
    
    init_get_bits(&gb, extra_data, extra_bits);
    
    for (i=0; i<count; i++) {
       int bits_left = dv_bits_left(bi);
#ifdef VLC_DEBUG
       if (bits_left)
           printf("------------> inserting %d bytes in %d:%d\n", bits_left, i/6, i%6);
#endif
       if (bits_left > extra_bits) {
           bit_copy(&bi->pb, &gb, extra_bits); 
	   extra_bits = 0;
	   break;
       } else
           bit_copy(&bi->pb, &gb, bits_left);
	   
       extra_bits -= bits_left;
       bi++;
    }
    
    if (extra_bits > 0 && heap)
	bit_copy(heap, &gb, extra_bits);
}

static inline void dv_set_class_number(EncBlockInfo* bi, int j)
{
    int i, max_ac = 0;

    for (i=1; i<64; i++) {
       int ac = abs(bi->mb[ff_zigzag_direct[i]]) / 4;
       if (max_ac < ac)
           max_ac = ac;
    }
    if (max_ac < 12)
        bi->cno = j;
    else if (max_ac < 24)
        bi->cno = j + 1;
    else if (max_ac < 36)
        bi->cno = j + 2;
    else
        bi->cno = j + 3;
    
    if (bi->cno > 3)
        bi->cno = 3;
}

#define SQ(a) ((a)*(a))
static int dv_score_lines(DCTELEM *s, int stride) {
    int score=0;
    int x, y;
    
    for(y=0; y<4; y++) {
        for(x=0; x<8; x+=4){
            score+= SQ(s[x  ] - s[x  +stride]) + SQ(s[x+1] - s[x+1+stride]) 
                   +SQ(s[x+2] - s[x+2+stride]) + SQ(s[x+3] - s[x+3+stride]);
        }
        s+= stride;
    }
    
    return score;
}

/*
 * This is a very rough initial implementaion. The performance is
 * horrible and the weighting is missing. But it's missing from the 
 * decoding step also -- so at least we're on the same page with decoder ;-)
 */
static inline void dv_encode_video_segment(DVVideoDecodeContext *s, 
                                           uint8_t *dif, 
                                           const uint16_t *mb_pos_ptr)
{
    int mb_index, i, j, v;
    int mb_x, mb_y, c_offset, linesize; 
    uint8_t*  y_ptr;
    uint8_t*  data;
    int       do_edge_wrap;
    DCTELEM  *block;
    EncBlockInfo  enc_blks[5*6];
    EncBlockInfo* enc_blk;
    int       free_vs_bits;
    int extra_bits;
    PutBitContext extra_vs;
    uint8_t   extra_vs_data[5*6*128];
    uint8_t   extra_mb_data[6*128];

    int       QNO = 15;
   
    /* Stage 1 -- doing DCT on 5 MBs */
    block = &s->block[0][0];
    enc_blk = &enc_blks[0];
    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);
	c_offset = (s->sys->pix_fmt == PIX_FMT_YUV411P) ?
	           ((mb_y * s->picture.linesize[1] * 8) + ((mb_x >> 2) * 8)) :
		   (((mb_y >> 1) * s->picture.linesize[1] * 8) + ((mb_x >> 1) * 8));
	do_edge_wrap = 0;
        for(j = 0;j < 6; j++) {
            if (j < 4) {  /* Four Y blocks */
		/* NOTE: at end of line, the macroblock is handled as 420 */
		if (s->sys->pix_fmt == PIX_FMT_YUV411P && mb_x < (704 / 8)) {
                    data = y_ptr + (j * 8);
                } else {
                    data = y_ptr + ((j & 1) * 8) + ((j >> 1) * 8 * s->picture.linesize[0]);
                }
		linesize = s->picture.linesize[0];
            } else {      /* Cr and Cb blocks */
	        /* don't ask Fabrice why they inverted Cb and Cr ! */
	        data = s->picture.data[6 - j] + c_offset;
		linesize = s->picture.linesize[6 - j];
		if (s->sys->pix_fmt == PIX_FMT_YUV411P && mb_x >= (704 / 8))
		    do_edge_wrap = 1;
	    }	
            
	    /* Everything is set up -- now just copy data -> DCT block */
	    if (do_edge_wrap) {  /* Edge wrap copy: 4x16 -> 8x8 */
		uint8_t* d;
		DCTELEM *b = block;
	        for (i=0;i<8;i++) {
		   d = data + 8 * linesize;
		   b[0] = data[0]; b[1] = data[1]; b[2] = data[2]; b[3] = data[3];
                   b[4] =    d[0]; b[5] =    d[1]; b[6] =    d[2]; b[7] =    d[3];
		   data += linesize;
		   b += 8;
		}
	    } else {             /* Simple copy: 8x8 -> 8x8 */
	        s->get_pixels(block, data, linesize);
	    }
	  
	    if (dv_score_lines(block, 8) + dv_score_lines(block+8*4, 8) - 100 >
	        dv_score_lines(block, 16) + dv_score_lines(block+8, 16)) {
               enc_blk->dct_mode = 1;
	       enc_blk->zigzag_scan = ff_zigzag248_direct; 
	    } else {
	       enc_blk->dct_mode = 0;
	       enc_blk->zigzag_scan = ff_zigzag_direct;
	    }
	    enc_blk->mb = block;
            enc_blk->block_size = block_sizes[j];
	    
	    s->fdct[enc_blk->dct_mode](block);
	    
	    dv_set_class_number(enc_blk, j/4*(j%2));

	    block += 64;
	    enc_blk++;
        }
    }

    /* Stage 2 -- encoding by trial-and-error */
encode_vs:
    enc_blk = &enc_blks[0];
    for (i=0; i<5; i++) {
       uint8_t* p = dif + i*80 + 4;
       for (j=0; j<6; j++) {
          enc_blk->qno = QNO;
	  enc_blk->dv_shift = &(s->dv_dct_shift[0]
	                           [QNO + dv_quant_offset[enc_blk->cno]][0]);
	  init_put_bits(&enc_blk->pb, p, block_sizes[j]/8);
	  enc_blk++;
	  p += block_sizes[j]/8;
       }
    }

    init_put_bits(&extra_vs, extra_vs_data, sizeof(extra_vs_data));
    free_vs_bits = 0;
    enc_blk = &enc_blks[0];
    for (i=0; i<5; i++) {
       PutBitContext extra_mb;
       EncBlockInfo* enc_blk2 = enc_blk;
       int free_mb_bits = 0;

       init_put_bits(&extra_mb, extra_mb_data, sizeof(extra_mb_data));
       dif[i*80 + 3] = enc_blk->qno;
       
       for (j=0; j<6; j++) {
	  uint16_t dc = ((enc_blk->mb[0] >> 3) - 1024) >> 2;

	  put_bits(&enc_blk->pb, 9, dc);
	  put_bits(&enc_blk->pb, 1, enc_blk->dct_mode);
	  put_bits(&enc_blk->pb, 2, enc_blk->cno);

#ifdef VLC_DEBUG
          printf("[%d, %d]: ", i, j);
#endif
	  dv_encode_ac(enc_blk, &extra_mb);
#ifdef VLC_DEBUG
          printf("\n");
#endif
	  
	  free_mb_bits += dv_bits_left(enc_blk);
	  enc_blk++;
       }
       
       /* We can't flush extra_mb just yet -- since it'll round up bit number */
       extra_bits = get_bit_count(&extra_mb);
       if (free_mb_bits > extra_bits)
           free_vs_bits += free_mb_bits - extra_bits;
    
       if (extra_bits) {  /* FIXME: speed up things when free_mb_bits == 0 */
           flush_put_bits(&extra_mb);
           dv_redistr_bits(enc_blk2, 6, extra_mb_data, extra_bits, &extra_vs);
       }
    }
    
    /* We can't flush extra_mb just yet -- since it'll round up bit number */
    extra_bits = get_bit_count(&extra_vs);
    if (extra_bits > free_vs_bits && QNO) { /* FIXME: very crude trial-and-error */
        QNO--;
	goto encode_vs;
    }
    
    if (extra_bits) {
        flush_put_bits(&extra_vs);
        dv_redistr_bits(&enc_blks[0], 5*6, extra_vs_data, extra_bits, NULL);
    }

    for (i=0; i<6*5; i++) {
       flush_put_bits(&enc_blks[i].pb);
#ifdef VLC_DEBUG
       printf("[%d:%d] qno=%d cno=%d\n", i/6, i%6, enc_blks[i].qno, enc_blks[i].cno);
#endif
    }
}

/* NOTE: exactly one frame must be given (120000 bytes for NTSC,
   144000 bytes for PAL) */
static int dvvideo_decode_frame(AVCodecContext *avctx, 
                                 void *data, int *data_size,
                                 uint8_t *buf, int buf_size)
{
    DVVideoDecodeContext *s = avctx->priv_data;
    int ds, vs;
    const uint16_t *mb_pos_ptr;
    
    s->sys = dv_frame_profile(buf);
    if (!s->sys || buf_size < s->sys->frame_size)
        return -1; /* NOTE: we only accept several full frames */

	
    if(s->picture.data[0])
        avctx->release_buffer(avctx, &s->picture);
    
    s->picture.reference = 0;
    avctx->pix_fmt = s->sys->pix_fmt;
    avctx->width = s->sys->width;
    avctx->height = s->sys->height;
    if(avctx->get_buffer(avctx, &s->picture) < 0) {
        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
        return -1;
    }
    s->picture.interlaced_frame = 1;
    s->picture.top_field_first = 0;

    /* for each DIF segment */
    mb_pos_ptr = s->sys->video_place;
    for (ds = 0; ds < s->sys->difseg_size; ds++) {
        buf += 6 * 80; /* skip DIF segment header */
        
        for(vs = 0; vs < 27; vs++) {
            if ((vs % 3) == 0)
	        buf += 80; /* skip audio block */
            
#ifdef VLC_DEBUG
            printf("********************* %d, %d **********************\n", ds, vs);
#endif
	    dv_decode_video_segment(s, buf, mb_pos_ptr);
            buf += 5 * 80;
            mb_pos_ptr += 5;
        }
    }

    emms_c();

    /* return image */
    *data_size = sizeof(AVFrame);
    *(AVFrame*)data= s->picture;
    
    return s->sys->frame_size;
}

static int dvvideo_encode_frame(AVCodecContext *c, uint8_t *buf, int buf_size, 
                                void *data)
{
    DVVideoDecodeContext *s = c->priv_data;
    const uint16_t *mb_pos_ptr;
    int ds, vs;

    s->sys = dv_codec_profile(c);
    if (!s->sys)
	return -1;
    
    c->pix_fmt = s->sys->pix_fmt;
    s->picture = *((AVFrame *)data);

    /* for each DIF segment */
    mb_pos_ptr = s->sys->video_place;
    for (ds = 0; ds < s->sys->difseg_size; ds++) {
        buf += 6 * 80; /* skip DIF segment header */
        
        for(vs = 0; vs < 27; vs++) {
            if ((vs % 3) == 0)
	        buf += 80; /* skip audio block */

#ifdef VLC_DEBUG
            printf("********************* %d, %d **********************\n", ds, vs);
#endif
	    dv_encode_video_segment(s, buf, mb_pos_ptr);
            buf += 5 * 80;
            mb_pos_ptr += 5;
        }
    }

    emms_c();
    return s->sys->frame_size;
}

static int dvvideo_end(AVCodecContext *avctx)
{
    avcodec_default_free_buffers(avctx);    
    return 0;
}

AVCodec dvvideo_decoder = {
    "dvvideo",
    CODEC_TYPE_VIDEO,
    CODEC_ID_DVVIDEO,
    sizeof(DVVideoDecodeContext),
    dvvideo_init,
    dvvideo_encode_frame,
    dvvideo_end,
    dvvideo_decode_frame,
    CODEC_CAP_DR1,
    NULL
};