mjpeg.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。

    /* ugly way to get the idct & scantable FIXME */
    memset(&s2, 0, sizeof(MpegEncContext));
    s2.flags= avctx->flags;
    s2.avctx= avctx;
//    s2->out_format = FMT_MJPEG;
    s2.width = 8;
    s2.height = 8;
    if (MPV_common_init(&s2) < 0)
       return -1;
    s->scantable= s2.intra_scantable;
    s->idct_put= s2.dsp.idct_put;
    MPV_common_end(&s2);

    s->mpeg_enc_ctx_allocated = 0;
    s->buffer_size = 102400; /* smaller buffer should be enough,
				but photojpg files could ahive bigger sizes */
    s->buffer = av_malloc(s->buffer_size);
    if (!s->buffer)
	return -1;
    s->start_code = -1;
    s->first_picture = 1;
    s->org_width = avctx->width;
    s->org_height = avctx->height;
    
    build_vlc(&s->vlcs[0][0], bits_dc_luminance, val_dc_luminance, 12);
    build_vlc(&s->vlcs[0][1], bits_dc_chrominance, val_dc_chrominance, 12);
    build_vlc(&s->vlcs[1][0], bits_ac_luminance, val_ac_luminance, 251);
    build_vlc(&s->vlcs[1][1], bits_ac_chrominance, val_ac_chrominance, 251);

    if (avctx->flags & CODEC_FLAG_EXTERN_HUFF)
    {
	av_log(avctx, AV_LOG_INFO, "mjpeg: using external huffman table\n");
	init_get_bits(&s->gb, avctx->extradata, avctx->extradata_size*8);
	mjpeg_decode_dht(s);
	/* should check for error - but dunno */
    }

    return 0;
}

/* quantize tables */
static int mjpeg_decode_dqt(MJpegDecodeContext *s)
{
    int len, index, i, j;
    
    len = get_bits(&s->gb, 16) - 2;

    while (len >= 65) {
        /* only 8 bit precision handled */
        if (get_bits(&s->gb, 4) != 0)
	{
	    dprintf("dqt: 16bit precision\n");
            return -1;
	}
        index = get_bits(&s->gb, 4);
        if (index >= 4)
            return -1;
        dprintf("index=%d\n", index);
        /* read quant table */
        for(i=0;i<64;i++) {
            j = s->scantable.permutated[i];
	    s->quant_matrixes[index][j] = get_bits(&s->gb, 8);
        }

        //XXX FIXME finetune, and perhaps add dc too
        s->qscale[index]= FFMAX(
            s->quant_matrixes[index][s->scantable.permutated[1]],
            s->quant_matrixes[index][s->scantable.permutated[8]]) >> 1;
	dprintf("qscale[%d]: %d\n", index, s->qscale[index]);
        len -= 65;
    }
    
    return 0;
}

/* decode huffman tables and build VLC decoders */
static int mjpeg_decode_dht(MJpegDecodeContext *s)
{
    int len, index, i, class, n, v, code_max;
    uint8_t bits_table[17];
    uint8_t val_table[256];
    
    len = get_bits(&s->gb, 16) - 2;

    while (len > 0) {
        if (len < 17)
            return -1;
        class = get_bits(&s->gb, 4);
        if (class >= 2)
            return -1;
        index = get_bits(&s->gb, 4);
        if (index >= 4)
            return -1;
        n = 0;
        for(i=1;i<=16;i++) {
            bits_table[i] = get_bits(&s->gb, 8);
            n += bits_table[i];
        }
        len -= 17;
        if (len < n || n > 256)
            return -1;

        code_max = 0;
        for(i=0;i<n;i++) {
            v = get_bits(&s->gb, 8);
            if (v > code_max)
                code_max = v;
            val_table[i] = v;
        }
        len -= n;

        /* build VLC and flush previous vlc if present */
        free_vlc(&s->vlcs[class][index]);
        dprintf("class=%d index=%d nb_codes=%d\n",
               class, index, code_max + 1);
        if(build_vlc(&s->vlcs[class][index], bits_table, val_table, code_max + 1) < 0){
            return -1;
        }
    }
    return 0;
}

static int mjpeg_decode_sof(MJpegDecodeContext *s)
{
    int len, nb_components, i, width, height;

    /* XXX: verify len field validity */
    len = get_bits(&s->gb, 16);
    s->bits= get_bits(&s->gb, 8);
    
    if(s->pegasus_rct) s->bits=9;  
    if(s->bits==9 && !s->pegasus_rct) s->rct=1;    //FIXME ugly

    if (s->bits != 8 && !s->lossless){
        av_log(s->avctx, AV_LOG_ERROR, "only 8 bits/component accepted\n");
        return -1;
    }
    height = get_bits(&s->gb, 16);
    width = get_bits(&s->gb, 16);
    dprintf("sof0: picture: %dx%d\n", width, height);

    nb_components = get_bits(&s->gb, 8);
    if (nb_components <= 0 ||
        nb_components > MAX_COMPONENTS)
        return -1;
    s->nb_components = nb_components;
    s->h_max = 1;
    s->v_max = 1;
    for(i=0;i<nb_components;i++) {
        /* component id */
        s->component_id[i] = get_bits(&s->gb, 8) - 1;
        s->h_count[i] = get_bits(&s->gb, 4);
        s->v_count[i] = get_bits(&s->gb, 4);
        /* compute hmax and vmax (only used in interleaved case) */
        if (s->h_count[i] > s->h_max)
            s->h_max = s->h_count[i];
        if (s->v_count[i] > s->v_max)
            s->v_max = s->v_count[i];
        s->quant_index[i] = get_bits(&s->gb, 8);
        if (s->quant_index[i] >= 4)
            return -1;
        dprintf("component %d %d:%d id: %d quant:%d\n", i, s->h_count[i],
	    s->v_count[i], s->component_id[i], s->quant_index[i]);
    }
    
    if(s->v_max==1 && s->h_max==1 && s->lossless==1) s->rgb=1;

    /* if different size, realloc/alloc picture */
    /* XXX: also check h_count and v_count */
    if (width != s->width || height != s->height) {
        av_freep(&s->qscale_table);
            
        s->width = width;
        s->height = height;
        /* test interlaced mode */
        if (s->first_picture &&
            s->org_height != 0 &&
            s->height < ((s->org_height * 3) / 4)) {
            s->interlaced = 1;
//	    s->bottom_field = (s->interlace_polarity) ? 1 : 0;
	    s->bottom_field = 0;
        }

        s->qscale_table= av_mallocz((s->width+15)/16);

        s->first_picture = 0;
    }
    
    if(s->interlaced && s->bottom_field)
        return 0;
 
    /* XXX: not complete test ! */
    switch((s->h_count[0] << 4) | s->v_count[0]) {
    case 0x11:
        if(s->rgb){
            s->avctx->pix_fmt = PIX_FMT_RGBA32;
        }else
            s->avctx->pix_fmt = PIX_FMT_YUV444P;
        break;
    case 0x21:
        s->avctx->pix_fmt = PIX_FMT_YUV422P;
        break;
    default:
    case 0x22:
        s->avctx->pix_fmt = PIX_FMT_YUV420P;
        break;
    }

    if(s->picture.data[0])
        s->avctx->release_buffer(s->avctx, &s->picture);

    s->picture.reference= 0;
    if(s->avctx->get_buffer(s->avctx, &s->picture) < 0){
        av_log(s->avctx, AV_LOG_ERROR, "get_buffer() failed\n");
        return -1;
    }
    s->picture.pict_type= I_TYPE;
    s->picture.key_frame= 1;
    
    for(i=0; i<3; i++){
        s->linesize[i]= s->picture.linesize[i] << s->interlaced;
    }

//    printf("%d %d %d %d %d %d\n", s->width, s->height, s->linesize[0], s->linesize[1], s->interlaced, s->avctx->height);
    
    if (len != (8+(3*nb_components)))
    {
	dprintf("decode_sof0: error, len(%d) mismatch\n", len);
    }
    
    return 0;
}

static inline int mjpeg_decode_dc(MJpegDecodeContext *s, int dc_index)
{
    int code;
    code = get_vlc2(&s->gb, s->vlcs[0][dc_index].table, 9, 2);
    if (code < 0)
    {
	dprintf("mjpeg_decode_dc: bad vlc: %d:%d (%p)\n", 0, dc_index,
                &s->vlcs[0][dc_index]);
        return 0xffff;
    }

    if(code)
        return get_xbits(&s->gb, code);
    else
        return 0;
}

/* decode block and dequantize */
static int decode_block(MJpegDecodeContext *s, DCTELEM *block, 
                        int component, int dc_index, int ac_index, int quant_index)
{
    int code, i, j, level, val;
    VLC *ac_vlc;
    int16_t *quant_matrix;

    /* DC coef */
    val = mjpeg_decode_dc(s, dc_index);
    if (val == 0xffff) {
        dprintf("error dc\n");
        return -1;
    }
    quant_matrix = s->quant_matrixes[quant_index];
    val = val * quant_matrix[0] + s->last_dc[component];
    s->last_dc[component] = val;
    block[0] = val;
    /* AC coefs */
    ac_vlc = &s->vlcs[1][ac_index];
    i = 1;
    for(;;) {
	code = get_vlc2(&s->gb, s->vlcs[1][ac_index].table, 9, 2);

        if (code < 0) {
            dprintf("error ac\n");
            return -1;
        }
        /* EOB */
        if (code == 0)
            break;
        if (code == 0xf0) {
            i += 16;
        } else {
            level = get_xbits(&s->gb, code & 0xf);
            i += code >> 4;
            if (i >= 64) {
                dprintf("error count: %d\n", i);
                return -1;
            }
            j = s->scantable.permutated[i];
            block[j] = level * quant_matrix[j];
            i++;
            if (i >= 64)
                break;
        }
    }
    return 0;
}

static int ljpeg_decode_rgb_scan(MJpegDecodeContext *s, int predictor, int point_transform){
    int i, mb_x, mb_y;
    uint16_t buffer[2048][4];
    int left[3], top[3], topleft[3];
    const int linesize= s->linesize[0];
    const int mask= (1<<s->bits)-1;
    
    for(i=0; i<3; i++){
        buffer[0][i]= 1 << (s->bits + point_transform - 1);
    }
    for(mb_y = 0; mb_y < s->mb_height; mb_y++) {
        const int modified_predictor= mb_y ? predictor : 1;
        uint8_t *ptr = s->picture.data[0] + (linesize * mb_y);

        if (s->interlaced && s->bottom_field)
            ptr += linesize >> 1;

        for(i=0; i<3; i++){
            top[i]= left[i]= topleft[i]= buffer[0][i];
        }
        for(mb_x = 0; mb_x < s->mb_width; mb_x++) {
            if (s->restart_interval && !s->restart_count)
                s->restart_count = s->restart_interval;

            for(i=0;i<3;i++) {
                int pred;

                topleft[i]= top[i];
                top[i]= buffer[mb_x][i];

                PREDICT(pred, topleft[i], top[i], left[i], modified_predictor);
                
                left[i]= 
                buffer[mb_x][i]= mask & (pred + (mjpeg_decode_dc(s, s->dc_index[i]) << point_transform));
            }

            if (s->restart_interval && !--s->restart_count) {
                align_get_bits(&s->gb);
                skip_bits(&s->gb, 16); /* skip RSTn */
            }
        }

        if(s->rct){
            for(mb_x = 0; mb_x < s->mb_width; mb_x++) {
                ptr[4*mb_x+1] = buffer[mb_x][0] - ((buffer[mb_x][1] + buffer[mb_x][2] - 0x200)>>2);
                ptr[4*mb_x+0] = buffer[mb_x][1] + ptr[4*mb_x+1];
                ptr[4*mb_x+2] = buffer[mb_x][2] + ptr[4*mb_x+1];
            }
        }else if(s->pegasus_rct){
            for(mb_x = 0; mb_x < s->mb_width; mb_x++) {
                ptr[4*mb_x+1] = buffer[mb_x][0] - ((buffer[mb_x][1] + buffer[mb_x][2])>>2);
                ptr[4*mb_x+0] = buffer[mb_x][1] + ptr[4*mb_x+1];
                ptr[4*mb_x+2] = buffer[mb_x][2] + ptr[4*mb_x+1];
            }
        }else{
            for(mb_x = 0; mb_x < s->mb_width; mb_x++) {
                ptr[4*mb_x+0] = buffer[mb_x][0];
                ptr[4*mb_x+1] = buffer[mb_x][1];
                ptr[4*mb_x+2] = buffer[mb_x][2];
            }
        }
    }
    return 0;
}

static int ljpeg_decode_yuv_scan(MJpegDecodeContext *s, int predictor, int point_transform){
    int i, mb_x, mb_y;
    const int nb_components=3;

    for(mb_y = 0; mb_y < s->mb_height; mb_y++) {
        for(mb_x = 0; mb_x < s->mb_width; mb_x++) {
            if (s->restart_interval && !s->restart_count)
                s->restart_count = s->restart_interval;

            if(mb_x==0 || mb_y==0 || s->interlaced){
                for(i=0;i<nb_components;i++) {
                    uint8_t *ptr;
                    int n, h, v, x, y, c, j, linesize;
                    n = s->nb_blocks[i];
                    c = s->comp_index[i];
                    h = s->h_scount[i];
                    v = s->v_scount[i];
                    x = 0;
                    y = 0;
                    linesize= s->linesize[c];
                    
                    for(j=0; j<n; j++) {
                        int pred;

                        ptr = s->picture.data[c] + (linesize * (v * mb_y + y)) + (h * mb_x + x); //FIXME optimize this crap
                        if(y==0 && mb_y==0){
                            if(x==0 && mb_x==0){
                                pred= 128 << point_transform;
                            }else{
                                pred= ptr[-1];
                            }
                        }else{
                            if(x==0 && mb_x==0){
                                pred= ptr[-linesize];
                            }else{
                                PREDICT(pred, ptr[-linesize-1], ptr[-linesize], ptr[-1], predictor);
                            }
                        }
                        
                        if (s->interlaced && s->bottom_field)
                            ptr += linesize >> 1;
                        *ptr= pred + (mjpeg_decode_dc(s, s->dc_index[i]) << point_transform);

                        if (++x == h) {
                            x = 0;
                            y++;
                        }
                    }
                }
            }else{
                for(i=0;i<nb_components;i++) {
                    uint8_t *ptr;
                    int n, h, v, x, y, c, j, linesize;
                    n = s->nb_blocks[i];
                    c = s->comp_index[i];
                    h = s->h_scount[i];
                    v = s->v_scount[i];
                    x = 0;
                    y = 0;
                    linesize= s->linesize[c];