mjpeg.c

Trolltech公司发布的图形界面操作系统。可在qt-embedded-2.3.7平台上编译为嵌入式图形界面操作系统。

        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 different size, realloc/alloc picture */
    /* XXX: also check h_count and v_count */
    if (width != s->width || height != s->height) {
        for(i=0;i<MAX_COMPONENTS;i++)
            av_freep(&s->current_picture[i]);
        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;
        }

        for(i=0;i<nb_components;i++) {
            int w, h;
            w = (s->width  + 8 * s->h_max - 1) / (8 * s->h_max);
            h = (s->height + 8 * s->v_max - 1) / (8 * s->v_max);
            w = w * 8 * s->h_count[i];
            h = h * 8 * s->v_count[i];
            if (s->interlaced)
                w *= 2;
            s->linesize[i] = w;
            /* memory test is done in mjpeg_decode_sos() */
            s->current_picture[i] = av_mallocz(w * h);
        }
        s->first_picture = 0;
    }

    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, diff;
#if 1
    code = get_vlc2(&s->gb, s->vlcs[0][dc_index].table, 9, 2);
#else
    code = get_vlc(&s->gb, &s->vlcs[0][dc_index]);
#endif
    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 == 0) {
        diff = 0;
    } else {
        diff = get_bits(&s->gb, code);
        if ((diff & (1 << (code - 1))) == 0) 
            diff = (-1 << code) | (diff + 1);
    }
    return diff;
}

/* decode block and dequantize */
static int decode_block(MJpegDecodeContext *s, DCTELEM *block, 
                        int component, int dc_index, int ac_index, int quant_index)
{
    int nbits, code, i, j, level;
    int run, val;
    VLC *ac_vlc;
    INT16 *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(;;) {
#if 1
	code = get_vlc2(&s->gb, s->vlcs[1][ac_index].table, 9, 2);
#else
        code = get_vlc(&s->gb, ac_vlc);
#endif
        if (code < 0) {
            dprintf("error ac\n");
            return -1;
        }
        /* EOB */
        if (code == 0)
            break;
        if (code == 0xf0) {
            i += 16;
        } else {
            run = code >> 4;
            nbits = code & 0xf;
            level = get_bits(&s->gb, nbits);
            if ((level & (1 << (nbits - 1))) == 0) 
                level = (-1 << nbits) | (level + 1);
            i += run;
            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 mjpeg_decode_sos(MJpegDecodeContext *s)
{
    int len, nb_components, i, j, n, h, v, ret;
    int mb_width, mb_height, mb_x, mb_y, vmax, hmax, index, id;
    int comp_index[4];
    int dc_index[4];
    int ac_index[4];
    int nb_blocks[4];
    int h_count[4];
    int v_count[4];
    
    /* XXX: verify len field validity */
    len = get_bits(&s->gb, 16);
    nb_components = get_bits(&s->gb, 8);
    if (len != 6+2*nb_components)
    {
	dprintf("decode_sos: invalid len (%d)\n", len);
	return -1;
    }
    /* XXX: only interleaved scan accepted */
    if (nb_components != 3)
    {
	dprintf("decode_sos: components(%d) mismatch\n", nb_components);
        return -1;
    }
    vmax = 0;
    hmax = 0;
    for(i=0;i<nb_components;i++) {
        id = get_bits(&s->gb, 8) - 1;
	dprintf("component: %d\n", id);
        /* find component index */
        for(index=0;index<s->nb_components;index++)
            if (id == s->component_id[index])
                break;
        if (index == s->nb_components)
	{
	    dprintf("decode_sos: index(%d) out of components\n", index);
            return -1;
	}

        comp_index[i] = index;
        nb_blocks[i] = s->h_count[index] * s->v_count[index];
        h_count[i] = s->h_count[index];
        v_count[i] = s->v_count[index];

        dc_index[i] = get_bits(&s->gb, 4);
        ac_index[i] = get_bits(&s->gb, 4);

	if (dc_index[i] < 0 || ac_index[i] < 0 ||
	    dc_index[i] >= 4 || ac_index[i] >= 4)
	    goto out_of_range;
	switch(s->start_code)
	{
	    case SOF0:
		if (dc_index[i] > 1 || ac_index[i] > 1)
		    goto out_of_range;
		break;
	    case SOF1:
	    case SOF2:
		if (dc_index[i] > 3 || ac_index[i] > 3)
		    goto out_of_range;
		break;
	    case SOF3:
		if (dc_index[i] > 3 || ac_index[i] != 0)
		    goto out_of_range;
		break;	
	}
    }
    skip_bits(&s->gb, 8); /* Ss */
    skip_bits(&s->gb, 8); /* Se */
    skip_bits(&s->gb, 8); /* Ah and Al (each are 4 bits) */

    for(i=0;i<nb_components;i++) 
        s->last_dc[i] = 1024;

    if (nb_components > 1) {
        /* interleaved stream */
        mb_width = (s->width + s->h_max * 8 - 1) / (s->h_max * 8);
        mb_height = (s->height + s->v_max * 8 - 1) / (s->v_max * 8);
    } else {
        h = s->h_max / s->h_count[comp_index[0]];
        v = s->v_max / s->v_count[comp_index[0]];
        mb_width = (s->width + h * 8 - 1) / (h * 8);
        mb_height = (s->height + v * 8 - 1) / (v * 8);
        nb_blocks[0] = 1;
        h_count[0] = 1;
        v_count[0] = 1;
    }
    
    for(mb_y = 0; mb_y < mb_height; mb_y++) {
        for(mb_x = 0; mb_x < mb_width; mb_x++) {
            for(i=0;i<nb_components;i++) {
                UINT8 *ptr;
                int x, y, c;
                n = nb_blocks[i];
                c = comp_index[i];
                h = h_count[i];
                v = v_count[i];
                x = 0;
                y = 0;
		if (s->restart_interval && !s->restart_count)
		    s->restart_count = s->restart_interval;
                for(j=0;j<n;j++) {
                    memset(s->block, 0, sizeof(s->block));
                    if (decode_block(s, s->block, i, 
                                     dc_index[i], ac_index[i], 
                                     s->quant_index[c]) < 0) {
                        dprintf("error y=%d x=%d\n", mb_y, mb_x);
                        ret = -1;
                        goto the_end;
                    }
//		    dprintf("mb: %d %d processed\n", mb_y, mb_x);
                    ptr = s->current_picture[c] + 
                        (s->linesize[c] * (v * mb_y + y) * 8) + 
                        (h * mb_x + x) * 8;
                    if (s->interlaced && s->bottom_field)
                        ptr += s->linesize[c] >> 1;
                    s->idct_put(ptr, s->linesize[c], s->block);
                    if (++x == h) {
                        x = 0;
                        y++;
                    }
                }
            }
	    /* (< 1350) buggy workaround for Spectralfan.mov, should be fixed */
            if (s->restart_interval && (s->restart_interval < 1350) &&
		!--s->restart_count) {
                align_get_bits(&s->gb);
                skip_bits(&s->gb, 16); /* skip RSTn */
                for (j=0; j<nb_components; j++) /* reset dc */
                    s->last_dc[j] = 1024;
            }
        }
    }
    ret = 0;
 the_end:
    emms_c();
    return ret;
 out_of_range:
    dprintf("decode_sos: ac/dc index out of range\n");
    return -1;
}

static int mjpeg_decode_dri(MJpegDecodeContext *s)
{
    if (get_bits(&s->gb, 16) != 4)
	return -1;
    s->restart_interval = get_bits(&s->gb, 16);
    dprintf("restart interval: %d\n", s->restart_interval);

    return 0;
}

static int mjpeg_decode_app(MJpegDecodeContext *s)
{
    int len, id;

    /* XXX: verify len field validity */
    len = get_bits(&s->gb, 16);
    if (len < 5)
	return -1;

    id = (get_bits(&s->gb, 16) << 16) | get_bits(&s->gb, 16);
    id = be2me_32(id);
    len -= 6;

    /* buggy AVID, it puts EOI only at every 10th frame */
    /* also this fourcc is used by non-avid files too, it holds some
       informations, but it's always present in AVID creates files */
    if (id == ff_get_fourcc("AVI1"))
    {
	/* structure:
	    4bytes	AVI1
	    1bytes	polarity
	    1bytes	always zero
	    4bytes	field_size
	    4bytes	field_size_less_padding
	*/
    	s->buggy_avid = 1;
//	if (s->first_picture)
//	    printf("mjpeg: workarounding buggy AVID\n");
	s->interlace_polarity = get_bits(&s->gb, 8);
#if 0
	skip_bits(&s->gb, 8);
	skip_bits(&s->gb, 32);
	skip_bits(&s->gb, 32);
	len -= 10;
#endif
//	if (s->interlace_polarity)
//	    printf("mjpeg: interlace polarity: %d\n", s->interlace_polarity);
	goto out;
    }
    
//    len -= 2;
    
    if (id == ff_get_fourcc("JFIF"))
    {
	int t_w, t_h;
	skip_bits(&s->gb, 8); /* the trailing zero-byte */
	printf("mjpeg: JFIF header found (version: %x.%x)\n",
	    get_bits(&s->gb, 8), get_bits(&s->gb, 8));
	if (get_bits(&s->gb, 8) == 0)
	{
	    s->avctx->aspect_ratio_info = FF_ASPECT_EXTENDED;
	    s->avctx->aspected_width = get_bits(&s->gb, 16);
	    s->avctx->aspected_height = get_bits(&s->gb, 16);
	}
	else
	{
	    skip_bits(&s->gb, 16);
	    skip_bits(&s->gb, 16);
	}
	t_w = get_bits(&s->gb, 8);
	t_h = get_bits(&s->gb, 8);
	if (t_w && t_h)
	{
	    /* skip thumbnail */
	    if (len-10-(t_w*t_h*3) > 0)
		len -= t_w*t_h*3;
	}
	len -= 10;
	goto out;
    }
    
    if (id == ff_get_fourcc("Adob") && (get_bits(&s->gb, 8) == 'e'))
    {
	printf("mjpeg: Adobe header found\n");
	skip_bits(&s->gb, 16); /* version */
	skip_bits(&s->gb, 16); /* flags0 */
	skip_bits(&s->gb, 16); /* flags1 */
	skip_bits(&s->gb, 8); /* transform */
	len -= 7;
	goto out;
    }
    
    /* Apple MJPEG-A */
    if ((s->start_code == APP1) && (len > (0x28 - 8)))
    {
	id = (get_bits(&s->gb, 16) << 16) | get_bits(&s->gb, 16);
	id = be2me_32(id);
	len -= 4;
	if (id == ff_get_fourcc("mjpg")) /* Apple MJPEG-A */
	{
#if 0
	    skip_bits(&s->gb, 32); /* field size */
	    skip_bits(&s->gb, 32); /* pad field size */
	    skip_bits(&s->gb, 32); /* next off */
	    skip_bits(&s->gb, 32); /* quant off */
	    skip_bits(&s->gb, 32); /* huff off */
	    skip_bits(&s->gb, 32); /* image off */
	    skip_bits(&s->gb, 32); /* scan off */
	    skip_bits(&s->gb, 32); /* data off */
#endif
	    if (s->first_picture)
		printf("mjpeg: Apple MJPEG-A header found\n");
	}
    }

out:
    /* slow but needed for extreme adobe jpegs */
    if (len < 0)
	printf("mjpeg: error, decode_app parser read over the end\n");
    while(--len > 0)
	skip_bits(&s->gb, 8);

    return 0;
}

static int mjpeg_decode_com(MJpegDecodeContext *s)
{
    int len, i;
    UINT8 *cbuf;

    /* XXX: verify len field validity */
    len = get_bits(&s->gb, 16)-2;
    cbuf = av_malloc(len+1);

    for (i = 0; i < len; i++)
	cbuf[i] = get_bits(&s->gb, 8);
    if (cbuf[i-1] == '\n')
	cbuf[i-1] = 0;
    else
	cbuf[i] = 0;

    printf("mjpeg comment: '%s'\n", cbuf);