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。

    /* buggy avid, it puts EOI only at every 10th frame */
    if (!strcmp(cbuf, "AVID"))
    {
	s->buggy_avid = 1;
//	if (s->first_picture)
//	    printf("mjpeg: workarounding buggy AVID\n");
    }
    
    av_free(cbuf);

    return 0;
}

#if 0
static int valid_marker_list[] =
{
        /* 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, a, b, c, d, e, f */
/* 0 */    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* 1 */    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* 2 */    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* 3 */    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* 4 */    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* 5 */    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* 6 */    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* 7 */    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* 8 */    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* 9 */    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* a */    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* b */    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
/* c */    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
/* d */    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
/* e */    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
/* f */    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0,
}
#endif

/* return the 8 bit start code value and update the search
   state. Return -1 if no start code found */
static int find_marker(UINT8 **pbuf_ptr, UINT8 *buf_end)
{
    UINT8 *buf_ptr;
    unsigned int v, v2;
    int val;
#ifdef DEBUG
    int skipped=0;
#endif

    buf_ptr = *pbuf_ptr;
    while (buf_ptr < buf_end) {
        v = *buf_ptr++;
	v2 = *buf_ptr;
        if ((v == 0xff) && (v2 >= 0xc0) && (v2 <= 0xfe)) {
	    val = *buf_ptr++;
	    goto found;
        }
#ifdef DEBUG
	skipped++;
#endif
    }
    val = -1;
found:
#ifdef DEBUG
    dprintf("find_marker skipped %d bytes\n", skipped);
#endif
    *pbuf_ptr = buf_ptr;
    return val;
}

static int mjpeg_decode_frame(AVCodecContext *avctx, 
                              void *data, int *data_size,
                              UINT8 *buf, int buf_size)
{
    MJpegDecodeContext *s = avctx->priv_data;
    UINT8 *buf_end, *buf_ptr;
    int i, start_code;
    AVPicture *picture = data;

    *data_size = 0;

    /* no supplementary picture */
    if (buf_size == 0)
        return 0;

    buf_ptr = buf;
    buf_end = buf + buf_size;
    while (buf_ptr < buf_end) {
        /* find start next marker */
        start_code = find_marker(&buf_ptr, buf_end);
	{
	    /* EOF */
            if (start_code < 0) {
		goto the_end;
            } else {
                dprintf("marker=%x avail_size_in_buf=%d\n", start_code, buf_end - buf_ptr);
		
		if ((buf_end - buf_ptr) > s->buffer_size)
		{
		    av_free(s->buffer);
		    s->buffer_size = buf_end-buf_ptr;
		    s->buffer = av_malloc(s->buffer_size);
		    dprintf("buffer too small, expanding to %d bytes\n",
			s->buffer_size);
		}
		
		/* unescape buffer of SOS */
		if (start_code == SOS)
		{
		    UINT8 *src = buf_ptr;
		    UINT8 *dst = s->buffer;

		    while (src<buf_end)
		    {
			UINT8 x = *(src++);

			*(dst++) = x;
			if (x == 0xff)
			{
			    while(*src == 0xff) src++;

			    x = *(src++);
			    if (x >= 0xd0 && x <= 0xd7)
				*(dst++) = x;
			    else if (x)
				break;
			}
		    }
		    init_get_bits(&s->gb, s->buffer, dst - s->buffer);
		    
		    dprintf("escaping removed %d bytes\n",
			(buf_end - buf_ptr) - (dst - s->buffer));
		}
		else
		    init_get_bits(&s->gb, buf_ptr, buf_end - buf_ptr);
		
		s->start_code = start_code;

		/* process markers */
		if (start_code >= 0xd0 && start_code <= 0xd7) {
		    dprintf("restart marker: %d\n", start_code&0x0f);
		} else if (s->first_picture) {
		    /* APP fields */
		    if (start_code >= 0xe0 && start_code <= 0xef)
			mjpeg_decode_app(s);
		    /* Comment */
		    else if (start_code == COM)
			mjpeg_decode_com(s);
		}

                switch(start_code) {
                case SOI:
		    s->restart_interval = 0;
                    /* nothing to do on SOI */
                    break;
                case DQT:
                    mjpeg_decode_dqt(s);
                    break;
                case DHT:
                    mjpeg_decode_dht(s);
                    break;
                case SOF0:
                    mjpeg_decode_sof0(s);
                    break;
		case EOI:
eoi_parser:
		    {
                        int l;
                        if (s->interlaced) {
                            s->bottom_field ^= 1;
                            /* if not bottom field, do not output image yet */
                            if (s->bottom_field)
                                goto not_the_end;
                        }
                        for(i=0;i<3;i++) {
                            picture->data[i] = s->current_picture[i];
#if 1
                            l = s->linesize[i];
                            if (s->interlaced)
                                l >>= 1;
                            picture->linesize[i] = l;
#else
			    picture->linesize[i] = (s->interlaced) ?
				s->linesize[i] >> 1 : s->linesize[i];
#endif
                        }
                        *data_size = sizeof(AVPicture);
                        avctx->height = s->height;
                        if (s->interlaced)
                            avctx->height *= 2;
                        avctx->width = s->width;
                        /* XXX: not complete test ! */
                        switch((s->h_count[0] << 4) | s->v_count[0]) {
                        case 0x11:
                            avctx->pix_fmt = PIX_FMT_YUV444P;
                            break;
                        case 0x21:
                            avctx->pix_fmt = PIX_FMT_YUV422P;
                            break;
                        default:
                        case 0x22:
                            avctx->pix_fmt = PIX_FMT_YUV420P;
                            break;
                        }
                        /* dummy quality */
                        /* XXX: infer it with matrix */
                    	avctx->quality = 3; 
                        goto the_end;
                    }
		    break;
                case SOS:
                    mjpeg_decode_sos(s);
		    /* buggy avid puts EOI every 10-20th frame */
		    /* if restart period is over process EOI */
		    if ((s->buggy_avid && !s->interlaced) || s->restart_interval)
			goto eoi_parser;
                    break;
		case DRI:
		    mjpeg_decode_dri(s);
		    break;
		case SOF1:
		case SOF2:
		case SOF3:
		case SOF5:
		case SOF6:
		case SOF7:
		case SOF9:
		case SOF10:
		case SOF11:
		case SOF13:
		case SOF14:
		case SOF15:
		case JPG:
		    printf("mjpeg: unsupported coding type (%x)\n", start_code);
		    break;
//		default:
//		    printf("mjpeg: unsupported marker (%x)\n", start_code);
//		    break;
                }

not_the_end:
		/* eof process start code */
		buf_ptr += (get_bits_count(&s->gb)+7)/8;
		dprintf("marker parser used %d bytes (%d bits)\n",
		    (get_bits_count(&s->gb)+7)/8, get_bits_count(&s->gb));
            }
        }
    }
the_end:
    dprintf("mjpeg decode frame unused %d bytes\n", buf_end - buf_ptr);
//    return buf_end - buf_ptr;
    return buf_ptr - buf;
}

static int mjpegb_decode_frame(AVCodecContext *avctx, 
                              void *data, int *data_size,
                              UINT8 *buf, int buf_size)
{
    MJpegDecodeContext *s = avctx->priv_data;
    UINT8 *buf_end, *buf_ptr;
    int i;
    AVPicture *picture = data;
    GetBitContext hgb; /* for the header */
    uint32_t dqt_offs, dht_offs, sof_offs, sos_offs, second_field_offs;
    uint32_t field_size;

    *data_size = 0;

    /* no supplementary picture */
    if (buf_size == 0)
        return 0;

    buf_ptr = buf;
    buf_end = buf + buf_size;
    
read_header:
    /* reset on every SOI */
    s->restart_interval = 0;

    init_get_bits(&hgb, buf_ptr, /*buf_size*/buf_end - buf_ptr);

    skip_bits(&hgb, 32); /* reserved zeros */
    
    if (get_bits(&hgb, 32) != be2me_32(ff_get_fourcc("mjpg")))
    {
	dprintf("not mjpeg-b (bad fourcc)\n");
	return 0;
    }

    field_size = get_bits(&hgb, 32); /* field size */
    dprintf("field size: 0x%x\n", field_size);
    skip_bits(&hgb, 32); /* padded field size */
    second_field_offs = get_bits(&hgb, 32);
    dprintf("second field offs: 0x%x\n", second_field_offs);
    if (second_field_offs)
	s->interlaced = 1;

    dqt_offs = get_bits(&hgb, 32);
    dprintf("dqt offs: 0x%x\n", dqt_offs);
    if (dqt_offs)
    {
	init_get_bits(&s->gb, buf+dqt_offs, buf_end - (buf+dqt_offs));
	s->start_code = DQT;
	mjpeg_decode_dqt(s);
    }
    
    dht_offs = get_bits(&hgb, 32);
    dprintf("dht offs: 0x%x\n", dht_offs);
    if (dht_offs)
    {
	init_get_bits(&s->gb, buf+dht_offs, buf_end - (buf+dht_offs));
	s->start_code = DHT;
	mjpeg_decode_dht(s);
    }

    sof_offs = get_bits(&hgb, 32);
    dprintf("sof offs: 0x%x\n", sof_offs);
    if (sof_offs)
    {
	init_get_bits(&s->gb, buf+sof_offs, buf_end - (buf+sof_offs));
	s->start_code = SOF0;
	mjpeg_decode_sof0(s);
    }

    sos_offs = get_bits(&hgb, 32);
    dprintf("sos offs: 0x%x\n", sos_offs);
    if (sos_offs)
    {
//	init_get_bits(&s->gb, buf+sos_offs, buf_end - (buf+sos_offs));
	init_get_bits(&s->gb, buf+sos_offs, field_size);
	s->start_code = SOS;
	mjpeg_decode_sos(s);
    }

    skip_bits(&hgb, 32); /* start of data offset */

    if (s->interlaced) {
        s->bottom_field ^= 1;
        /* if not bottom field, do not output image yet */
        if (s->bottom_field && second_field_offs)
	{
	    buf_ptr = buf + second_field_offs;
	    second_field_offs = 0;
	    goto read_header;
    	}
    }

    for(i=0;i<3;i++) {
        picture->data[i] = s->current_picture[i];
        picture->linesize[i] = (s->interlaced) ?
    	    s->linesize[i] >> 1 : s->linesize[i];
    }
    *data_size = sizeof(AVPicture);
    avctx->height = s->height;
    if (s->interlaced)
        avctx->height *= 2;
    avctx->width = s->width;
    /* XXX: not complete test ! */
    switch((s->h_count[0] << 4) | s->v_count[0]) {
        case 0x11:
    	    avctx->pix_fmt = PIX_FMT_YUV444P;
            break;
        case 0x21:
            avctx->pix_fmt = PIX_FMT_YUV422P;
            break;
        default:
	case 0x22:
            avctx->pix_fmt = PIX_FMT_YUV420P;
            break;
    }
    /* dummy quality */
    /* XXX: infer it with matrix */
    avctx->quality = 3; 

    return buf_ptr - buf;
}


static int mjpeg_decode_end(AVCodecContext *avctx)
{
    MJpegDecodeContext *s = avctx->priv_data;
    int i, j;

    av_free(s->buffer);
    for(i=0;i<MAX_COMPONENTS;i++)
        av_free(s->current_picture[i]);
    for(i=0;i<2;i++) {
        for(j=0;j<4;j++)
            free_vlc(&s->vlcs[i][j]);
    }
    return 0;
}

AVCodec mjpeg_decoder = {
    "mjpeg",
    CODEC_TYPE_VIDEO,
    CODEC_ID_MJPEG,
    sizeof(MJpegDecodeContext),
    mjpeg_decode_init,
    NULL,
    mjpeg_decode_end,
    mjpeg_decode_frame,
    0,
    NULL
};

AVCodec mjpegb_decoder = {
    "mjpegb",
    CODEC_TYPE_VIDEO,
    CODEC_ID_MJPEGB,
    sizeof(MJpegDecodeContext),
    mjpeg_decode_init,
    NULL,
    mjpeg_decode_end,
    mjpegb_decode_frame,
    0,
    NULL
};