dv.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。

               standard IDCT */
            dc += 1024;
            block[0] = dc;
            last_index = block_sizes[j];
            buf_ptr += last_index >> 3;
            mb->pos = 0;
            mb->partial_bit_count = 0;

            dv_decode_ac(s, mb, block, last_index);

            /* write the remaining bits  in a new buffer only if the
               block is finished */
            bits_left = last_index - s->gb.index;
            if (mb->eob_reached) {
                mb->partial_bit_count = 0;
                mb_bit_count += bits_left;
                bit_copy(&pb, &s->gb, bits_left);
            } else {
                /* should be < 16 bits otherwise a codeword could have
                   been parsed */
                mb->partial_bit_count = bits_left;
                mb->partial_bit_buffer = get_bits(&s->gb, bits_left);
            }
            block += 64;
            mb++;
        }
        
        flush_put_bits(&pb);

        /* pass 2 : we can do it just after */
#ifdef VLC_DEBUG
        printf("***pass 2 size=%d\n", mb_bit_count);
#endif
        block = block1;
        mb = mb1;
        init_get_bits(&s->gb, mb_bit_buffer, 80);
        for(j = 0;j < 6; j++) {
            if (!mb->eob_reached && s->gb.index < mb_bit_count) {
                dv_decode_ac(s, mb, block, mb_bit_count);
                /* if still not finished, no need to parse other blocks */
                if (!mb->eob_reached) {
                    /* we could not parse the current AC coefficient,
                       so we add the remaining bytes */
                    bits_left = mb_bit_count - s->gb.index;
                    if (bits_left > 0) {
                        mb->partial_bit_count += bits_left;
                        mb->partial_bit_buffer = 
                            (mb->partial_bit_buffer << bits_left) | 
                            get_bits(&s->gb, bits_left);
                    }
                    goto next_mb;
                }
            }
            block += 64;
            mb++;
        }
        /* all blocks are finished, so the extra bytes can be used at
           the video segment level */
        bits_left = mb_bit_count - s->gb.index;
        vs_bit_count += bits_left;
        bit_copy(&vs_pb, &s->gb, bits_left);
    next_mb:
        mb1 += 6;
        block1 += 6 * 64;
    }

    /* we need a pass other the whole video segment */
    flush_put_bits(&vs_pb);
        
#ifdef VLC_DEBUG
    printf("***pass 3 size=%d\n", vs_bit_count);
#endif
    block = &s->block[0][0];
    mb = mb_data;
    init_get_bits(&s->gb, vs_bit_buffer, 5 * 80);
    for(mb_index = 0; mb_index < 5; mb_index++) {
        for(j = 0;j < 6; j++) {
            if (!mb->eob_reached) {
#ifdef VLC_DEBUG
                printf("start %d:%d\n", mb_index, j);
#endif
                dv_decode_ac(s, mb, block, vs_bit_count);
            }
            block += 64;
            mb++;
        }
    }
    
    /* compute idct and place blocks */
    block = &s->block[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->current_picture[0] + (mb_y * s->linesize[0] * 8) + (mb_x * 8);
        if (s->sampling_411)
            c_offset = (mb_y * s->linesize[1] * 8) + ((mb_x >> 2) * 8);
        else
            c_offset = ((mb_y >> 1) * s->linesize[1] * 8) + ((mb_x >> 1) * 8);
        for(j = 0;j < 6; j++) {
            idct_put = s->idct_put[mb->dct_mode];
            if (j < 4) {
                if (s->sampling_411 && mb_x < (704 / 8)) {
                    /* NOTE: at end of line, the macroblock is handled as 420 */
                    idct_put(y_ptr + (j * 8), s->linesize[0], block);
                } else {
                    idct_put(y_ptr + ((j & 1) * 8) + ((j >> 1) * 8 * s->linesize[0]),
                             s->linesize[0], block);
                }
            } else {
                if (s->sampling_411 && mb_x >= (704 / 8)) {
                    uint8_t pixels[64], *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->linesize[6 - j];
                    c_ptr = s->current_picture[6 - j] + c_offset;
                    ptr = pixels;
                    for(y = 0;y < 8; y++) {
                        /* convert to 411P */
                        c_ptr1 = c_ptr + linesize;
                        c_ptr1[0] = c_ptr[0] = (ptr[0] + ptr[1]) >> 1;
                        c_ptr1[1] = c_ptr[1] = (ptr[2] + ptr[3]) >> 1;
                        c_ptr1[2] = c_ptr[2] = (ptr[4] + ptr[5]) >> 1;
                        c_ptr1[3] = c_ptr[3] = (ptr[6] + ptr[7]) >> 1;
                        c_ptr += linesize * 2;
                        ptr += 8;
                    }
                } else {
                    /* don't ask me why they inverted Cb and Cr ! */
                    idct_put(s->current_picture[6 - j] + c_offset, 
                             s->linesize[6 - j], block);
                }
            }
            block += 64;
            mb++;
        }
    }
}


/* 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 *buf, int buf_size)
{
    DVVideoDecodeContext *s = avctx->priv_data;
    int sct, dsf, apt, ds, nb_dif_segs, vs, width, height, i, packet_size;
    unsigned size;
    UINT8 *buf_ptr;
    const UINT16 *mb_pos_ptr;
    AVPicture *picture;
    
    /* parse id */
    init_get_bits(&s->gb, buf, buf_size);
    sct = get_bits(&s->gb, 3);
    if (sct != 0)
        return -1;
    skip_bits(&s->gb, 5);
    get_bits(&s->gb, 4); /* dsn (sequence number */
    get_bits(&s->gb, 1); /* fsc (channel number) */
    skip_bits(&s->gb, 3);
    get_bits(&s->gb, 8); /* dbn (diff block number 0-134) */

    dsf = get_bits(&s->gb, 1); /* 0 = NTSC 1 = PAL */
    if (get_bits(&s->gb, 1) != 0)
        return -1;
    skip_bits(&s->gb, 11);
    apt = get_bits(&s->gb, 3); /* apt */

    get_bits(&s->gb, 1); /* tf1 */
    skip_bits(&s->gb, 4);
    get_bits(&s->gb, 3); /* ap1 */

    get_bits(&s->gb, 1); /* tf2 */
    skip_bits(&s->gb, 4);
    get_bits(&s->gb, 3); /* ap2 */

    get_bits(&s->gb, 1); /* tf3 */
    skip_bits(&s->gb, 4);
    get_bits(&s->gb, 3); /* ap3 */
    
    /* init size */
    width = 720;
    if (dsf) {
        avctx->frame_rate = 25 * FRAME_RATE_BASE;
        packet_size = PAL_FRAME_SIZE;
        height = 576;
        nb_dif_segs = 12;
    } else {
        avctx->frame_rate = 30 * FRAME_RATE_BASE;
        packet_size = NTSC_FRAME_SIZE;
        height = 480;
        nb_dif_segs = 10;
    }
    /* NOTE: we only accept several full frames */
    if (buf_size < packet_size)
        return -1;
    
    /* XXX: is it correct to assume that 420 is always used in PAL
       mode ? */
    s->sampling_411 = !dsf;
    if (s->sampling_411) {
        mb_pos_ptr = dv_place_411;
        avctx->pix_fmt = PIX_FMT_YUV411P;
    } else {
        mb_pos_ptr = dv_place_420;
        avctx->pix_fmt = PIX_FMT_YUV420P;
    }

    avctx->width = width;
    avctx->height = height;

    if (avctx->flags & CODEC_FLAG_DR1)
    {
	s->width = -1;
	avctx->dr_buffer[0] = avctx->dr_buffer[1] = avctx->dr_buffer[2] = 0;
	if(avctx->get_buffer_callback(avctx, width, height, I_TYPE) < 0
	   && avctx->flags & CODEC_FLAG_DR1) {
	    fprintf(stderr, "get_buffer() failed\n");
	    return -1;
	}
    }

    /* (re)alloc picture if needed */
    if (s->width != width || s->height != height) {
	if (!(avctx->flags & CODEC_FLAG_DR1))
	    for(i=0;i<3;i++) {
		if (avctx->dr_buffer[i] != s->current_picture[i])
		    av_freep(&s->current_picture[i]);
		avctx->dr_buffer[i] = 0;
	    }

        for(i=0;i<3;i++) {
	    if (avctx->dr_buffer[i]) {
		s->current_picture[i] = avctx->dr_buffer[i];
		s->linesize[i] = (i == 0) ? avctx->dr_stride : avctx->dr_uvstride;
	    } else {
		size = width * height;
		s->linesize[i] = width;
		if (i >= 1) {
		    size >>= 2;
		    s->linesize[i] >>= s->sampling_411 ? 2 : 1;
		}
		s->current_picture[i] = av_malloc(size);
	    }
            if (!s->current_picture[i])
                return -1;
        }
        s->width = width;
        s->height = height;
    }

    /* for each DIF segment */
    buf_ptr = buf;
    for (ds = 0; ds < nb_dif_segs; ds++) {
        buf_ptr += 6 * 80; /* skip DIF segment header */
        
        for(vs = 0; vs < 27; vs++) {
            if ((vs % 3) == 0) {
                /* skip audio block */
                buf_ptr += 80;
            }
            dv_decode_video_segment(s, buf_ptr, mb_pos_ptr);
            buf_ptr += 5 * 80;
            mb_pos_ptr += 5;
        }
    }

    emms_c();

    /* return image */
    *data_size = sizeof(AVPicture);
    picture = data;
    for(i=0;i<3;i++) {
        picture->data[i] = s->current_picture[i];
        picture->linesize[i] = s->linesize[i];
    }
    return packet_size;
}

static int dvvideo_decode_end(AVCodecContext *avctx)
{
    DVVideoDecodeContext *s = avctx->priv_data;
    int i;

    for(i=0;i<3;i++)
	if (avctx->dr_buffer[i] != s->current_picture[i])
        av_freep(&s->current_picture[i]);
    return 0;
}

AVCodec dvvideo_decoder = {
    "dvvideo",
    CODEC_TYPE_VIDEO,
    CODEC_ID_DVVIDEO,
    sizeof(DVVideoDecodeContext),
    dvvideo_decode_init,
    NULL,
    dvvideo_decode_end,
    dvvideo_decode_frame,
    CODEC_CAP_DR1,
    NULL
};

typedef struct DVAudioDecodeContext {
    AVCodecContext *avctx;
    GetBitContext gb;

} DVAudioDecodeContext;

static int dvaudio_decode_init(AVCodecContext *avctx)
{
    //    DVAudioDecodeContext *s = avctx->priv_data;
    return 0;
}

/* NOTE: exactly one frame must be given (120000 bytes for NTSC,
   144000 bytes for PAL) */
static int dvaudio_decode_frame(AVCodecContext *avctx, 
                                 void *data, int *data_size,
                                 UINT8 *buf, int buf_size)
{
    //    DVAudioDecodeContext *s = avctx->priv_data;
    return buf_size;
}

static int dvaudio_decode_end(AVCodecContext *avctx)
{
    //    DVAudioDecodeContext *s = avctx->priv_data;
    return 0;
}

AVCodec dvaudio_decoder = {
    "dvaudio",
    CODEC_TYPE_AUDIO,
    CODEC_ID_DVAUDIO,
    sizeof(DVAudioDecodeContext),
    dvaudio_decode_init,
    NULL,
    dvaudio_decode_end,
    dvaudio_decode_frame,
    0,
    NULL
};