cinepak.c

uclinux 下的vlc播放器源代码

            PIX_SET_Y( 2*j + 1, 2*i + 1,
                       p_context->codebook_v1[i_strip][i_index].i_y[2*i+j] );

            PIX_SET_UV( 1,p_dst_u, j, i,
                        p_context->codebook_v1[i_strip][i_index].i_u );
            PIX_SET_UV( 2,p_dst_v, j, i,
                        p_context->codebook_v1[i_strip][i_index].i_v );
        }
    }

#undef PIX_SET_Y
#undef PIX_SET_UV
}

/*****************************************************************************
 * The function that decode one frame
 *****************************************************************************/
static int cinepak_decode_frame( cinepak_context_t *p_context,
                                 int i_length, uint8_t *p_data )
{
    int i_strip;

    int i_frame_flags;
    int i_frame_size;
    int i_width, i_height;
    int i_frame_strips;
    int i_index;
    int i_strip_x1 =0, i_strip_y1=0;
    int i_strip_x2 =0, i_strip_y2=0;

    if( i_length <= 10 )
    {
        /* Broken header or no data */
        return( -1 );
    }

    /* get header */
    i_frame_flags  = *(p_data++);
    i_frame_size = GET3BYTES( p_data );
    i_width  = GET2BYTES( p_data );
    i_height = GET2BYTES( p_data );
    i_frame_strips = GET2BYTES( p_data );

    if( !i_frame_size || !i_width || !i_height )
    {
        /* Broken header */
        return( -1 );
    }

    /* Check if we have a picture buffer with good size */
    if( ( p_context->i_width != i_width ) ||
        ( p_context->i_height != i_height ) )
    {
        int i;
        for( i = 0; i < 3; i++ )
        {
            FREE( p_context->p_pix[i] );
        }

        p_context->i_width = i_width;
        p_context->i_height = i_height;

        p_context->i_stride[0] = ( i_width + 3 ) & 0xfffc;
        p_context->i_stride[1] = p_context->i_stride[2] =
                p_context->i_stride[0] / 2;

        p_context->i_lines[0] = ( i_height + 3 ) & 0xfffc;
        p_context->i_lines[1] = p_context->i_lines[2] =
                p_context->i_lines[0] /2;

        for( i = 0; i < 3; i++ )
        {
            p_context->p_pix[i] = malloc( p_context->i_stride[i] *
                                          p_context->i_lines[i] );
            /* Set it to all black */
            memset( p_context->p_pix[i], ( i == 0 ) ? 0 : 128 ,
                    p_context->i_stride[i] * p_context->i_lines[i] );
        }
    }

    if( i_frame_size != i_length )
    {
        i_length = __MIN( i_length, i_frame_size );
    }
    i_length -= 10;

    if( i_frame_strips >= CINEPAK_MAXSTRIP )
    {
        i_frame_strips = CINEPAK_MAXSTRIP;
    }

    /* Now decode each strip */
    for( i_strip = 0; i_strip < i_frame_strips; i_strip++ )
    {
        int i_strip_id;
        int i_strip_size;

        if( i_length <= 12 )
        {
            break;
        }

        i_strip_id   = GET2BYTES( p_data );
        i_strip_size = GET2BYTES( p_data );
        i_strip_size = __MIN( i_strip_size, i_length );
        /* FIXME I don't really understand how it's work; */
        i_strip_y1  = i_strip_y2 + GET2BYTES( p_data );
        i_strip_x1  = GET2BYTES( p_data );
        i_strip_y2  = i_strip_y2 + GET2BYTES( p_data );
        i_strip_x2  = GET2BYTES( p_data );

        i_length -= i_strip_size;

        i_strip_size -= 12;
        /* init codebook , if needed */
        if( ( i_strip > 0 )&&( !(i_frame_flags&0x01) ) )
        {
            memcpy( &p_context->codebook_v1[i_strip],
                    &p_context->codebook_v1[i_strip-1],
                    sizeof(cinepak_codebook_t[256] ) );

            memcpy( &p_context->codebook_v4[i_strip],
                    &p_context->codebook_v4[i_strip-1],
                    sizeof(cinepak_codebook_t[256] ) );
        }

        /* Now parse all chunk in this strip */
        while( i_strip_size > 0 )
        {
            cinepak_codebook_t (*p_codebook)[CINEPAK_MAXSTRIP][256];
            int i_mode;

            int i_chunk_id;
            int i_chunk_size;
            uint32_t i_vector_flags;
            int i_count;
            int i;
            int i_x, i_y; /* (0,0) begin in fact at (x1,y1) ... */

            i_chunk_id   = GET2BYTES( p_data );
            i_chunk_size = GET2BYTES( p_data );
            i_chunk_size  = __MIN( i_chunk_size, i_strip_size );
            i_strip_size -= i_chunk_size;

            i_chunk_size -= 4;

            i_x = 0;
            i_y = 0;
            if( i_chunk_size < 0 )
            {
                break;
            }

            switch( i_chunk_id )
            {
            case( 0x2000 ): /* 12bits v4 Intra*/
            case( 0x2200 ): /* 12bits v1 Intra*/
            case( 0x2400 ): /* 8bits v4 Intra*/
            case( 0x2600 ): /* 8bits v1 Intra */
                i_mode = ( ( i_chunk_id&0x0400 ) == 0 );
                p_codebook = ( i_chunk_id&0x0200 ) ?
                               &p_context->codebook_v1 :
                               &p_context->codebook_v4;

                i_count = __MIN( i_chunk_size / ( i_mode ? 6 : 4 ), 256 );

                for( i = 0; i < i_count; i++ )
                {
                    cinepak_LoadCodebook( &((*p_codebook)[i_strip][i]),
                                          p_data,
                                          i_mode&~p_context->b_grayscale );
                    p_data += i_mode ? 6 : 4;
                    i_chunk_size -= i_mode ? 6 : 4;
                }
                break;

            case( 0x2100 ): /* selective 12bits v4 Inter*/
            case( 0x2300 ): /* selective 12bits v1 Inter*/
            case( 0x2500 ): /* selective 8bits v4 Inter*/
            case( 0x2700 ): /* selective 8bits v1 Inter*/
                i_mode = ( ( i_chunk_id&0x0400 ) == 0 );
                p_codebook = ( i_chunk_id&0x0200 ) ?
                               &p_context->codebook_v1 :
                               &p_context->codebook_v4;

                i_index = 0;
                while( (i_chunk_size > 4)&&(i_index<256))
                {
                    i_vector_flags = GET4BYTES( p_data );
                    i_chunk_size -= 4;
                    for( i = 0; i < 32; i++ )
                    {
                        if( ( i_chunk_size < ( i_mode ? 6 : 4 ) )
                            || (i_index >= 256 ) )
                        {
                            break;
                        }
                        if( i_vector_flags&0x80000000UL )
                        {
                            cinepak_LoadCodebook(
                                &((*p_codebook)[i_strip][i_index]),
                                p_data, i_mode&~p_context->b_grayscale );

                            p_data += i_mode ? 6 : 4;
                            i_chunk_size -= i_mode ? 6 : 4;
                        }
                        i_index++;
                        i_vector_flags <<= 1;
                    }
                }
                break;

            case( 0x3000 ): /* load image Intra */
                while( (i_chunk_size >= 4 )&&(i_y<i_strip_y2-i_strip_y1) )
                {
                    i_vector_flags = GET4BYTES( p_data );
                    i_chunk_size -= 4;
                    i_strip_size -= 4;
                    i_length     -= 4;

                    for( i = 0; i < 32; i++ )
                    {
                        if( ( i_y >= i_strip_y2 - i_strip_y1) ||
                            ( i_chunk_size<=0 ) )
                        {
                            break;
                        }
                        if( i_vector_flags&0x80000000UL )
                        {
                            cinepak_Getv4( p_context,
                                           i_strip,
                                           i_strip_x1 + i_x,
                                           i_strip_y1 + i_y,
                                           i_strip_x2, i_strip_y2,
                                           p_data );
                            p_data += 4;
                            i_chunk_size -= 4;
                        }
                        else
                        {
                            cinepak_Getv1( p_context,
                                           i_strip,
                                           i_strip_x1 + i_x,
                                           i_strip_y1 + i_y,
                                           i_strip_x2, i_strip_y2,
                                           p_data );
                            p_data++;
                            i_chunk_size--;
                        }

                        i_x += 4;
                        if( i_x >= i_strip_x2 - i_strip_x1 )
                        {
                            i_x = 0;
                            i_y += 4;
                        }
                        i_vector_flags <<= 1;
                    }
                }
                break;

            case( 0x3100 ): /* load image Inter */
                while( ( i_chunk_size > 4 )&&( i_y < i_strip_y2 - i_strip_y1) )
                {
                    uint32_t i_mask;
                    i_vector_flags = GET4BYTES( p_data );
                    i_chunk_size -= 4;
                    i_mask = 0x80000000UL;

                    while( (i_chunk_size > 0 ) && ( i_mask )
                           && ( i_y < i_strip_y2 - i_strip_y1 ) )
                    {
                        if( i_vector_flags&i_mask )
                        {
                            i_mask >>= 1;
                            if( !i_mask )
                            {
                                if( i_chunk_size < 4 )
                                {
                                    break;
                                }
                                i_vector_flags = GET4BYTES( p_data );
                                i_chunk_size -= 4;
                                i_mask = 0x80000000UL;
                            }
                            if( i_vector_flags&i_mask )
                            {
                                if( i_chunk_size < 4 ) break;
                                cinepak_Getv4( p_context,
                                               i_strip,
                                               i_strip_x1 + i_x,
                                               i_strip_y1 + i_y,
                                               i_strip_x2, i_strip_y2,
                                               p_data );
                                p_data += 4;
                                i_chunk_size -= 4;
                            }
                            else
                            {
                                if( i_chunk_size < 1 ) break;
                                cinepak_Getv1( p_context,
                                               i_strip,
                                               i_strip_x1 + i_x,
                                               i_strip_y1 + i_y,
                                               i_strip_x2, i_strip_y2,
                                               p_data );
                                p_data++;
                                i_chunk_size--;
                            }
                        }
                        i_mask >>= 1;

                        i_x += 4;
                        if( i_x >= i_strip_x2 - i_strip_x1 )
                        {
                            i_x = 0;
                            i_y += 4;
                        }
                    }
                }
                break;

            case( 0x3200 ): /* load intra picture but all v1*/
                while( ( i_chunk_size > 0 ) &&
                       ( i_y < i_strip_y2 - i_strip_y1 ) )
                {
                    cinepak_Getv1( p_context,
                                   i_strip,
                                   i_strip_x1 + i_x,
                                   i_strip_y1 + i_y,
                                   i_strip_x2, i_strip_y2,
                                   p_data );
                    p_data++;
                    i_chunk_size--;

                    i_x += 4;
                    if( i_x >= i_strip_x2 - i_strip_x1 )
                    {
                        i_x = 0;
                        i_y += 4;
                    }
                }
                break;

            default:
                break;

            }
            p_data += i_chunk_size ; /* skip remains bytes */
        }
    }

    return( 0 );
}