decoder.c

图象压缩程序

    }
    else if( h->sps->i_poc_type == 1 )
    {
        /* FIXME */
        return -1;
    }
    else
    {
        if( nal->i_type == NAL_SLICE_IDR )
        {
            h->i_frame_offset = 0;
            h->i_poc = 0;
        }
        else
        {
            if( h->sh.i_frame_num < h->i_frame_num )
            {
                h->i_frame_offset += 1 << h->sps->i_log2_max_frame_num;
            }
            if( nal->i_ref_idc > 0 )
            {
                h->i_poc = 2 * ( h->i_frame_offset + h->sh.i_frame_num );
            }
            else
            {
                h->i_poc = 2 * ( h->i_frame_offset + h->sh.i_frame_num ) - 1;
            }
        }
        h->i_frame_num = h->sh.i_frame_num;
    }

    fprintf( stderr, "x264: pic type=%s poc:%d\n",
             h->sh.i_type == SLICE_TYPE_I ? "I" : (h->sh.i_type == SLICE_TYPE_P ? "P" : "B?" ),
             h->i_poc );

    if( h->sh.i_type != SLICE_TYPE_I && h->sh.i_type != SLICE_TYPE_P )
    {
        fprintf( stderr, "only SLICE I/P supported\n" );
        return -1;
    }

    /* read and do the ref pic reordering */
    if( x264_slice_header_ref_pic_reordering( h, s ) < 0 )
    {
        return -1;
    }

    if( ( (h->sh.i_type == SLICE_TYPE_P || h->sh.i_type == SLICE_TYPE_SP) && h->sh.pps->b_weighted_pred  ) ||
        ( h->sh.i_type == SLICE_TYPE_B && h->sh.pps->b_weighted_bipred ) )
    {
        if( x264_slice_header_pred_weight_table( h, s ) < 0 )
        {
            return -1;
        }
    }

    if( nal->i_ref_idc != 0 )
    {
        x264_slice_header_dec_ref_pic_marking( h, s, nal->i_type );
    }

    if( x264_slice_header_part2_read( s, &h->sh ) < 0 )
    {
        return -1;
    }

    return 0;
}

static int x264_slice_data_decode( x264_t *h, bs_t *s )
{
    int mb_xy = h->sh.i_first_mb;
    int i_ret = 0;

    if( h->pps->b_cabac )
    {
        /* TODO: alignement and cabac init */
    }

    /* FIXME field decoding */
    for( ;; )
    {
        x264_mb_context_t context;
        x264_macroblock_t *mb;

        if( mb_xy >= h->sps->i_mb_width * h->sps->i_mb_height )
        {
            break;
        }

        mb = &h->mb[mb_xy];

        /* load neighbour */
        x264_macroblock_context_load( h, mb, &context );


        if( h->pps->b_cabac )
        {
            if( h->sh.i_type != SLICE_TYPE_I && h->sh.i_type != SLICE_TYPE_SI )
            {
                /* TODO */
            }
            i_ret = x264_macroblock_read_cabac( h, s, mb );
        }
        else
        {
            if( h->sh.i_type != SLICE_TYPE_I && h->sh.i_type != SLICE_TYPE_SI )
            {
                int i_skip = bs_read_ue( s );

                while( i_skip > 0 )
                {
                    x264_macroblock_decode_skip( h, mb );

                    /* next macroblock */
                    mb_xy++;
                    if( mb_xy >= h->sps->i_mb_width * h->sps->i_mb_height )
                    {
                        break;
                    }
                    mb++;

                    /* load neighbour */
                    x264_macroblock_context_load( h, mb, &context );

                    i_skip--;
                }
                if( mb_xy >= h->sps->i_mb_width * h->sps->i_mb_height )
                {
                    break;
                }
            }
            i_ret = x264_macroblock_read_cavlc( h, s, mb );
        }

        if( i_ret < 0 )
        {
            fprintf( stderr, "x264_macroblock_read failed [%d,%d]\n", mb->i_mb_x, mb->i_mb_y );
            break;
        }

        if( x264_macroblock_decode( h, mb ) < 0 )
        {
            fprintf( stderr, "x264_macroblock_decode failed\n" );
            /* try to do some error correction ;) */
        }

        mb_xy++;
    }

    if( i_ret >= 0 )
    {
        int i;

        /* expand border for frame reference TODO avoid it when using b-frame */
        x264_frame_expand_border( h->fdec );

        /* apply deblocking filter to the current decoded picture */
        if( !h->pps->b_deblocking_filter_control || h->sh.i_disable_deblocking_filter_idc != 1 )
        {
            x264_frame_deblocking_filter( h, h->sh.i_type );
        }

#if 0
        /* expand border for frame reference TODO avoid it when using b-frame */
        x264_frame_expand_border( h->fdec );
#endif

        h->picture->i_plane = h->fdec->i_plane;
        for( i = 0; i < h->picture->i_plane; i++ )
        {
            h->picture->i_stride[i] = h->fdec->i_stride[i];
            h->picture->plane[i]    = h->fdec->plane[i];
        }

        /* move frame in the buffer FIXME won't work for B-frame */
        h->fdec = h->freference[h->sps->i_num_ref_frames];
        for( i = h->sps->i_num_ref_frames; i > 0; i-- )
        {
            h->freference[i] = h->freference[i-1];
        }
        h->freference[0] = h->fdec;
    }

    return i_ret;
}

/****************************************************************************
 *
 ******************************* x264 libs **********************************
 *
 ****************************************************************************/
int x264_nal_decode( x264_nal_t *nal, void *p_data, int i_data )
{
    uint8_t *src = p_data;
    uint8_t *end = &src[i_data];
    uint8_t *dst = nal->p_payload;

    nal->i_type    = src[0]&0x1f;
    nal->i_ref_idc = (src[0] >> 5)&0x03;

    src++;

    while( src < end )
    {
        if( src < end - 3 && src[0] == 0x00 && src[1] == 0x00  && src[2] == 0x03 )
        {
            *dst++ = 0x00;
            *dst++ = 0x00;

            src += 3;
        }
        *dst++ = *src++;
    }

    nal->i_payload = dst - (uint8_t*)p_data;
    return 0;
}

/****************************************************************************
 * x264_decoder_open:
 ****************************************************************************/
x264_t *x264_decoder_open   ( x264_param_t *param )
{
    x264_t *h = x264_malloc( sizeof( x264_t ) );
    int i;

    memcpy( &h->param, param, sizeof( x264_param_t ) );

    h->cpu = param->cpu;

    /* no SPS and PPS active yet */
    h->sps = NULL;
    h->pps = NULL;

    for( i = 0; i < 32; i++ )
    {
        h->sps_array[i].i_id = -1;  /* invalidate it */
    }
    for( i = 0; i < 256; i++ )
    {
        h->pps_array[i].i_id = -1;  /* invalidate it */
    }

    h->picture = x264_malloc( sizeof( x264_picture_t ) );
    h->picture->i_width = 0;
    h->picture->i_height= 0;

    /* init predict_XxX */
    x264_predict_16x16_init( h->cpu, h->predict_16x16 );
    x264_predict_8x8_init( h->cpu, h->predict_8x8 );
    x264_predict_4x4_init( h->cpu, h->predict_4x4 );

    x264_pixel_init( h->cpu, &h->pixf );
    x264_dct_init( h->cpu, &h->dctf );

    x264_mc_init( h->cpu, h->mc );

    /* create the vlc table (we could remove it from x264_t but it will need
     * to introduce a x264_init() for global librarie) */
    for( i = 0; i < 5; i++ )
    {
        /* max 2 step */
        h->x264_coeff_token_lookup[i] = x264_vlc_table_lookup_new( x264_coeff_token[i], 17*4, 4 );
    }
    /* max 2 step */
    h->x264_level_prefix_lookup = x264_vlc_table_lookup_new( x264_level_prefix, 16, 8 );

    for( i = 0; i < 15; i++ )
    {
        /* max 1 step */
        h->x264_total_zeros_lookup[i] = x264_vlc_table_lookup_new( x264_total_zeros[i], 16, 9 );
    }
    for( i = 0;i < 3; i++ )
    {
        /* max 1 step */
        h->x264_total_zeros_dc_lookup[i] = x264_vlc_table_lookup_new( x264_total_zeros_dc[i], 4, 3 );
    }
    for( i = 0;i < 7; i++ )
    {
        /* max 2 step */
        h->x264_run_before_lookup[i] = x264_vlc_table_lookup_new( x264_run_before[i], 15, 6 );
    }

    return h;
}

/****************************************************************************
 * x264_decoder_decode: decode one nal unit
 ****************************************************************************/
int     x264_decoder_decode( x264_t *h,
                             x264_picture_t **pp_pic, x264_nal_t *nal )
{
    int i_ret = 0;
    bs_t bs;

    /* no picture */
    *pp_pic = NULL;

    /* init bitstream reader */
    bs_init( &bs, nal->p_payload, nal->i_payload );

    switch( nal->i_type )
    {
        case NAL_SPS:
            if( ( i_ret = x264_sps_read( &bs, h->sps_array ) ) < 0 )
            {
                fprintf( stderr, "x264: x264_sps_read failed\n" );
            }
            break;

        case NAL_PPS:
            if( ( i_ret = x264_pps_read( &bs, h->pps_array ) ) < 0 )
            {
                fprintf( stderr, "x264: x264_pps_read failed\n" );
            }
            break;

        case NAL_SLICE_IDR:
            fprintf( stderr, "x264: NAL_SLICE_IDR\n" );
            x264_slice_idr( h );

        case NAL_SLICE:
            if( ( i_ret = x264_slice_header_decode( h, &bs, nal ) ) < 0 )
            {
                fprintf( stderr, "x264: x264_slice_header_decode failed\n" );
            }
            if( h->sh.i_redundant_pic_cnt == 0 && i_ret == 0 )
            {
                if( ( i_ret = x264_slice_data_decode( h, &bs ) ) < 0 )
                {
                    fprintf( stderr, "x264: x264_slice_data_decode failed\n" );
                }
                else
                {
                    *pp_pic = h->picture;
                }
            }
            break;

        case NAL_SLICE_DPA:
        case NAL_SLICE_DPB:
        case NAL_SLICE_DPC:
            fprintf( stderr, "partitioned stream unsupported\n" );
            i_ret = -1;
            break;

        case NAL_SEI:
        default:
            break;
    }

    /* restore CPU state (before using float again) */
    x264_cpu_restore( h->cpu );

    return i_ret;
}

/****************************************************************************
 * x264_decoder_close:
 ****************************************************************************/
void    x264_decoder_close  ( x264_t *h )
{
    int i;

    if( h->picture->i_width != 0 && h->picture->i_height != 0 )
    {
        for( i = 0; i < h->sps->i_num_ref_frames + 1; i++ )
        {
            x264_frame_delete( h->freference[i]);
        }
        x264_free( h->mb );
    }

    /* free vlc table */
    for( i = 0; i < 5; i++ )
    {
        x264_vlc_table_lookup_delete( h->x264_coeff_token_lookup[i] );
    }
    x264_vlc_table_lookup_delete( h->x264_level_prefix_lookup );

    for( i = 0; i < 15; i++ )
    {
        x264_vlc_table_lookup_delete( h->x264_total_zeros_lookup[i] );
    }
    for( i = 0;i < 3; i++ )
    {
        x264_vlc_table_lookup_delete( h->x264_total_zeros_dc_lookup[i] );
    }
    for( i = 0;i < 7; i++ )
    {
        x264_vlc_table_lookup_delete( h->x264_run_before_lookup[i] );
    }

    x264_free( h->picture );
    x264_free( h );
}