a52tofloat32.c

VLC Player Source Code

    p_sys->i_flags |= A52_ADJUST_LEVEL;

    /* Initialize liba52 */
    p_sys->p_liba52 = a52_init( 0 );
    if( p_sys->p_liba52 == NULL )
    {
        msg_Err( p_this, "unable to initialize liba52" );
        free( p_sys );
        return VLC_EGENERIC;
    }

    aout_CheckChannelReorder( pi_channels_in, NULL,
                              output.i_physical_channels & AOUT_CHAN_PHYSMASK,
                              p_sys->i_nb_channels,
                              p_sys->pi_chan_table );

    return VLC_SUCCESS;
}

/*****************************************************************************
 * Interleave: helper function to interleave channels
 *****************************************************************************/
static void Interleave( float * p_out, const float * p_in, int i_nb_channels,
                        int *pi_chan_table )
{
    /* We do not only have to interleave, but also reorder the channels */

    int i, j;
    for ( j = 0; j < i_nb_channels; j++ )
    {
        for ( i = 0; i < 256; i++ )
        {
            p_out[i * i_nb_channels + pi_chan_table[j]] = p_in[j * 256 + i];
        }
    }
}

/*****************************************************************************
 * Duplicate: helper function to duplicate a unique channel
 *****************************************************************************/
static void Duplicate( float * p_out, const float * p_in )
{
    int i;

    for ( i = 256; i--; )
    {
        *p_out++ = *p_in;
        *p_out++ = *p_in;
        p_in++;
    }
}

/*****************************************************************************
 * Exchange: helper function to exchange left & right channels
 *****************************************************************************/
static void Exchange( float * p_out, const float * p_in )
{
    int i;
    const float * p_first = p_in + 256;
    const float * p_second = p_in;

    for ( i = 0; i < 256; i++ )
    {
        *p_out++ = *p_first++;
        *p_out++ = *p_second++;
    }
}

/*****************************************************************************
 * DoWork: decode an ATSC A/52 frame.
 *****************************************************************************/
static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
                    aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
{
    filter_sys_t    *p_sys = (filter_sys_t *)p_filter->p_sys;
#ifdef LIBA52_FIXED
    sample_t        i_sample_level = (1 << 24);
#else
    sample_t        i_sample_level = 1;
#endif
    int             i_flags = p_sys->i_flags;
    int             i_bytes_per_block = 256 * p_sys->i_nb_channels
                      * sizeof(float);
    int             i;

    /* Do the actual decoding now. */
    a52_frame( p_sys->p_liba52, p_in_buf->p_buffer,
               &i_flags, &i_sample_level, 0 );

    if ( (i_flags & A52_CHANNEL_MASK) != (p_sys->i_flags & A52_CHANNEL_MASK)
          && !p_sys->b_dontwarn )
    {
        msg_Warn( p_aout,
                  "liba52 couldn't do the requested downmix 0x%x->0x%x",
                  p_sys->i_flags  & A52_CHANNEL_MASK,
                  i_flags & A52_CHANNEL_MASK );

        p_sys->b_dontwarn = 1;
    }

    if( !p_sys->b_dynrng )
    {
        a52_dynrng( p_sys->p_liba52, NULL, NULL );
    }

    for ( i = 0; i < 6; i++ )
    {
        sample_t * p_samples;

        if( a52_block( p_sys->p_liba52 ) )
        {
            msg_Warn( p_aout, "a52_block failed for block %d", i );
        }

        p_samples = a52_samples( p_sys->p_liba52 );

        if ( ((p_sys->i_flags & A52_CHANNEL_MASK) == A52_CHANNEL1
               || (p_sys->i_flags & A52_CHANNEL_MASK) == A52_CHANNEL2
               || (p_sys->i_flags & A52_CHANNEL_MASK) == A52_MONO)
              && (p_filter->output.i_physical_channels
                   & (AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT)) )
        {
            Duplicate( (float *)(p_out_buf->p_buffer + i * i_bytes_per_block),
                       p_samples );
        }
        else if ( p_filter->output.i_original_channels
                    & AOUT_CHAN_REVERSESTEREO )
        {
            Exchange( (float *)(p_out_buf->p_buffer + i * i_bytes_per_block),
                      p_samples );
        }
        else
        {
            /* Interleave the *$£%ù samples. */
            Interleave( (float *)(p_out_buf->p_buffer + i * i_bytes_per_block),
                        p_samples, p_sys->i_nb_channels, p_sys->pi_chan_table);
        }
    }

    p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
    p_out_buf->i_nb_bytes = i_bytes_per_block * 6;
}

/*****************************************************************************
 * Destroy : deallocate data structures
 *****************************************************************************/
static void Destroy( vlc_object_t *p_this )
{
    aout_filter_t *p_filter = (aout_filter_t *)p_this;
    filter_sys_t *p_sys = (filter_sys_t *)p_filter->p_sys;

    a52_free( p_sys->p_liba52 );
    free( p_sys );
}

/*****************************************************************************
 * OpenFilter:
 *****************************************************************************/
static int OpenFilter( vlc_object_t *p_this )
{
    filter_t *p_filter = (filter_t *)p_this;
    filter_sys_t *p_sys;
    int i_ret;

    if( p_filter->fmt_in.i_codec != VLC_FOURCC('a','5','2',' ')  )
    {
        return VLC_EGENERIC;
    }

    p_filter->fmt_out.audio.i_format =
#ifdef LIBA52_FIXED
        p_filter->fmt_out.i_codec = VLC_FOURCC('f','i','3','2');
#else
        p_filter->fmt_out.i_codec = VLC_FOURCC('f','l','3','2');
#endif
    p_filter->fmt_out.audio.i_bitspersample =
        aout_BitsPerSample( p_filter->fmt_out.i_codec );

    /* Allocate the memory needed to store the module's structure */
    p_filter->p_sys = p_sys = malloc( sizeof(filter_sys_t) );
    if( p_sys == NULL )
        return VLC_ENOMEM;

    i_ret = Open( VLC_OBJECT(p_filter), p_sys,
                  p_filter->fmt_in.audio, p_filter->fmt_out.audio );

    p_filter->pf_audio_filter = Convert;
    p_filter->fmt_out.audio.i_rate = p_filter->fmt_in.audio.i_rate;

    return i_ret;
}

/*****************************************************************************
 * CloseFilter : deallocate data structures
 *****************************************************************************/
static void CloseFilter( vlc_object_t *p_this )
{
    filter_t *p_filter = (filter_t *)p_this;
    filter_sys_t *p_sys = p_filter->p_sys;

    a52_free( p_sys->p_liba52 );
    free( p_sys );
}

static block_t *Convert( filter_t *p_filter, block_t *p_block )
{
    aout_filter_t aout_filter;
    aout_buffer_t in_buf, out_buf;
    block_t *p_out;
    int i_out_size;

    if( !p_block || !p_block->i_samples )
    {
        if( p_block )
            block_Release( p_block );
        return NULL;
    }

    i_out_size = p_block->i_samples *
      p_filter->fmt_out.audio.i_bitspersample *
        p_filter->fmt_out.audio.i_channels / 8;

    p_out = p_filter->pf_audio_buffer_new( p_filter, i_out_size );
    if( !p_out )
    {
        msg_Warn( p_filter, "can't get output buffer" );
        block_Release( p_block );
        return NULL;
    }

    p_out->i_samples = p_block->i_samples;
    p_out->i_dts = p_block->i_dts;
    p_out->i_pts = p_block->i_pts;
    p_out->i_length = p_block->i_length;

    aout_filter.p_sys = (struct aout_filter_sys_t *)p_filter->p_sys;
    aout_filter.input = p_filter->fmt_in.audio;
    aout_filter.input.i_format = p_filter->fmt_in.i_codec;
    aout_filter.output = p_filter->fmt_out.audio;
    aout_filter.output.i_format = p_filter->fmt_out.i_codec;

    in_buf.p_buffer = p_block->p_buffer;
    in_buf.i_nb_bytes = p_block->i_buffer;
    in_buf.i_nb_samples = p_block->i_samples;
    out_buf.p_buffer = p_out->p_buffer;
    out_buf.i_nb_bytes = p_out->i_buffer;
    out_buf.i_nb_samples = p_out->i_samples;

    DoWork( (aout_instance_t *)p_filter, &aout_filter, &in_buf, &out_buf );

    p_out->i_buffer = out_buf.i_nb_bytes;
    p_out->i_samples = out_buf.i_nb_samples;

    block_Release( p_block );

    return p_out;
}