/***************************************************************************** * trivial.c : trivial resampler (skips samples or pads with zeroes) ***************************************************************************** * Copyright (C) 2002 VideoLAN * $Id: trivial.c,v 1.11 2003/03/04 03:27:40 gbazin Exp $ * * Authors: Christophe Massiot <massiot@via.ecp.fr> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. *  * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA. *****************************************************************************//***************************************************************************** * Preamble *****************************************************************************/#include <stdlib.h>                                      /* malloc(), free() */#include <string.h>#include <vlc/vlc.h>#include "audio_output.h"#include "aout_internal.h"/***************************************************************************** * Local prototypes *****************************************************************************/static int  Create    ( vlc_object_t * );static void DoWork    ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,                        aout_buffer_t * );/***************************************************************************** * Module descriptor *****************************************************************************/vlc_module_begin();    set_description( _("audio filter for trivial resampling") );    set_capability( "audio filter", 1 );    set_callbacks( Create, NULL );vlc_module_end();/***************************************************************************** * Create: allocate trivial resampler *****************************************************************************/static int Create( vlc_object_t *p_this ){    aout_filter_t * p_filter = (aout_filter_t *)p_this;    if ( p_filter->input.i_rate == p_filter->output.i_rate          || p_filter->input.i_format != p_filter->output.i_format          || p_filter->input.i_physical_channels              != p_filter->output.i_physical_channels          || p_filter->input.i_original_channels              != p_filter->output.i_original_channels          || (p_filter->input.i_format != VLC_FOURCC('f','l','3','2')               && p_filter->input.i_format != VLC_FOURCC('f','i','3','2')) )    {        return -1;    }    p_filter->pf_do_work = DoWork;    p_filter->b_in_place = VLC_TRUE;    return 0;}/***************************************************************************** * DoWork: convert a buffer *****************************************************************************/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 ){    int i_in_nb = p_in_buf->i_nb_samples;    int i_out_nb = i_in_nb * p_filter->output.i_rate                    / p_filter->input.i_rate;    int i_sample_bytes = aout_FormatNbChannels( &p_filter->input )                          * sizeof(int32_t);    /* Check if we really need to run the resampler */    if( p_aout->mixer.mixer.i_rate == p_filter->input.i_rate )    {        return;    }    if ( p_out_buf != p_in_buf )    {        /* For whatever reason the buffer allocator decided to allocate         * a new buffer. Currently, this never happens. */        p_aout->p_vlc->pf_memcpy( p_out_buf->p_buffer, p_in_buf->p_buffer,                                  __MIN(i_out_nb, i_in_nb) * i_sample_bytes );    }    if ( i_out_nb > i_in_nb )    {        /* Pad with zeroes. */        memset( p_out_buf->p_buffer + i_in_nb * i_sample_bytes,                0, (i_out_nb - i_in_nb) * i_sample_bytes );    }    p_out_buf->i_nb_samples = i_out_nb;    p_out_buf->i_nb_bytes = i_out_nb * i_sample_bytes;    p_out_buf->start_date = p_in_buf->start_date;    p_out_buf->end_date = p_out_buf->start_date + p_out_buf->i_nb_samples *        1000000 / p_filter->output.i_rate;}