1 /*****************************************************************************
2 * trivial.c : trivial resampler (skips samples or pads with zeroes)
3 *****************************************************************************
4 * Copyright (C) 2002 VideoLAN
5 * $Id: trivial.c,v 1.5 2002/08/24 16:07:48 sam Exp $
7 * Authors: Christophe Massiot <massiot@via.ecp.fr>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
22 *****************************************************************************/
24 /*****************************************************************************
26 *****************************************************************************/
28 #include <stdlib.h> /* malloc(), free() */
32 #include "audio_output.h"
33 #include "aout_internal.h"
35 /*****************************************************************************
37 *****************************************************************************/
38 static int Create ( vlc_object_t * );
40 static void DoWork ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
43 /*****************************************************************************
45 *****************************************************************************/
47 set_description( _("audio filter for trivial resampling") );
48 set_capability( "audio filter", 1 );
49 set_callbacks( Create, NULL );
52 /*****************************************************************************
53 * Create: allocate trivial resampler
54 *****************************************************************************/
55 static int Create( vlc_object_t *p_this )
57 aout_filter_t * p_filter = (aout_filter_t *)p_this;
59 if ( p_filter->input.i_rate == p_filter->output.i_rate
60 || p_filter->input.i_format != p_filter->output.i_format
61 || p_filter->input.i_channels != p_filter->output.i_channels
62 || (p_filter->input.i_format != AOUT_FMT_FLOAT32
63 && p_filter->input.i_format != AOUT_FMT_FIXED32) )
68 p_filter->pf_do_work = DoWork;
69 p_filter->b_in_place = 1;
74 /*****************************************************************************
75 * DoWork: convert a buffer
76 *****************************************************************************/
77 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
78 aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
80 int i_in_nb = p_in_buf->i_nb_samples;
81 int i_out_nb = i_in_nb * p_filter->output.i_rate
82 / p_filter->input.i_rate;
83 int i_frame_bytes = p_filter->input.i_channels * sizeof(s32);
85 if ( p_out_buf != p_in_buf )
87 /* For whatever reason the buffer allocator decided to allocate
88 * a new buffer. Currently, this never happens. */
89 p_aout->p_vlc->pf_memcpy( p_out_buf->p_buffer, p_in_buf->p_buffer,
90 __MIN(i_out_nb, i_in_nb) * i_frame_bytes );
93 if ( i_out_nb > i_in_nb )
95 /* Pad with zeroes. */
96 memset( p_out_buf->p_buffer + i_in_nb * i_frame_bytes,
97 0, (i_out_nb - i_in_nb) * i_frame_bytes );
100 p_out_buf->i_nb_samples = i_out_nb;
101 p_out_buf->i_nb_bytes = i_out_nb * i_frame_bytes;