1 /*****************************************************************************
2 * trivial.c : trivial resampler (skips samples or pads with zeroes)
3 *****************************************************************************
4 * Copyright (C) 2002 VideoLAN
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 *****************************************************************************/
27 #include <stdlib.h> /* malloc(), free() */
31 #include "audio_output.h"
32 #include "aout_internal.h"
34 /*****************************************************************************
36 *****************************************************************************/
37 static int Create ( vlc_object_t * );
39 static void DoWork ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
42 /*****************************************************************************
44 *****************************************************************************/
46 set_description( _("audio filter for trivial resampling") );
47 set_capability( "audio filter", 1 );
48 set_category( CAT_AUDIO );
49 set_subcategory( SUBCAT_AUDIO_MISC );
50 set_callbacks( Create, NULL );
53 /*****************************************************************************
54 * Create: allocate trivial resampler
55 *****************************************************************************/
56 static int Create( vlc_object_t *p_this )
58 aout_filter_t * p_filter = (aout_filter_t *)p_this;
60 if ( p_filter->input.i_rate == p_filter->output.i_rate
61 || p_filter->input.i_format != p_filter->output.i_format
62 || p_filter->input.i_physical_channels
63 != p_filter->output.i_physical_channels
64 || p_filter->input.i_original_channels
65 != p_filter->output.i_original_channels
66 || (p_filter->input.i_format != VLC_FOURCC('f','l','3','2')
67 && p_filter->input.i_format != VLC_FOURCC('f','i','3','2')) )
72 p_filter->pf_do_work = DoWork;
73 p_filter->b_in_place = VLC_TRUE;
78 /*****************************************************************************
79 * DoWork: convert a buffer
80 *****************************************************************************/
81 static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
82 aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
84 int i_in_nb = p_in_buf->i_nb_samples;
85 int i_out_nb = i_in_nb * p_filter->output.i_rate
86 / p_filter->input.i_rate;
87 int i_sample_bytes = aout_FormatNbChannels( &p_filter->input )
90 /* Check if we really need to run the resampler */
91 if( p_aout->mixer.mixer.i_rate == p_filter->input.i_rate )
96 if ( p_out_buf != p_in_buf )
98 /* For whatever reason the buffer allocator decided to allocate
99 * a new buffer. Currently, this never happens. */
100 p_aout->p_vlc->pf_memcpy( p_out_buf->p_buffer, p_in_buf->p_buffer,
101 __MIN(i_out_nb, i_in_nb) * i_sample_bytes );
104 if ( i_out_nb > i_in_nb )
106 /* Pad with zeroes. */
107 memset( p_out_buf->p_buffer + i_in_nb * i_sample_bytes,
108 0, (i_out_nb - i_in_nb) * i_sample_bytes );
111 p_out_buf->i_nb_samples = i_out_nb;
112 p_out_buf->i_nb_bytes = i_out_nb * i_sample_bytes;
113 p_out_buf->start_date = p_in_buf->start_date;
114 p_out_buf->end_date = p_out_buf->start_date + p_out_buf->i_nb_samples *
115 1000000 / p_filter->output.i_rate;