mirror of
https://code.videolan.org/videolan/vlc
synced 2024-09-28 23:09:59 +02:00
added a new resampler based on linear interpolation, giving a fair tradeoff
between sound quality and speed
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@ -553,7 +553,7 @@ PLUGINS="${PLUGINS} idct idctclassic motion mpeg_video spudec mpeg_audio"
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PLUGINS="${PLUGINS} lpcm a52"
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PLUGINS="${PLUGINS} deinterlace invert yuv wall transform distort clone crop motionblur"
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PLUGINS="${PLUGINS} float32tos16 float32tos8 float32tou16 float32tou8 a52tospdif fixed32tofloat32 fixed32tos16 s16tofloat32 s16tofloat32swab"
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PLUGINS="${PLUGINS} trivial_resampler ugly_resampler"
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PLUGINS="${PLUGINS} trivial_resampler ugly_resampler linear_resampler"
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PLUGINS="${PLUGINS} trivial_channel_mixer"
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PLUGINS="${PLUGINS} trivial_mixer spdif_mixer"
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PLUGINS="${PLUGINS} aout_file"
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@ -1,3 +1,4 @@
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SOURCES_trivial_resampler = modules/audio_filter/resampler/trivial.c
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SOURCES_ugly_resampler = modules/audio_filter/resampler/ugly.c
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SOURCES_linear_resampler = modules/audio_filter/resampler/linear.c
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#SOURCES_fast = modules/audio_filter/resampler/fast.c
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122
modules/audio_filter/resampler/linear.c
Normal file
122
modules/audio_filter/resampler/linear.c
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@ -0,0 +1,122 @@
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/*****************************************************************************
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* ugly.c : linear interpolation resampler
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*****************************************************************************
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* Copyright (C) 2002 VideoLAN
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* $Id: linear.c,v 1.1 2002/11/07 21:09:59 sigmunau Exp $
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*
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* Authors: Sigmund Augdal <sigmunau@idi.ntnu.no>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
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*****************************************************************************/
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/*****************************************************************************
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* Preamble
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*****************************************************************************/
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#include <errno.h>
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#include <stdlib.h> /* malloc(), free() */
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#include <string.h>
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#include <vlc/vlc.h>
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#include "audio_output.h"
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#include "aout_internal.h"
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/*****************************************************************************
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* Local prototypes
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*****************************************************************************/
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static int Create ( vlc_object_t * );
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static void DoWork ( aout_instance_t *, aout_filter_t *, aout_buffer_t *,
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aout_buffer_t * );
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/*****************************************************************************
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* Module descriptor
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*****************************************************************************/
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vlc_module_begin();
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set_description( _("audio filter for linear interpolation resampling") );
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set_capability( "audio filter", 10 );
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set_callbacks( Create, NULL );
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vlc_module_end();
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/*****************************************************************************
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* Create: allocate ugly resampler
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*****************************************************************************/
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static int Create( vlc_object_t *p_this )
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{
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aout_filter_t * p_filter = (aout_filter_t *)p_this;
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msg_Dbg( p_this, " trying the linear resampler");
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if ( p_filter->input.i_rate == p_filter->output.i_rate
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|| p_filter->input.i_format != p_filter->output.i_format
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|| p_filter->input.i_channels != p_filter->output.i_channels
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|| p_filter->input.i_format != VLC_FOURCC('f','l','3','2') )
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{
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return VLC_EGENERIC;
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}
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p_filter->pf_do_work = DoWork;
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p_filter->b_in_place = VLC_FALSE;
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return VLC_SUCCESS;
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}
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/*****************************************************************************
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* DoWork: convert a buffer
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*****************************************************************************/
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static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
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aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
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{
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float* p_in = (float*)p_in_buf->p_buffer;
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float* p_out = (float*)p_out_buf->p_buffer;
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int i_nb_channels = aout_FormatNbChannels( &p_filter->input );
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int i_in_nb = p_in_buf->i_nb_samples;
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int i_out_nb = i_in_nb * p_filter->output.i_rate
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/ p_filter->input.i_rate;
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int i_frame_bytes = i_nb_channels * sizeof(s32);
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int i_in, i_chan, i_out = 0;
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double f_step = (float)i_in_nb/i_out_nb;
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float f_pos = 1;
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for( i_in = 0 ; i_in < i_in_nb - 1; i_in++ )
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{
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f_pos--;
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while( f_pos < 1 )
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{
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for( i_chan = i_nb_channels ; i_chan ; )
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{
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i_chan--;
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p_out[i_chan] = p_in[i_chan] +
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( p_in[i_chan + i_nb_channels] - p_in[i_chan] ) * f_pos;
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i_out++;
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}
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f_pos += f_step;
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p_out += i_nb_channels;
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}
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p_in += i_nb_channels;
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}
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if ( f_step < 1 ) {
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for( i_chan = i_nb_channels ; i_chan ; )
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{
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i_chan--;
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p_out[i_chan] = p_in[i_chan];
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i_out++;
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}
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}
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if ( i_out != i_out_nb * i_nb_channels ) {
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msg_Warn( p_aout, "mismatch in sample nubers: %d requested, %d generated", i_out_nb* i_nb_channels, i_out);
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}
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p_out_buf->i_nb_samples = i_out_nb;
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p_out_buf->i_nb_bytes = i_out_nb * i_frame_bytes;
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}
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