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Viewing changes to mediastreamer/msAlawdec.c

  • Committer: Bazaar Package Importer
  • Author(s): Samuel Mimram
  • Date: 2004-06-30 13:58:16 UTC
  • Revision ID: james.westby@ubuntu.com-20040630135816-wwx75gdlodkqbabb
Tags: upstream-0.12.2
Import upstream version 0.12.2

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mediastreamer/msAlawdec.c
 
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 /*
 
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  The mediastreamer library aims at providing modular media processing and I/O
 
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        for linphone, but also for any telephony application.
 
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  Copyright (C) 2001  Simon MORLAT simon.morlat@linphone.org
 
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  This library is free software; you can redistribute it and/or
 
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  modify it under the terms of the GNU Lesser General Public
 
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  License as published by the Free Software Foundation; either
 
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  version 2.1 of the License, or (at your option) any later version.
 
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  This library 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 GNU
 
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  Lesser General Public License for more details.
 
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  You should have received a copy of the GNU Lesser General Public
 
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  License along with this library; if not, write to the Free Software
 
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  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
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*/
 
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#include <msAlawdec.h>
 
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#include <g711common.h>
 
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extern MSFilter * ms_ALAWencoder_new(void);
 
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MSCodecInfo ALAWinfo={
 
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        {
 
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                "ALAW codec",
 
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                0,
 
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                MS_FILTER_AUDIO_CODEC,
 
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                ms_ALAWencoder_new,
 
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                "This is the classic A-law codec. Good quality, but only usable with high speed network connections."
 
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        },
 
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        ms_ALAWencoder_new,
 
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        ms_ALAWdecoder_new,
 
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        320,
 
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        160,
 
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        64000,
 
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        8000,
 
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        8,
 
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        "PCMA",
 
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        1,
 
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        1,
 
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};
 
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static MSALAWDecoderClass *ms_ALAWdecoder_class=NULL;
 
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MSFilter * ms_ALAWdecoder_new(void)
 
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{
 
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        MSALAWDecoder *r;
 
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        r=g_new(MSALAWDecoder,1);
 
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        ms_ALAWdecoder_init(r);
 
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        if (ms_ALAWdecoder_class==NULL)
 
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        {
 
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                ms_ALAWdecoder_class=g_new(MSALAWDecoderClass,1);
 
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                ms_ALAWdecoder_class_init(ms_ALAWdecoder_class);
 
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        }
 
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        MS_FILTER(r)->klass=MS_FILTER_CLASS(ms_ALAWdecoder_class);
 
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        return(MS_FILTER(r));
 
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}
 
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/* FOR INTERNAL USE*/
 
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void ms_ALAWdecoder_init(MSALAWDecoder *r)
 
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{
 
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        ms_filter_init(MS_FILTER(r));
 
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        MS_FILTER(r)->infifos=r->f_inputs;
 
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        MS_FILTER(r)->outfifos=r->f_outputs;
 
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        MS_FILTER(r)->r_mingran=ALAW_DECODER_RMAXGRAN;
 
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        memset(r->f_inputs,0,sizeof(MSFifo*)*MSALAWDECODER_MAX_INPUTS);
 
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        memset(r->f_outputs,0,sizeof(MSFifo*)*MSALAWDECODER_MAX_INPUTS);
 
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}
 
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void ms_ALAWdecoder_class_init(MSALAWDecoderClass *klass)
 
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{
 
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        ms_filter_class_init(MS_FILTER_CLASS(klass));
 
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        ms_filter_class_set_name(MS_FILTER_CLASS(klass),"ALAWDecoder");
 
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        MS_FILTER_CLASS(klass)->info=(MSFilterInfo*)&ALAWinfo;
 
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        MS_FILTER_CLASS(klass)->max_finputs=MSALAWDECODER_MAX_INPUTS;
 
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        MS_FILTER_CLASS(klass)->max_foutputs=MSALAWDECODER_MAX_INPUTS;
 
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        MS_FILTER_CLASS(klass)->r_maxgran=ALAW_DECODER_RMAXGRAN;
 
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        MS_FILTER_CLASS(klass)->w_maxgran=ALAW_DECODER_WMAXGRAN;
 
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        MS_FILTER_CLASS(klass)->destroy=(MSFilterDestroyFunc)ms_ALAWdecoder_destroy;
 
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        MS_FILTER_CLASS(klass)->process=(MSFilterProcessFunc)ms_ALAWdecoder_process;
 
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}
 
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void ms_ALAWdecoder_process(MSALAWDecoder *r)
 
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{
 
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        MSFifo *fi,*fo;
 
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        int inlen,outlen;
 
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        gchar *s,*d;
 
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        int i;
 
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        /* process output fifos, but there is only one for this class of filter*/
 
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        /* this is the simplest process function design:
 
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        the filter declares a r_mingran of ALAW_DECODER_RMAXGRAN, so the mediastreamer's
 
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        scheduler will call the process function each time there is ALAW_DECODER_RMAXGRAN
 
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        bytes to read in the input fifo. If there is more, then it will call it several
 
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        time in order to the fifo to be completetly processed.
 
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        This is very simple, but not very efficient because of the multiple call function
 
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        of MSFilterProcessFunc that may happen.
 
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        The MSAlawEncoder implements another design; see it.
 
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        */
 
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        fi=r->f_inputs[0];
 
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        fo=r->f_outputs[0];
 
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        g_return_if_fail(fi!=NULL);
 
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        g_return_if_fail(fo!=NULL);
 
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        inlen=ms_fifo_get_read_ptr(fi,ALAW_DECODER_RMAXGRAN,(void**)&s);
 
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        if (s==NULL) return;
 
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        outlen=ms_fifo_get_write_ptr(fo,ALAW_DECODER_WMAXGRAN,(void**)&d);
 
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        if (d!=NULL)
 
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        {
 
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                for(i=0;i<ALAW_DECODER_RMAXGRAN;i++)
 
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                {
 
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                        ((gint16*)d)[i]=alaw_to_s16( (unsigned char) s[i]);
 
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                }
 
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        }
 
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        else g_warning("MSALAWDecoder: Discarding samples !!");
 
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}
 
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void ms_ALAWdecoder_destroy( MSALAWDecoder *obj)
 
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{
 
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        g_free(obj);
 
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}