LinuxAudioInputDevice.cpp

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/*
 *  Copyright (C) Massimo Cora' 2006 <maxcvs@email.it>
 *  This class is a "subclass" of AudioInputDevice from LiveMedia.
 *
 *  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 Library 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 02111-1307, USA.
 */


#include "LinuxAudioInputDevice.hh"



AudioInputDevice*
AudioInputDevice::createNew(UsageEnvironment& env, int inputPortNumber,
                            unsigned char bitsPerSample,
                            unsigned char numChannels,
                            unsigned samplingFrequency,
                            unsigned granularityInMS) 
{
        return new LinuxAudioInputDevice( env, inputPortNumber,
                                  bitsPerSample, numChannels,
                                  samplingFrequency, granularityInMS );
}

AudioPortNames* AudioInputDevice::getPortNames() 
{
        AudioPortNames* portNames = new AudioPortNames;
        portNames->numPorts = 1;
        portNames->portName = new char*[1];
  
  
        return portNames;
}




LinuxAudioInputDevice::LinuxAudioInputDevice(UsageEnvironment& env, int inputPortNumber,
                          unsigned char bitsPerSample,
                          unsigned char numChannels,
                          unsigned samplingFrequency,
                          unsigned granularityInMS  ) : 
                AudioInputDevice( env, bitsPerSample, numChannels, samplingFrequency, granularityInMS )
{
        DEBUG_PRINT ("hey from LinuxAudioInputDevice::LinuxAudioInputDevice\n");

        _initialized = false;
        
    // initialize libavcodec, and register all codecs and formats
        avcodec_init();
        avcodec_register_all();
    av_register_all();

        AVFormatParameters ap;
        _ap = new AVFormatParameters;
        
        memset( &ap, 0, sizeof(AVFormatParameters));
        ap.channels = 2;
        ap.sample_rate = 44100;
        
        // search a suitable codec for PCM data.
        _pcm_codec = avcodec_find_decoder( CODEC_ID_PCM_S16LE );
    if ( !_pcm_codec ) {
        DEBUG_PRINT( "codec not found\n" );
        return;
    }   

        _format_context = av_alloc_format_context ();

        _audio_grab_format = "audio_device";
    _input_fmt = av_find_input_format( _audio_grab_format );
    if ( !_input_fmt ) {
        DEBUG_PRINT( "_input_fmt == NULL \n" );
        return;
        }       
        
        ap.device = strdup("/dev/dsp");
        

        if ( av_open_input_file( &_format_context, "", _input_fmt, 0, &ap ) < 0 ) {
        DEBUG_PRINT( "Could not find audio grab device\n" );
        return;
        }
        
        if ( (_format_context->ctx_flags & AVFMTCTX_NOHEADER) && av_find_stream_info( _format_context ) < 0 ) {
        DEBUG_PRINT ( "Could not find video grab parameters\n" );
        return;
    }   
        
        
        AVCodecContext *codec_context = NULL;
        codec_context = _format_context->streams[0]->codec;
        
        
    // open it 
    if ( avcodec_open( codec_context, _pcm_codec ) < 0 ) {
        DEBUG_PRINT( "could not open codec\n" );
        return;
    }
        
        
        _initialized = true;
}


LinuxAudioInputDevice::~LinuxAudioInputDevice()
{
}


void LinuxAudioInputDevice::doGetNextFrame() 
{
        AVPacket pkt;

        if ( _initialized == false ) {
                DEBUG_PRINT ("device not initialized \n");
                return;
        }
        
        if ( av_read_frame( _format_context, &pkt ) < 0) {
                DEBUG_PRINT( "error in getting packet......\n" );       
        }
        
        fFrameSize = pkt.size;
        
        if ( pkt.size > fMaxSize ) {
                DEBUG_PRINT( "pkt.size > fMaxSize \n" );        
                return;
        }

        DEBUG_PRINT ("read from mic pkt.size %d\n", pkt.size );
        memcpy( fTo, pkt.data, pkt.size );      
}

void LinuxAudioInputDevice::doStopGettingFrames() 
{
        // Turn off the audio poller:
        envir().taskScheduler().unscheduleDelayedTask(nextTask()); 
        nextTask() = NULL;
}


Boolean LinuxAudioInputDevice::setInputPort(int port_index)
{
        return true;
}

double LinuxAudioInputDevice::getAverageLevel() const 
{
        return 0;       
}

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