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hlrc / server / src / AudioPlayerLibAO.cpp @ 38936fe1

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/*
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* This file is part of hlrc_server
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*
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* Copyright(c) sschulz <AT> techfak.uni-bielefeld.de
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* http://opensource.cit-ec.de/projects/hlrc_server
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*
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* This file may be licensed under the terms of the
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* GNU General Public License Version 3 (the ``GPL''),
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* or (at your option) any later version.
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*
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* Software distributed under the License is distributed
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* on an ``AS IS'' basis, WITHOUT WARRANTY OF ANY KIND, either
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* express or implied. See the GPL for the specific language
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* governing rights and limitations.
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*
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* You should have received a copy of the GPL along with this
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* program. If not, go to http://www.gnu.org/licenses/gpl.html
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* or write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* The development of this software was supported by the
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* Excellence Cluster EXC 277 Cognitive Interaction Technology.
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* The Excellence Cluster EXC 277 is a grant of the Deutsche
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* Forschungsgemeinschaft (DFG) in the context of the German
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* Excellence Initiative.
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*
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*/
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#include "AudioPlayerLibAO.h"
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#include <thread>
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#include <chrono>
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using namespace std;
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//new audio player with gievn device type (default is pulse)
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AudioPlayerLibAO::AudioPlayerLibAO(string driver): AudioPlayer(driver){
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    printf("> using libao for playback\n");
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    //initialize
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    ao_initialize();
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    //configure driver
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    if (audio_driver.empty()){
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        //use default:
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        driver = ao_default_driver_id();
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    }else{
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        driver = ao_driver_id(audio_driver.c_str());
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    }
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    //start audio playback thread:
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    playback_thread_ptr = new boost::thread(boost::bind(&AudioPlayerLibAO::playback_thread, this));
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}
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//this will return once we start playing
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void AudioPlayerLibAO::play(std::shared_ptr<AudioData> audio){
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    audio_data = audio;
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    printf("> AudioPlayerLibAO: play() %d samples requested\n",(int)audio_data->samples.size());
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    //skip empty audio data
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    if (audio_data->samples.size() == 0){
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        printf("> warning: empty audio data - skipped.\n");
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        return;
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    }
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    //check if we can play this file:
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    while(playback_state != IDLE){
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        printf("> player not ready yet, waiting for 10ms\n");
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        std::this_thread::sleep_for(std::chrono::milliseconds(10));
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    }
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    audio_format = extract_ao_format(audio_data);
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    playback_requested = true;
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    //wait for playback to start:
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    printf("> waiting for playback start...\n");
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    while(playback_requested){
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        std::this_thread::sleep_for(std::chrono::milliseconds(1));
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    }
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    printf("> playback running.\n");
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}
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ao_sample_format AudioPlayerLibAO::extract_ao_format(std::shared_ptr<AudioData> audio){
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    ao_sample_format ao_format;
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    //get bits per sample
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    ao_format.bits = audio->sample_bit;
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    //bitrate
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    ao_format.rate = audio->sample_rate;
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    //endianess
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    ao_format.byte_format = audio->sample_big_endian?AO_FMT_BIG:AO_FMT_LITTLE;
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    //number of channels
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    ao_format.channels = audio->sample_channels;
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    //format matrix:
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    if (ao_format.channels == 1){
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        ao_format.matrix = (char *)"L";
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    }else if(ao_format.channels == 2){
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        ao_format.matrix = (char *)"L,R";
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    }else{
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        printf("> invalid AudioData channel count given. ignoring request\n");
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        throw runtime_error("AudioPlayerLibAO::extract_ao_format() unsupported number of audio channels given in AudioData");
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    }
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    printf("> AudioPlayerLibAO: format=%d rate=%d endianess=%d channels=%d\n", ao_format.bits, ao_format.rate, ao_format.byte_format, ao_format.channels);
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    return ao_format;
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}
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void AudioPlayerLibAO::playback_thread(){
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    printf("> playback thread started\n");
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    playback_state = IDLE;
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    while(playback_state != EXITING){
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        switch (playback_state){
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            default:
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            case(INITIALIZING):
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                //waiting to be ready
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                break;
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            case(IDLE):
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                //nothing to do, wait here until we are triggered to play!
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                if (playback_requested){
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                    printf("> AudioPlayer: loading\n");
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                    playback_state = LOADING;
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                }
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                break;
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            case(LOADING):
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                //check if we can play that format:
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                device = ao_open_live(driver, &audio_format, NULL /* no options */);
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                if (device == NULL){
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                    printf("> AudioPlayer: WARNING: can not open requested audio device. trying to fall back to default driver\n");
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                    driver = ao_default_driver_id();
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                    device = ao_open_live(driver, &audio_format, NULL /* no options */);
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                }
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                if (device == NULL){
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                    //failed to init device for format:
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                    printf("> AudioPlayer: WARNING: can not open audio device, not playing audio file!\n");
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                    playback_active = false;
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                    playback_requested = false;
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                    playback_state = IDLE;
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                    break;
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                }else{
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                    //ok we can now play the data
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                    printf("> AudioPlayer: playback started\n");
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                    //mark request as beeing processed
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                    playback_requested = false;
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                    //enter actual playing state
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                    playback_state = PLAYING;
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                    playback_active = true;
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                    ao_play(device, audio_data->samples.data(), audio_data->samples.size());
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                    printf("> AudioPlayer: finished playback\n");
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                }
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                break;
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            case(PLAYING):
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                //when we reach this case, the ao_play() call finished
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                //-> we can close this now:
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                ao_close(device);
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                playback_state = IDLE;
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                playback_active = false;
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                printf("> AudioPlayer: device closed\n");
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                break;
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            case(ERROR):
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                printf("> AudioPlayer ERROR! exiting\n");
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                exit(EXIT_FAILURE);
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                break;
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        }
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        //1ms delay to safe cpu time
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        std::this_thread::sleep_for(std::chrono::milliseconds(1));
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    }
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    //shutdown audio!
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    ao_shutdown();
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    //done
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    playback_state = CLOSED;
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}
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AudioPlayerLibAO::~AudioPlayerLibAO(){
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}