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schoenebeck |
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/*************************************************************************** |
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* * |
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* LinuxSampler - modular, streaming capable sampler * |
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* * |
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* Copyright (C) 2003 by Benno Senoner and Christian Schoenebeck * |
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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, * |
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* MA 02111-1307 USA * |
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***************************************************************************/ |
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#include "audioio.h" |
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AudioIO::AudioIO() { |
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pcm_handle = NULL; |
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pOutputBuffer = NULL; |
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} |
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AudioIO::~AudioIO() { |
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Close(); |
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} |
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int AudioIO::Initialize(uint channels, uint samplerate, uint numfragments, uint fragmentsize) { |
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this->Channels = channels; |
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this->Samplerate = samplerate; |
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this->Fragments = numfragments; |
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this->FragmentSize = fragmentsize; |
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/* Playback stream */ |
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snd_pcm_stream_t stream = SND_PCM_STREAM_PLAYBACK; |
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/* This structure contains information about */ |
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/* the hardware and can be used to specify the */ |
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/* configuration to be used for the PCM stream. */ |
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snd_pcm_hw_params_t* hwparams; |
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snd_pcm_sw_params_t* swparams; |
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/* Name of the PCM device, like plughw:0,0 */ |
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/* The first number is the number of the soundcard, */ |
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/* the second number is the number of the device. */ |
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char* pcm_name; |
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/* Init pcm_name. Of course, later you */ |
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int err; |
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pcm_name = strdup("hw:0,0"); |
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/* Allocate the snd_pcm_hw_params_t structure on the stack. */ |
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snd_pcm_hw_params_alloca(&hwparams); |
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/* Open PCM. The last parameter of this function is the mode. */ |
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/* If this is set to 0, the standard mode is used. Possible */ |
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/* other values are SND_PCM_NONBLOCK and SND_PCM_ASYNC. */ |
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/* If SND_PCM_NONBLOCK is used, read / write access to the */ |
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/* PCM device will return immediately. If SND_PCM_ASYNC is */ |
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/* specified, SIGIO will be emitted whenever a period has */ |
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/* been completely processed by the soundcard. */ |
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if ((err = snd_pcm_open(&pcm_handle, pcm_name, stream, 0)) < 0) { |
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fprintf(stderr, "Error opening PCM device %s: %s\n", pcm_name, snd_strerror(err)); |
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return EXIT_FAILURE; |
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} |
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if ((err = snd_pcm_hw_params_any(pcm_handle, hwparams)) < 0) { |
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fprintf(stderr, "Error, cannot initialize hardware parameter structure: %s.\n", snd_strerror(err)); |
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return EXIT_FAILURE; |
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} |
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/* Set access type. This can be either */ |
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/* SND_PCM_ACCESS_RW_INTERLEAVED or */ |
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/* SND_PCM_ACCESS_RW_NONINTERLEAVED. */ |
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if ((err = snd_pcm_hw_params_set_access(pcm_handle, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) { |
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fprintf(stderr, "Error snd_pcm_hw_params_set_access: %s.\n", snd_strerror(err)); |
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return EXIT_FAILURE; |
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} |
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/* Set sample format */ |
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if ((err = snd_pcm_hw_params_set_format(pcm_handle, hwparams, SND_PCM_FORMAT_S16_LE)) < 0) { |
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fprintf(stderr, "Error setting sample format. : %s\n", snd_strerror(err)); |
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return EXIT_FAILURE; |
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} |
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/* Set sample rate. If the exact rate is not supported */ |
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/* by the hardware, use nearest possible rate. */ |
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if((err = snd_pcm_hw_params_set_rate_near(pcm_handle, hwparams, samplerate, 0)) < 0) { |
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fprintf(stderr, "Error setting sample rate. : %s\n", snd_strerror(err)); |
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return EXIT_FAILURE; |
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} |
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if ((err = snd_pcm_hw_params_set_channels(pcm_handle, hwparams, channels)) < 0) { |
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fprintf(stderr, "Error setting number of channels. : %s\n", snd_strerror(err)); |
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return EXIT_FAILURE; |
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} |
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/* Set number of periods. Periods used to be called fragments. */ |
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if ((err = snd_pcm_hw_params_set_periods(pcm_handle, hwparams, numfragments, 0)) < 0) { |
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fprintf(stderr, "Error setting number of periods. : %s\n", snd_strerror(err)); |
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return EXIT_FAILURE; |
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} |
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/* Set buffer size (in frames). The resulting latency is given by */ |
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/* latency = periodsize * periods / (rate * bytes_per_frame) */ |
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if ((err = snd_pcm_hw_params_set_buffer_size(pcm_handle, hwparams, (fragmentsize * numfragments))) < 0) { |
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fprintf(stderr, "Error setting buffersize. : %s\n", snd_strerror(err)); |
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return EXIT_FAILURE; |
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} |
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/* Apply HW parameter settings to */ |
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/* PCM device and prepare device */ |
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if ((err = snd_pcm_hw_params(pcm_handle, hwparams)) < 0) { |
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fprintf(stderr, "Error setting HW params. : %s\n", snd_strerror(err)); |
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return EXIT_FAILURE; |
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} |
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if (snd_pcm_sw_params_malloc(&swparams) != 0) { |
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fprintf(stderr, "Error in snd_pcm_sw_params_malloc. : %s\n", snd_strerror(err)); |
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return EXIT_FAILURE; |
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} |
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if (snd_pcm_sw_params_current(pcm_handle, swparams) != 0) { |
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fprintf(stderr, "Error in snd_pcm_sw_params_current. : %s\n", snd_strerror(err)); |
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return EXIT_FAILURE; |
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} |
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if (snd_pcm_sw_params_set_stop_threshold(pcm_handle, swparams, 0xffffffff) != 0) { |
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fprintf(stderr, "Error in snd_pcm_sw_params_set_stop_threshold. : %s\n", snd_strerror(err)); |
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return EXIT_FAILURE; |
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} |
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if (snd_pcm_sw_params(pcm_handle, swparams) != 0) { |
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fprintf(stderr, "Error in snd_pcm_sw_params. : %s\n", snd_strerror(err)); |
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return EXIT_FAILURE; |
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} |
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if ((err = snd_pcm_prepare(pcm_handle)) < 0) { |
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fprintf(stderr, "Error snd_pcm_prepare : %s\n", snd_strerror(err)); |
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return EXIT_FAILURE; |
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} |
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// allocate the audio output buffer |
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pOutputBuffer = new int16_t[channels * fragmentsize]; |
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return EXIT_SUCCESS; |
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} |
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int AudioIO::Output() { |
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int err = snd_pcm_writei(pcm_handle, pOutputBuffer, FragmentSize); |
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if (err < 0) { |
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fprintf(stderr, "Error snd_pcm_writei failed. : %s\n", snd_strerror(err)); |
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return EXIT_FAILURE; |
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} |
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return EXIT_SUCCESS; |
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} |
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void AudioIO::Close(void) { |
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if (pcm_handle) { |
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snd_pcm_close(pcm_handle); |
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pcm_handle = NULL; |
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} |
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if (pOutputBuffer) { |
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delete[] pOutputBuffer; |
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pOutputBuffer = NULL; |
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} |
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} |