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183 lines
4.7 KiB
C
183 lines
4.7 KiB
C
/* FluidSynth FX - An example of using effects with fluidsynth
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*
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* This code is in the public domain.
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*
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* To compile:
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* gcc -g -O -o fluidsynth_fx fluidsynth_fx.c -lfluidsynth
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*
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* To run
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* fluidsynth_fx soundfont gain
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*
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* [Peter Hanappe]
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <fluidsynth.h>
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/* The structure with the effects data. This example simply applies a
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* linear gain the to synthesizer output. */
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struct fx_data_t
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{
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fluid_synth_t *synth;
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float gain;
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} fx_data_t;
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/* This function implements the callback function of the audio driver
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* (see new_fluid_audio_driver2 below). The data argument is a pointer
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* to your private data structure. 'len' is the number of audio frames
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* in the buffers. 'nfx' and 'nout' are the number of input and output
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* audio buffers. 'fx' and 'out' are arrays of float buffers containing
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* the audio. The audio driver fills zero-initializes those buffers.
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* You are responsible for filling up those buffers, as the result will
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* be sent to the sound card. This is usually done by asking the synth
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* to fill those buffers appropriately using fluid_synth_process()
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*
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* NOTE: The API was designed to be generic. Audio driver may fill the
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* buffers with audio input from the soundcard, rather than zeros.
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*/
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int fx_function(void *data, int len,
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int nfx, float **fx,
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int nout, float **out)
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{
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struct fx_data_t *fx_data = (struct fx_data_t *) data;
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int i, k;
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if(fx == 0)
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{
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/* Note that some audio drivers may not provide buffers for effects like
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* reverb and chorus. In this case it's your decision what to do. If you
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* had called fluid_synth_process() like in the else branch below, no
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* effects would have been rendered. Instead, you may mix the effects
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* directly into the out buffers. */
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if(fluid_synth_process(fx_data->synth, len, nout, out, nout, out) != FLUID_OK)
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{
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/* Some error occurred. Very unlikely to happen, though. */
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return FLUID_FAILED;
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}
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}
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else
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{
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/* Call the synthesizer to fill the output buffers with its
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* audio output. */
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if(fluid_synth_process(fx_data->synth, len, nfx, fx, nout, out) != FLUID_OK)
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{
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/* Some error occurred. Very unlikely to happen, though. */
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return FLUID_FAILED;
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}
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}
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/* Apply your effects here. In this example, the gain is
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* applied to all the dry-audio output buffers. */
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for(i = 0; i < nout; i++)
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{
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float *out_i = out[i];
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for(k = 0; k < len; k++)
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{
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out_i[k] *= fx_data->gain;
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}
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}
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/* Apply the same effect to all available effect buffer. */
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for(i = 0; i < nfx; i++)
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{
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float *fx_i = fx[i];
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for(k = 0; k < len; k++)
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{
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fx_i[k] *= fx_data->gain;
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}
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}
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return FLUID_OK;
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}
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int main(int argc, char **argv)
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{
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fluid_settings_t *settings;
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fluid_synth_t *synth = NULL;
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fluid_audio_driver_t *adriver = NULL;
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int err = 0;
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struct fx_data_t fx_data;
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if(argc != 3)
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{
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fprintf(stderr, "Usage: fluidsynth_simple [soundfont] [gain]\n");
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return 1;
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}
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/* Create the settings object. This example uses the default
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* values for the settings. */
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settings = new_fluid_settings();
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if(settings == NULL)
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{
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fprintf(stderr, "Failed to create the settings\n");
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err = 2;
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goto cleanup;
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}
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/* Create the synthesizer */
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synth = new_fluid_synth(settings);
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if(synth == NULL)
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{
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fprintf(stderr, "Failed to create the synthesizer\n");
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err = 3;
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goto cleanup;
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}
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/* Load the soundfont */
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if(fluid_synth_sfload(synth, argv[1], 1) == -1)
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{
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fprintf(stderr, "Failed to load the SoundFont\n");
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err = 4;
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goto cleanup;
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}
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/* Fill in the data of the effects unit */
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fx_data.synth = synth;
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fx_data.gain = (float)atof(argv[2]);
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/* Create the audio driver. As soon as the audio driver is
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* created, the synthesizer can be played. */
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adriver = new_fluid_audio_driver2(settings, fx_function, (void *) &fx_data);
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if(adriver == NULL)
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{
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fprintf(stderr, "Failed to create the audio driver\n");
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err = 5;
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goto cleanup;
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}
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/* Play a note */
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fluid_synth_noteon(synth, 0, 60, 100);
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printf("Press \"Enter\" to stop: ");
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fgetc(stdin);
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printf("done\n");
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cleanup:
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if(adriver)
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{
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delete_fluid_audio_driver(adriver);
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}
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if(synth)
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{
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delete_fluid_synth(synth);
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}
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if(settings)
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{
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delete_fluid_settings(settings);
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}
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return err;
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}
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