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// Copyright (C) 2020 Natanael Mojica <neithanmo@gmail.com>
//
// This Source Code Form is subject to the terms of the Mozilla Public License, v2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at
// <https://mozilla.org/MPL/2.0/>.
//
// SPDX-License-Identifier: MPL-2.0
use gst::prelude::*;
use std::error::Error;
const AUDIO_SRC: &str = "audiotestsrc";
const AUDIO_SINK: &str = "audioconvert ! autoaudiosink";
// This example defines two instruments, the first instrument send to the output that is at its input and accumulates the received audio samples
// into a global variable called gasig. The execution of this instrument last the first 2 seconds.
// The second instrument starts it execution at 1.8 second, This instrument creates two audio buffers with samples that are read
// from the global accumulator(gasig), then reads these buffers at a fixed delay time, creating the adelL, adelM and adelR buffers,
// also, It multiplies the audio samples in the right channel by 0.5 * kdel, being kdel a line of values starting at 0.5 at increments of 0.001.
// Finally, those buffers are mixed with the accumulator, and an audio envelop is applied(aseg) to them.
// The result is similar to an audio echo in which the buffered samples are read at different delay times and also modified in frequency(right channel),
// this creates an space effect using just one channel audio input.
const CSD: &str = "
<CsoundSynthesizer>
<CsOptions>
</CsOptions>
<CsInstruments>
sr = 44100
ksmps = 7
nchnls_i = 1
nchnls = 2
gasig init 0
gidel = 1
instr 1
ain in
outs ain, ain
vincr gasig, ain
endin
instr 2
ifeedback = p4
aseg linseg 1., p3, 0.0
abuf2 delayr gidel
adelL deltap .4
adelM deltap .5
delayw gasig + (adelL * ifeedback)
abuf3 delayr gidel
kdel line .5, p3, .001
adelR deltap .5 * kdel
delayw gasig + (adelR * ifeedback)
outs (adelL + adelM) * aseg, (adelR + adelM) * aseg
clear gasig
endin
</CsInstruments>
<CsScore>
i 1 0 2
i 2 1.8 5 .8
e
</CsScore>
</CsoundSynthesizer>";
fn create_pipeline() -> Result<gst::Pipeline, Box<dyn Error>> {
let pipeline = gst::Pipeline::default();
let audio_src = gst::parse_bin_from_description(AUDIO_SRC, true)?.upcast();
let audio_sink = gst::parse_bin_from_description(AUDIO_SINK, true)?.upcast();
let csoundfilter = gst::ElementFactory::make("csoundfilter")
.property("csd-text", CSD)
.build()
.unwrap();
pipeline.add_many([&audio_src, &csoundfilter, &audio_sink])?;
audio_src.link_pads(Some("src"), &csoundfilter, Some("sink"))?;
csoundfilter.link_pads(Some("src"), &audio_sink, Some("sink"))?;
Ok(pipeline)
}
fn main_loop(pipeline: gst::Pipeline) -> Result<(), Box<dyn Error>> {
pipeline.set_state(gst::State::Playing)?;
let bus = pipeline
.bus()
.expect("Pipeline without bus. Shouldn't happen!");
for msg in bus.iter_timed(gst::ClockTime::NONE) {
use gst::MessageView;
match msg.view() {
MessageView::Eos(..) => break,
MessageView::Error(err) => {
println!(
"Error from {:?}: {} ({:?})",
msg.src().map(|s| s.path_string()),
err.error(),
err.debug()
);
break;
}
_ => (),
}
}
pipeline.set_state(gst::State::Null)?;
Ok(())
}
fn main() -> Result<(), Box<dyn Error>> {
gst::init().unwrap();
gstcsound::plugin_register_static().expect("Failed to register csound plugin");
create_pipeline().and_then(main_loop)
}
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