Aegisub/src/audio_provider_dummy.cpp

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// Copyright (c) 2005-2006, Rodrigo Braz Monteiro, Fredrik Mellbin
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
// * Neither the name of the Aegisub Group nor the names of its contributors
// may be used to endorse or promote products derived from this software
// without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
// Aegisub Project http://www.aegisub.org/
/// @file audio_provider_dummy.cpp
/// @brief Dummy (silence or noise) audio provider
/// @ingroup audio_input
///
#include "config.h"
#include "audio_provider_dummy.h"
#include "utils.h"
#include <libaegisub/fs.h>
#include <boost/algorithm/string/predicate.hpp>
/*
* scheme ::= "dummy-audio" ":" signal-specifier "?" signal-parameters
* signal-specifier ::= "silence" | "noise" | "sine" "/" frequency
* frequency ::= integer
* signal-parameters ::= signal-parameter [ "&" signal-parameters ]
* signal-parameter ::= signal-parameter-name "=" integer
* signal-parameter-name ::= "sr" | "bd" | "ch" | "ln"
*
* Signal types:
* "silence", a silent signal is generated.
* "noise", a white noise signal is generated.
* "sine", a sine wave is generated at the specified frequency.
*
* Signal parameters:
* "sr", sample rate to generate signal at.
* "bd", bit depth to generate signal at (usually 16).
* "ch", number of channels to generate, usually 1 or 2. The same signal is generated
* in every channel even if one would be LFE.
* "ln", length of signal in samples. ln/sr gives signal length in seconds.
*/
DummyAudioProvider::DummyAudioProvider(agi::fs::path const& uri) {
if (!boost::starts_with(uri.string(), "dummy-audio:"))
throw agi::fs::FileNotFound(std::string("Not a dummy audio URI"));
noise = boost::contains(uri.string(), ":noise?");
channels = 1;
sample_rate = 44100;
bytes_per_sample = 2;
float_samples = false;
num_samples = (int64_t)5*30*60*1000 * sample_rate / 1000;
}
void DummyAudioProvider::FillBuffer(void *buf, int64_t, int64_t count) const {
if (noise) {
short *workbuf = (short*)buf;
while (count-- > 0)
*workbuf++ = (rand() - RAND_MAX/2) * 10000 / RAND_MAX;
}
else {
memset(buf, 0, count * bytes_per_sample);
}
}