dtmfgenerator.cpp

Go to the documentation of this file.

/*
 *  Copyright (C) 2004-2026 Savoir-faire Linux Inc.
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program. If not, see <https://www.gnu.org/licenses/>.
 */
#include "dtmfgenerator.h"
#include "libav_deps.h"
 
#include <cmath>
#include <cassert>
 
namespace jami {
 
struct DTMFTone
{
    unsigned char code; 
    unsigned lower;     
    unsigned higher;    
};
 
/*
 * Tone frequencies
 */
constexpr DTMFTone TONES[] = {{'0', 941, 1336},
                              {'1', 697, 1209},
                              {'2', 697, 1336},
                              {'3', 697, 1477},
                              {'4', 770, 1209},
                              {'5', 770, 1336},
                              {'6', 770, 1477},
                              {'7', 852, 1209},
                              {'8', 852, 1336},
                              {'9', 852, 1477},
                              {'A', 697, 1633},
                              {'B', 770, 1633},
                              {'C', 852, 1633},
                              {'D', 941, 1633},
                              {'*', 941, 1209},
                              {'#', 941, 1477}};
 
/*
 * Initialize the generator
 */
DTMFGenerator::DTMFGenerator(unsigned int sampleRate, AVSampleFormat sampleFormat)
    : state()
    , sampleRate_(sampleRate)
    , tone_("", sampleRate, sampleFormat)
{
    state.offset = 0;
    state.sample = 0;
 
    for (int i = 0; i < NUM_TONES; i++)
        toneBuffers_[i] = fillToneBuffer(i);
}
 
DTMFGenerator::~DTMFGenerator() {}
 
void
DTMFGenerator::getSamples(AVFrame* frame, unsigned char code)
{
    code = toupper(code);
 
    if (code >= '0' and code <= '9')
        state.sample = toneBuffers_[code - '0'].get();
    else if (code >= 'A' and code <= 'D')
        state.sample = toneBuffers_[code - 'A' + 10].get();
    else {
        switch (code) {
        case '*':
            state.sample = toneBuffers_[NUM_TONES - 2].get();
            break;
 
        case '#':
            state.sample = toneBuffers_[NUM_TONES - 1].get();
            break;
 
        default:
            throw DTMFException("Invalid code");
            break;
        }
    }
 
    av_samples_copy(frame->data,
                    state.sample->data,
                    0,
                    state.offset,
                    frame->nb_samples,
                    frame->ch_layout.nb_channels,
                    (AVSampleFormat) frame->format);
    state.offset = frame->nb_samples % sampleRate_;
}
 
/*
 * Get next n samples (continues where previous call to
 * genSample or genNextSamples stopped
 */
void
DTMFGenerator::getNextSamples(AVFrame* frame)
{
    if (state.sample == 0)
        throw DTMFException("DTMF generator not initialized");
 
    av_samples_copy(frame->data,
                    state.sample->data,
                    0,
                    state.offset,
                    frame->nb_samples,
                    frame->ch_layout.nb_channels,
                    (AVSampleFormat) frame->format);
    state.offset = (state.offset + frame->nb_samples) % sampleRate_;
}
 
libjami::FrameBuffer
DTMFGenerator::fillToneBuffer(unsigned index)
{
    assert(index < NUM_TONES);
    libjami::FrameBuffer ptr(av_frame_alloc());
    ptr->nb_samples = sampleRate_;
    ptr->format = tone_.getFormat().sampleFormat;
    ptr->sample_rate = sampleRate_;
    ptr->channel_layout = AV_CH_LAYOUT_MONO;
    av_channel_layout_from_mask(&ptr->ch_layout, AV_CH_LAYOUT_MONO);
    av_frame_get_buffer(ptr.get(), 0);
    tone_.genSin(ptr.get(), 0, ptr->nb_samples, TONES[index].higher, TONES[index].lower);
    return ptr;
}
 
} // namespace jami