audio_frame_resizer.cpp

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/*
 *  Copyright (C) 2004-2025 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 "audio_frame_resizer.h"
#include "libav_deps.h"
#include "logger.h"
 
extern "C" {
#include <libavutil/audio_fifo.h>
}
 
#include <stdexcept>
 
namespace jami {
 
AudioFrameResizer::AudioFrameResizer(const AudioFormat& format,
                                     int size,
                                     std::function<void(std::shared_ptr<AudioFrame>&&)> cb)
    : format_(format)
    , frameSize_(size)
    , cb_(cb)
    , queue_(av_audio_fifo_alloc(format.sampleFormat, format.nb_channels, frameSize_))
{}
 
AudioFrameResizer::~AudioFrameResizer()
{
    av_audio_fifo_free(queue_);
}
 
int
AudioFrameResizer::samples() const
{
    return av_audio_fifo_size(queue_);
}
 
int
AudioFrameResizer::frameSize() const
{
    return frameSize_;
}
 
AudioFormat
AudioFrameResizer::format() const
{
    return format_;
}
 
void
AudioFrameResizer::setFormat(const AudioFormat& format, int size)
{
    if (size)
        setFrameSize(size);
    if (format != format_) {
        if (auto discarded = samples())
            JAMI_WARN("Discarding %d samples", discarded);
        av_audio_fifo_free(queue_);
        format_ = format;
        queue_ = av_audio_fifo_alloc(format.sampleFormat, format.nb_channels, frameSize_);
    }
}
 
void
AudioFrameResizer::setFrameSize(int frameSize)
{
    if (frameSize_ != frameSize) {
        frameSize_ = frameSize;
        if (cb_)
            while (auto frame = dequeue())
                cb_(std::move(frame));
    }
}
 
void
AudioFrameResizer::enqueue(std::shared_ptr<AudioFrame>&& frame)
{
    if (not frame or frame->pointer() == nullptr)
        return;
 
    int ret = 0;
    auto f = frame->pointer();
    AudioFormat format(f->sample_rate, f->ch_layout.nb_channels, (AVSampleFormat) f->format);
    if (format != format_) {
        JAMI_WARNING("Expected {} but got {}", format_.toString(), format.toString());
        setFormat(format, frameSize_);
    }
 
    auto nb_samples = samples();
    if (cb_ && nb_samples == 0 && f->nb_samples == frameSize_) {
        nextOutputPts_ = frame->pointer()->pts + frameSize_;
        cb_(std::move(frame));
        return; // return if frame was just passed through
    }
 
    // voice activity
    hasVoice_ = frame->has_voice;
 
    // queue reallocates itself if need be
    if ((ret = av_audio_fifo_write(queue_, reinterpret_cast<void**>(f->data), f->nb_samples)) < 0) {
        JAMI_ERR() << "Audio resizer error: " << libav_utils::getError(ret);
        throw std::runtime_error("Failed to add audio to frame resizer");
    }
 
    if (nextOutputPts_ == 0)
        nextOutputPts_ = frame->pointer()->pts - nb_samples;
 
    if (cb_)
        while (auto frame = dequeue())
            cb_(std::move(frame));
}
 
std::shared_ptr<AudioFrame>
AudioFrameResizer::dequeue()
{
    if (samples() < frameSize_)
        return {};
 
    auto frame = std::make_shared<AudioFrame>(format_, frameSize_);
    int ret;
    if ((ret = av_audio_fifo_read(queue_,
                                  reinterpret_cast<void**>(frame->pointer()->data),
                                  frameSize_))
        < 0) {
        JAMI_ERR() << "Unable to read samples from queue: " << libav_utils::getError(ret);
        return {};
    }
    frame->pointer()->pts = nextOutputPts_;
    frame->has_voice = hasVoice_;
    nextOutputPts_ += frameSize_;
    return frame;
}
 
} // namespace jami