audio_source.h

/*
 * Copyright 2025 LiveKit
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an “AS IS” BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
#pragma once
 
#include <cstdint>
 
#include "livekit/audio_frame.h"
#include "livekit/ffi_handle.h"
#include "livekit/visibility.h"
 
namespace livekit {
 
namespace proto {
class FfiRequest;
class FfiResponse;
} // namespace proto
 
class FfiClient;
 
class LIVEKIT_API AudioSource {
public:
  AudioSource(int sample_rate, int num_channels, int queue_size_ms = 0);
  virtual ~AudioSource() = default;
 
  AudioSource(const AudioSource&) = delete;
  AudioSource& operator=(const AudioSource&) = delete;
  AudioSource(AudioSource&&) noexcept = default;
  AudioSource& operator=(AudioSource&&) noexcept = default;
 
  int sampleRate() const noexcept { return sample_rate_; }
 
  int numChannels() const noexcept { return num_channels_; }
 
  std::uint64_t ffiHandleId() const noexcept { return static_cast<std::uint64_t>(handle_.get()); }
 
  double queuedDuration() const noexcept;
 
  void clearQueue();
 
  void captureFrame(const AudioFrame& frame, int timeout_ms = 20);
 
private:
  // Internal helper to reset the local queue tracking (like _release_waiter).
  void resetQueueTracking() noexcept;
 
  int sample_rate_;
  int num_channels_;
  int queue_size_ms_;
 
  // RAII wrapper for this audio source's FFI handle
  FfiHandle handle_;
 
  // Queue tracking (all in seconds; based on steady_clock in the .cpp).
  mutable double last_capture_{0.0};
  mutable double q_size_{0.0};
};
 
} // namespace livekit