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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set sw=2 ts=8 et ft=cpp : */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at */
#ifndef mozilla_VideoEngine_h
#define mozilla_VideoEngine_h
#include "MediaEngine.h"
#include "VideoFrameUtils.h"
#include "mozilla/media/MediaUtils.h"
#include "modules/video_capture/video_capture_impl.h"
#include "modules/video_capture/video_capture_defines.h"
#include "modules/video_capture/video_capture_factory.h"
#include <memory>
#include <functional>
namespace mozilla::camera {
enum class CaptureDeviceType { Camera, Screen, Window, Browser };
struct CaptureDeviceInfo {
CaptureDeviceType type;
CaptureDeviceInfo() : type(CaptureDeviceType::Camera) {}
explicit CaptureDeviceInfo(CaptureDeviceType t) : type(t) {}
const char* TypeName() const {
switch (type) {
case CaptureDeviceType::Camera: {
return "Camera";
case CaptureDeviceType::Screen: {
return "Screen";
case CaptureDeviceType::Window: {
return "Window";
case CaptureDeviceType::Browser: {
return "Browser";
return "UNKOWN-CaptureDeviceType!";
// Historically the video engine was part of webrtc
// it was removed (and reimplemented in Talk)
class VideoEngine {
virtual ~VideoEngine();
// Base cache expiration period
// Note because cameras use HW plug event detection, this
// only applies to screen based modes.
static const int64_t kCacheExpiryPeriodMs = 2000;
static already_AddRefed<VideoEngine> Create(
const CaptureDeviceType& aCaptureDeviceType);
#if defined(ANDROID)
static int SetAndroidObjects();
// Returns a non-negative capture identifier or -1 on failure.
int32_t CreateVideoCapture(const char* aDeviceUniqueIdUTF8);
int ReleaseVideoCapture(const int32_t aId);
// VideoEngine is responsible for any cleanup in its modules
static void Delete(VideoEngine* aEngine) {}
/** Returns an existing or creates a new new DeviceInfo.
* Camera info is cached to prevent repeated lengthy polling for "realness"
* of the hardware devices. Other types of capture, e.g. screen share info,
* are cached for 1 second. This could be handled in a more elegant way in
* the future.
* @return on failure the shared_ptr will be null, otherwise it will contain
* a DeviceInfo.
class CaptureEntry {
CaptureEntry(int32_t aCapnum,
rtc::scoped_refptr<webrtc::VideoCaptureModule> aCapture);
int32_t Capnum() const;
rtc::scoped_refptr<webrtc::VideoCaptureModule> VideoCapture();
int32_t mCapnum;
rtc::scoped_refptr<webrtc::VideoCaptureModule> mVideoCaptureModule;
friend class VideoEngine;
// Returns true iff an entry for capnum exists
bool WithEntry(const int32_t entryCapnum,
const std::function<void(CaptureEntry& entry)>&& fn);
explicit VideoEngine(const CaptureDeviceType& aCaptureDeviceType);
int32_t mId;
const CaptureDeviceInfo mCaptureDevInfo;
std::shared_ptr<webrtc::VideoCaptureModule::DeviceInfo> mDeviceInfo;
std::map<int32_t, CaptureEntry> mCaps;
std::map<int32_t, int32_t> mIdMap;
// The validity period for non-camera capture device infos`
webrtc::Timestamp mExpiryTime = webrtc::Timestamp::Micros(0);
int32_t GenerateId();
} // namespace mozilla::camera