ReplayRecorder.cs

namespace MyProject.Core
{
    using MyProject.Utilities;
    using NatCorderU.Core;
    using System.Collections;
    using UnityEngine;

    public class ReplayRecorder : MonoBehaviour
    {
        public int width = 960;
        public int height = 540;
        public int framesPerSecond = 30;
        public int replayLengthSeconds = 5;

        private CircularBuffer<Frame> _buffer;
        private bool _isRendering = false;

        private IEnumerator Start()
        {
            // Create the buffer for storing the latest N frames
            _buffer = new CircularBuffer<Frame>(framesPerSecond * replayLengthSeconds);

            // Start NatCorder
            NatCorder.StartRecording(
                    Container.MP4,
                    new VideoFormat(width, height, framesPerSecond),
                    AudioFormat.None,
                    OnReplay);

            // (Temporary) Stop recording after 10 seconds to test out replay
            yield return new WaitForSeconds(10f);
            RenderReplay();
        }

        private void OnRenderImage(RenderTexture source, RenderTexture destination)
        {
            if (NatCorder.IsRecording && !_isRendering)
            {
                if (_buffer.IsFull)
                {
                    RenderTexture.ReleaseTemporary(_buffer.Front());
                }

                var frame = NatCorder.AcquireFrame();
                Graphics.Blit(source, frame);
                _buffer.PushBack(frame);
            }

            Graphics.Blit(source, destination);
        }

        public void RenderReplay()
        {
            if (NatCorder.IsRecording)
            {
                _isRendering = true;

                for (int i = 0; i < _buffer.Size; i++)
                {
                    var frame = _buffer[i];
                    NatCorder.CommitFrame(frame);
                }

                NatCorder.StopRecording();
            }
        }

        void OnReplay(string videoPath)
        {
            _isRendering = false;

            Debug.Log("Video saved to: " + videoPath);
            string localURL = "file://" + videoPath;
#if (UNITY_IOS || UNITY_ANDROID) && !UNITY_EDITOR
            Handheld.PlayFullScreenMovie(
                localURL,
                Color.black,
                FullScreenMovieControlMode.Full,
                FullScreenMovieScalingMode.AspectFit);
#else
            Application.OpenURL(localURL);
#endif
        }
    }
}