ARCoreSessionRecorder.cs

using System.Collections.Generic;
using System.IO;

#if UNITY_ANDROID && ARCORE_4_2_OR_NEWER
using UnityEngine.XR.ARCore;
#endif

namespace UnityEngine.XR.ARFoundation.Samples
{
    class LogUtil
    {
        List<string> m_Entries = new List<string>();

        string m_FullLog = "";

        int m_Count;

        bool m_Dirty;

        public int maxCount { get; set; } = 10;

        public void Log(string msg)
        {
            m_Entries.Add($"{m_Count}> {msg}");
            m_Count++;
            m_Dirty = true;
        }

        public override string ToString()
        {
            if (m_Dirty)
            {
                var removeCount = m_Entries.Count - maxCount;
                if (removeCount > 0)
                {
                    m_Entries.RemoveRange(0, removeCount);
                }

                m_FullLog = string.Join("\n", m_Entries);
                m_Dirty = false;
            }

            return m_FullLog;
        }
    }

    [RequireComponent(typeof(ARSession))]
    public class ARCoreSessionRecorder : MonoBehaviour
    {
        LogUtil m_Log = new LogUtil();

        ARSession m_Session;

#if UNITY_ANDROID && ARCORE_4_2_OR_NEWER
        ArStatus? m_SetMp4DatasetResult;
        ArPlaybackStatus m_PlaybackStatus = (ArPlaybackStatus)(-1);
        ArRecordingStatus m_RecordingStatus = (ArRecordingStatus)(-1);
#endif

        string m_PlaybackStatusMessage;

        string m_RecordingStatusMessage;

        string m_Mp4LocalFilePath;
        string m_Mp4PathUri;

        void Awake()
        {
            m_Session = GetComponent<ARSession>();
            m_Mp4LocalFilePath = Path.Combine(Application.persistentDataPath, "arcore-session.mp4");
            // NOTE: The Uri class with C# does NOT correctly format the URI needed for 
            // native Android APIs that require a "Uri as string" parameter.
            // However, so long as the path does not require escaping, or slash separator
            // modification, then prepending "file://" is sufficient.
            m_Mp4PathUri = $"file://{m_Mp4LocalFilePath}";
            Log($"Setting recording Uri to [{m_Mp4PathUri}]");
        }

        static int GetRotation() => Screen.orientation switch
        {
            ScreenOrientation.Portrait => 0,
            ScreenOrientation.LandscapeLeft => 90,
            ScreenOrientation.PortraitUpsideDown => 180,
            ScreenOrientation.LandscapeRight => 270,
            _ => 0
        };

        void Log(string msg)
        {
            Debug.Log(msg);
            m_Log.Log(msg);
        }

        static string GetFileSize(string path)
        {
            var byteCount = new FileInfo(path).Length;
            const long kiloBytes = 1024;
            const long megaBytes = kiloBytes * kiloBytes;

            if (byteCount / megaBytes > 0)
            {
                var size = (float)byteCount / megaBytes;
                return $"{size:F2} Mb";
            }

            if (byteCount / kiloBytes > 0)
            {
                var size = (float)byteCount / kiloBytes;
                return $"{size:F2} Kb";
            }

            return $"{byteCount} Bytes";
        }

        void OnGUI()
        {
            GUI.skin.label.fontSize = 50;
            GUI.skin.button.fontSize = 50;
            GUI.skin.button.padding = new RectOffset(10, 10, 25, 25);
            GUILayout.Space(50);

#if UNITY_ANDROID && ARCORE_4_2_OR_NEWER
            if (m_Session.subsystem is ARCoreSessionSubsystem subsystem)
            {
                var session = subsystem.session;
                if (session == null)
                    return;

                var playbackStatus = subsystem.playbackStatus;
                var recordingStatus = subsystem.recordingStatus;

                if (!playbackStatus.Playing() &&
                    !recordingStatus.Recording())
                {
                    if (playbackStatus != ArPlaybackStatus.Finished && GUILayout.Button("Start recording"))
                    {
                        using (var config = new ArRecordingConfig(session))
                        {
                            config.SetMp4DatasetUri(session, m_Mp4PathUri);
                            config.SetRecordingRotation(session, GetRotation());
                            var status = subsystem.StartRecording(config);
                            Log($"StartRecording to {config.GetMp4DatasetUri(session)} => {status}");
                        }
                    }

                    if (File.Exists(m_Mp4LocalFilePath) && GUILayout.Button("Start playback"))
                    {
                        var status = subsystem.StartPlaybackUri(m_Mp4PathUri);
                        Log($"StartPlayback({m_Mp4PathUri}) => {status}");
                    }
                }

                if (playbackStatus.Playing() &&
                    !recordingStatus.Recording() &&
                    GUILayout.Button("Stop playback"))
                {
                    var status = subsystem.StopPlaybackUri();
                    Log($"StopPlayback() => {status}");
                }

                if (playbackStatus == ArPlaybackStatus.Finished &&
                    GUILayout.Button("Return to live feed"))
                {
                    var status = subsystem.StopPlaybackUri();
                    Log($"StopPlayback() => {status}");
                }

                if (recordingStatus.Recording() &&
                    GUILayout.Button("Stop recording"))
                {
                    var status = subsystem.StopRecording();
                    Log($"StopRecording() => {status}");

                    if (status == ArStatus.Success)
                    {
                        Log(File.Exists(m_Mp4LocalFilePath)
                            ? $"ARCore session saved to {m_Mp4LocalFilePath} ({GetFileSize(m_Mp4LocalFilePath)})"
                            : "Recording completed, but no file was produced.");
                    }
                }

                if (m_PlaybackStatus != playbackStatus)
                {
                    m_PlaybackStatus = playbackStatus;
                    m_PlaybackStatusMessage = $"Playback status: {m_PlaybackStatus}";
                }

                if (m_RecordingStatus != recordingStatus)
                {
                    m_RecordingStatus = recordingStatus;
                    m_RecordingStatusMessage = $"Recording status: {m_RecordingStatus}";
                }

                GUILayout.Label(m_PlaybackStatusMessage);
                GUILayout.Label(m_RecordingStatusMessage);
                GUILayout.Space(50);
                GUILayout.Label(m_Log.ToString());
            }
            else
            {
                GUILayout.Label("No " + nameof(ARCoreSessionSubsystem) + " available. Cannot perform session recording.");
            }
#else
            GUILayout.Label("ARCore session recording is only supported on Android.");
#endif // UNITY_ANDROID && ARCORE_4_2_OR_NEWER
        }
    }
}