ScreenRecorder - High Performance Unity Video Capture Script

ScreenRecorder.cs

using UnityEngine;
using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Threading;

class BitmapEncoder
{
	public static void WriteBitmap(Stream stream, int width, int height, byte[] imageData)
	{
		using (BinaryWriter bw = new BinaryWriter(stream)) {

			// define the bitmap file header
			bw.Write ((UInt16)0x4D42); 								// bfType;
			bw.Write ((UInt32)(14 + 40 + (width * height * 4))); 	// bfSize;
			bw.Write ((UInt16)0);									// bfReserved1;
			bw.Write ((UInt16)0);									// bfReserved2;
			bw.Write ((UInt32)14 + 40);								// bfOffBits;
	 
			// define the bitmap information header
			bw.Write ((UInt32)40);  								// biSize;
			bw.Write ((Int32)width); 								// biWidth;
			bw.Write ((Int32)height); 								// biHeight;
			bw.Write ((UInt16)1);									// biPlanes;
			bw.Write ((UInt16)32);									// biBitCount;
			bw.Write ((UInt32)0);  									// biCompression;
			bw.Write ((UInt32)(width * height * 4));  				// biSizeImage;
			bw.Write ((Int32)0); 									// biXPelsPerMeter;
			bw.Write ((Int32)0); 									// biYPelsPerMeter;
			bw.Write ((UInt32)0);  									// biClrUsed;
			bw.Write ((UInt32)0);  									// biClrImportant;

			// switch the image data from RGB to BGR
			for (int imageIdx = 0; imageIdx < imageData.Length; imageIdx += 3) {
				bw.Write(imageData[imageIdx + 2]);
				bw.Write(imageData[imageIdx + 1]);
				bw.Write(imageData[imageIdx + 0]);
				bw.Write((byte)255);
			}
			
		}
	}

}

/// <summary>
/// Captures frames from a Unity camera in real time
/// and writes them to disk using a background thread.
/// </summary>
/// 
/// <description>
/// Maximises speed and quality by reading-back raw
/// texture data with no conversion and writing 
/// frames in uncompressed BMP format.
/// Created by Richard Copperwaite.
/// </description>
/// 
[RequireComponent(typeof(Camera))]
public class ScreenRecorder : MonoBehaviour 
{
	// Public Properties
	public int maxFrames; // maximum number of frames you want to record in one video
	public int frameRate = 30; // number of frames to capture per second

	// The Encoder Thread
	private Thread encoderThread;

	// Texture Readback Objects
	private RenderTexture tempRenderTexture;
	private Texture2D tempTexture2D;

	// Timing Data
	private float captureFrameTime;
	private float lastFrameTime;
	private int frameNumber;
	private int savingFrameNumber;

	// Encoder Thread Shared Resources
	private Queue<byte[]> frameQueue;
	private string persistentDataPath;
	private int screenWidth;
	private int screenHeight;
	private bool threadIsProcessing;
	private bool terminateThreadWhenDone;
	
	void Start () 
	{
		// Set target frame rate (optional)
		Application.targetFrameRate = frameRate;

		// Prepare the data directory
		persistentDataPath = Application.persistentDataPath + "/ScreenRecorder";

		print ("Capturing to: " + persistentDataPath + "/");

		if (!System.IO.Directory.Exists(persistentDataPath))
		{
			System.IO.Directory.CreateDirectory(persistentDataPath);
		}

		// Prepare textures and initial values
		screenWidth = GetComponent<Camera>().pixelWidth;
		screenHeight = GetComponent<Camera>().pixelHeight;
		
		tempRenderTexture = new RenderTexture(screenWidth, screenHeight, 0);
		tempTexture2D = new Texture2D(screenWidth, screenHeight, TextureFormat.RGB24, false);
		frameQueue = new Queue<byte[]> ();

		frameNumber = 0;
		savingFrameNumber = 0;

		captureFrameTime = 1.0f / (float)frameRate;
		lastFrameTime = Time.time;

		// Kill the encoder thread if running from a previous execution
		if (encoderThread != null && (threadIsProcessing || encoderThread.IsAlive)) {
			threadIsProcessing = false;
			encoderThread.Join();
		}

		// Start a new encoder thread
		threadIsProcessing = true;
		encoderThread = new Thread (EncodeAndSave);
		encoderThread.Start ();
	}
	
	void OnDisable() 
	{
		// Reset target frame rate
		Application.targetFrameRate = -1;

		// Inform thread to terminate when finished processing frames
		terminateThreadWhenDone = true;
	}

	void OnRenderImage(RenderTexture source, RenderTexture destination)
	{
		if (frameNumber <= maxFrames)
		{
			// Check if render target size has changed, if so, terminate
			if(source.width != screenWidth || source.height != screenHeight)
			{
				threadIsProcessing = false;
				this.enabled = false;
				throw new UnityException("ScreenRecorder render target size has changed!");
			}

			// Calculate number of video frames to produce from this game frame
			// Generate 'padding' frames if desired framerate is higher than actual framerate
			float thisFrameTime = Time.time;
			int framesToCapture = ((int)(thisFrameTime / captureFrameTime)) - ((int)(lastFrameTime / captureFrameTime));

			// Capture the frame
			if(framesToCapture > 0)
			{
				Graphics.Blit (source, tempRenderTexture);
				
				RenderTexture.active = tempRenderTexture;
				tempTexture2D.ReadPixels(new Rect(0, 0, Screen.width, Screen.height),0,0);
				RenderTexture.active = null;
			}

			// Add the required number of copies to the queue
			for(int i = 0; i < framesToCapture && frameNumber <= maxFrames; ++i)
			{
				frameQueue.Enqueue(tempTexture2D.GetRawTextureData());

				frameNumber ++;

				if(frameNumber % frameRate == 0)
				{
					print ("Frame " + frameNumber);
				}
			}
			
			lastFrameTime = thisFrameTime;

		}
		else //keep making screenshots until it reaches the max frame amount
		{
			// Inform thread to terminate when finished processing frames
			terminateThreadWhenDone = true;

			// Disable script
			this.enabled = false;
		}

		// Passthrough
		Graphics.Blit (source, destination);
	}
	
	private void EncodeAndSave()
	{
		print ("SCREENRECORDER IO THREAD STARTED");

		while (threadIsProcessing) 
		{
			if(frameQueue.Count > 0)
			{
				// Generate file path
				string path = persistentDataPath + "/frame" + savingFrameNumber + ".bmp";

				// Dequeue the frame, encode it as a bitmap, and write it to the file
				using(FileStream fileStream = new FileStream(path, FileMode.Create))
				{
					BitmapEncoder.WriteBitmap(fileStream, screenWidth, screenHeight, frameQueue.Dequeue());
					fileStream.Close();
				}

				// Done
				savingFrameNumber ++;
				print ("Saved " + savingFrameNumber + " frames. " + frameQueue.Count + " frames remaining.");
			}
			else
			{
				if(terminateThreadWhenDone)
				{
					break;
				}

				Thread.Sleep(1);
			}
		}

		terminateThreadWhenDone = false;
		threadIsProcessing = false;

		print ("SCREENRECORDER IO THREAD FINISHED");
	}
}

I had the same wish... extend the OnRenderImage event by an iterator over inactive cameras (if you want to record more than one). You can use something like this to capture images from inactive cameras:

            foreach (Camera inactiveCam in inactiveCameras)
            {
                int resWidth = inactiveCam.pixelWidth;
                int resHeight = inactiveCam.pixelHeight;
                RenderTexture rt = RenderTexture.GetTemporary(resWidth, resHeight, 24);
                inactiveCam.targetTexture = rt;
                inactiveCam.Render();
                Texture2D ss = new Texture2D(resWidth, resHeight, TextureFormat.RGB24, false);
                RenderTexture.active = rt;
                ss.ReadPixels(inactiveCam.pixelRect, 0, 0);
                ss.Apply();
                queues[inactiveCam.name].Enqueue(ss.EncodeToPNG());
                inactiveCam.targetTexture = null;
                RenderTexture.active = null;
                rt.Release();
            }

Don't forget to extend the encoder as well

I would recommend Unity's Recorder, which is totally free on the Asset Store:
https://assetstore.unity.com/packages/essentials/unity-recorder-94079

As someone else said, that official solution is only usable in Editor, it uses the media encoder supplied in the UnityEditor.Media namespace which is not included in build.

Can this script be used in android or ios build?

Unity Recorder is no longer available on the asset store.

Unity Recorder is no longer available on the asset store.

It's a package now and you can find it in package manager.

Unity Recorder is no longer available on the asset store.

https://docs.unity3d.com/Packages/com.unity.recorder@latest

Would this work to capture audio with fmod? Unity recorder doesn't work with Fmod enabled.