FrameEncoder.cs

using UnityEngine;
using System.Collections;
using System.Diagnostics;
using System.IO;
using UnityEngine.UI;

public class FrameEncoder : MonoBehaviour {

    public string videoDir;
    public int FPS = 30;
    public int width = 1280;
    public int height = 1440;

    public Camera dispCamera;
    private Texture2D targetTexture;

    private bool isRecording;
    private Process ffmpegProcess;
    private BinaryWriter ffmpegInput;

    private float frameInterval;
    private float prevTime;


    public void ToggleRecording(Text text)
    {
        var message = "Start";
        if (!isRecording) {
            StartRecording();
            message = "Stop";
        }
        else
        {
            StopRecordnig();
        } 
        if (text != null)
        {
            text.text = message;
        }
    }

    public void StartRecording()
    {
        if (!isRecording)
        {
            isRecording = true;

            ffmpegProcess = new Process();
            string filePath = videoDir + "\\" + System.DateTime.Now.ToString("yyyyMMdd-hhmmss") +".mp4";
            ffmpegProcess.StartInfo.FileName = "ffmpeg";
            ffmpegProcess.StartInfo.Arguments = string.Format("-framerate {1} -i - -r 20 -s {2}x{3} -an -vcodec nvenc -pix_fmt yuv420p -b:v 100M {0}",
                filePath, FPS, width, height);
            UnityEngine.Debug.Log(ffmpegProcess.StartInfo.Arguments);
            ffmpegProcess.StartInfo.UseShellExecute = false;
            ffmpegProcess.StartInfo.RedirectStandardInput = true;

            ffmpegProcess.Start();
            ffmpegInput = new BinaryWriter(ffmpegProcess.StandardInput.BaseStream);

            var tex = dispCamera.targetTexture;
            targetTexture = new Texture2D(tex.width, tex.height, TextureFormat.ARGB32, false);
        }
    }

    public void StopRecordnig() {

        if (isRecording)
        {
            ffmpegInput.Close();
            ffmpegInput = null;
            ffmpegProcess.Close();
            ffmpegProcess = null;

            isRecording = false;
        }
    }

	// Use this for initialization
	void Start () {
        isRecording = false;
        frameInterval = 1.0f / FPS;
        prevTime = 0;
    }
    
  // Update is called once per frame
	void Update () {

        if (isRecording)
        {
            var T = Time.time;
            var t = T - prevTime;
            if (t >= frameInterval)
            {
                if (!ffmpegProcess.HasExited)
                {
                    var tex = dispCamera.targetTexture;

                    RenderTexture.active = dispCamera.targetTexture;
                    targetTexture.ReadPixels(new Rect(0, 0, tex.width, tex.height), 0, 0);
                    targetTexture.Apply();

                    byte[] imgData = targetTexture.EncodeToJPG();
                    ffmpegProcess.Refresh();
                    ffmpegInput.Write(imgData);
                    ffmpegInput.Flush();
                }

                prevTime = T;
            }
        }
        else if (Input.GetKeyUp(KeyCode.R))
        {
            StartRecording();
        }

        if (Input.GetKeyUp(KeyCode.E))
        {
            StopRecordnig();
        }
	}
}