好多开发者问我们，Unity环境下，除了RTSP或RTMP的播放，如果有录像诉求，怎么实现？实际上录像相对播放来说，更简单一些，因为不涉及到绘制，只要拉流下来数据，直接写mp4文件就好了。

本文以大牛直播SDK的Windows平台为例，大概介绍下如何实现Unity环境下的录制，Linux、Android、iOS平台实现也类似，都是原生接口，然后对接下就好：

开始录像

因为涉及到可能同时录制多路的场景（考虑到磁盘读写IO，Windows平台一般不建议多录录制），录像的话，需要考虑的是，设置好文件录制规则，比如，是否录制纯音频或纯视频、单个录制文件大小、文件录制目录等，并设置录像回调事件：

/*
 * SmartPlayerWinMono.cs
 * Author: daniusdk.com
 */
private void StartRecorder(int sel)
{
  Debug.Log("StartRecorder++, sel: " + sel);

  if (videoctrl[sel].is_recording_)
  {
    Debug.Log("StartRecorder, already started.. sel: " + sel);
    return;
  }

  if (!videoctrl[sel].is_playing_)
  {
    if (!OpenPlayerHandle(sel))
    {
      Debug.LogError("call OpenPlayerHandle failed..");
      return;
    }
  }

  bool is_rec_video = true;
  bool is_rec_audio = true;
  NTSmartPlayerSDK.NT_SP_SetRecorderVideo(videoctrl[sel].player_handle_, is_rec_video ? 1 : 0);
  NTSmartPlayerSDK.NT_SP_SetRecorderAudio(videoctrl[sel].player_handle_, is_rec_audio ? 1 : 0);

  String rec_dir = "D:\\Rec";     //录像目录可自行指定
  String rec_name_file_prefix_= "daniu" + sel.ToString();
  UInt32 max_file_size = 200 * 1024; // 单位是KByte, 默认200MB
  bool is_append_date = true;
  bool is_append_time = true;
  bool is_audio_transcode_aac = true;

  UInt32 ret = NTSmartPlayerSDK.NT_SP_SetRecorderDirectory(videoctrl[sel].player_handle_, rec_dir);
  if (NT.NTBaseCodeDefine.NT_ERC_OK != ret)
  {
    Debug.LogError("设置录像目录失败，请确保目录存在且是英文目录");
    return;
  }

  NTSmartPlayerSDK.NT_SP_SetRecorderFileMaxSize(videoctrl[sel].player_handle_, max_file_size);

  NT_SP_RecorderFileNameRuler rec_name_ruler = new NT_SP_RecorderFileNameRuler();

  rec_name_ruler.type_ = 0;
  rec_name_ruler.file_name_prefix_ = rec_name_file_prefix_;
  rec_name_ruler.append_date_ = is_append_date ? 1 : 0;
  rec_name_ruler.append_time_ = is_append_time ? 1 : 0;

  NTSmartPlayerSDK.NT_SP_SetRecorderFileNameRuler(videoctrl[sel].player_handle_, ref rec_name_ruler);

  NTSmartPlayerSDK.NT_SP_SetRecorderAudioTranscodeAAC(videoctrl[sel].player_handle_, is_audio_transcode_aac ? 1 : 0);

  videoctrl[sel].record_call_back_ = new SP_SDKRecorderCallBack(NT_SP_SDKRecorderCallBack);
  NTSmartPlayerSDK.NT_SP_SetRecorderCallBack(videoctrl[sel].player_handle_, IntPtr.Zero, videoctrl[sel].record_call_back_);
  videoctrl[sel].set_record_call_back_ = new VideoControl.SetRecordCallBack(RecordCallBack);

  if (NT.NTBaseCodeDefine.NT_ERC_OK != NTSmartPlayerSDK.NT_SP_StartRecorder(videoctrl[sel].player_handle_))
  {
    Debug.LogError("call NT_SP_StartRecorder failed..");
    return;
  }

  videoctrl[sel].is_recording_ = true;
}

其中OpenPlayerHandle()实现如下，通过调用Open()接口生成个player实例句柄，然后后续针对这个句柄操作即可，如果同一个实例句柄下需要播放，直接调用播放接口就好了。

private bool OpenPlayerHandle(int sel)
{
  if (videoctrl[sel].player_handle_ != IntPtr.Zero)
    return true;

  window_handle_ = IntPtr.Zero;

  if (videoctrl[sel].player_handle_ == IntPtr.Zero)
  {
    videoctrl[sel].player_handle_ = new IntPtr();
    UInt32 ret_open = NTSmartPlayerSDK.NT_SP_Open(out videoctrl[sel].player_handle_, window_handle_, 0, IntPtr.Zero);
    if (ret_open != 0)
    {
      videoctrl[sel].player_handle_ = IntPtr.Zero;
      Debug.LogError("call NT_SP_Open failed, sel: " + sel);
      return false;
    }
  }

  videoctrl[sel].event_call_back_ = new SP_SDKEventCallBack(NT_SP_SDKEventCallBack);
  NTSmartPlayerSDK.NT_SP_SetEventCallBack(videoctrl[sel].player_handle_, window_handle_, videoctrl[sel].event_call_back_);
  videoctrl[sel].sdk_event_call_back_ = new VideoControl.SetEventCallBack(SDKEventCallBack);

  if (IntPtr.Zero == videoctrl[sel].player_handle_)
    return false;

  /* ++ 播放前参数配置可加在此处 ++ */

  int play_buffer_time_ = 100;
  NTSmartPlayerSDK.NT_SP_SetBuffer(videoctrl[sel].player_handle_, play_buffer_time_);                 //设置buffer time

  int is_using_tcp = 1;        //TCP模式
  NTSmartPlayerSDK.NT_SP_SetRTSPTcpMode(videoctrl[sel].player_handle_, is_using_tcp);

  int timeout = 10;
  NTSmartPlayerSDK.NT_SP_SetRtspTimeout(videoctrl[sel].player_handle_, timeout);

  int is_auto_switch_tcp_udp = 1;
  NTSmartPlayerSDK.NT_SP_SetRtspAutoSwitchTcpUdp(videoctrl[sel].player_handle_, is_auto_switch_tcp_udp);

  Boolean is_mute_ = false;
  NTSmartPlayerSDK.NT_SP_SetMute(videoctrl[sel].player_handle_, is_mute_ ? 1 : 0);                    //是否启动播放的时候静音

  int is_fast_startup = 1;
  NTSmartPlayerSDK.NT_SP_SetFastStartup(videoctrl[sel].player_handle_, is_fast_startup);              //设置快速启动模式

  Boolean is_low_latency_ = false;
  NTSmartPlayerSDK.NT_SP_SetLowLatencyMode(videoctrl[sel].player_handle_, is_low_latency_ ? 1 : 0);    //设置是否启用低延迟模式

  //设置旋转角度(设置0， 90， 180， 270度有效，其他值无效)
  int rotate_degrees = 0;
  NTSmartPlayerSDK.NT_SP_SetRotation(videoctrl[sel].player_handle_, rotate_degrees);

  int volume = 100;
  NTSmartPlayerSDK.NT_SP_SetAudioVolume(videoctrl[sel].player_handle_, volume);	//设置播放音量, 范围是[0, 100], 0是静音，100是最大音量, 默认是100

  // 设置上传下载报速度
  int is_report = 0;
  int report_interval = 2;
  NTSmartPlayerSDK.NT_SP_SetReportDownloadSpeed(videoctrl[sel].player_handle_, is_report, report_interval);

  //设置播放URL
  NTSmartPlayerSDK.NT_SP_SetURL(videoctrl[sel].player_handle_, videoctrl[sel].playback_url_);
  /* -- 播放前参数配置可加在此处 -- */

  return true;
}

录像回调事件如下：

public void RecordCallBack(UInt32 status, [MarshalAs(UnmanagedType.LPStr)] String file_name, int sel)
{
  if (status == 1)    //status 1:表示开始写一个新录像文件
  {
    Debug.Log("RecordCallBack, 开始一个新的录像文件, sel: " + sel + " status: " + status + ", filename: " + file_name);
  }
  else if (status == 2)    //status 2:表示已经写好一个录像文件
  {
    Debug.Log("RecordCallBack, 已生成一个录像文件, sel: " + sel + " status: " + status + ", filename: " + file_name);
  }
}

停止录像

private void StopRecorder(int sel)
{
  Debug.Log("StopRecorder++, sel: " + sel);

  if (videoctrl[sel].player_handle_ == IntPtr.Zero)
  {
    return;
  }

  NTSmartPlayerSDK.NT_SP_StopRecorder(videoctrl[sel].player_handle_);

  videoctrl[sel].is_recording_ = false;

  if (!videoctrl[sel].is_playing_)
  {
    NTSmartPlayerSDK.NT_SP_Close(videoctrl[sel].player_handle_);
    videoctrl[sel].player_handle_ = IntPtr.Zero;
  }
}

以上是Unity平台RTMP或RTSP播放端录像相关接口设计和调用实例，感兴趣的开发者可以参考。