Unity平台如何实现RTSP转RTMP推送？

技术背景

Unity平台下，RTSP、RTMP播放和RTMP推送，甚至包括轻量级RTSP服务这块都不再赘述，今天探讨的一位开发者提到的问题，如果在Unity下，实现RTSP播放的同时，随时转RTMP推送出去？

RTSP转RTMP，在原生环境下老早已经有了，这里，其实就是把原生的挪到Unity即可，相关流程如下：

技术实现

本文以Windows平台为例，在RTSP播放模块的基础上，加个RTSP转RTMP推送模块，废话不多说，上代码：

实时播放、停止播放

/*
 * SmartPlayerWinMono.cs.cs
 * 
 * Author: daniusdk.com
 * Created on 2017/04/19.
 */
public void StartPlayer(int sel)
{
  Debug.Log("StartPlayer++, sel: " + sel);

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

  lock (videoctrl[sel].frame_lock_)
  {
    videoctrl[sel].cur_video_frame_ = null;
  }

  if (!videoctrl[sel].is_recording_ && !videoctrl[sel].is_pulling_)
  {
    if (!OpenPlayerHandle(sel))
    {
      Debug.LogError("call OpenPlayerHandle failed, sel:" + sel);
      return;
    }
  }

  if (is_enable_hardware_decoder_)
  {
    NTSmartPlayerSDK.NT_SP_SetH264HardwareDecoder(videoctrl[sel].player_handle_, is_support_h264_hardware_decoder_ ? 1 : 0, 0);
    NTSmartPlayerSDK.NT_SP_SetH265HardwareDecoder(videoctrl[sel].player_handle_, is_support_h265_hardware_decoder_ ? 1 : 0, 0);
  }
  else
  {
    NTSmartPlayerSDK.NT_SP_SetH264HardwareDecoder(videoctrl[sel].player_handle_, 0, 0);
    NTSmartPlayerSDK.NT_SP_SetH265HardwareDecoder(videoctrl[sel].player_handle_, 0, 0);
  }

  //video frame callback (YUV/RGB)
  videoctrl[sel].sdk_video_frame_call_back_ = new VideoControl.SetVideoFrameCallBack(SDKVideoFrameCallBack);
  videoctrl[sel].video_frame_call_back_ = new SP_SDKVideoFrameCallBack(NT_SP_SetVideoFrameCallBack);
  NTSmartPlayerSDK.NT_SP_SetVideoFrameCallBack(videoctrl[sel].player_handle_, (Int32)NT.NTSmartPlayerDefine.NT_SP_E_VIDEO_FRAME_FORMAT.NT_SP_E_VIDEO_FRAME_FROMAT_I420, window_handle_, videoctrl[sel].video_frame_call_back_);

  UInt32 flag = NTSmartPlayerSDK.NT_SP_StartPlay(videoctrl[sel].player_handle_);

  if (flag == DANIULIVE_RETURN_OK)
  {
    videoctrl[sel].is_need_get_frame_ = true;
    Debug.Log("NT_SP_StartPlay succeed, sel:" + sel);
  }
  else
  {
    videoctrl[sel].is_need_get_frame_ = false;
    Debug.LogError("NT_SP_StartPlay failed, sel:" + sel);
  }

  videoctrl[sel].is_playing_ = true;
}

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

  videoctrl[sel].is_need_get_frame_ = false;
  videoctrl[sel].is_need_init_texture_ = false;

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

  UInt32 flag = NTSmartPlayerSDK.NT_SP_StopPlay(videoctrl[sel].player_handle_);
  if (flag == DANIULIVE_RETURN_OK)
  {
    Debug.Log("call NT_SP_StopPlay succeed, sel: " + sel);
  }
  else
  {
    Debug.LogError("call NT_SP_StopPlay failed, sel: " + sel);
  }

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

  videoctrl[sel].is_playing_ = false;
}

如果需要转RTMP出去，首先拉流端，需要调用拉流接口：

开始拉流、停止拉流

public void StartPull(int sel)
{
  if (videoctrl[sel].is_pulling_)
  {
    Debug.Log("StartPull, already started.. sel: " + sel);
    return;
  }

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

  videoctrl[sel].pull_stream_video_data_call_back_ = new SP_SDKPullStreamVideoDataCallBack(OnVideoDataHandle);
  videoctrl[sel].pull_stream_audio_data_call_back_ = new SP_SDKPullStreamAudioDataCallBack(OnAudioDataHandle);

  NTSmartPlayerSDK.NT_SP_SetPullStreamVideoDataCallBack(videoctrl[sel].player_handle_, IntPtr.Zero, videoctrl[sel].pull_stream_video_data_call_back_);
  NTSmartPlayerSDK.NT_SP_SetPullStreamAudioDataCallBack(videoctrl[sel].player_handle_, IntPtr.Zero, videoctrl[sel].pull_stream_audio_data_call_back_);

  int is_transcode_aac = 1;   //PCMA/PCMU/Speex格式转AAC后 再转发
  NTSmartPlayerSDK.NT_SP_SetPullStreamAudioTranscodeAAC(videoctrl[sel].player_handle_, is_transcode_aac);

  UInt32 ret = NTSmartPlayerSDK.NT_SP_StartPullStream(videoctrl[sel].player_handle_);

  if (NTBaseCodeDefine.NT_ERC_OK != ret)
  {
    if (!videoctrl[sel].is_playing_ && !videoctrl[sel].is_recording_)
    {
      NTSmartPlayerSDK.NT_SP_Close(videoctrl[sel].player_handle_);
      videoctrl[sel].player_handle_ = IntPtr.Zero;
    }

    return;
  }

  videoctrl[sel].is_pulling_ = true;
}

public void StopPull(int sel)
{
  if (!videoctrl[sel].is_pulling_)
    return;

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

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

  videoctrl[sel].is_pulling_ = false;
}

拉流设置的时候，需要注意的是，如果是其他比如PCMA、PCMU的，考虑到通用性，可以转AAC后再回调数据上来，此外，拉流或播放的时候，判断是不是已经打开了RTSP URL，确保同一路流在一个实例内，不要开两个实例，占用额外的资源。

此外，关闭播放或拉流的时候，需要判断是不是处于拉流或播放状态，只要二者有一个还没关闭，实例就无法关闭。

开始转推RTMP、停止转推：

public bool StartPush(int sel, String url)
{
  if (videoctrl[sel].is_pushing_)
    return false;

  if (String.IsNullOrEmpty(url))
    return false;

  if (!OpenPushHandle(sel))
    return false;

  if (GetPushHandle(sel) == IntPtr.Zero)
    return false;

  IntPtr push_handle = GetPushHandle(sel);

  if (NTBaseCodeDefine.NT_ERC_OK != NTSmartPublisherSDK.NT_PB_SetURL(push_handle, url, IntPtr.Zero))
  {
    NTSmartPublisherSDK.NT_PB_Close(push_handle);
    SetPushHandle(sel, IntPtr.Zero);

    return false;
  }

  if (NTBaseCodeDefine.NT_ERC_OK != NTSmartPublisherSDK.NT_PB_StartPublisher(push_handle, IntPtr.Zero))
  {
    NTSmartPublisherSDK.NT_PB_Close(push_handle);
    SetPushHandle(sel, IntPtr.Zero);

    return false;
  }

  videoctrl[sel].is_pushing_ = true;

  return true;
}

public void StopPush(int sel)
{
  if (!videoctrl[sel].is_pushing_)
    return;

  videoctrl[sel].is_pushing_ = false;

  lock (videoctrl[sel].push_handle_mutex_)
  {
    if (videoctrl[sel].push_handle_ == IntPtr.Zero)
      return;

    NTSmartPublisherSDK.NT_PB_StopPublisher(videoctrl[sel].push_handle_);

    NTSmartPublisherSDK.NT_PB_Close(videoctrl[sel].push_handle_);
    videoctrl[sel].push_handle_ = IntPtr.Zero;
  }
}

音视频数据回调

private void OnVideoDataHandle(IntPtr handle, IntPtr user_data,
                               UInt32 video_codec_id, IntPtr data, UInt32 size,
                               IntPtr info, IntPtr reserve)
{
  int cur_sel = -1;

  for ( int i = 0; i < videoctrl.Length; i++)
  {
    if(handle == videoctrl[i].player_handle_)
    {
      cur_sel = i;
      break;
    }
  }

  if (cur_sel < 0)
    return;

  if (!videoctrl[cur_sel].is_pushing_)
    return;

  if (data == IntPtr.Zero)
    return;

  if (size < 1)
    return;

  if (info == IntPtr.Zero)
    return;

  NT_SP_PullStreamVideoDataInfo video_info = (NT_SP_PullStreamVideoDataInfo)Marshal.PtrToStructure(info, typeof(NT_SP_PullStreamVideoDataInfo));

  lock (videoctrl[cur_sel].push_handle_mutex_)
  {
    if (!videoctrl[cur_sel].is_pushing_)
      return;

    if (videoctrl[cur_sel].push_handle_ == IntPtr.Zero)
      return;

    //新接口
    NTSmartPublisherSDK.NT_PB_PostVideoEncodedDataV2(videoctrl[cur_sel].push_handle_, video_codec_id,
                                                     data, size, video_info.is_key_frame_, video_info.timestamp_, video_info.presentation_timestamp_);
  }
}

private void OnAudioDataHandle(IntPtr handle, IntPtr user_data,
                               UInt32 audio_codec_id, IntPtr data, UInt32 size,
                               IntPtr info, IntPtr reserve)
{
  int cur_sel = -1;

  for (int i = 0; i < videoctrl.Length; i++)
  {
    if (handle == videoctrl[i].player_handle_)
    {
      cur_sel = i;
      break;
    }
  }

  if (cur_sel < 0)
    return;

  if (!videoctrl[cur_sel].is_pushing_)
    return;

  if (data == IntPtr.Zero)
    return;

  if (size < 1)
    return;

  if (info == IntPtr.Zero)
    return;

  NT_SP_PullStreamAuidoDataInfo audio_info = (NT_SP_PullStreamAuidoDataInfo)Marshal.PtrToStructure(info, typeof(NT_SP_PullStreamAuidoDataInfo));

  lock (videoctrl[cur_sel].push_handle_mutex_)
  {
    if (!videoctrl[cur_sel].is_pushing_)
      return;

    if (videoctrl[cur_sel].push_handle_ == IntPtr.Zero)
      return;

    NTSmartPublisherSDK.NT_PB_PostAudioEncodedData(videoctrl[cur_sel].push_handle_, audio_codec_id, data, size,
                                                   audio_info.is_key_frame_, audio_info.timestamp_,
                                                   audio_info.parameter_info_, audio_info.parameter_info_size_);
  }
}

总结

实际上，Unity环境下的RTSP转RTMP推送，相对RTMP、RTSP播放或推流，对接更容易，因为基本不涉及到页面交互，感兴趣的开发者可以尝试看。