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• Screenrecorder application output video resolution issues [closed]

  23 juin 2022, par JessieK

  Using Github code for ScreenRecorder on Linux
Everything works fine, besides the resolution of output video.
Tried to play with setting, quality has significantly improved, but still no way to change resolution.
I need to get output video with the same size as input video

  


  using namespace std;

    /* initialize the resources*/
    ScreenRecorder::ScreenRecorder()
    {
    
        av_register_all();
        avcodec_register_all();
        avdevice_register_all();
        cout<<"\nall required functions are registered successfully";
    }
    
    /* uninitialize the resources */
    ScreenRecorder::~ScreenRecorder()
    {
    
        avformat_close_input(&pAVFormatContext);
        if( !pAVFormatContext )
        {
            cout<<"\nfile closed sucessfully";
        }
        else
        {
            cout<<"\nunable to close the file";
            exit(1);
        }
    
        avformat_free_context(pAVFormatContext);
        if( !pAVFormatContext )
        {
            cout<<"\navformat free successfully";
        }
        else
        {
            cout<<"\nunable to free avformat context";
            exit(1);
        }
    
    }
    
    /* function to capture and store data in frames by allocating required memory and auto deallocating the memory.   */
    int ScreenRecorder::CaptureVideoFrames()
    {
        int flag;
        int frameFinished;//when you decode a single packet, you still don't have information enough to have a frame [depending on the type of codec, some of them //you do], when you decode a GROUP of packets that represents a frame, then you have a picture! that's why frameFinished will let //you know you decoded enough to have a frame.
    
        int frame_index = 0;
        value = 0;
    
        pAVPacket = (AVPacket *)av_malloc(sizeof(AVPacket));
        av_init_packet(pAVPacket);
    
        pAVFrame = av_frame_alloc();
        if( !pAVFrame )
        {
         cout<<"\nunable to release the avframe resources";
         exit(1);
        }
    
        outFrame = av_frame_alloc();//Allocate an AVFrame and set its fields to default values.
        if( !outFrame )
        {
         cout<<"\nunable to release the avframe resources for outframe";
         exit(1);
        }
    
        int video_outbuf_size;
        int nbytes = av_image_get_buffer_size(outAVCodecContext->pix_fmt,outAVCodecContext->width,outAVCodecContext->height,32);
        uint8_t *video_outbuf = (uint8_t*)av_malloc(nbytes);
        if( video_outbuf == NULL )
        {
            cout<<"\nunable to allocate memory";
            exit(1);
        }
    
        // Setup the data pointers and linesizes based on the specified image parameters and the provided array.
        value = av_image_fill_arrays( outFrame->data, outFrame->linesize, video_outbuf , AV_PIX_FMT_YUV420P, outAVCodecContext->width,outAVCodecContext->height,1 ); // returns : the size in bytes required for src
        if(value < 0)
        {
            cout<<"\nerror in filling image array";
        }
    
        SwsContext* swsCtx_ ;
    
        // Allocate and return swsContext.
        // a pointer to an allocated context, or NULL in case of error
        // Deprecated : Use sws_getCachedContext() instead.
        swsCtx_ = sws_getContext(pAVCodecContext->width,
                            pAVCodecContext->height,
                            pAVCodecContext->pix_fmt,
                            outAVCodecContext->width,
                    outAVCodecContext->height,
                            outAVCodecContext->pix_fmt,
                            SWS_BICUBIC, NULL, NULL, NULL);
    
    
    int ii = 0;
    int no_frames = 100;
    cout<<"\nenter No. of frames to capture : ";
    cin>>no_frames;
    
        AVPacket outPacket;
        int j = 0;
    
        int got_picture;
    
        while( av_read_frame( pAVFormatContext , pAVPacket ) >= 0 )
        {
        if( ii++ == no_frames )break;
            if(pAVPacket->stream_index == VideoStreamIndx)
            {
                value = avcodec_decode_video2( pAVCodecContext , pAVFrame , &frameFinished , pAVPacket );
                if( value < 0)
                {
                    cout<<"unable to decode video";
                }
    
                if(frameFinished)// Frame successfully decoded :)
                {
                    sws_scale(swsCtx_, pAVFrame->data, pAVFrame->linesize,0, pAVCodecContext->height, outFrame->data,outFrame->linesize);
                    av_init_packet(&outPacket);
                    outPacket.data = NULL;    // packet data will be allocated by the encoder
                    outPacket.size = 0;
    
                    avcodec_encode_video2(outAVCodecContext , &outPacket ,outFrame , &got_picture);
    
                    if(got_picture)
                    {
                        if(outPacket.pts != AV_NOPTS_VALUE)
                            outPacket.pts = av_rescale_q(outPacket.pts, video_st->codec->time_base, video_st->time_base);
                        if(outPacket.dts != AV_NOPTS_VALUE)
                            outPacket.dts = av_rescale_q(outPacket.dts, video_st->codec->time_base, video_st->time_base);
                    
                        printf("Write frame %3d (size= %2d)\n", j++, outPacket.size/1000);
                        if(av_write_frame(outAVFormatContext , &outPacket) != 0)
                        {
                            cout<<"\nerror in writing video frame";
                        }
    
                    av_packet_unref(&outPacket);
                    } // got_picture
    
                av_packet_unref(&outPacket);
                } // frameFinished
    
            }
        }// End of while-loop


  


  One part of two parts is above...Actually original app seem to record video of same size as does my application, but still it has not any use

  


  ---

  


  Second part of the code

  


  av_free(video_outbuf);

}

/* establishing the connection between camera or screen through its respective folder */
int ScreenRecorder::openCamera()
{

    value = 0;
    options = NULL;
    pAVFormatContext = NULL;

    pAVFormatContext = avformat_alloc_context();//Allocate an AVFormatContext.
/*

X11 video input device.
To enable this input device during configuration you need libxcb installed on your system. It will be automatically detected during configuration.
This device allows one to capture a region of an X11 display. 
refer : https://www.ffmpeg.org/ffmpeg-devices.html#x11grab
*/
    /* current below is for screen recording. to connect with camera use v4l2 as a input parameter for av_find_input_format */ 
    pAVInputFormat = av_find_input_format("x11grab");
    value = avformat_open_input(&pAVFormatContext, ":0.0+10,250", pAVInputFormat, NULL);
    if(value != 0)
    {
       cout<<"\nerror in opening input device";
       exit(1);
    }

    /* set frame per second */
    value = av_dict_set( &options,"framerate","30",0 );
    if(value < 0)
    {
      cout<<"\nerror in setting dictionary value";
       exit(1);
    }

    value = av_dict_set( &options, "preset", "medium", 0 );
    if(value < 0)
    {
      cout<<"\nerror in setting preset values";
      exit(1);
    }

//  value = avformat_find_stream_info(pAVFormatContext,NULL);
    if(value < 0)
    {
      cout<<"\nunable to find the stream information";
      exit(1);
    }

    VideoStreamIndx = -1;

    /* find the first video stream index . Also there is an API available to do the below operations */
    for(int i = 0; i < pAVFormatContext->nb_streams; i++ ) // find video stream posistion/index.
    {
      if( pAVFormatContext->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO )
      {
         VideoStreamIndx = i;
         break;
      }

    } 

    if( VideoStreamIndx == -1)
    {
      cout<<"\nunable to find the video stream index. (-1)";
      exit(1);
    }

    // assign pAVFormatContext to VideoStreamIndx
    pAVCodecContext = pAVFormatContext->streams[VideoStreamIndx]->codec;

    pAVCodec = avcodec_find_decoder(pAVCodecContext->codec_id);
    if( pAVCodec == NULL )
    {
      cout<<"\nunable to find the decoder";
      exit(1);
    }

    value = avcodec_open2(pAVCodecContext , pAVCodec , NULL);//Initialize the AVCodecContext to use the given AVCodec.
    if( value < 0 )
    {
      cout<<"\nunable to open the av codec";
      exit(1);
    }
}

/* initialize the video output file and its properties  */
int ScreenRecorder::init_outputfile()
{
    outAVFormatContext = NULL;
    value = 0;
    output_file = "../media/output.mp4";

    avformat_alloc_output_context2(&outAVFormatContext, NULL, NULL, output_file);
    if (!outAVFormatContext)
    {
        cout<<"\nerror in allocating av format output context";
        exit(1);
    }

/* Returns the output format in the list of registered output formats which best matches the provided parameters, or returns NULL if there is no match. */
    output_format = av_guess_format(NULL, output_file ,NULL);
    if( !output_format )
    {
     cout<<"\nerror in guessing the video format. try with correct format";
     exit(1);
    }

    video_st = avformat_new_stream(outAVFormatContext ,NULL);
    if( !video_st )
    {
        cout<<"\nerror in creating a av format new stream";
        exit(1);
    }

    outAVCodecContext = avcodec_alloc_context3(outAVCodec);
    if( !outAVCodecContext )
    {
        cout<<"\nerror in allocating the codec contexts";
        exit(1);
    }

    /* set property of the video file */
    outAVCodecContext = video_st->codec;
    outAVCodecContext->codec_id = AV_CODEC_ID_MPEG4;// AV_CODEC_ID_MPEG4; // AV_CODEC_ID_H264 // AV_CODEC_ID_MPEG1VIDEO
    outAVCodecContext->codec_type = AVMEDIA_TYPE_VIDEO;
    outAVCodecContext->pix_fmt  = AV_PIX_FMT_YUV420P;
    outAVCodecContext->bit_rate = 2500000; // 2500000
    outAVCodecContext->width = 1920;
    outAVCodecContext->height = 1080;
    outAVCodecContext->gop_size = 3;
    outAVCodecContext->max_b_frames = 2;
    outAVCodecContext->time_base.num = 1;
    outAVCodecContext->time_base.den = 30; // 15fps

    {
     av_opt_set(outAVCodecContext->priv_data, "preset", "slow", 0);
    }

    outAVCodec = avcodec_find_encoder(AV_CODEC_ID_MPEG4);
    if( !outAVCodec )
    {
     cout<<"\nerror in finding the av codecs. try again with correct codec";
    exit(1);
    }

    /* Some container formats (like MP4) require global headers to be present
       Mark the encoder so that it behaves accordingly. */

    if ( outAVFormatContext->oformat->flags & AVFMT_GLOBALHEADER)
    {
        outAVCodecContext->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
    }

    value = avcodec_open2(outAVCodecContext, outAVCodec, NULL);
    if( value < 0)
    {
        cout<<"\nerror in opening the avcodec";
        exit(1);
    }

    /* create empty video file */
    if ( !(outAVFormatContext->flags & AVFMT_NOFILE) )
    {
     if( avio_open2(&outAVFormatContext->pb , output_file , AVIO_FLAG_WRITE ,NULL, NULL) < 0 )
     {
      cout<<"\nerror in creating the video file";
      exit(1);
     }
    }

    if(!outAVFormatContext->nb_streams)
    {
        cout<<"\noutput file dose not contain any stream";
        exit(1);
    }

    /* imp: mp4 container or some advanced container file required header information*/
    value = avformat_write_header(outAVFormatContext , &options);
    if(value < 0)
    {
        cout<<"\nerror in writing the header context";
        exit(1);
    }


    cout<<"\n\nOutput file information :\n\n";
    av_dump_format(outAVFormatContext , 0 ,output_file ,1);


  


  Github link https://github.com/abdullahfarwees/screen-recorder-ffmpeg-cpp

  


• Screen Recording with FFmpeg-Lib with c++

  27 janvier 2020, par Baschdel

  I’m trying to record the whole desktop stream with FFmpeg on Windows.
  I found a working example here. The Problem is that some og the functions depricated. So I tried to replace them with the updated ones.

  But there are some slight problems. The error "has triggered a breakpoint." occurse and also "not able to read the location."
  The bigger problem is that I don’t know if this is the right way to do this..

  My code looks like this :

  using namespace std;
  
  
  
  /* initialize the resources*/
  
  Recorder::Recorder()
  
  {
  
  
  
      av_register_all();
  
      avcodec_register_all();
  
      avdevice_register_all();
  
      cout<<"\nall required functions are registered successfully";
  
  }
  
  
  
  /* uninitialize the resources */
  
  Recorder::~Recorder()
  
  {
  
  
  
      avformat_close_input(&pAVFormatContext);
  
      if( !pAVFormatContext )
  
      {
  
          cout<<"\nfile closed sucessfully";
  
      }
  
      else
  
      {
  
          cout<<"\nunable to close the file";
  
          exit(1);
  
      }
  
  
  
      avformat_free_context(pAVFormatContext);
  
      if( !pAVFormatContext )
  
      {
  
          cout<<"\navformat free successfully";
  
      }
  
      else
  
      {
  
          cout<<"\nunable to free avformat context";
  
          exit(1);
  
      }
  
  
  
  }
  
  
  
  /* establishing the connection between camera or screen through its respective folder */
  
  int Recorder::openCamera()
  
  {
  
  
  
      value = 0;
  
      options = NULL;
  
      pAVFormatContext = NULL;
  
  
  
      pAVFormatContext = avformat_alloc_context();//Allocate an AVFormatContext.
  
  
  
      openScreen(pAVFormatContext);
  
  
  
      /* set frame per second */
  
      value = av_dict_set( &options,"framerate","30",0 );
  
      if(value < 0)
  
      {
  
        cout<<"\nerror in setting dictionary value";
  
         exit(1);
  
      }
  
  
  
      value = av_dict_set( &options, "preset", "medium", 0 );
  
      if(value < 0)
  
      {
  
        cout<<"\nerror in setting preset values";
  
        exit(1);
  
      }
  
  
  
  //  value = avformat_find_stream_info(pAVFormatContext,NULL);
  
      if(value < 0)
  
      {
  
        cout<<"\nunable to find the stream information";
  
        exit(1);
  
      }
  
  
  
      VideoStreamIndx = -1;
  
  
  
      /* find the first video stream index . Also there is an API available to do the below operations */
  
      for(int i = 0; i < pAVFormatContext->nb_streams; i++ ) // find video stream posistion/index.
  
      {
  
        if( pAVFormatContext->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO )
  
        {
  
           VideoStreamIndx = i;
  
           break;
  
        }
  
  
  
      } 
  
  
  
      if( VideoStreamIndx == -1)
  
      {
  
        cout<<"\nunable to find the video stream index. (-1)";
  
        exit(1);
  
      }
  
  
  
      // assign pAVFormatContext to VideoStreamIndx
  
      pAVCodecContext = pAVFormatContext->streams[VideoStreamIndx]->codec;
  
  
  
      pAVCodec = avcodec_find_decoder(pAVCodecContext->codec_id);
  
      if( pAVCodec == NULL )
  
      {
  
        cout<<"\nunable to find the decoder";
  
        exit(1);
  
      }
  
  
  
      value = avcodec_open2(pAVCodecContext , pAVCodec , NULL);//Initialize the AVCodecContext to use the given AVCodec.
  
      if( value < 0 )
  
      {
  
        cout<<"\nunable to open the av codec";
  
        exit(1);
  
      }
  
  }
  
  
  
  /* initialize the video output file and its properties  */
  
  int Recorder::init_outputfile()
  
  {
  
      outAVFormatContext = NULL;
  
      value = 0;
  
      output_file = "output.mp4";
  
  
  
      avformat_alloc_output_context2(&outAVFormatContext, NULL, NULL, output_file);
  
      if (!outAVFormatContext)
  
      {
  
          cout<<"\nerror in allocating av format output context";
  
          exit(1);
  
      }
  
  
  
  /* Returns the output format in the list of registered output formats which best matches the provided parameters, or returns NULL if there is no match. */
  
      output_format = av_guess_format(NULL, output_file ,NULL);
  
      if( !output_format )
  
      {
  
       cout<<"\nerror in guessing the video format. try with correct format";
  
       exit(1);
  
      }
  
  
  
      video_st = avformat_new_stream(outAVFormatContext ,NULL);
  
      if( !video_st )
  
      {
  
          cout<<"\nerror in creating a av format new stream";
  
          exit(1);
  
      }
  
  
  
      if (codec_id == AV_CODEC_ID_H264)
  
      {
  
          av_opt_set(outAVCodecContext->priv_data, "preset", "slow", 0);
  
      }
  
  
  
      outAVCodec = avcodec_find_encoder(AV_CODEC_ID_MPEG4);
  
      if (!outAVCodec)
  
      {
  
          cout << "\nerror in finding the av codecs. try again with correct codec";
  
          exit(1);
  
      }
  
  
  
      outAVCodecContext = avcodec_alloc_context3(outAVCodec);
  
      if( !outAVCodecContext )
  
      {
  
          cout<<"\nerror in allocating the codec contexts";
  
          exit(1);
  
      }
  
  
  
      /* set property of the video file */
  
      outAVCodecContext = video_st->codec;
  
      outAVCodecContext->codec_id = AV_CODEC_ID_MPEG4;// AV_CODEC_ID_MPEG4; // AV_CODEC_ID_H264 // AV_CODEC_ID_MPEG1VIDEO
  
      outAVCodecContext->codec_type = AVMEDIA_TYPE_VIDEO;
  
      outAVCodecContext->pix_fmt  = AV_PIX_FMT_YUV420P;
  
      outAVCodecContext->bit_rate = 400000; // 2500000
  
      outAVCodecContext->width = 1920;
  
      outAVCodecContext->height = 1080;
  
      outAVCodecContext->gop_size = 3;
  
      outAVCodecContext->max_b_frames = 2;
  
      outAVCodecContext->time_base.num = 1;
  
      outAVCodecContext->time_base.den = 30; //15fps
  
  
  
  
  
      /* Some container formats (like MP4) require global headers to be present
  
         Mark the encoder so that it behaves accordingly. */
  
  
  
      if ( outAVFormatContext->oformat->flags & AVFMT_GLOBALHEADER)
  
      {
  
          outAVCodecContext->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
  
      }
  
  
  
      value = avcodec_open2(outAVCodecContext, outAVCodec, NULL);
  
      if( value < 0)
  
      {
  
          cout<<"\nerror in opening the avcodec";
  
          exit(1);
  
      }
  
  
  
      /* create empty video file */
  
      if ( !(outAVFormatContext->flags & AVFMT_NOFILE) )
  
      {
  
       if( avio_open2(&outAVFormatContext->pb , output_file , AVIO_FLAG_WRITE ,NULL, NULL) < 0 )
  
       {
  
        cout<<"\nerror in creating the video file";
  
        exit(1);
  
       }
  
      }
  
  
  
      if(!outAVFormatContext->nb_streams)
  
      {
  
          cout<<"\noutput file dose not contain any stream";
  
          exit(1);
  
      }
  
  
  
      /* imp: mp4 container or some advanced container file required header information*/
  
      value = avformat_write_header(outAVFormatContext , &options);
  
      if(value < 0)
  
      {
  
          cout<<"\nerror in writing the header context";
  
          exit(1);
  
      }
  
  
  
      /*
  
      // uncomment here to view the complete video file informations
  
      cout<<"\n\nOutput file information :\n\n";
  
      av_dump_format(outAVFormatContext , 0 ,output_file ,1);
  
      */
  
  }
  
  
  
  int Recorder::stop() {
  
      threading = false;
  
  
  
      demux->join();
  
      rescale->join();
  
      mux->join();
  
  
  
      return 0;
  
  }
  
  
  
  int Recorder::start() {
  
      initVideoThreads();
  
      return 0;
  
  }
  
  
  
  int Recorder::initVideoThreads() {
  
      demux = new thread(&Recorder::demuxVideoStream, this, pAVCodecContext, pAVFormatContext, VideoStreamIndx);
  
  
  
      rescale = new thread(&Recorder::rescaleVideoStream, this, pAVCodecContext, outAVCodecContext);
  
  
  
      demux = new thread(&Recorder::encodeVideoStream, this, outAVCodecContext);
  
      return 0;
  
  }
  
  
  
  void Recorder::demuxVideoStream(AVCodecContext* codecContext, AVFormatContext* formatContext, int streamIndex)
  
  {
  
      // init packet
  
      AVPacket* packet = (AVPacket*)av_malloc(sizeof(AVPacket));
  
      av_init_packet(packet);
  
  
  
      int ctr = 0;
  
  
  
      while (threading)
  
      {
  
          if (av_read_frame(formatContext, packet) < 0) {
  
              exit(1);
  
          }
  
  
  
          if (packet->stream_index == streamIndex)
  
          {
  
              int return_value; // = 0;
  
              ctr++;
  
  
  
              do
  
              {
  
                  return_value = avcodec_send_packet(codecContext, packet);
  
              } while (return_value == AVERROR(EAGAIN) && threading);
  
  
  
              //int i = avcodec_send_packet(codecContext, packet);
  
              if (return_value < 0 && threading) { // call Decoder
  
                  cout << "unable to decode video";
  
                  exit(1);
  
              }
  
          }
  
      }
  
  
  
      avcodec_send_packet(codecContext, NULL); // flush decoder
  
  
  
      // return 0;
  
  }
  
  
  
  void Recorder::rescaleVideoStream(AVCodecContext* inCodecContext, AVCodecContext* outCodecContext)
  
  {
  
      bool closing = false;
  
      AVFrame* inFrame = av_frame_alloc();
  
      if (!inFrame)
  
      {
  
          cout << "\nunable to release the avframe resources";
  
          exit(1);
  
      }
  
  
  
      int nbytes = av_image_get_buffer_size(outAVCodecContext->pix_fmt, outAVCodecContext->width, outAVCodecContext->height, 32);
  
      uint8_t* video_outbuf = (uint8_t*)av_malloc(nbytes);
  
      if (video_outbuf == NULL)
  
      {
  
          cout << "\nunable to allocate memory";
  
          exit(1);
  
      }
  
  
  
      AVFrame* outFrame = av_frame_alloc();//Allocate an AVFrame and set its fields to default values.
  
      if (!outFrame)
  
      {
  
          cout << "\nunable to release the avframe resources for outframe";
  
          exit(1);
  
      }
  
  
  
      // Setup the data pointers and linesizes based on the specified image parameters and the provided array.
  
      int value = av_image_fill_arrays(outFrame->data, outFrame->linesize, video_outbuf, AV_PIX_FMT_YUV420P, outAVCodecContext->width, outAVCodecContext->height, 1); // returns : the size in bytes required for src
  
      if (value < 0)
  
      {
  
          cout << "\nerror in filling image array";
  
      }
  
      int ctr = 0;
  
  
  
      while (threading || !closing) {
  
          int value = avcodec_receive_frame(inCodecContext, inFrame);
  
          if (value == 0) {
  
              ctr++;
  
              SwsContext* swsCtx_ = sws_getContext(inCodecContext->width,
  
                  inCodecContext->height,
  
                  inCodecContext->pix_fmt,
  
                  outAVCodecContext->width,
  
                  outAVCodecContext->height,
  
                  outAVCodecContext->pix_fmt,
  
                  SWS_BICUBIC, NULL, NULL, NULL);
  
              sws_scale(swsCtx_, inFrame->data, inFrame->linesize, 0, inCodecContext->height, outFrame->data, outFrame->linesize);
  
  
  
  
  
              int return_value;
  
              do
  
              {
  
                  return_value = avcodec_send_frame(outCodecContext, outFrame);
  
              } while (return_value == AVERROR(EAGAIN) && threading);
  
          }
  
          closing = (value == AVERROR_EOF);
  
      }
  
      avcodec_send_frame(outCodecContext, NULL);
  
  
  
  
  
      // av_free(video_outbuf);
  
  
  
      // return 0;
  
  }
  
  
  
  void Recorder::encodeVideoStream(AVCodecContext* codecContext)
  
  {
  
      bool closing = true;
  
      AVPacket* packet = (AVPacket*)av_malloc(sizeof(AVPacket));
  
      av_init_packet(packet);
  
  
  
      int ctr = 0;
  
  
  
      while (threading || !closing) {
  
          packet->data = NULL;    // packet data will be allocated by the encoder
  
          packet->size = 0;
  
          ctr++;
  
          int value = avcodec_receive_packet(codecContext, packet);
  
          if (value == 0) {
  
              if (packet->pts != AV_NOPTS_VALUE)
  
                  packet->pts = av_rescale_q(packet->pts, video_st->codec->time_base, video_st->time_base);
  
              if (packet->dts != AV_NOPTS_VALUE)
  
                  packet->dts = av_rescale_q(packet->dts, video_st->codec->time_base, video_st->time_base);
  
  
  
              //printf("Write frame %3d (size= %2d)\n", j++, packet->size / 1000);
  
              if (av_write_frame(outAVFormatContext, packet) != 0)
  
              {
  
                  cout << "\nerror in writing video frame";
  
              }
  
          }
  
  
  
          closing = (value == AVERROR_EOF);
  
      }
  
  
  
      value = av_write_trailer(outAVFormatContext);
  
      if (value < 0)
  
      {
  
          cout << "\nerror in writing av trailer";
  
          exit(1);
  
      }
  
  
  
      // av_free(packet);
  
  
  
      // return 0;
  
  }
  
  
  
  
  
  int Recorder::openScreen(AVFormatContext* pFormatCtx) {
  
      /*
  
  
  
      X11 video input device.
  
      To enable this input device during configuration you need libxcb installed on your system. It will be automatically detected during configuration.
  
      This device allows one to capture a region of an X11 display.
  
      refer : https://www.ffmpeg.org/ffmpeg-devices.html#x11grab
  
      */
  
      /* current below is for screen recording. to connect with camera use v4l2 as a input parameter for av_find_input_format */
  
      pAVInputFormat = av_find_input_format("gdigrab");
  
      //value = avformat_open_input(&pAVFormatContext, ":0.0+10,250", pAVInputFormat, NULL);
  
  
  
      value = avformat_open_input(&pAVFormatContext, "desktop", pAVInputFormat, NULL);
  
      if (value != 0)
  
      {
  
          cout << "\nerror in opening input device";
  
          exit(1);
  
      }
  
      return 0;
  
  }

• Converting a voice recording into an mp3

  21 juillet 2023, par Raphael M

  For a vue.js messaging project, I'm using the wavesurfer.js library to record voice messages. However Google chrome gives me an audio/webm blob and Safari gives me an audio/mp4 blob.

  


  I'm trying to find a solution to transcode the blob into audio/mp3. I've tried several methods, including ffmpeg. However, ffmpeg gives me an error when compiling "npm run dev" : "Can't resolve '/node_modules/@ffmpeg/core/dist/ffmpeg-core.js'".

  


  "@ffmpeg/core": "^0.11.0",
"@ffmpeg/ffmpeg": "^0.11.6"


  


  I tried to downgrade ffmpeg

  


  "@ffmpeg/core": "^0.9.0",
"@ffmpeg/ffmpeg": "^0.9.8"


  


  I no longer get the error message when compiling, but when I want to convert my audio stream, the console displays a problem with SharedBuffer : "Uncaught (in promise) ReferenceError : SharedArrayBuffer is not defined".

  


  Here's my complete code below.
Is there a reliable way of transcoding the audio stream into mp3 ?

  


  Can you give me an example ?

  


  Thanks

  


  <template>&#xA;  <div class="left-panel">&#xA;    <header class="radial-blue">&#xA;      <div class="container">&#xA;        <h1 class="mb-30">Posez votre premi&#xE8;re question &#xE0; nos th&#xE9;rapeutes</h1>&#xA;        <p><b>Attention</b>, vous disposez seulement de 2 messages. Veillez &#xE0; les utiliser de mani&#xE8;re judicieuse !</p>&#xA;        <div class="available-messages">&#xA;          <div class="item disabled">&#xA;            <span>Message 1</span>&#xA;          </div>&#xA;          <div class="item">&#xA;            <span>Message 2</span>&#xA;          </div>&#xA;        </div>&#xA;      </div>&#xA;    </header>&#xA;  </div>&#xA;  <div class="right-panel">&#xA;    <div class="messagerie bg-light">&#xA;      <messaging ref="messagingComponent"></messaging>&#xA;      <footer>&#xA;        <button type="button"><img src="http://stackoverflow.com/assets/backoffice/images/record-start.svg" style='max-width: 300px; max-height: 300px' /></button>&#xA;        <div class="loading-animation">&#xA;          <img src="http://stackoverflow.com/assets/backoffice/images/record-loading.svg" style='max-width: 300px; max-height: 300px' />&#xA;        </div>&#xA;        <button type="button"><img src="http://stackoverflow.com/assets/backoffice/images/record-stop.svg" style='max-width: 300px; max-height: 300px' /></button>&#xA;        <div class="textarea gradient text-dark">&#xA;          <textarea placeholder="Posez votre question"></textarea>&#xA;        </div>&#xA;        <div class="loading-text">Chargement de votre microphone en cours...</div>&#xA;        <div class="loading-text">Envoi de votre message en cours...</div>&#xA;        <div ref="visualizer"></div>&#xA;        <button type="button"><img src="http://stackoverflow.com/assets/backoffice/images/send.svg" style='max-width: 300px; max-height: 300px' /></button>&#xA;        <div>&#xA;          {{ formatTimer() }}&#xA;        </div>&#xA;      </footer>&#xA;    </div>&#xA;  </div>&#xA;</template>&#xA;&#xA;<code class="echappe-js">&lt;script&gt;&amp;#xA;import Messaging from &quot;./Messaging.vue&quot;;&amp;#xA;import { createFFmpeg, fetchFile } from &amp;#x27;@ffmpeg/ffmpeg&amp;#x27;;&amp;#xA;&amp;#xA;export default {&amp;#xA;  data() {&amp;#xA;    return {&amp;#xA;      isMicrophoneLoading: false,&amp;#xA;      isSubmitLoading: false,&amp;#xA;      isMobile: false,&amp;#xA;      isMessagerie: false,&amp;#xA;      isRecording: false,&amp;#xA;      audioUrl: &amp;#x27;&amp;#x27;,&amp;#xA;      messageText: &amp;#x27;&amp;#x27;,&amp;#xA;      message:null,&amp;#xA;      wavesurfer: null,&amp;#xA;      access:(this.isMobile?&amp;#x27;denied&amp;#x27;:&amp;#x27;granted&amp;#x27;),&amp;#xA;      maxMinutes: 5,&amp;#xA;      orangeTimer: 3,&amp;#xA;      redTimer: 4,&amp;#xA;      timer: 0,&amp;#xA;      timerInterval: null,&amp;#xA;      ffmpeg: null,&amp;#xA;    };&amp;#xA;  },&amp;#xA;  components: {&amp;#xA;    Messaging,&amp;#xA;  },&amp;#xA;  mounted() {&amp;#xA;    this.checkScreenSize();&amp;#xA;    window.addEventListener(&amp;#x27;resize&amp;#x27;, this.checkScreenSize);&amp;#xA;&amp;#xA;    if(!this.isMobile)&amp;#xA;    {&amp;#xA;      this.$moment.locale(&amp;#x27;fr&amp;#x27;);&amp;#xA;      window.addEventListener(&amp;#x27;beforeunload&amp;#x27;, (event) =&gt; {&amp;#xA;        if (this.isMessagerie) {&amp;#xA;          event.preventDefault();&amp;#xA;          event.returnValue = &amp;#x27;&amp;#x27;;&amp;#xA;        }&amp;#xA;      });&amp;#xA;&amp;#xA;      this.initializeWaveSurfer();&amp;#xA;    }&amp;#xA;  },&amp;#xA;  beforeUnmount() {&amp;#xA;    window.removeEventListener(&amp;#x27;resize&amp;#x27;, this.checkScreenSize);&amp;#xA;  },&amp;#xA;  methods: {&amp;#xA;    checkScreenSize() {&amp;#xA;      this.isMobile = window.innerWidth &lt; 1200;&amp;#xA;&amp;#xA;      const windowHeight = window.innerHeight;&amp;#xA;      const navbarHeight = this.$navbarHeight;&amp;#xA;      let padding = parseInt(navbarHeight &amp;#x2B;181);&amp;#xA;&amp;#xA;      const messageListHeight = windowHeight - padding;&amp;#xA;      this.$refs.messagingComponent.$refs.messageList.style.height = messageListHeight &amp;#x2B; &amp;#x27;px&amp;#x27;;&amp;#xA;    },&amp;#xA;    showMessagerie() {&amp;#xA;      this.isMessagerie = true;&amp;#xA;      this.$refs.messagingComponent.scrollToBottom();&amp;#xA;    },&amp;#xA;    checkMicrophoneAccess() {&amp;#xA;      if (navigator.mediaDevices &amp;amp;&amp;amp; navigator.mediaDevices.getUserMedia) {&amp;#xA;&amp;#xA;        return navigator.mediaDevices.getUserMedia({audio: true})&amp;#xA;            .then(function (stream) {&amp;#xA;              stream.getTracks().forEach(function (track) {&amp;#xA;                track.stop();&amp;#xA;              });&amp;#xA;              return true;&amp;#xA;            })&amp;#xA;            .catch(function (error) {&amp;#xA;              console.error(&amp;#x27;Erreur lors de la demande d\&amp;#x27;acc&amp;#xE8;s au microphone:&amp;#x27;, error);&amp;#xA;              return false;&amp;#xA;            });&amp;#xA;      } else {&amp;#xA;        console.error(&amp;#x27;getUserMedia n\&amp;#x27;est pas support&amp;#xE9; par votre navigateur.&amp;#x27;);&amp;#xA;        return false;&amp;#xA;      }&amp;#xA;    },&amp;#xA;    initializeWaveSurfer() {&amp;#xA;      this.wavesurfer = this.$wavesurfer.create({&amp;#xA;        container: &amp;#x27;#visualizer&amp;#x27;,&amp;#xA;        barWidth: 3,&amp;#xA;        barHeight: 1.5,&amp;#xA;        height: 46,&amp;#xA;        responsive: true,&amp;#xA;        waveColor: &amp;#x27;rgba(108,115,202,0.3)&amp;#x27;,&amp;#xA;        progressColor: &amp;#x27;rgba(108,115,202,1)&amp;#x27;,&amp;#xA;        cursorColor: &amp;#x27;transparent&amp;#x27;&amp;#xA;      });&amp;#xA;&amp;#xA;      this.record = this.wavesurfer.registerPlugin(this.$recordPlugin.create());&amp;#xA;    },&amp;#xA;    startRecording() {&amp;#xA;      const _this = this;&amp;#xA;      this.isMicrophoneLoading = true;&amp;#xA;&amp;#xA;      setTimeout(() =&gt;&amp;#xA;      {&amp;#xA;        _this.checkMicrophoneAccess().then(function (accessible)&amp;#xA;        {&amp;#xA;          if (accessible) {&amp;#xA;            _this.record.startRecording();&amp;#xA;&amp;#xA;            _this.record.once(&amp;#x27;startRecording&amp;#x27;, () =&gt; {&amp;#xA;              _this.isMicrophoneLoading = false;&amp;#xA;              _this.isRecording = true;&amp;#xA;              _this.updateChildMessage( &amp;#x27;server&amp;#x27;, &amp;#x27;Allez-y ! Vous pouvez enregistrer votre message audio maintenant. La dur&amp;#xE9;e maximale autoris&amp;#xE9;e pour votre enregistrement est de 5 minutes.&amp;#x27;, &amp;#x27;text&amp;#x27;, &amp;#x27;&amp;#x27;, &amp;#x27;Message automatique&amp;#x27;);&amp;#xA;              _this.startTimer();&amp;#xA;            });&amp;#xA;          } else {&amp;#xA;            _this.isRecording = false;&amp;#xA;            _this.isMicrophoneLoading = false;&amp;#xA;            _this.$swal.fire({&amp;#xA;              title: &amp;#x27;Microphone non d&amp;#xE9;tect&amp;#xE9;&amp;#x27;,&amp;#xA;              html: &amp;#x27;&lt;p&gt;Le microphone de votre appareil est inaccessible ou l\&amp;#x27;acc&amp;#xE8;s a &amp;#xE9;t&amp;#xE9; refus&amp;#xE9;.&lt;/p&gt;&lt;p&gt;Merci de v&amp;#xE9;rifier les param&amp;#xE8;tres de votre navigateur afin de v&amp;#xE9;rifier les autorisations de votre microphone.&lt;/p&gt;&amp;#x27;,&amp;#xA;              footer: &amp;#x27;&lt;a href='http://stackoverflow.com/contact'&gt;Vous avez besoin d\&amp;#x27;aide ?&lt;/a&gt;&amp;#x27;,&amp;#xA;            });&amp;#xA;          }&amp;#xA;        });&amp;#xA;      }, 100);&amp;#xA;    },&amp;#xA;    stopRecording() {&amp;#xA;      this.stopTimer();&amp;#xA;      this.isRecording = false;&amp;#xA;      this.isSubmitLoading = true;&amp;#xA;      this.record.stopRecording();&amp;#xA;&amp;#xA;      this.record.once(&amp;#x27;stopRecording&amp;#x27;, () =&gt; {&amp;#xA;        const blobUrl = this.record.getRecordedUrl();&amp;#xA;        fetch(blobUrl).then(response =&gt; response.blob()).then(blob =&gt; {&amp;#xA;          this.uploadAudio(blob);&amp;#xA;        });&amp;#xA;      });&amp;#xA;    },&amp;#xA;    startTimer() {&amp;#xA;      this.timerInterval = setInterval(() =&gt; {&amp;#xA;        this.timer&amp;#x2B;&amp;#x2B;;&amp;#xA;        if (this.timer === this.maxMinutes * 60) {&amp;#xA;          this.stopRecording();&amp;#xA;        }&amp;#xA;      }, 1000);&amp;#xA;    },&amp;#xA;    stopTimer() {&amp;#xA;      clearInterval(this.timerInterval);&amp;#xA;      this.timer = 0;&amp;#xA;    },&amp;#xA;    formatTimer() {&amp;#xA;      const minutes = Math.floor(this.timer / 60);&amp;#xA;      const seconds = this.timer % 60;&amp;#xA;      const formattedMinutes = minutes &lt; 10 ? `0${minutes}` : minutes;&amp;#xA;      const formattedSeconds = seconds &lt; 10 ? `0${seconds}` : seconds;&amp;#xA;      return `${formattedMinutes}:${formattedSeconds}`;&amp;#xA;    },&amp;#xA;    async uploadAudio(blob)&amp;#xA;    {&amp;#xA;      const format = blob.type === &amp;#x27;audio/webm&amp;#x27; ? &amp;#x27;webm&amp;#x27; : &amp;#x27;mp4&amp;#x27;;&amp;#xA;&amp;#xA;      // Convert the blob to MP3&amp;#xA;      const mp3Blob = await this.convertToMp3(blob, format);&amp;#xA;&amp;#xA;      const s3 = new this.$AWS.S3({&amp;#xA;        accessKeyId: &amp;#x27;xxx&amp;#x27;,&amp;#xA;        secretAccessKey: &amp;#x27;xxx&amp;#x27;,&amp;#xA;        region: &amp;#x27;eu-west-1&amp;#x27;&amp;#xA;      });&amp;#xA;&amp;#xA;      var currentDate = new Date();&amp;#xA;      var filename = currentDate.getDate().toString() &amp;#x2B; &amp;#x27;-&amp;#x27; &amp;#x2B; currentDate.getMonth().toString() &amp;#x2B; &amp;#x27;-&amp;#x27; &amp;#x2B; currentDate.getFullYear().toString() &amp;#x2B; &amp;#x27;--&amp;#x27; &amp;#x2B; currentDate.getHours().toString() &amp;#x2B; &amp;#x27;-&amp;#x27; &amp;#x2B; currentDate.getMinutes().toString() &amp;#x2B; &amp;#x27;.mp4&amp;#x27;;&amp;#xA;&amp;#xA;      const params = {&amp;#xA;        Bucket: &amp;#x27;xxx/audio&amp;#x27;,&amp;#xA;        Key: filename,&amp;#xA;        Body: mp3Blob,&amp;#xA;        ACL: &amp;#x27;public-read&amp;#x27;,&amp;#xA;        ContentType: &amp;#x27;audio/mp3&amp;#x27;&amp;#xA;      }&amp;#xA;&amp;#xA;      s3.upload(params, (err, data) =&gt; {&amp;#xA;        if (err) {&amp;#xA;          console.error(&amp;#x27;Error uploading audio:&amp;#x27;, err)&amp;#xA;        } else {&amp;#xA;          const currentDate = this.$moment();&amp;#xA;          const timestamp = currentDate.format(&amp;#x27;dddd DD MMMM YYYY HH:mm&amp;#x27;);&amp;#xA;&amp;#xA;          this.updateChildMessage( &amp;#x27;client&amp;#x27;, &amp;#x27;&amp;#x27;, &amp;#x27;audio&amp;#x27;, mp3Blob, timestamp);&amp;#xA;          this.isSubmitLoading = false;&amp;#xA;        }&amp;#xA;      });&amp;#xA;    },&amp;#xA;    async convertToMp3(blob, format) {&amp;#xA;      const ffmpeg = createFFmpeg({ log: true });&amp;#xA;      await ffmpeg.load();&amp;#xA;&amp;#xA;      const inputPath = &amp;#x27;input.&amp;#x27; &amp;#x2B; format;&amp;#xA;      const outputPath = &amp;#x27;output.mp3&amp;#x27;;&amp;#xA;&amp;#xA;      ffmpeg.FS(&amp;#x27;writeFile&amp;#x27;, inputPath, await fetchFile(blob));&amp;#xA;&amp;#xA;      await ffmpeg.run(&amp;#x27;-i&amp;#x27;, inputPath, &amp;#x27;-acodec&amp;#x27;, &amp;#x27;libmp3lame&amp;#x27;, outputPath);&amp;#xA;&amp;#xA;      const mp3Data = ffmpeg.FS(&amp;#x27;readFile&amp;#x27;, outputPath);&amp;#xA;      const mp3Blob = new Blob([mp3Data.buffer], { type: &amp;#x27;audio/mp3&amp;#x27; });&amp;#xA;&amp;#xA;      ffmpeg.FS(&amp;#x27;unlink&amp;#x27;, inputPath);&amp;#xA;      ffmpeg.FS(&amp;#x27;unlink&amp;#x27;, outputPath);&amp;#xA;&amp;#xA;      return mp3Blob;&amp;#xA;    },&amp;#xA;    sendMessage() {&amp;#xA;      this.isSubmitLoading = true;&amp;#xA;      if (this.messageText.trim() !== &amp;#x27;&amp;#x27;) {&amp;#xA;        const emmet = &amp;#x27;client&amp;#x27;;&amp;#xA;        const text = this.escapeHTML(this.messageText)&amp;#xA;            .replace(/\n/g, &amp;#x27;&lt;br&gt;&amp;#x27;);&amp;#xA;&amp;#xA;        const currentDate = this.$moment();&amp;#xA;        const timestamp = currentDate.format(&amp;#x27;dddd DD MMMM YYYY HH:mm&amp;#x27;);&amp;#xA;&amp;#xA;        this.$nextTick(() =&gt; {&amp;#xA;          this.messageText = &amp;#x27;&amp;#x27;;&amp;#xA;&amp;#xA;          const textarea = document.getElementById(&amp;#x27;messageTextarea&amp;#x27;);&amp;#xA;          if (textarea) {&amp;#xA;            textarea.scrollTop = 0;&amp;#xA;            textarea.scrollLeft = 0;&amp;#xA;          }&amp;#xA;        });&amp;#xA;&amp;#xA;        this.updateChildMessage(emmet, text, &amp;#x27;text&amp;#x27;, &amp;#x27;&amp;#x27;, timestamp);&amp;#xA;        this.isSubmitLoading = false;&amp;#xA;      }&amp;#xA;    },&amp;#xA;    escapeHTML(text) {&amp;#xA;      const map = {&amp;#xA;        &amp;#x27;&amp;amp;&amp;#x27;: &amp;#x27;&amp;amp;amp;&amp;#x27;,&amp;#xA;        &amp;#x27;&lt;&amp;#x27;: &amp;#x27;&amp;amp;lt;&amp;#x27;,&amp;#xA;        &amp;#x27;&gt;&amp;#x27;: &amp;#x27;&amp;amp;gt;&amp;#x27;,&amp;#xA;        &amp;#x27;&quot;&amp;#x27;: &amp;#x27;&amp;amp;quot;&amp;#x27;,&amp;#xA;        &quot;&amp;#x27;&quot;: &amp;#x27;&amp;amp;#039;&amp;#x27;,&amp;#xA;        &quot;`&quot;: &amp;#x27;&amp;amp;#x60;&amp;#x27;,&amp;#xA;        &quot;/&quot;: &amp;#x27;&amp;amp;#x2F;&amp;#x27;&amp;#xA;      };&amp;#xA;      return text.replace(/[&amp;amp;&lt;&gt;&quot;&amp;#x27;`/]/g, (match) =&gt; map[match]);&amp;#xA;    },&amp;#xA;    updateChildMessage(emmet, text, type, blob, timestamp) {&amp;#xA;      const newMessage = {&amp;#xA;        id: this.$refs.messagingComponent.lastMessageId &amp;#x2B; 1,&amp;#xA;        emmet: emmet,&amp;#xA;        text: text,&amp;#xA;        type: type,&amp;#xA;        blob: blob,&amp;#xA;        timestamp: timestamp&amp;#xA;      };&amp;#xA;&amp;#xA;      this.$refs.messagingComponent.updateMessages(newMessage);&amp;#xA;    }&amp;#xA;  },&amp;#xA;};&amp;#xA;&lt;/script&gt;&#xA;