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• Unhandled stream error in pipe : write EPIPE in Node.js

  13 juillet 2020, par Michael Romanenko

  The idea is to serve screenshots of RTSP video stream with Express.js server. There is a continuously running spawned openRTSP process in flowing mode (it's stdout is consumed by another ffmpeg process) :

  



  function spawnProcesses (camera) {
  var openRTSP = spawn('openRTSP', ['-c', '-v', '-t', camera.rtsp_url]),
      encoder = spawn('ffmpeg', ['-i', 'pipe:', '-an', '-vcodec', 'libvpx', '-r', 10, '-f', 'webm', 'pipe:1']);

  openRTSP.stdout.pipe(encoder.stdin);

  openRTSP.on('close', function (code) {
    if (code !== 0) {
      console.log('Encoder process exited with code ' + code);
    }
  });

  encoder.on('close', function (code) {
    if (code !== 0) {
      console.log('Encoder process exited with code ' + code);
    }
  });

  return { rtsp: openRTSP, encoder: encoder };
}

...

camera.proc = spawnProcesses(camera);


  



  There is an Express server with single route :

  



  app.get('/cameras/:id.jpg', function(req, res){
  var camera = _.find(cameras, {id: parseInt(req.params.id, 10)});
  if (camera) {
    res.set({'Content-Type': 'image/jpeg'});
    var ffmpeg = spawn('ffmpeg', ['-i', 'pipe:', '-an', '-vframes', '1', '-s', '800x600', '-f', 'image2', 'pipe:1']);
    camera.proc.rtsp.stdout.pipe(ffmpeg.stdin);
    ffmpeg.stdout.pipe(res);
  } else {
    res.status(404).send('Not found');
  }
});

app.listen(3333);


  



  When i request http://localhost:3333/cameras/1.jpg i get desired image, but from time to time app breaks with error :

  



  stream.js:94
  throw er; // Unhandled stream error in pipe.
        ^
Error: write EPIPE
    at errnoException (net.js:901:11)
    at Object.afterWrite (net.js:718:19)


  



  Strange thing is that sometimes it successfully streams image to res stream and closes child process without any error, but, sometimes, streams image and falls down.

  



  I tried to create on('error', ...) event handlers on every possible stream, tried to change pipe(...) calls to on('data',...) constructions, but could not succeed.

  



  My environment : node v0.10.22, OSX Mavericks 10.9.

  



  UPDATE :

  



  I wrapped spawn('ffmpeg',... block with try-catch :

  



  app.get('/cameras/:id.jpg', function(req, res){
....
    try {
      var ffmpeg = spawn('ffmpeg', ['-i', 'pipe:', '-an', '-vframes', '1', '-s', '800x600', '-f', 'image2', 'pipe:1']);
      camera.proc.rtsp.stdout.pipe(ffmpeg.stdin);
      ffmpeg.stdout.pipe(res);
    } catch (e) {
      console.log("Gotcha!", e);
    }
....
});


  



  ... and this error disappeared, but log is silent, it doesn't catch any errors. What's wrong ?

  


• How to not allow upload of HD content ?More than 1920 x 1080 || 1080 x 1920 resolution files are not allowed since hardware reasons

  23 juillet 2020, par azaono

  Struggling with making limitation to uploade HD file/content. Intent is to have possibility to rotate content. Limits are required due to hardware reasons.

  


          val ffmpeg = FFmpeg("ffmpeg")
        val ffprobe = FFprobe("ffprobe")
        val probeResult = ffprobe.probe("$targetLocation")
        val stream: FFmpegStream = probeResult.getStreams()[0]
        val aspectRatio = stream.width.toDouble() / stream.height
        
        if (stream.width > 1920) {
            Files.delete(targetLocation)
            throw IncorrectResolutionFileException()
        } else if (stream.height > 1080) {
            Files.delete(targetLocation)
            throw IncorrectResolutionFileException()
        }

        if (type == "image") {
            part.transferTo(thumbnailLocation)
        }

        val builder: FFmpegBuilder = FFmpegBuilder()
            .setInput("$targetLocation")
            .addOutput("$thumbnailLocation")
            .setFrames(1)
            .setVideoFilter("select='gte(n\\,10)',scale=200:-1")
            .done()
        val executor = FFmpegExecutor(ffmpeg)
        executor.createJob(builder).run()

        return aspectRatio
    } catch (ex: Exception) {
        throw FileStorageException("Could not store file $cleanPath. Please try again!", ex)
    }
}


  


• avcodec_send_packet causing memory leak

  23 juin 2020, par AleksaJanjatovic

  I'm trying to fetch a frame from an Rtsp stream, but it seems that I'm forgetting to free some element, causing my RAM to rapidly fill. Here are the code snippets :

  


  Here is the initialization before frame fetching

  


  bool CRtspStream::Init(void* _userData) {
    InitParam* param = (CBaseStream::InitParam*)_userData;
    m_InputPath = param->m_InputPath;
    m_OutputPath = param->m_OutputPath;
    m_Logger.SetLogLevel(param->m_LoggerLevel);

    av_register_all();
    avformat_network_init();

    int ffmpegFatalLogLevel = 8;
    av_log_set_level(ffmpegFatalLogLevel);

    AVCodec* codec = avcodec_find_decoder(param->m_CodecID);
    if(!codec)
        throw DetectionUtility::StreamException("Unable to open codec.");

    m_FormatContext = avformat_alloc_context();
    m_CodecContext = avcodec_alloc_context3(codec);

    if(avformat_open_input(&m_FormatContext, param->m_InputPath.c_str(), nullptr, nullptr) < 0)
        throw DetectionUtility::StreamException("Unable to open stream: " + param->m_InputPath);

    if(avformat_find_stream_info(m_FormatContext, nullptr) < 0)
        throw DetectionUtility::StreamException("Unable to get stream info into format context.");

    for(unsigned int i = 0;i < m_FormatContext->nb_streams; i++){
        if(m_FormatContext->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO)
            m_VideoStreamIndex = i;
    }

    if (avcodec_open2(m_CodecContext, codec, nullptr) < 0)
        throw DetectionUtility::StreamException("Unable to open codec.");

    return m_InitSuccesful = true;
}


  


  And here is the actual frame fetching, i made sure that retVal frame is being freed afterward. Main evidence that this is what causes memory leaks is that valgrind is also pointing to the avcodec_send_packet() line : valgrind_results

  


  AVFrame* CRtspStream::RequestNewFrame() {
    AVPacket packet;
    AVFrame* retVal = av_frame_alloc();
    bool frameAvailable = false;

//    avformat_flush(m_FormatContext);
//    avcodec_flush_buffers(m_CodecContext);
    av_read_play(m_FormatContext);
    int readFrameRes;
    while(!frameAvailable) {
        if((readFrameRes = av_read_frame(m_FormatContext, &packet)) >= 0) {
            if(packet.stream_index == m_VideoStreamIndex) {
                int res = 1;
                if((res = avcodec_send_packet(m_CodecContext, &packet)) < 0) {
                    av_packet_unref(&packet);
                    continue;
                }
                av_packet_unref(&packet);
                res = 1;
                while(res > 0) {
                    res = avcodec_receive_frame(m_CodecContext, retVal);
                    if(res == AVERROR(EAGAIN)) {
                        break;
                    } else if (res < 0) {
                        throw DetectionUtility::StreamException("Unable to receive a frame from the codec.");
                    } else {
                        frameAvailable = true;
                    }
                }
            }
        }
        av_packet_unref(&packet);
    }

    if(readFrameRes < 0) {
        av_frame_free(&retVal);
        av_packet_unref(&packet);
        throw DetectionUtility::StreamException("Unable to fetcha a new frame.");
    } else {
        try {
            if(CheckOutputSupported())
                DetectionUtility::AVFrameHelper::SaveFrame(retVal, "Rtsp" + m_OutputPath, m_CurrentFrameNumber);
            ++m_CurrentFrameNumber;
        } catch (const Utility::BaseException& e) {
            m_Logger.Error(e.GetMessage());
        }
    }
    return retVal;
}