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• openCV save frames from RTSP non blocking

  1er janvier 2020, par Jacob nighFor

  I am building an app that records frames from IP camera through RTSP.

  My engine is in charge to save a video in mp4 with Opencv VideoWriter working well.
  What I am looking for is to create a startRecord and a stopRecord class method that will respectively start and stop recording according to a trigger (it could be an argument that I pass to the thread).
  Is anyone know what the best way to do that kind of stuff ?

  Here is my class :

  from threading import Thread
  
  import cv2
  
  import time
  
  import multiprocessing
  
  import threading
  
  class RTSPVideoWriterObject(object):
  
      def __init__(self, src=0):
  
          # Create a VideoCapture object
  
          self.capture = cv2.VideoCapture(src)
  
  
  
          # Start the thread to read frames from the video stream
  
          self.thread = Thread(target=self.update, args=())
  
          self.thread.daemon = True
  
          self.thread.start()
  
  
  
      def update(self):
  
          # Read the next frame from the stream in a different thread
  
          while True:
  
              if self.capture.isOpened():
  
                  (self.status, self.frame) = self.capture.read()
  
  
  
      def endRecord(self):
  
          self.capture.release()
  
          self.output_video.release()
  
          exit(1)
  
  
  
      def startRecord(self,endRec):
  
  
  
          self.frame_width = int(self.capture.get(3))
  
          self.frame_height = int(self.capture.get(4))
  
          self.codec = cv2.VideoWriter_fourcc(*'mp4v')
  
          self.output_video = cv2.VideoWriter('fileOutput.mp4', self.codec, 30, (self.frame_width, self.frame_height))
  
          while True:          
  
              try:
  
                  self.output_video.write(self.frame)
  
                  if endRec:
  
                      self.endRecord()
  
              except AttributeError:
  
                  pass
  
  
  
  
  
  
  
  
  
  if __name__ == '__main__':
  
  
  
      rtsp_stream_link = 'rtsp://foo:192.5545....'
  
      video_stream_widget = RTSPVideoWriterObject(rtsp_stream_link)
  
  
  
      stop_threads = False
  
      t1 = threading.Thread(target = video_stream_widget.startRecord, args =[stop_threads]) 
  
      t1.start() 
  
      time.sleep(15)
  
      stop_threads = True

  As you can see in the main I reading frames and store them in a separate thread. Then I am starting to record (record method is with an infinite loop so blocking) and then after 15 sec, I am trying to pass a ’stop_record’ argument to stop recording properly.

  A part of the code comes from Storing RTSP stream as video file with OpenCV VideoWriter

  Is someone have an idea ?
  I read a lot that OpenCV can be very tricky for multithreading

  N.

• Alfresco fails to create video thumbnail

  17 octobre 2019, par Deckard

  As error log says : Empty input file ... It turned out that the source image for ImageMagick is zero sized. (/data/was/alfresco/tomcat/temp/Alfresco/ImageMagickContentTransformerWorker_source_8718262212685093199.jpg). When I manually replace the source image to normal image and execute the command again, there’s no error.

  command:    /data/was/alfresco/common/bin/convert /data/was/alfresco/tomcat/temp/Alfresco/ImageMagickContentTransformerWorker_source_8718262212685093199.jpg[0] -auto-orient -resize "100x100>" -strip -quiet /data/was/alfresco/tomcat/temp/Alfresco/ImageMagickContentTransformerWorker_target_7652060684136589026.png

  So I think the source image is maybe made by FFMPEG by capturing some frame of the video.
  And the FFMPEG somehow failed to do it. Not sure my guess is right...

  But my FFMPEG works good as ffmpeg -version shows proper version info. And FFMPEG is run by root and the Alfresco daemon instance is run by root. It seems that there’s nothing wrong.

  Please review it. Here’s the whole Alfresco-share log :

  Caused by: org.alfresco.service.cmr.repository.ContentIOException: 09160037 Content conversion failed:
  
     reader: ContentAccessor[ contentUrl=store:///data/was/alfresco/tomcat/temp/Alfresco/ComplextTransformer_intermediate_mp4_262176879279399174.jpg, mimetype=image/jpeg, size=0, encoding=UTF-8, locale=en_US]
  
     writer: ContentAccessor[ contentUrl=store:///data/was/alfresco/tomcat/temp/Alfresco/FailoverTransformer_intermediate_ComplexContentTransformer_5223852355212570043.png, mimetype=image/png, size=0, encoding=UTF-8, locale=en_US]
  
     options: {use=doclib, contentReaderNodeRef=null, contentWriterNodeRef=null, sourceContentProperty=null, imageAutoOrient=true, targetContentProperty=null, commandOptions=, imageResizeOptions=ImageResizeOptions [width=100, height=100, maintainAspectRatio=true, percentResize=false, resizeToThumbnail=false, allowEnlargement=false], includeEmbedded=null}
  
     limits: {timeoutMs=120000, pageLimit=1}
  
          at org.alfresco.repo.content.transform.AbstractContentTransformer2.transform(AbstractContentTransformer2.java:350)
  
          at org.alfresco.repo.content.transform.ComplexContentTransformer.transformInternal(ComplexContentTransformer.java:492)
  
          at org.alfresco.repo.content.transform.AbstractContentTransformer2.transform(AbstractContentTransformer2.java:272)
  
          ... 32 more
  
  Caused by: org.alfresco.service.cmr.repository.ContentIOException: 09160036 Failed to perform ImageMagick transformation:
  
  Execution result:
  
     os:         Linux
  
     command:    /data/was/alfresco/common/bin/convert /data/was/alfresco/tomcat/temp/Alfresco/ImageMagickContentTransformerWorker_source_8718262212685093199.jpg[0] -auto-orient -resize "100x100>" -strip -quiet /data/was/alfresco/tomcat/temp/Alfresco/ImageMagickContentTransformerWorker_target_7652060684136589026.png
  
     succeeded:  false
  
     exit code:  1
  
     out:
  
     err:        .convert.bin: Empty input file `/data/was/alfresco/tomcat/temp/Alfresco/ImageMagickContentTransformerWorker_source_8718262212685093199.jpg' @ error/jpeg.c/JPEGErrorHandler/331.
  
  .convert.bin: NoImageForProperty "%w" @ warning/property
  
          at org.alfresco.repo.content.transform.magick.ImageMagickContentTransformerWorker.transformInternal(ImageMagickContentTransformerWorker.java:205)
  
          at org.alfresco.repo.content.transform.magick.AbstractImageMagickContentTransformerWorker.transform(AbstractImageMagickContentTransformerWorker.java:284)
  
          at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  
          at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
  
          at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  
          at java.lang.reflect.Method.invoke(Method.java:498)
  
          at org.alfresco.repo.management.subsystems.SubsystemProxyFactory$1.invoke(SubsystemProxyFactory.java:79)
  
          at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
  
          at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
  
          at com.sun.proxy.$Proxy28.transform(Unknown Source)
  
          at org.alfresco.repo.content.transform.ProxyContentTransformer.transformInternal(ProxyContentTransformer.java:107)
  
          at org.alfresco.repo.content.transform.AbstractContentTransformer2.transform(AbstractContentTransformer2.java:272)
  
          ... 34 more

  In alfresco-global.properties : ffmpeg.exe=/usr/local/bin/ffmpeg/ffmpeg

  * Update As Robert suggested, TransFormer log level changed to debug.
  But the log is too long to paste here. There’s 30,000 characters limit of body in SO which github doesn’t have.
  So please refer to github issue, I pasted the log there.
  https://github.com/Alfresco/share/issues/127

• avformat_open_input crash using ffmpeg on android

  2 octobre 2019, par Timmy K

  I am writing an Android app to capture audio streams from a USB device using ffmpeg, and mux them into an m4a file. I then open the recording file to read back the audio data. The app works fine on Samsung S8 (Android 8.0) and S9 (Android 9.0). On a Moto G5+ (Android 8.1), however the app crashes inside avformat_open_input() when I try to open the recording file ; but if I restart the app and it reads the same file with the same code, it works without crashing.

  I thought maybe that I hadn’t closed the recording file properly ; or there was maybe a race condition : trying to read the file before it was written. However I have established that av_write_trailer() is called successfully and avio_closep() is called successfully before the call to avformat_open_input. I also established that the length of the file is the same just before the call to avformat_open_input() in the crash case as it is in the non-crash case.

  The code that finishes the recording :

  // AVFormatContext *mAvFormatContext
  
  // ...
  
  int ret = av_write_trailer(mAvFormatContext);
  
  if ( ret != 0 )
  
  {
  
      __android_log_print(ANDROID_LOG_DEBUG, "MyTag", "failed to write trailer %s", av_err2str( ret ) );
  
      goto fail;
  
  }
  
  
  
  ret = avio_close( mAvFormatContext->pb );
  
  if ( ret < 0 )
  
  {
  
      __android_log_print(ANDROID_LOG_DEBUG, "MyTag", "failed to avio_close %s", av_err2str( ret ) );
  
      goto fail;
  
  }
  
  
  
  avformat_free_context(mAvFormatContext);

  The call that causes a crash immediately after the above code, on a Moto 5G+ (but not Samsung S8/S9) :

  mAvFormatContext = nullptr;
  
  if ( (ret = avformat_open_input( &mAvFormatContext, filePath, 0, 0)) < 0 )
  
  {
  
      __android_log_print(ANDROID_LOG_DEBUG, "MyTag++", "Could not open input file '%s' error %s ", filePath, av_err2str(ret) );
  
      cleanup();
  
      return false;
  
  }

  Also, when the call to avformat_open_input() does not crash, there is no output in logcat from within that call. However, I’ve noticed that in the crash case there is output of what seems to be corrupted data :

  2019-09-02 09:39:14.105 19999-19999/fm.x.y D/AudioEngine: Opening '@�7���-d��@�7�' for 
  
  2019-09-02 09:39:14.106 19999-19999/fm.x.y D/AudioEngine: Setting default whitelist '<��'
  
  2019-09-02 09:39:14.106 19999-19999/fm.x.y D/AudioEngine: Probing ���d score:-1828887548 size:-1093138844
  
  2019-09-02 09:39:14.106 19999-19999/fm.x.y D/AudioEngine: Format ��� probed with size=-1093138756 and score=-1093138748
  
  (crash occurs)

  Any advice on what to look into further to investigate this problem ? Is there something I am missing when cleaning up the muxing state before I try to open the recording file for demuxing ? For simplicity I have not included the freeing of codec contexts, AVFrames and AVPackets.