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• Android sws_scale RGB Frame taking long time and cause of latency in the video

  17 avril 2018, par AJit

  I am reading frames from FFMPEG and try to directly draw to surface window in Native android, If i scale image to exact size what we are getting from camera and apply YUV420P to RGBA it take 1ms to scale through av_image_fill_arrays but if i try to scale image what i need for surface, then i take 25 to 30ms to scale same frame. so latency is the problem.

  In below example getting YUV420P pixel format.

  Low latency :[ 1ms by sws_scale]

  swsContext = sws_getContext(videoCodecContext->width,
  
                                      videoCodecContext->height,
  
                                      videoCodecContext->pix_fmt,
  
                                      videoCodecContext->width,
  
                                      videoCodecContext->height,
  
                                      AV_PIX_FMT_RGB0,
  
                                      SWS_FAST_BILINEAR, NULL, NULL, NULL);
  
  av_image_fill_arrays()
  
  av_read_frame()
  
  avcodec_decode_video2(
  
  sws_scale(swsContext,
  
            (const uint8_t *const *) videoFrame->data,
  
            videoFrame->linesize,
  
            0,
  
            videoCodecContext->height,
  
            pictureFrame->data,
  
            pictureFrame->linesize);
  
  ANativeWindow_lock()
  
  Write all buffer bytes to window.
  
  ANativeWindow_unlockAndPost()

  Low latency :[ 30ms by sws_scale]

  [videoContext Width: 848 Height: 608]
  
  swsContext = sws_getContext(videoCodecContext->width,
  
                                      videoCodecContext->height,
  
                                      videoCodecContext->pix_fmt,
  
                                      1080,
  
                                      608,
  
                                      AV_PIX_FMT_RGB0,
  
                                      SWS_FAST_BILINEAR, NULL, NULL, NULL);

  Whenever we change context width and height other then videoContext it will take more then 30ms and we are delaying the video.

  TRY 1 : Pass the buffer from JNI to Java and create bitmap there to scale later on but createBitmap itself take 500ms so no useful.

  TRY 2 : Direct YUV420P to RGB conversion. still long time then sws_scale.

  TRY 3 : Direct write YUV to window bites but it show without color(If anyone have solution here will might helpful).

  TRY 4 : Use yuvlib, no luck.

  TRY 5 : Different color combinations and flags in swsContext.

  Any help would appreciated.

• Is celery a good choice for long running tasks ?

  2 décembre 2024, par jasoos

  We are using a combination of django, rabbitmq, celery and ffmpeg to read camera streams and break them into images to be stored into filesystem. This setup works 24x7. Now, for each camera stream we are creating a separate task and each will theoretically run for indefinite period.

  


  If a stream goes down, we wait for n number of frames, create an exception and in the exception handler, after creating a delay of 1 min using time.sleep we rerun the ffmpeg process.

  


  My questions are,
Is this a right approach ?
Should we use celery for reading streams ?
Is celery the right tool to use for this task ?
Can we create delay in celery task using time.sleep ? Will it affect the other tasks ?

  


• Evolution #4416 : Utiliser des mots de passe plus long par défaut

  20 janvier 2021, par Peet du

  Hop,

  je suis tombé là-dessus : CNIL | Authentification par mot de passe : les mesures de sécurité élémentaires
  https://www.cnil.fr/fr/authentification-par-mot-de-passe-les-mesures-de-securite-elementaires