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• how can I get the total number of frames using ffmpegkit on Android (Kotlin) ?

  1er mars 2023, par user44551

  I'm developing an Android app to encode a video using

  


  


  com.arthenica.ffmpegkit.FFmpegKit

  


  


  I would like to show users some information on the progress.
I managed to show how many frames are processed in real time. I would like to get the total number of frames in the original stream, so I can show a percentage.

  


  How can I get the total number of frames in a video before I start encoding it ?

  


• Fire events at specific timestamps during video playback

  27 octobre 2017, par Simon

  I’m using a Raspberry Pi 3 running Raspbian. I need to play a video file via HDMI, and I need events to be fired at specific timecodes during the playback of the video. The events are simple write operations to the GPIO. My problem is : what approach should I use to do this ?

  My first approach was to use OpenCv (python) and VideoCapture(), but the raspberry pi is too slow, and my FPS is very low (I need at least 25 FPS @ 1080p).

  So now I’m looking into other solutions : Gstreamer, FFMPEG, omxplayer, I read the documentations but I can’t figure out which tool to use for this job.

• swr_resamble() Receive First-Chance Exception Notifications

  5 janvier 2019, par RekiDunois

  I am using ffmpeg to resample the pcm data which I record from audio device in windows 10. When I call swr_resample(), visual studio get a First-Chance Exception.

  I thought it might be something wrong with the type of inputdata. Cause It is a void pointer, and swr_convert() need a const uint8_t ** , so I try convert inputdata to a short type pointer, and then convert it to uint8_t, and dump the data to a pcm file, the pcm file can be listened when I set correct parameter. but swr_resamble still can’t work.

  audio_resamble(void *inputdata, void *outputdata, int input_sample_rate)
  
  {
  
      AVFrame *outputframe;
  
      struct SwrContext *swr_ctx;
  
      int in_nb_samples = 441;
  
      outputframe = av_frame_alloc();
  
      outputframe->nb_sample = 480;
  
      outputframe->format = AV_SAMPLE_FMT_S16;
  
      outputframe->channel_layout = AV_CH_LAYOUT_STEREO;
  
      /*alloc swrcontext*/
  
      swr_alloc_set_opts(swr_ctx, 2, outputframe->format, 44100, 
  
                         2, AV_SAMPLE_FMT_FLT, input_sample_rate, 0, NULL);
  
      swr_convert(swr_ctx, outputdata, outputframe->nb_samples,
  
                 (const uint8_t **)inputdata, in_nb_samples); 
  
      // when code run here, visual studio get a First-Chance Exception
  
  }