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• How can I programmatically write and read random video watermarks ?

  13 novembre 2017, par GreenTriangle

  I spent a few minutes trying to think of a clearer way to word my title, but I couldn’t manage it, sorry.

  I want to essentially canary trap video files : I am (hypothetically, this is not real but a personal exercise) offering them up to 5,000 different people, and if one gets leaked, I want to know who leaked it. Metadata is too easily emoved, so what I’d like to do is add a random and subtle watermark to each file, and store information about that in a database.

  For example : on Joe Smith’s copy, a 10x10 pixel 80% transparent red square in the upper left corner for 5 frames. On Diane Brown’s copy, a full-width 5-pixel 90% transparent black bar on the bottom edge for 15 frames. Then, if I find a leaked copy, I could check it against the database.

  I know this still isn’t foolproof : cropping would break co-ordinates, hue/brightness transforms would break colour reading, cutting time would break timestamps. But if I did want to do this anyway, what would be a good strategy for it ?

  My idea was to generate PNG overlays randomly, split the video into parts with mkvtoolnix/ffmpeg, re-encode the middle part with ffmpeg + overlay filter, and then rejoin them. But is this silly when there’s a "proper" way to do it ? And what would I be doing to read the watermarks, which I can’t even really conceive of ?

• Gujarati text properly not show on output video using FFmpeg Library in Android

  15 mars 2024, par sanjay dangar

  Gujarati text overly on video using FFmpeg Library on Android

  


  below my code in Gujarati text twin word proper does not show

  


  I am Enter this text ="વડાપ્રધાનશ્રી નરેન્દ્રભાઇ મોદી." but output video in proper not show

  


   fun addFrame2VideoEditFun(&#xA;        videoPath: String,&#xA;        fontPath: String,&#xA;        outputPath: String&#xA;    ): Array<string> {&#xA;        val inputs: ArrayList<string> = ArrayList()&#xA;     var textFile = "વડાપ્રધાનશ્રી નરેન્દ્રભાઇ મોદી."&#xA;        inputs.apply {&#xA;            add("-i")&#xA;            add(videoPath)&#xA;            add("-vf")&#xA;            add("drawtext=fontfile=$fontPath:text=$textFile:fontsize=24:fontcolor=white:x=(w-text_w)/2:y=h-line_h")&#xA;            add("-c:a")&#xA;            add("copy")&#xA;            add(outputPath)&#xA;        }&#xA;        return inputs.toArray(arrayOfNulls(inputs.size))&#xA;    }&#xA;</string></string>

  


  my output video in below text show

  


  

  


  Gujarati text properly does not show on output video using FFmpeg Library.

  


• Splitting audio tracks with incorrect length - FFMPEG

  26 mars 2018, par channae

  Version : com.writingminds:FFmpegAndroid:0.3.2

  I have an audio file with length 43 seconds. And I wrote an algorithm to split at each 10 seconds mark where a word ends (For this I used IBM Watson to get ending timestamp). So cropping duration is always around 10 seconds to 11 seconds. Of course except the 5th one. I have printed my commands so that you will understand my use-case better.

  System.out: Split Command: -y -i /storage/emulated/0/AudioClipsForSpeakerRecognition/merge.wav -ss 00:00:00.000 -codec copy -t 00:00:10.010 /storage/emulated/0/AudioClipsForSpeakerRecognition/segment_1.wav
  
  
  
  System.out: Split Command: -y -i /storage/emulated/0/AudioClipsForSpeakerRecognition/merge.wav -ss 00:00:10.010 -codec copy -t 00:00:21.090 /storage/emulated/0/AudioClipsForSpeakerRecognition/segment_2.wav
  
  
  
  System.out: Split Command: -y -i /storage/emulated/0/AudioClipsForSpeakerRecognition/merge.wav -ss 00:00:21.090 -codec copy -t 00:00:30.480 /storage/emulated/0/AudioClipsForSpeakerRecognition/segment_3.wav
  
  
  
  System.out: Split Command: -y -i /storage/emulated/0/AudioClipsForSpeakerRecognition/merge.wav -ss 00:00:30.480 -codec copy -t 00:00:40.120 /storage/emulated/0/AudioClipsForSpeakerRecognition/segment_4.wav
  
  
  
  System.out: Split Command: -y -i /storage/emulated/0/AudioClipsForSpeakerRecognition/merge.wav -ss 00:00:40.120 -codec copy -t 00:00:43.000 /storage/emulated/0/AudioClipsForSpeakerRecognition/segment_5.wav

  However when playing all cropped audio files I noticed segment_1 is about 10 seconds and segment_2 is about 20 seconds etc. Therefore some of the audio parts belong to segment_1 also available in segment 2 etc etc. Why is this happening ?

  Appreciate your response.