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• What is the point of encrypting HLS files ?

  29 janvier 2016, par APITC

  I am currently working on a project of videos on demand where I convert videos to HLS using FFMPEG.

  Videos are publicly hosted on AWS S3 and there is an API giving the URL of the HLS playlist.

  Now, I was looking at encrypting HLS files with AES-128 so that people can’t download and watch the video offline.
  I found the procedure which consists in hosting the key online and using that key while converting the video to encrypt the segments.

  The URL of the key is written in the HLS playlist, and the file is publicly available online.

  So anyone has access to the encryption key.

  I don’t understand what is the point of encrypting the segments if anyone has access to the key.

  Can someone enlighten me ? I know I must be missing something. Thanks !

• Efficient way to stream a sequence of frames

  3 juin 2020, par DoriHp 0

  I'm facing with an issue : I implemented a device to detect stranger for my home, which includes inputs from some IP camera and use a tensorflow model to process frame got from them.

  



  Now I want to build a dashboard (use Flask or Django - python framework as backend) to streaming the processed frames I got from the system, and if possible, do some transform on them (such as stack multi frames into one, etc), and run the server so I can watch it from distances. Currently, I'm sending frame by frame as independent images but it costs so much bandwidth. I read how h264 encoder work and felt very exicted about it. Now, the question is, how can I use h264 or any encoder like it transfer my data and reduce the bandwidth ?

  


• ffmpeg - Concat multi mp4 files with audio file not working

  29 mars 2017, par Thanh Dao

  I follow this thread to concat multi mp4 files with audio file.
  But its not success. Have a lots error notifications had been displayed. I dont know how to fix it.
  Below is my command :

  "ffmpeg" -f concat -safe 0 \
  
  -i /path/to/text.txt \
  
  -i /path/to/audio.mp3 -vsync vfr -vf scale="640:640" -pix_fmt yuv420p \
  
  /path/to/output.mp4 2>&1

  The detail contents of text.txt

  file '/path/to/file1.mp4'
  
  file '/path/to/file2.mp4'
  
  file '/path/to/file3.mp4'
  
  file '/path/to/file4.mp4'
  
  file '/path/to/file5.mp4'
  
  file '/path/to/file6.mp4'
  
  file '/path/to/file7.mp4'
  
  file '/path/to/file8.mp4'
  
  file '/path/to/file9.mp4'
  
  file '/path/to/file10.mp4'
  
  file '/path/to/file11.mp4'
  
  file '/path/to/file12.mp4'
  
  file '/path/to/file13.mp4'
  
  file '/path/to/file14.mp4'
  
  file '/path/to/file15.mp4'
  
  file '/path/to/file16.mp4'
  
  file '/path/to/file17.mp4'
  
  file '/path/to/file18.mp4'

  And some lines of output errors :

  [concat @ 0x357e620] DTS 192000 < 229888 out of order
  
  [h264 @ 0x36920e0] top block unavailable for requested intra mode -1
  
  [h264 @ 0x36920e0] error while decoding MB 32 0
  
  [h264 @ 0x36920e0] concealing 2025 DC, 2025 AC, 2025 MV errors in I frame
  
  [h264 @ 0x36b7a80] concealing 1449 DC, 1449 AC, 1449 MV errors in P frame
  
  [h264 @ 0x36ff440] corrupted macroblock 26 1 (total_coeff=-1)
  
  [h264 @ 0x36ff440] error while decoding MB 26 1
  
  [h264 @ 0x36ff440] concealing 2003 DC, 2003 AC, 2003 MV errors in P frame
  
  [h264 @ 0x371af40] concealing 1456 DC, 1456 AC, 1456 MV errors in P frame
  
  [h264 @ 0x3736a40] ref 5 overflow
  
  [h264 @ 0x3736a40] error while decoding MB 1 1
  
  [h264 @ 0x3736a40] concealing 2025 DC, 2025 AC, 2025 MV errors in P frame
  
  [h264 @ 0x3752520] concealing 1449 DC, 1449 AC, 1449 MV errors in P frame
  
  [h264 @ 0x376dfa0] P sub_mb_type 8 out of range at 2 1
  
  [h264 @ 0x376dfa0] error while decoding MB 2 1
  
  [h264 @ 0x376dfa0] concealing 2025 DC, 2025 AC, 2025 MV errors in P frame
  
  [h264 @ 0x37a55a0] ref 6 overflow
  
  [h264 @ 0x37a55a0] error while decoding MB 3 1
  
  [h264 @ 0x37a55a0] concealing 2025 DC, 2025 AC, 2025 MV errors in P frame
  
  [h264 @ 0x3789aa0] concealing 1449 DC, 1449 AC, 1449 MV errors in P frame
  
  [h264 @ 0x36b7a80] ref 5 overflow
  
  [h264 @ 0x36b7a80] error while decoding MB 4 1
  
  [h264 @ 0x36b7a80] concealing 2025 DC, 2025 AC, 2025 MV errors in P frame
  
  [h264 @ 0x36920e0] concealing 1449 DC, 1449 AC, 1449 MV errors in P frame