Recherche avancée

Sur d’autres sites (2634)

• Restoring corrupted video after recovery

  22 août 2019, par Harold.Demure

  I have recently recovered the content of an old drive of mine using photorec.

  To my surprise, photorec recovered a lot of files with non-video extensions (.sqlite, .apple, .pdf, .torrent...) that contain fragments of video. I can see these fragments only using mplayer/mencoder (quicktime and vlc cannot). Some of the files are even hundreds of megabyte large, but mplayer only shows me a few seconds of the video.

  Is there any script/data carving tool that I can use to see if I can recover more video fragments from these files ? I am not afraid of trying solutions that require some coding or manual inspection (e.g., search for headers via hex editors).

  Thank you for your help, any suggestion is highly appreciated.
  Harol.

• avutil/aes : Don't use misaligned pointers

  21 octobre 2022, par Andreas Rheinhardt

  avutil/aes : Don't use misaligned pointers
  The AES code uses av_aes_block, a union consisting of
  
  uint64_t[2], uint32_t[4], uint8_t[4][4] and uint8_t[16].
  
  subshift() performs byte-wise manipulations of two av_aes_blocks,
  
  but when encrypting, it does so with a shift of two bytes ;
  
  more precisely, it uses
  
  "av_aes_block *s1 = (av_aes_block *) (s0[0].u8 - s)"
  
  and lateron uses the uint8_t[16] member to access s0.
  
  Yet av_aes_block requires to be suitably aligned for
  
  the uint64_t[2] member, which s0[0].u8 - 2 is certainly
  
  not. This is in violation of 6.3.2.3 (7) of C11. UBSan
  
  reports this in the aes_ctr, mov-3elist-encrypted,
  
  mov-frag-encrypted, mov-tenc-only-encrypted and srtp
  
  tests.
  
  Furthermore, there is another issue here : The pointer points
  
  outside of s0 ; this works, because all the accesses lateron
  
  use an index >= 3. (Clang-)UBSan reports this as
  
  "runtime error : index -2 out of bounds for type 'uint8_t[16]'".
  This commit fixes both of these issues : The latter issue
  
  is fixed by applying an offset of "+ 3" during the cast
  
  and subtracting this from the indices used lateron.
  
  The former issue is solved by not casting to av_aes_block*
  
  at all ; instead simply cast to unsigned char*.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavutil/aes.c

• How to stop ffmpeg that runs through java process

  28 avril 2021, par Ruben

  I am running ffmpeg in Java. Using p = Runtime.getRuntime().exec(command); It is used to stream video through a red5 server.

  



  My problem is that ffmpeg requires "q" to be pressed in order to stop. How can I do that ? How can I send the q character to the running process so it will execute p.destroy(); or something similar ? At the moment it runs forever until I kill the process in the task manager. I am using Windows7.