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• Playing 120fps in browser between original and re-made video, original is normal speed, new video is slo-mo

  1er mars 2023, par Patrick Vellia

  I used my GoPro Hero10 to record at 4k 120fps on a green screen. This original video plays slo-mo in QuickTime but "normal" speed in the browser. I want it playing normal speed, and if end user wants to slow it down they have the extra frames for that to maintain clarity, which is why I record at 120.

  


  I then used FFMPEG to create an image sequence of the video.

  


  Then I ran Image Magic to create the transparent frames.

  


  Then I put it back together with the following command for a HEVC mov file :

  


  ffmpeg -r 120 -f image2 -i transparent/image_transparent_%08d.png -vcodec hevc_videotoolbox -crf 28 -alpha_quality 1  -tag:v hvc1 output.mov


  


  I am still on an Intel MacBook Pro running FFMPEG 4.6 (as I've found 5+ was buggy with one of my commands a few months ago but can't remember which one, I think it was the videotoolbox).

  


  The GoPro video has the following stream data as input to the FFMPEG :

  


  Duration: 00:00:08.15, start: 0.000000, bitrate: 60160 kb/s
  Stream #0:0(eng): Video: hevc (Main) (hvc1 / 0x31637668), yuvj420p(pc, bt709), 3840x2160 [SAR 1:1 DAR 16:9], 59891 kb/s, 119.88 fps, 119.88 tbr, 120k tbn, 119.88 tbc (default)
    Metadata:
      creation_time   : 2023-02-28T19:06:41.000000Z
      handler_name    : GoPro H.265
      vendor_id       : [0][0][0][0]
      encoder         : GoPro H.265 encoder
      timecode        : 19:05:32:105
  Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 189 kb/s (default)
    Metadata:
      creation_time   : 2023-02-28T19:06:41.000000Z
      handler_name    : GoPro AAC  
      vendor_id       : [0][0][0][0]
      timecode        : 19:05:32:105
  Stream #0:2(eng): Data: none (tmcd / 0x64636D74), 0 kb/s (default)
    Metadata:
      creation_time   : 2023-02-28T19:06:41.000000Z
      handler_name    : GoPro TCD  
      timecode        : 19:05:32:105
  Stream #0:3(eng): Data: bin_data (gpmd / 0x646D7067), 76 kb/s (default)
    Metadata:
      creation_time   : 2023-02-28T19:06:41.000000Z
      handler_name    : GoPro MET  


  


  Whereas the re-constructed video has the following data :

  


  Duration: 00:00:08.13, start: 0.000000, bitrate: 763650 kb/s
  Stream #0:0: Video: hevc (Main) (hvc1 / 0x31637668), yuv420p(tv, progressive), 3840x2160 [SAR 1:1 DAR 16:9], 763696 kb/s, 120 fps, 120 tbr, 15360 tbn, 15360 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      vendor_id       : FFMP
      encoder         : Lavc58.134.100 hevc_videotoolbo


  


  When this re-constructed video plays in the browser, it is in slow-mo and I need to set the playbackRate to 4.0 for it to play "normally".

  


  Is there something I need to add to the video for the browser to play it at "normal" speed ?

  


• Revision 36317 : Il y a certains cas où l’on ne peut pas passer par revision_mot notamment ...

  16 mars 2010, par kent1@… — Log

  Il y a certains cas où l’on ne peut pas passer par revision_mot notamment si on s’insère dans un formulaire d’édition d’article dans un pipeline pre_edition ... On ne passe pas la gestion des conflits dans ce cas là

• Add support for playing Audible AAXC (.aaxc) files [PATCH v4]

  1er janvier 2000, par Vesselin Bontchev

  Add support for playing Audible AAXC (.aaxc) files [PATCH v4]
  The AAXC container format is the same as the (already supported) Audible
  
  AAX format but it uses a different encryption scheme.
  Note : audible_key and audible_iv values are variable (per file) and are
  
  externally fed.
  It is possible to extend https://github.com/mkb79/Audible to derive the
  
  audible_key and audible_key values.
  Relevant code :
  def decrypt_voucher(deviceSerialNumber, customerId, deviceType, asin, voucher) :
  
      buf = (deviceType + deviceSerialNumber + customerId + asin).encode("ascii")
  
      digest = hashlib.sha256(buf).digest()
  
      key = digest[0:16]
  
      iv = digest[16 :]
      # decrypt "voucher" using AES in CBC mode with no padding
  
      cipher = AES.new(key, AES.MODE_CBC, iv)
  
      plaintext = cipher.decrypt(voucher).rstrip(b"\x00")  # improve this !
  
      return json.loads(plaintext)
  The decrypted "voucher" has the required audible_key and audible_iv
  
  values.
  Update (Nov-2020) : This patch has now been tested by multiple folks -
  
  details at the following URL :
  https://github.com/mkb79/Audible/issues/3
  Signed-off-by : Vesselin Bontchev <vesselin.bontchev@yandex.com>
  

  • [DH] libavformat/isom.h
  • [DH] libavformat/mov.c