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• Merging 3 separate commands into one that re-encodes a video, extracts a thumbnail, delete original and rename new video in subdirectories

  16 janvier 2017, par Ali Samii

  I am trying to execute a find bash command to process hundreds of video files that are all named video-original.mp4 but are in subdirectories of a parent directory.

  Here’s an example of the directory structure :

  videos
  
  ├── 01a
  
  │   └── video-original.mp4
  
  ├── 01b
  
  │   └── video-original.mp4
  
  ├── 02a
  
  │   └── video-original.mp4
  
  ├── 02b
  
  │   └── video-original.mp4
  
  ├── 03a
  
  │   └── video-original.mp4
  
  └── 03b
  
      └── video-original.mp4

  I am using the following command :

  find ./ -name 'video-original.mp4' -exec bash -c 'ffmpeg -i "$0" -f mp4 -vcodec libx264 -preset veryslow -profile:v high -acodec aac -movflags faststart video.mp4 -hide_banner' {} \;

  The problem I am having is that it is saving the file video.mp4 in the parent videos directory, instead of in the subdirectory next to the original video-original.mp4

  Afterwards, I want to delete the file video-original.mp4. Currently, my process entails waiting for all the videos to be reencoded, and then once complete, issuing a separate command to delete the file video-original.mp4 :

  find ./ -name 'video-original.mp4' -exec bash -c 'rm -rf "$0"' {} \;

  And my final step would be to extract a screenshot of the new video.mp4 at 10 seconds and save it as thumbnail.jpg. Again, I am currently doing that as a separate step that I execute after the previous two steps are completed.

  find ./ -name 'video.mp4' -exec bash -c 'ffmpeg -i "$0" -ss 00:00:10 -vframes 1 thumbnail.jpg' {} \;

  What I would like to do is combine these three steps into a single command so the end result will be :

  videos
  
  ├── 01a
  
  │   ├── thumbnail.jpg
  
  │   └── video.mp4
  
  ├── 01b
  
  │   ├── thumbnail.jpg
  
  │   └── video.mp4
  
  ├── 02a
  
  │   ├── thumbnail.jpg
  
  │   └── video.mp4
  
  ├── 02b
  
  │   ├── thumbnail.jpg
  
  │   └── video.mp4
  
  ├── 03a
  
  │   ├── thumbnail.jpg
  
  │   └── video.mp4
  
  └── 03b
  
      ├── thumbnail.jpg
  
      └── video.mp4

  Finally, it would be great to save that as a bash script and include it in my path in /usr/local/bin or ~/bin as an executable so I could just issue the command reencode and it would run. Would be even better if the input file could have any video file, for example, random_name.mp4 or random_name.mov or random_name.webm, basically any video file (but skipping video.mp4 at the encoding step).

• creating FFMPEG-based android apps with BAMBUSER

  22 novembre 2013, par Blaze Tama

  First, im a beginner in FFMPEG so please bear with me.

  And more, my java is not a "master", and i only have a very little experience in C.

  I interested in bambuser's ffmpeg library but theres still some doubt in my mind :

  1. Dont they have any step by step tutorial ? The only tutorial i found, which is good but not suitable for beginner is http://www.quora.com/What-are-the-steps-for-integrating-FFMPEG-on-Android#
  2. DO I HAVE TO CODE IN C ? Sorry this might be a stupid question..but ehm i dont really understand what im doing and where im going...LOL
     What i mean is, can i just use FFMPEG syntax like -i, -vf and run it inside my apps like in the ubuntu's terminal ?

  Im well aware that this question should not be suitable for SO, but i have no choice. I have tried to use many different lbraries, like GUARDIAN PROJECT (well, i have the UNSOLVED question here) but its not working like i hope.

  Thanks very much for your time, and your help. Please help me here, its alreay a month LOL :D

• How to calculate the "Range" header for mp4 file to play/download a part of it ? [youtube-dl]

  5 décembre 2016, par supersan

  I’m using youtube-dl to download videos from YouTube. Unfortunately, sometimes I just need to download a part of the video like 10 seconds of a 3 hour video and here is how I see I can do it.

  Step 1 : Get the URL of the mp4 file from youtube-dl.

  youtube-dl -g -f "[ext=mp4]" https://www.youtube.com/watch?v=qOZ1u9VpoMk

  This returns $url : the full URL of mp4 file on server.

  Step 2 : Download part of the video using curl

  curl -r $startBytes-$endBytes $url

  But how to calculate $startBytes and $endBytes. What is the formula for that ?

  P.S I was thinking could be something as simple but this isn’t it..

  $startBytes = (total_size_of_video / total_length_of_video_secs) * start_seconds

  P.P.S. When I play the mp4 video in Chrome and use the scrub bar to jump around in the video, Chrome too send the Range header to the same URL (as I can see in fiddler)