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• ffmpeg does not follow vframes

  15 décembre 2020, par oo92

  I'm trying to take screenshots of Twitch streams through the API using ffmpeg. I want to take 500 screens per category but I am getting an average of 50 screenshots. This is what I have :

  


  username = streams_now[i]['channel']['name']
id = streams_now[i]['id']
game = streams_now[i]['game']
game = game.translate(str.maketrans({':':'-', ' ':'-', "'":'', '!':'', '&':'_', '.':'', '+':'_'}))
streaming = streamlink.streams('http://twitch.tv/' + username)
stream = streaming["best"].url
dir_path = current_dir + '/logorec-dataset/' + game
os.mkdir(dir_path)

subprocess.call('ffmpeg -i ' + stream + f' -ss 20 -threads 2 -vframes 500 -r 1 -f image2 -strftime 1 {dir_path}/%Y%m%d%H%M%S_' + str(id) +'_'+ '.jpg&', shell=True)



  


• Concatenation and Transcoding of MPEG-TS files FFMPEG

  20 décembre 2020, par SquawkBirdies

  I have a DVR which records over-the-air TV and saves the recordings in the MPEG-TS format, splitting each episode across multiple files, each 500 MB in size.

  



  To simplify archiving, I have been trying to write a shell script to automate the process of concatenating the files together and transcoding them into a more common video format, like h.264.

  



  Here are the steps I have performed so far :

  



  

  • I wanted to make sure that the files I was getting were valid in the first place. To test this, each section was transcoded in Handbrake before being merged using ffmpeg's concat command. This worked, but was manual and added an annoying black frame between each section.

  


  • I wrote a shell script to find all the sections of an episode in a folder and put the file names into a text file that the concat demuxer could parse.

  


  • Tested this command :

  


  



  


  


  ffmpeg -hide_banner -f concat -i video_files_tmp.txt -c:v libx264 -pix_fmt yuv420p -c:a aac $2$OUTPUT_FILE_NAME

  


  


  




  During the transcode, this would throw many warnings and errors, such as "PES packet size mismatch". At some point, it would warn that more than 1,000 frame were skipped. When the output was played, it would skip frames and result in a file where the video froze partway through but the audio continued playing. I tried adding -vsync 0 to the output as well.

  



  

  • Then, tried splitting the concatenation and transcode into two steps :

  


  



  


  


  ffmpeg -hide_banner -f concat -i video_files_tmp.txt -c copy output_tmp.ts
ffmpeg -hide_banner -i output_tmp.ts -c:v libx265 -pix_fmt yuv420p -c:a aac $2$OUTPUT_FILE_NAME

  


  


  




  This did basically the same thing as before.

  



  

  • Tried using the libx265 encoder instead. Same result.

  


  • Then, I tried just playing the concatenated MPEG-TS file directly, which also would freeze at some point during the playback.

  


  



  I was wondering about what ffmpeg flags or options to set to get this working, or other options I could try ? Thanks !

  


• exec() with SuPHP and SafeMode Off (php.ini local) show wrong path and fail execution

  29 juillet 2013, par abkrim

  Try this

  <?php
  
       if (exec('/usr/bin/ffmpeg -i 47.mp4 -acodec aac -ab 128kb -vcodec mpeg4 -b 1220kb -mbd 1 -s 320x180 final_video.mov"'))
  
           { echo "Success"; }
  
       else { echo "No good"; }
  
  ?>

  But on shell see—>

  sh: /usr/local/php/bin/ffmpeg: No such file or directory

  Server it's Apache+SuPHP with a local php.ini file for disable SafeMode

  I don't understand why show sh : /usr/local/php/bin/ffmpeg : No such file or directory instead real path put on php script.