Recherche avancée

Sur d’autres sites (7161)

• Python, FFMPEG : Redirecting output of FFMPEG subprocess call to a string

  31 décembre 2019, par user1452030

  I’ve managed to run an FFMPEG command using the subprocess module as shown below :

  output = subprocess.check_output(command, shell=True)

  This works fine, but it prints the verbose FFMPEG output to console. The program I’m writing is supposed to run for hundreds/thousands of files in a batch and I don’t want detailed outputs for every file processed, unless the user chooses to do so. Can I redirect the console outputs and errors to strings, so that I can decide when I should and shouldn’t print them ?

  This might be lame, but I tried the following snippet :

  outputBuffer = BytesIO()
  
  output = subprocess.check_output(command, shell=True, stdout=outputBuffer)

  But it gave me the following error :

  ValueError: stdout argument not allowed, it will be overridden.

  I saw other examples where the POpen interface was used, but given that I’m not communicating with the external command as it is running, and that I need to run this for a large number of items, I’d prefer something simpler, if possible.

  Thanks in advance !

  Note : I’ve found lots of questions in this broad topic, but I couldn’t find anything perfectly relevant to my situation.

• What's the best way to get video metadata from a video file in ASP.Net MVC using C# ?

  15 mars 2021, par Maddhacker24

  I've been searching on Google and StackOverflow for a good couple of hours. There seems to be a lot of similar questions on StackOverflow but they are all about 3-5 years old.

  



  Is using FFMPEG still the best way these days to pull metadata from a video file in a .NET web application ? And if so, what's the best C# wrapper out there ?

  



  I've tried MediaToolkit, MediaFile.dll without any luck. I saw ffmpeg-csharpe but that looks like it hasn't been touched in a few years.

  



  I haven't found any current data on this subject. Is the ability to pull metadata from a video built into the latest version of .NET now ?

  



  I'm basically looking for any direction at this point.

  



  I should add that whatever I use could be invoked thousands of times per hour so it will need to be efficient.

  


• ffmpeg can't transcode DVD ac3 audio stream, but VLC can play it

  21 février 2020, par RalphORama

  I’m attempting to transcode a DVD to a single MKV file. I’ve had success in the past with other DVDs, but I’m running into an error I haven’t seen before.

  First I concatenate the VOB files I want to transcode :

  cat VTS_02_1.VOB VTS_02_2.VOB VTS_02_3.VOB > WMAV.VOB

  ffprobe output :

  $ ffprobe -analyzeduration 100M -probesize 100M WMAV.VOB                                                                         Input #0, mpeg, from 'WMAV.VOB':
  
    Duration: 01:05:19.42, start: 0.300300, bitrate: 5686 kb/s
  
      Stream #0:0[0x1bf]: Data: dvd_nav_packet
  
      Stream #0:1[0x1e0]: Video: mpeg2video (Main), yuv420p(tv, smpte170m, top first), 720x480 [SAR 32:27 DAR 16:9], 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
  
      Stream #0:2[0x80]: Audio: ac3, 48000 Hz, stereo, fltp, 192 kb/s
  
  Unsupported codec with id 100357 for input stream 0

  Then I run this command to transcode the file :

  ffmpeg -analyzeduration 100M -probesize 100M \
  
    -i WMAV.VOB \
  
    -map 0:1 -map 0:2 \
  
    -c:v libx264 -preset slow -tune film -crf 21 \
  
    -c:a aac -b:a 192k \
  
    wmav.mkv

  However, when I include -c:a aac, I get thousands of errors like this :

  Error while decoding stream #0:2: Error number -16976906 occurred
  
  [ac3 @ 000002bd24d8eec0] expacc 127 is out-of-range
  
  [ac3 @ 000002bd24d8eec0] error decoding the audio block

  There doesn’t seem to be any issue with the audio stream since it plays back fine in VLC. The transcode succeeds if I use -c:a copy.

  What is causing this error and how could I fix the problem ?