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• Can I decode this audio format ?

  30 octobre 2013, par Naftuli Tzvi Kay

  I'm writing a Python program which depends on FFMPEG to decode audio into WAV format. I'd like to be able to process as many types of audio, but I need a way to quickly check if I can actually work with the uploaded file or not. I've compiled my own FFMPEG installation here.

  Specifically, I'd like to enforce logic like this in my application :

  if ffmpeg_type(file_path) is not "audio":
  
      raise Exception("Bro, that's not an audio file.")
  
  elif not ffmpeg_can_decode_audio(file_path):
  
      raise Exception("I have no way of working with this.")

  (I realize that it wouldn't be as easy as just calling these methods, I assume I'd need to parse output from a system call.)

  Is there a way that I could use the command-line ffmpeg, ffprobe, etc. to determine if a given file is an audio file and if I can decode it ?

• Java : How to merge and cut H.264 mp4 files with ffmpeg

  15 novembre 2016, par Nico

  I wrote an java application to handle my GoPro video data. Recording for a couple of hours the GoPro produces several chapters (mp4-files). Now the program is able to cut out a sequence no matter if it is in just one chapter or it touches more. I execute the outstanding tool ffmpeg.exe with the Processbuilder.
  First the program exports the mp4-files to *.ts-files and then it merges it togehter to one only mp4-file. At least a sequence will be cut out of this merged mp4-file using ffmpeg.exe for the second time. It works quite reliable and quickly.

  But : I do not have one application in its entirely, but also I have two files (jar-Application and ffmpeg.exe). I think there is are java-libraries of ffmpeg but I do not know how to include and how to use them. I am just searching for a one-file-solution.

  Do you know which library I need and where I can download it ? How may I have to use it ? If that is not possible, do you know some other user-friendly libraries doing the same job with less lines of code ? How to use them ?

  I am very grateful about your help and the examples you will give !

• ffmpeg Muxing Recovered Files - Audio dropping

  7 avril 2020, par Chris McL

  A few years ago, we accidentally deleted all our home movies. We recovered the files from the camera. They have lost their headers and are not playable. I have used a recovery program (recover_mp4) to get an h264 and aac file.

  



  When I try to mux these together, the audio drops off from the stream. It also crackles badly at times. If I play the AAC file by itself, it sounds fine. For some movies, the audio works for a while, on others it drops out quickly.

  



  One thing I noticed is that the resulting muxed mp4 file is often shorter than the audio.

  



  I've tried various ffmpeg commands that look generally like this :

  



  ffmpeg -r 30000/1001 -i recovered_video.h264 -i recovered_audio -bsf:a aac_adtstoasc -c:v copy -c:a copy output.mp4

  



  Any ideas on how to marry the two files together ?