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• FFprobe (part of FFmpeg) command output to variable in a Windows Batch File [duplicate]

  12 décembre 2017, par Bazza DownUnder

  This question already has an answer here :

  • batch store ffprobe as variable
    
    1 answer
    

  I want to capture the Audio codec in a variable when I execute an FFprobe command within a batch file.

  The FFprobe command when executed on its own :

  ffprobe "myvideo.mkv" -v error -select_streams a:0 -show_entries stream=codec_name -of default=noprint_wrappers=1:nokey=1

  Results in :

  aac

  I want to check if the audio codec of the video is aac. If so then no need to convert the videos audio.

  This is the bat file :

  @echo off
  
  
  
  for %%f in (*.%1) do (
  
  
  
      (Echo "%%f" | FIND /I ".srt" 1>NUL) || (
  
  
  
  
  
          For /F %%I in ('ffprobe "%%~nf.%1" -v error -select_streams a:0 -show_entries stream=codec_name -of default=noprint_wrappers=1:nokey=1') Do Set StrCodecs=%%I
  
  
  
          echo Audio Codecs = %StrCodecs%
  
  
  
          echo Creating "New\%%~nf.%1"
  
          ffmpeg -i "%%~nf.%1" -loglevel panic -movflags +faststart -c:v copy -c:a aac -b:a 384k "New\%%~nf.%1"
  
          echo Done with "New\%%~nf.%1"
  
      )
  
  )

  The error I get with above is :

  Argument ’codec_name’ provided as input filename, but ’myvideo.mkv’
  was already specified.

  Even if I remove the single quotes, those in the brackets just after in, and have it look like this :

  For /F %%I in (ffprobe "%%~nf.%1" -v error -select_streams a:0 
  
  -show_entries stream=codec_name -of default=noprint_wrappers=1:nokey=1) 
  
  Do Set StrCodecs=%%I

  The result is :

  The system cannot find the file ffprobe.

  Audio Codecs = Creating

  "New\myvideo.mkv"

  Everything else works in the bat file.

• H264 decoder in opencv for real time video transmission

  4 avril 2014, par Narendra

  I am writing a client-server application which does real time video transmission from an android based phone to a server. The captured video from the phone camera is encoded using the android provided h264 encoder and transmitted via UDP socket. The frames are not RTP encapsulated. I need it to reduce the overhead and hence the delay.
  On the receiver, I need to decode the incoming encoded frame. The data being sent on the UDP socket not only contains the encoded frame but some other information related to the frame as a part of its header. Each frame is encoded as an nal unit.

  I am able to retrieve the frames from the received packet as a byte array. I can save this byte array as raw h264 file and playback using vlc and everything works fine.
  However, I need to do some processing on this frame and hence need to use it with opencv.
  Can anyone help me with decoding a raw h264 byte array in opencv ?
  Can ffmpeg be used for this ?

• H264 decoder in opencv for real time video transmission

  30 mai 2019, par Narendra

  I am writing a client-server application which does real time video transmission from an android based phone to a server. The captured video from the phone camera is encoded using the android provided h264 encoder and transmitted via UDP socket. The frames are not RTP encapsulated. I need it to reduce the overhead and hence the delay.
  On the receiver, I need to decode the incoming encoded frame. The data being sent on the UDP socket not only contains the encoded frame but some other information related to the frame as a part of its header. Each frame is encoded as an nal unit.

  I am able to retrieve the frames from the received packet as a byte array. I can save this byte array as raw h264 file and playback using vlc and everything works fine.
  However, I need to do some processing on this frame and hence need to use it with opencv.
  Can anyone help me with decoding a raw h264 byte array in opencv ?
  Can ffmpeg be used for this ?