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• Piping input AND output of ffmpeg in python

  16 mai 2017, par bluesummers

  I’m using ffmpeg to create a video, from a list of base64 encoded images that I pipe into ffmpeg.

  Outputting to a file (using the attached code below) works perfectly, but what I would like to achieve is to get the output to a Python variable instead - meaning piping input and piping output but I can’t seem to get it to work

  My current code :

  output = os.path.join(screenshots_dir, 'video1.mp4')
  
  
  
  cmd_out = ['ffmpeg',
  
             '-y',  # (optional) overwrite output file if it exists
  
             '-f', 'image2pipe',
  
             '-vcodec', 'png',
  
             '-r', str(fps),  # frames per second
  
             '-i', '-',  # The input comes from a pipe
  
             '-vcodec', 'png',
  
             '-qscale', '0',
  
             output]
  
  
  
  pipe = sp.Popen(cmd_out, stdin=sp.PIPE)
  
  
  
  for screenshot in screenshot_list:
  
      im = Image.open(BytesIO(base64.b64decode(screenshot)))
  
      im.save(pipe.stdin, 'PNG')
  
  
  
  pipe.stdin.close()
  
  pipe.wait()

  This results in a working mp4, but I would like to avoid saving to local.

  Running the same code with changing output to '-' or 'pipe:1' and adding stdout=sp.PIPE results in an error

  [NULL @ 0x2236000] Unable to find a suitable output format for ’pipe :’

• ffmpeg - Not outputting Opus audio

  3 mars 2016, par Dustin

  I’m currently writing a small script that coverts an MP4 to Opus audio on the fly and sends it to Discord in golang. Initially my script would pass an MP4 as it was downloading to ffmpeg through stdin and then pass stdout to an Opus encoder, then to Discord (exactly like this). After learning I could build ffmpeg with Opus, I’d like to cut out the opus encoder I previous had and pass ffmpeg’s output directly to Discord.

  Previous, my ffmpeg command looked like this (with using the second opus encoder)

  ffmpeg -i - -f s16le -ar 48000 -ac 2 pipe:1

  Now, without the encoder and letting ffmpeg do all the work, this is what I’ve come up with so far.

  ffmpeg -i - -f s16le -ar 48000 -ac 2 -acodec libopus -b:a 192k -vbr on -compression_level 10 pipe:1

  With this command however the audio doesn’t get accepted by Discord’s server, meaning I’m suspecting opus audio isn’t coming out the other end. No errors outputted. Have I done something wrong with ffmpeg that could of caused this ?

• Building FFMPEG library for iOS5.1 ARMv7

  25 octobre 2012, par Jimmy

  I'm trying to use the FFMPEG library in an XCode 4.5.1 project. And I'm trying to build it for ARMv7

  But I'm running into some major issues, I'm hoping that someone can walk me through how to do it ? I feel a little sketched out reading material thats a couple months old. I'm not aware of the changes.

  New Update (after a lot of time)

  I want to help everyone out that is having this problem because its so frustrating. heres how you do it. I've pasted the configuration stage. This is my ./configure

  ./configure --disable-doc --disable-ffmpeg --disable-ffplay --disable-ffserver --enable-cross-compile --arch=arm --target-os=darwin
  
     --cc=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/llvm-gcc-4.2/bin/arm-apple-darwin10-llvm-gcc-4.2
  
     --as='gas-preprocessor/gas-preprocessor.pl /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/llvm-gcc-4.2/bin/arm-apple-darwin10-llvm-gcc-4.2'
  
     --sysroot=/applications/xcode.app/contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk
  
     --cpu=cortex-a8
  
     --extra-ldflags='-isysroot /applications/xcode.app/contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk'
  
     --enable-pic
  
     --disable-bzlib --disable-gpl --disable-shared --enable-static --disable-mmx --disable-debug --disable-neon
  
     --extra-cflags='-pipe -Os -gdwarf-2 -isysroot /applications/xcode.app/contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk -m${thumb_opt:-no-thumb} -mthumb-interwork'

  This ended up working for me. I had the following problems.

  • I had to download ( https://github.com/yuvi/gas-preprocessor ) copy the file gas-preprocessor.pl at /usr/local/bin. Set permissions to read write (777)
  • Make sure I'm using the right GCC compiler : /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/llvm-gcc-4.2/bin/arm-apple-darwin10-llvm-gcc-4.2
  • Make sure I'm using the right SDK : /applications/xcode.app/contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.1.sdk
  • —extra-cflags="-arch armv7" causes bugs in the configure. take it out. This was causing my gcc compile errors. (specifically this one : error : unrecognized command line option “-arch”.)

  I'll let you guys know how much further I get.