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• ffmpeg - convert movie AND show original input (as resized picture-in-picture, top-left corner) in the final output file

  2 octobre 2019, par raven

  this is my first post on this forum, so please be gentle in case I accidentally do trip over any forum rules that I would not know of yet :).

  I would like to apply some color-grading to underwater GoPro footage. To quicker gauge the effect of my color settings (trial-and-error, as of yet), would like to see the original input video stream as a PIP (e.g., scaled down 50%), in the top-left corner of the converted output movie.

  I have one input movie that is going to be color graded. The PIP should use the original as an input, just a scaled-down version of it.

  I would like to use ffmpeg’s -filter_complex option to do the PIP, but all examples I can find on "-filter_complex" would use two already existing movies. Instead, I would like to make the color-corrected stream an on-the-fly input to "-filter_complex", which then renders the PIP.

  Is that doable, all in one go ?

  Both the individual snippets below work fine, I now would like to combine these and skip the creation of an intermediate color-graded video. Your help combining these two steps into one single process is greatly appreciated !

  Thanks in advance,
  raven.

  [existing code snippets (M$ batch files)]
  
  
  
  ::declarations/defines::
  
  set "INPUT="
  
  set "TMP="
  
  set "OUTPUT="
  
  set "FFMPG="
  
  set "QU=9" :: quality settings
  
  
  
  set "CONV='"0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 0 -1 0:0 -1 0 -1 5 -1 
  
  0 -1 0:0 -1 0 -1 5 -1 0 -1 0'"" :: sharpening convolution filter
  
  
  
  ::color-grading part::
  
  %FFMPG% -i %INPUT% -vf convolution=%CONV%,colorbalance=rs=%rs%:gs=%gs%:bs=%bs%:rm=%rm%:gm=%gm%:bm=%bm%:rh=%rh%:gh=%gh%:bh=%bh% -q:v %QU% -codec:v mpeg4 %TMP%
  
  
  
  ::PIP part::
  
  %FFMPG% -i %INPUT% -i %TMP% -filter_complex "[1]scale=iw/3:ih/3 
  
  [pip]; [0][pip] overlay=main_w-overlay_w-10:main_h-overlay_h-10" -q:v 
  
  %QU% -codec:v mpeg4 %OUTPUT%
  
  
  
  [/existing code]

• librosa can't load wav file in aws lambda docker

  30 novembre 2022, par Luka Savic

  I have an AWS Lambda function created using Docker.
I have librosa installed, ffmpeg installed using the solution from this question : install ffmpeg on amazon ecr linux python

  


  I checked in a Lambda function with os.system("ffmpeg -version") and I managed to get valid output, stating different versions and parts of ffmpeg.

  


  Problem is that when I do librosa.load(wav_file) it gives the following error :

  


  /your/path/.venv/lib/python3.9/site-packages/librosa/util/decorators.py:88: UserWarning: PySoundFile failed. Trying audioread instead.
  return f(*args, **kwargs) 


  


  From what I've read, librosa should natively support .wav files, even without ffmpeg, and even though I have ffmpeg installed, it doesn't work.

  


  One more information, .wav file was downloaded, player, and loaded with librosa on my local PC without any problems. I tried also on different wav and mp3 files, and the problems were still there.

  


• How to process video stream ?

  27 avril 2016, par sharpener

  I would like to ask some experienced multimedia professional how to proceed with following task :

  Given URL provides video stream and we would like to get access to decoded frames (byte stream in memory) in managed Win7+ application (C#). We don’t want to render/present the frames the standard way. The video format is known but not fixed (might get changed between two successive sessions, but we will know the parameters).

  So far, I have found there are several methods and I have build following picture in my mind :

  1. ffmpeg wrapper
     • Pros
       1. Self contained (no dependency to windows technologies)
       2. Powerful
     • Cons
       1. Little more complex to understand
       2. Lot of different wrapping variants (FFmpeg.NET, ffmpeg-sharp, ffmpeg-shard, FFmpeg.AutoGen, ...)
  2. DirectShow wrapper
     • Pros
       1. Widely used/supported technology (variaous filters freely available)
       2. Nice/detailed documentation on MSDN
     • Cons
       1. Quite old
       2. Considered obsolete from the point of author’s view (available only for desktop model on runtime >= Win8)
  3. MediaFoundation wrapper
     • Pros
       1. Theoretical successor of DirectShow, so should be available in the future
     • Cons
       1. Seems to be not as good as DirectShow
       2. Not very popular, limited "community" support
  4. FFmpegInterop wrapper
     • Pros
       1. Microsoft’s open source wrapper alternative
     • Cons
       1. Not available for runtime < Win8