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• How to find mp4 metadata with ffmpeg-light in haskell ?

  21 décembre 2015, par Noughtmare

  I’m using ffmpeg-light, JuicyPixels and gloss to display a video with Haskell. I want to find the metadata of videos I’m playing automatically, but I have not yet found a way to do so.

  I would like to access metadata like the resolution and the framerate of the video.

  Can you help me ?

  EDIT :

  I have tried your solution @CRDrost, but the video is now playing at 2x normal speed. I assume the function imageReaderTime is giving the wrong timestamps.

  EDIT 2 :

  The abnormal playing speed is a bug in the ffmpeg-light library. I’ve opened an issue at the github repository.

  My updated code :

  import Graphics.Gloss
  
  import Codec.FFmpeg
  
  import Codec.FFmpeg.Juicy
  
  import Codec.Picture
  
  import Control.Applicative
  
  import Data.Maybe
  
  import Graphics.Gloss.Juicy
  
  import Control.Monad
  
  -- import System.IO.Unsafe (unsafePerformIO)-- for debugging purposes
  
  
  
  resolution :: (Int,Int)
  
  resolution = (640, 360)
  
  
  
  frameCount :: Int
  
  frameCount = 100
  
  
  
  main :: IO ()
  
  main = do
  
      initFFmpeg
  
      (getFrame, cleanup) <- imageReaderTime "big_buck_bunny.mp4"
  
      frames <- replicateM frameCount $ nextFrame getFrame
  
      cleanup
  
      animate (InWindow "Nice Window" resolution (10,10)) white (frameAt frames)
  
  
  
  nextFrame :: IO (Maybe (Image PixelRGB8, Double)) -> IO (Picture, Float)
  
  nextFrame getFrame = mapSnd realToFrac . mapFst fromImageRGB8 . fromJust <$> getFrame
  
  
  
  frameAt :: [(Picture, Float)] -> Float -> Picture
  
  frameAt list time = fst . head . dropWhile ((< time) . snd) $ list
  
  
  
  mapFst :: (a -> c) -> (a, b) -> (c, b)
  
  mapFst f (a, b) = (f a, b) -- applies f to first element of a 2-tuple
  
  
  
  mapSnd :: (b -> c) -> (a, b) -> (a, c)
  
  mapSnd f (a, b) = (a, f b) -- applies f to the second element of a 2-tuple

• Discord music Bot Python starts ffmpeg, green light appears around bot but no audio plays [closed]

  27 avril 2023, par QuestionHaver99

  I've tried using FFmpegOpusAudio and FFMPEGPCMaudio instead, but it gives the same issue. FFMPEG starts and the green light of the bot in the channel shows, but no audio plays, and then the bot exits the channel when the song should be over and FFMPEG terminates. I've tried streaming the audio and playing from a local file, and the same issue.

  


  and just as a quick checklist of confirmed not the issues : the volume is fine and the permissions are fine and ffmpeg is in environment variables and set up correctly.

  


  any advice would be greatly appreciated

  


• Install ffmpeg-light with cabal

  20 septembre 2016, par WirflBirfl

  I want to install the ffmpeg-light library from hackage via cabal on Windows 10 (64 bit). So I downloaded ffmpeg and extracted it to C :\FFmpeg.

  At first pkg-config was complaining that it could not find various packages. I solved this problem with .pc files.

  When I tried to use the command : cabal install ffmpeg-light cabal complained about missing C-libraries, being exactly those for which I created the .pc files.

  Then I tried the command : cabal install ffmpeg-light --extra-lib-dirs=C:\FFmpeg\lib. Now I have a different error message, which says :

  Enums.hsc:7:32: fatal error: libavcodec/avcodec.h: No such file or directory

  Edit :
  Then I tried the following command :

  cabal install ffmpeg-light --extra-lib-dirs=C:\FFmpeg\lib \
  
                             --extra-include-dirs=C:\FFmpeg\include

  Now first the compiler gives some warnings about deprecated functions in ffmpeg and redundant imports in ffmpeg-light, but compiles 11 of 11. But the build is still not successfull.

  In-place registering ffmpeg-light-0.11.1...
  
  setup-Simple-Cabal-1.22.5.0-x86_64-windows-ghc-7.10.3.exe:
  
  'C:\Haskell\bin\ghc-pkg.exe' exited with an error:
  
  ffmpeg-light-0.11.1: Warning: haddock-interfaces:
  
  C:\Users\HOLEYC~1\AppData\Local\Temp\cabal-tmp-2824\ffmpeg-light-0.11.1\dist\doc\html\ffmpeg-light\ffmpeg-light.haddock
  
  doesn't exist or isn't a file
  
  ffmpeg-light-0.11.1: Warning: haddock-html:
  
  C:\Users\HOLEYC~1\AppData\Local\Temp\cabal-tmp-2824\ffmpeg-light-0.11.1\dist\doc\html\ffmpeg-light
  
  doesn't exist or isn't a directory
  
  ffmpeg-light-0.11.1: library-dirs: C:FFmpeglib is a relative path which makes
  
  no sense (as there is nothing for it to be relative to). You can make paths
  
  relative to the package database itself by using ${pkgroot}. (use --force to
  
  override)
  
  ffmpeg-light-0.11.1: include-dirs: C:FFmpeginclude is a relative path which
  
  makes no sense (as there is nothing for it to be relative to). You can make
  
  paths relative to the package database itself by using ${pkgroot}. (use
  
  --force to override)
  
  cabal: Error: some packages failed to install:
  
  ffmpeg-light-0.11.1 failed during the building phase. The exception was:
  
  ExitFailure 1

  Some additional information :

  cabal version: cabal-install version 1.22.6.0
  
  using version 1.22.5.0 of the Cabal library
  
  gcc version of my installed Haskell platform: 5.2.0

  Example .pc file I used for pkg-config :

  Name: libavcodec
  
  Description: Library for ffmpeg
  
  Version: 57
  
  Cflags: -IC:\FFmpeg\include
  
  Libs: -LC:\FFmpeg\lib -llibavcodec