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• Can I run ffmpeg from my Python code and return a signal when it's done compressing ?

  7 février 2016, par xavier

  Seems that what I am looking for ( a simple ffmpeg interface for python ) is not available for python 3.5. I want to run a commandline from my code that I will fill with variables like :

  video_file = "/path/to/video/video.file"
  
  sound_file = "/path/to/sound/sound.file"
  
  output_name= (video.file + 'mp4')
  
  fmpeg -loop 1 -i video_file -i sound_file -c:v libx264 -tune stillimage -c:a aac -strict experimental -b:a 192k -pix_fmt yuv420p -shortest output_name

  Is it possible to return a signal to trigger the next function that would use output_name as value to do next thing ? Is this even possible ¿ ?

• lavc/ccaption_dec : reap_screen() is responsible for clearing output buffer and signal...

  5 janvier 2016, par Aman Gupta

  lavc/ccaption_dec : reap_screen() is responsible for clearing output buffer and signaling screen_changed
  moves the screen_changed bit and the bprint_clear into reap_screen() so
  
  the logic is centralized and callers do not need to touch the bit or the
  
  buffer before calling reap_screen()
  

  • [DH] libavcodec/ccaption_dec.c

• 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