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• Convert pictures to live video using ffmpeg and python

  31 mars 2015, par zerzer

  I’m trying to record a live video (using H.264 codec) from a series of pictures that i receive by socket using python.

  I tried to use the MoviePy package (documentation here : github.com/Zulko/moviepy) on python to do that but i didn’t figured it out.

  If anyone have a guide on how to get started with python and saving pictures I receive as frames in real time using ffmpeg, I would really appreciate it .

  what I have is something like this , but it gives only the last captured image in the video it doesn’t save continuously the stream of images :

  from moviepy.editor import *
  
  import numpy as np
  
  
  
  while True:
  
     data = sock.recv()
  
     image = np.fromstring(data)
  
     folder = [image] 
  
     cv = ImageSequenceClip(folder, fps = 1)
  
     cv.write_videofile("video.mp4")

• ffmpeg options that work with Chrome

  21 avril 2015, par James

  I am trying to find the magic options that make mp4 work in Chrome. I think my videos were working, but don’t seem to any more after Chrome updated.

  Chrome, Version 41.0.2272.101 (Windows)

  I tried some other machines and found some of the videos worked on older versions, and my Mac seems to still work on the latest Chrome.

  I am using the ffmpeg options to convert from png series,

  ffmpeg -framerate 10 -i dance%02d.png  -r 10 -pix_fmt yuv420p dance.mp4

  Some videos work, some don’t, some work some of the time, or stop half way through.

  I tried various other options like,

  ffmpeg -start_number 16 -framerate 10 -i dance%02d.png -r 10 -an -s hd720 \
  
  -vcodec libx264 -pix_fmt yuv420p -preset slow -profile:v baseline \
  
  -movflags faststart -y dance.mp4

  but this just seemed to make things worse.

  here is one of the videos,
  http://www.botlibre.com/media/a786625.mp4

  and another one,
  http://www.botlibre.com/media/a812450.mp4

  Firefox seems to work no problem, on any version, grey background though.
  IE works fine, white background.
  Safari works, grey background.

  Another thing, they videos used to have white background on older Chrome version, but now are grey, except on Mac still white.

  and one more thing. Webm format works, but anyone know the option to remove transparency ? I’m using,

  ffmpeg -i dance%02d.png  -r 10 -c:v libvpx -crf 10 -b:v 512k -c:a libvorbis dance.webm

  just want a solid white background.

• Flash player seek not working when ffmpeg encoded with gop(-g) = 1 [migrated]

  3 mars 2015, par Brian

  I am trying to deliver video content with frame-by-frame viewing via the SMP Flash player. For encoding, I am using FFMPEG with the x264 video codec for files with .mp4 containers. I am using the latest ffmpeg build and using the OSMF SMP flash video player.

  I am taking a series of png files and creating a .mp4 file :

  ffmpeg -nostdin -loglevel warning  -i out.%d.png -g 1 -crf 15 -c:v libx264 -movflags faststart -pix_fmt yuv420p -r 24 out.mp4

  By encoding with the gop(-g) flag = 1, I am encoding to make each frame a keyframe. When I seek using the scrub bar of the SMP flash player, it always seeks to the start of the video. If I play and scrub/seek the video using the default HTML player, it works perfectly.

  When I encode with the gop(-g) flag = 2, the SMP Flash player scrubs/seeks and plays correctly.

  It looks like there may be some kind of bug or incompatibility with the Flash player. I have found this problem mentioned back in 2009. I think my only hope is to find a work around. Any suggestions ?