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• Split a movie so that each GIF is under a certain file size

  9 novembre 2014, par Terence Eden

  Problem

  I want to convert a long movie into a series on animated GIFs.

  Each GIF needs to be <5MB.

  Is there any way to determine how large a GIF will be while it is being encoded ?

  Progress So Far

  I can split the movie into individual frames :

  ffmpeg -i movie.ogv -r 25 frameTemp.%05d.gif

  I can then use convert from ImageMagick to create GIFs. However, I can’t find a way to determine the likely file size before running the command.

  Alternatively, I can split the movie into chunks :

  ffmpeg -i movie.ogv -vcodec copy -ss 00:00:00 -t 00:20:00 output1.ogv

  But I’ve no way of knowing if, when I convert the file to a GIF it will be under 5MB.

  A 10 second scene with a lot of action may be over 5MB (bad !) and a static scene could be under 5MB (not a problem, but not very efficient).

  Ideas

  I think that what I want to do is convert the entire movie into a GIF, then find a way to split it by file size.

  Looking at ImageMagick, I can split a GIF into frames, but I don’t see a way to split it into animated GIFs of a certain size / length.

  So, is this possible ?

• Revision 80a4f55989 : Enable background detection for adaptive quantizer control This commit enables

  17 avril 2014, par Jingning Han

  Changed Paths :
   Modify /vp9/encoder/vp9_aq_cyclicrefresh.c

  
   Modify /vp9/encoder/vp9_block.h

  
   Modify /vp9/encoder/vp9_encodeframe.c

  
  
  Enable background detection for adaptive quantizer control

  This commit enables a background detection approach for adaptive
  quantizer control. It combines the cyclic refresh pattern and the
  background information to determine the segment id for adaptive
  quantizer selection, prior to the non-RD mode decision process.
  It hence allows proper quantization information update for a more
  precise rate-distortion modeling in the non-RD mode decision.

  The compression performance of speed -5 for rtc set is improved
  by 2.5%, at no speed change.

  Change-Id : Ic3713e8ed9185b403b5b1679d19dabd57506d452

• Make video from individual frames (PNGs) and add audio track

  30 novembre 2020, par IntergalacticSpaceMonkey

  I have been working on a video processing tool that takes each frame from an input video and saves the result as a series of images. So, in essence, if my video has a length of 5 minutes, and has 25 fps, I will get 7500 individual frames.

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  What I want is then to put this back into a video format, but at the same time also add the audio track from the original source. Is this possible with ffmpeg ? Also, would it be possible to automatically determine the fps on the original video source and then use this as fps value for ffmpeg for the video + audio track in the new video file ?

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