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• RoQ decoder: Remove misleading diagnostics.

  29 January 2014, by addr-see-the-website@aetey.se

  RoQ decoder: Remove misleading diagnostics.
  It is not necessarily an error when a chunk does not cover a whole block.
  
  Messages did not reflect the actual situation either.
  Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavcodec/roqvideodec.c

• How to create an animated GIF using FFMPEG with an interval?

  26 October 2014, by Jeff Wilbert

  Hello fellow overflowers,

  A brief overview of what I’m trying to accomplish; I have a site that will accept video uploads, uploads get converted into the mp4 format to be uniformed and playable on the web using one of the many available players. That part is all fine and dandy.

  The problem now is I want to show the user a short scaled preview (animated gif) of the video before they click to play it. The code I’m working with now is

  ffmpeg -i test.mp4 -vf scale=150:-1 -t 10 -r 1 test.gif

  Which works for creating a scaled animated gif with a fixed width of 150px at a rate of 1 frame per second but its only an animation of the first 10 seconds of the video. I’m trying to do something that spreads out the frame gap to cover the whole video length but create an animated gift that’s no more then 10 seconds long.

  For example say I have a video that’s 30 seconds I want the gif to be 10 seconds long but cover frames of the entire 30 seconds so it might start at frame 3 or 3 seconds in and create a frame in the gif, then at 6 seconds in the video create another frame, then 9 seconds in another, and so forth where the final outcome is

      example video 30 seconds long          example video 1 minute 45 second long 
  
  
  
  video position - gif frame/per second      video position - gif frame/per second
  
        00:03:00   1                               00:10:50   1
  
        00:06:00   2                               00:21:00   2
  
        00:09:00   3                               00:31:50   3
  
        00:12:00   4                               00:42:00   4
  
        00:15:00   5                               00:52:50   5
  
        00:18:00   6                               01:03:00   6
  
        00:21:00   7                               01:13:50   7
  
        00:24:00   8                               01:24:00   8
  
        00:27:00   9                               01:34:50   9
  
        00:30:00   10                              01:45:00   10
  
  
  
    3 second interval between frames         10.5 second interval between frames

  Where you end up with an animated gif that’s 10 seconds long showing a preview of the entire video no matter the length of it. Which basically just boils down to
  video length / 10 (length of desired animated gif) = interval to use between frames but I don’t know how I can use that data to accomplish my problem...

  So does anyone have an idea or suggestion on how this can be accomplished with relative ease? I can probably do it by calculating the length through code and running a command to extract each individual frame from the video that’s needed then generate a gif from the images but I’d like to be able to do it all with just one command. Thanks.

• alpha/blockdsp: move clear_blocks out of dsputil

  19 June 2014, by James Almer

  alpha/blockdsp: move clear_blocks out of dsputil
  The blockdsp split did not cover Alpha optimizations
  Signed-off-by: James Almer <jamrial@gmail.com>
  
  Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavcodec/alpha/Makefile
  • [DH] libavcodec/alpha/blockdsp_alpha.c
  • [DH] libavcodec/alpha/dsputil_alpha.c
  • [DH] libavcodec/blockdsp.c
  • [DH] libavcodec/blockdsp.h