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• FFmpeg zoom not smooth-centered (but zigzag)

  10 juin 2016, par SebSob

  I try to perform a basic zoompan with FFmpeg. I have an input image (.png 1280x720) and i create an 8 seconds video (.mp4 320x180) from it, with a zoom. This is my command :

  ffmpeg -loop 1 -i in_img.png -c:v libx264 -pix_fmt yuv420p -strict experimental -framerate 25 -vf zoompan=z=’min(zoom+0.011835363,2.1835363)’:d=375:x=400:y=247 -s 320x180 -t 00:00:08.882 out_vid.mp4

  Everything works...but the zoom is not looking okay. It is going zig-zag.

  Does anyone know how to make it zoom smooth, like centered ? (And not first left then right)

  Thanks

  EDIT

  ---

  I’ve come a small step closer to a solution by slightly modifying the ’x’ and ’y’ in the -vf filter (rest of the command is the same as above) :

  -vf
  zoompan=z=’min(zoom+0.022,3.25)’:d=375:x=’if(gte(zoom,3.25),x,x+8.24)’:y=’if(gte(zoom,3.25),y,y+4.72)’:s=1280x720

  I incement x and y every frame (for x +8.24, for y +4.72, i know those values because i know how many frames it takes get to the end-zoom state) so that it will move to its end zoom state coordinate (1011,582), see image :

  
  This is the video of the result, as you can see it does not do the zig-zag effect, but now it looks like its going first to the center and then to the zoomed result. Or is that only an illusion ??
  Any idea’s ?

• HTTP Live streaming iOS not refreshing the index .m3u8 file

  27 février 2013, par Emerson Fittipaldi

  I searched all similar questions on StackOverflow, but found none to answer my problem.

  I am trying to stream some movies from my Linux computer (openSuSE 12.1) to my iPad. I convert them with ffmpeg, segment them with my own segmenter, place them in the www folder of my apache2 server and also place inside the .m3u8 playlist. Til here - all is ok !

  I start playing the movie (HTML page with tag) and it plays nicely, but only the first five segments, which have been loaded with the first load of the playlist. The HTML page (the browser, or the player - no idea) does not refresh (re-download) the playlist from the server. Here is what my .m3u8 playlist file looks like :

  #EXTM3U
  
  #EXT-X-MEDIA-SEQUENCE:19
  
  #EXT-X-TARGETDURATION:8
  
  
  
  #EXTINF:8,
  
  http://192.168.1.4/segment_19.ts
  
  #EXTINF:8,
  
  http://192.168.1.4/segment_20.ts
  
  #EXTINF:8,
  
  http://192.168.1.4/segment_21.ts
  
  #EXTINF:8,
  
  http://192.168.1.4/segment_22.ts
  
  #EXTINF:8,
  
  http://192.168.1.4/segment_23.ts

  Segments are in the same folder as the playlist file, segments are correctly encoded (because I can see at least the first five ones :D). I also watch the access_log from the apache server and I see the first load of the playlist, then the consequent load of all 5 segments and it stops till there. It doesn't even try to further refresh the m3u8 file.

  If it matters - iOS 5.0, iPad 2, Wi-Fi version only, not jailbroken

  Ideas ? What am I doing wrong ?

• Encoding video stream by http protocol using ffmpeg library

  20 juillet 2014, par user3780677

  I’m trying to encode video files, that users upload on my server.
  I interpretate file as stream, incoming on my server by http protocol and use ffmpeg for realtime file encoding, while upload procedure executes.

  When source file have .avi format, I have successful encoding result, but on .mp4 format appears error :

  ---------------------
  
  [buffer @ 0000000000308380] Unable to parse option value "-1" as pixel format
  
  Last message repeated 1 times
  
  [buffer @ 0000000000308380] Error setting option pix_fmt to value -1.
  
  ---------------------

  I think this might be because .mp4 contains "moov atom" data in the end of file.
  I think so because when I processing file by "-movflags faststart" command before encoding, I also have successful result.

  That is the command i using now :

  ffmpeg -i http://myhost.com/app/video/video2.mp4 -f mp4 -vcodec libx264 -b:v 800K -acodec libvo_aacenc -b:a 128K -ar 44100 -ac 2 -y c:/watch-and-get/video/video5.mp4

  Can I resolve this problem and encode multiple video formats as a stream without any excess steps ?