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• encoding a video for looping ?

  24 janvier 2013, par bennettk

  This is somewhat related to Looping a video with AVFoundation AVPlayer but that question is answered. What I'm trying to achieve is seamless looping using an AVPlayer. There is a noticeable stutter between loops using h264-encoded videos* that has gotten worse for some reason with the update to iOS 5. Could this have something to do with the way the videos are encoded rather than the AVPlayer ? The looping is triggered by a playerItemDidReachEnd notification as described in the link above.

  Thanks.

  * here's the ffmpeg command we're using to encode the videos, if that helps :

  ffmpeg -i -y -sameq -vcodec libx264 -vpre hq -crf 20 -an

  (yes, the files don't have sound (yet) so the -an is intentional.)

• Change file format from flv to anything android will play

  19 octobre 2011, par Bilthon

  I need to take this file which encoded is in h264 but in a flv container and just put it in a mp4, 3gp or whatever file format the android MediaPlayer will understand.

  I want to do this natively. As I will not be decoding nor encoding anything I think I will not be wasting a lot of power (am I wrong ?)

  I followed the instructions from here http://www.roman10.net/?p=394 and could sucessfully compile and use ffmpeg and use it with mp4 and 3gp files.

  But when it comes to flv files it fails. I understand there is no format definition for flv files in that specific port of ffmpeg for android.

  There is no libavformat/flv.h header file for instance.

  Maybe that's why this works :

  extern AVInputFormat ff_mov_demuxer ;
  av_register_input_format(&ff_mov_demuxer) ;

  While this fails :

  extern AVInputFormat ff_flv_demuxer;
  
  av_register_input_format(&ff_flv_demuxer);

  Question is, is there a light at the end of the tunnel ? has someone done something similar ? is it useful ? I mean, I can always just throw the flv media file into a flash player and voila.. the thing is that this would be a parcial solution, as it will not work for all those folks running slower devices that can't yet run Flash.

  Nelson

  PS. Just in case. Here's some info about the file I'm talking about :

  ffmpeg -i rio.flv 
  
  ffmpeg version N-32624-gea8de10, Copyright (c) 2000-2011 the FFmpeg developers
  
    built on Sep 15 2011 23:31:42 with gcc 4.5.2
  
    configuration: --enable-libfaac --enable-libmp3lame --enable-librtmp --enable-libtheora --enable-libx264 --enable-libxvid --enable-gpl --enable-nonfree
  
    libavutil    51. 16. 0 / 51. 16. 0
  
    libavcodec   53. 15. 0 / 53. 15. 0
  
    libavformat  53. 12. 0 / 53. 12. 0
  
    libavdevice  53.  3. 0 / 53.  3. 0
  
    libavfilter   2. 42. 0 /  2. 42. 0
  
    libswscale    2.  1. 0 /  2.  1. 0
  
    libpostproc  51.  2. 0 / 51.  2. 0
  
  
  
  Seems stream 0 codec frame rate differs from container frame rate: 2000.00 (2000/1) -> 14.99 (15000/1001)
  
  Input #0, flv, from 'rio.flv':
  
    Duration: 00:01:00.06, start: 0.000000, bitrate: 783 kb/s
  
      Stream #0.0: Video: h264 (Main), yuv420p, 704x480 [SAR 10:11 DAR 4:3], 14.99 tbr, 1k tbn, 2k tbc

• File parameter substitution : Movie creation with png files

  9 mai 2012, par John Rumpel

  I've a simple question : I try to create a movie file like mentioned above (have a lot of png-files with name plt_.png). When I try to run the commandline input :

  ffmpeg -q:v 5 -r 2 -b:v 9600 -i plt_%d.png movie.mp4

  ... I receive the error message : "plt_d.png : No such file or directory".

  This is because XP tries to substitute % by command line paramenter 0, I think. But this substitution shouldn't be done here but one stage deeper by ffmpeg.

  Do you have an idea to fix this ?

  Thanks a lot !