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• Mathematically lossless encoding and decoding of RGB24 image sequence

  25 avril 2013, par curryage

  I am trying to encode a RGB24 image sequence into a mathematically (not merely visually) lossless video. huffyuv was suggested on many online forums so I tried the following.

  ffmpeg -i frames\%06d.png  -vcodec huffyuv test.avi

  The resulting video was then decoded into frames again using ffmpeg

  ffmpeg -i test.avi outframes\%06d.png

  However, the input and output frames are not bit-by-bit identical as promised by huffyuv here. Any idea how I can accomplish this ? My eventual goal is to read the video file using OpenCV but I am willing to cross that bridge later once I obtain a losslessly encoded video file.

  This SO question mentions an attempt to obtain a lossless h264 avi and the summary of responses seems to indicate h264 cannot completely accomplish lossless encoding.

  Once again, to emphasize, I am interested in bit-by-bit identical encoding, not just visually similar. Large file sizes are acceptable as is large compression/decompression time.

• mplayer generating online three thumbnail of video

  5 mai 2013, par soac

  I am trying to create thumbnail of video using mplayer but it is only creating 3 thumbnail of video and then repeating the last thumbnail again and again.

  MPlayer command 1 :

  mplayer video/1.mp4 -sstep 5 -endpos 25 -nosound -vf scale=96:64 -vo jpeg:quality=80:outdir=$tmpPath 2>log.txt

  Problem : It create 3 different image and then repeat last image again and again.

  MPlayer command 2 :

  mplayer video/1.mp4 -sstep 5 -endpos 25 -nosound -frames 5 -vf scale=96:64 -vo jpeg:quality=80:outdir=$tmpPath 2>log.txt

  Problem : It create 3 different image and then repeat last image 2 times, If I change -frames to 10 than it repeat last image 7 times.

  MPlayer command 3 :

  mplayer video/1.mp4 -ss 5 -nosound -frames 1 -vf scale=96:64 -vo jpeg:quality=80:outdir=$tmpPath /
  video/1.mp4 -ss 10 -nosound -frames 1 -vf scale=96:64 -vo jpeg:quality=80:outdir=$tmpPath /
  video/1.mp4 -ss 15 -nosound -frames 1 -vf scale=96:64 -vo jpeg:quality=80:outdir=$tmpPath /
  video/1.mp4 -ss 20 -nosound -frames 1 -vf scale=96:64 -vo jpeg:quality=80:outdir=$tmpPath /
  video/1.mp4 -ss 15 -nosound -frames 1 -vf scale=96:64 -vo jpeg:quality=80:outdir=$tmpPath /
  2>log.txt
  

  Problem : Same problem as above described. 3 thumbnail difference and other are same. Duration of video is 27 seconds. I run this command on mplayer and mplayer2 but same result. MPlayer Binary are taken from http://sourceforge.net/projects/smplayer/files/

  I want MPlayer to capture thumbnail after every X seconds using MPlayer not FFMPEG. I am already using FFMPEG for creating thumbnail and it is working fine. My Operating System is Windows 7. Log File

  MPlayer Redxii-SVN-r36237-4.6.3 (C) 2000-2013 MPlayer Team Custom build by
  Redxii, http://smplayer.sourceforge.net Compiled against FFmpeg version
  N-52748-g1ef82cc Build date : Sun May 5 03:45:49 EDT 2013 getch2 : 6 can't get
  number of input events [disabling console input] Playing
  D :/wamp/www/videoconverter/content/original/3.mp4. libavformat version 55.4.101
  (internal) libavformat file format detected. [lavf] stream 0 : video (h264), -vid
  0 [lavf] stream 1 : audio (aac), -aid 0, -alang und VIDEO : [H264] 960x540 24bpp
  25.000 fps 2087.1 kbps (254.8 kbyte/s) Clip info : major_brand : isom
  minor_version : 512 compatible_brands : isomiso2avc1mp41 creation_time : 1970-01-01
  00:00:00 encoder : Lavf52.77.0 comment : www.freemake.com Load subtitles in
  D :/wamp/www/videoconverter/content/original/ jpeg : Progressive JPEG disabled.
  jpeg : Baseline JPEG enabled. Opening video filter : [scale w=96 h=64]
  ==========================================================================
  Opening video decoder : [ffmpeg] FFmpeg's libavcodec codec family libavcodec
  version 55.7.100 (internal) Selected video codec : [ffh264] vfm : ffmpeg (FFmpeg
  H.264)
  ==========================================================================
  Audio : no sound Starting playback... Movie-Aspect is 1.78:1 - prescaling to
  correct movie aspect. [swscaler @ 01400520]BICUBIC scaler, from yuv420p to rgb24
  using MMXEXT VO : [jpeg] 96x64 => 113x64 RGB 24-bit jpeg :
  content/tmp/sprites/HxHtQGKbsV - Output directory already exists and is
  writable. Movie-Aspect is 1.78:1 - prescaling to correct movie aspect. VO :
  [jpeg] 96x64 => 113x64 RGB 24-bit jpeg : content/tmp/sprites/HxHtQGKbsV - Output
  directory already exists and is writable. V : 0.0 0/ 0 ??% ??% ??, ?% 0 0 V : 5.8
  0/ 0 ??% ??% ??, ?% 0 0 V : 10.6 0/ 0 ??% ??% ??, ?% 0 0 V : 18.5 0/ 0 ??% ??% ??, ?%
  0 0 V : 25.6 0/ 0 ??% ??% ??, ?% 0 0 V : 35.8 0/ 0 ??% ??% ??, ?% 0 0 V : 35.8 0/ 0
   ??% ??% ??, ?% 0 0 V : 35.8 0/ 0 ??% ??% ??, ?% 0 0 V : 35.8 0/ 0 ??% ??% ??, ?% 0 0
  V : 35.8 0/ 0 ??% ??% ??, ?% 0 0 V : 35.8 0/ 0 ??% ??% ??, ?% 0 0 V : 35.8 0/ 0 ??%
   ??% ??, ?% 0 0 Exiting... (End of file)
  

• online free media hosting for live streaming

  30 novembre 2013, par Abdul Ali

  wanted to ask two things :

  1- How can we put the output of FFMPEG to a stream (online address to put the stream).

  2- Is there any free service (for testing purpose) to use FFMPEG and pass the output to it for live streaming .

  apologies if am unable to explain properly what is intended.

  to summarize, wish to convert images to video using FFMPEG (have tried the image to video conversion locally and seems to be working) and put the output to an online resource for live streaming and possibly also have VOD (so users who later logon can view at least from some point behind which they have missed).

  regards,