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• ffmpeg converts .flv video to .gif with awful quality [migrated]

  22 février 2013, par Kamil Hismatullin

  I'm converting .flv movie to .gif file with ffmpeg.

  ffmpeg -i input.flv -ss 00:00:00.000 -pix_fmt rgb24 -r 10 -s 320x240 -t 00:00:10.000  output.gif

  It works great, but output gif file has a very law quality.

  Any ideas how can I improve quality of converted gif ?

  Output of command :

  $ ffmpeg -i input.flv -ss 00:00:00.000 -pix_fmt rgb24 -r 10 -s 320x240 -t 00:00:10.000  output.gif 
  
  
  
  ffmpeg version 0.8.5-6:0.8.5-0ubuntu0.12.10.1, Copyright (c) 2000-2012 the Libav developers
  
    built on Jan 24 2013 14:52:53 with gcc 4.7.2
  
  *** THIS PROGRAM IS DEPRECATED ***
  
  This program is only provided for compatibility and will be removed in a future release. Please use avconv instead.
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.flv':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 0
  
      compatible_brands: isommp42
  
      creation_time   : 2013-02-14 04:00:07
  
    Duration: 00:00:18.85, start: 0.000000, bitrate: 3098 kb/s
  
      Stream #0.0(und): Video: h264 (High), yuv420p, 1280x720, 2905 kb/s, 25 fps, 25 tbr, 50 tbn, 50 tbc
  
      Metadata:
  
        creation_time   : 1970-01-01 00:00:00
  
      Stream #0.1(und): Audio: aac, 44100 Hz, stereo, s16, 192 kb/s
  
      Metadata:
  
        creation_time   : 2013-02-14 04:00:07
  
  [buffer @ 0x92a8ea0] w:1280 h:720 pixfmt:yuv420p
  
  [scale @ 0x9215100] w:1280 h:720 fmt:yuv420p -> w:320 h:240 fmt:rgb24 flags:0x4
  
  Output #0, gif, to 'output.gif':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 0
  
      compatible_brands: isommp42
  
      creation_time   : 2013-02-14 04:00:07
  
      encoder         : Lavf53.21.1
  
      Stream #0.0(und): Video: rawvideo, rgb24, 320x240, q=2-31, 200 kb/s, 90k tbn, 10 tbc
  
      Metadata:
  
        creation_time   : 1970-01-01 00:00:00
  
  Stream mapping:
  
    Stream #0.0 -> #0.0
  
  Press ctrl-c to stop encoding
  
  frame=  101 fps= 32 q=0.0 Lsize=    8686kB time=10.10 bitrate=7045.0kbits/s dup=0 drop=149    
  
  video:22725kB audio:0kB global headers:0kB muxing overhead -61.778676%

  Thanks.

• Encode video of powerpoint presentation for HTML5 playback

  17 avril 2013, par user2291446

  We have a number of powerpoint presentations that have been converted to 16:9
  aspect ratio and then converted into mp4 "master videos" with an "apple TV" 720p
  profile. These powerpoint presentations are voice annotated. So in essence, we
  show a slide and then let the annotation sound play for a while, then go to the
  next slide, and so on. The resulting mp4 master video is somewhere around 900MB
  on average.

  Here is an example of the master video

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.mp4' :
  Metadata :
      major_brand : isom
      minor_version : 512
      compatible_brands : isomiso2avc1mp41
      creation_time : 1970-01-01 00:00:00
      encoder : Lavf52.104.0
    Duration : 02:00:57.65, start : 0.000000, bitrate : 970 kb/s
      Stream #0:0(und) : Video : h264 (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 836 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc
      Metadata :
        creation_time : 1970-01-01 00:00:00
        handler_name : VideoHandler
      Stream #0:1(und) : Audio : aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 127 kb/s
      Metadata :
        creation_time : 1970-01-01 00:00:00
        handler_name : SoundHandler
  

  We are trying to get these presentations to play on the web on as many
  devices/browsers as possible including some that don't do HTML5 (IE7/IE8). We
  have narrowed down our player of choice which is mediaElement and have extracted
  some "cue points" from the powerpoint presentation that mark where the slides
  are changing. We have also captured thumbnails for those cuepoints such that we
  now have a nice list of thumbnails for each slide and an associated cuepoint in
  the video where the particular slide begins.

  Here comes the problem...due to the large size of the master video it is not
  practical for us to use the master video with our mediaElement player. We do
  need to transcode the master video to mp4 and ogv in order to get decent
  device/browser coverage.

  We do not seem to be able to find a suitable transcoding strategy to reduce the
  size of the video. We have played with numerous ffmpeg settings and were able to
  reduce the size but when we do so we compromise the ability to jump to specific
  cue points.

  It works well for browsers that do HTML5 video natively (Chrome and Firefox) but
  not for the flash fallback of mediaElement (IE7/IE8) which uses the mp4 file and
  seemingly is very tied to the number and frequency of key frames in the video in
  order to allow for clean seeking and skipping using the cue points.

  Seeing that we are talking about a video that has only slides (practically 90
  static images per presentation) and some sound we imagine it must be possible to
  transcode as such that the keyframes fall at the cue points or near the
  cuepoints, and that the size of the video could be drastically reduced while
  still allowing for smooth seeking and skipping.

• 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)