Recherche avancée

Sur d’autres sites (5490)

• ffmpeg - set variable video duration

  21 février 2017, par Vee

  I use this command to convert files in batch plus crop and re-scale :

  for i in $( ls *.mp4 ); do
  
      ffmpeg -y -i "$i" -acodec libfaac -ab 128k -ar 44100 -vcodec libx264 -b 850k -threads 0 -vf [in]crop=in_w-112:in_h-63:56:0,scale=1280:720[out] "../../archive/${i/.mp4/}.mp4"
  
  done

  this command will start at second 15, and makes video 30 seconds long :

  for i in $( ls *.mp4 ); do
  
      ffmpeg -ss 00:00:15 -t 30 -y -i "$i" -acodec libfaac -ab 128k -ar 44100 -vcodec libx264 -b 850k -threads 0 -vf [in]crop=in_w-112:in_h-63:56:0,scale=1280:720[out] "${i/.mp4/}_test.mp4"
  
  done

  what I would like is a command that cuts off 15s from the beginning and 15s from the end of EACH video from the BATCH ... the trick is that each video has different duration, so "how long it is" must be a variable (duration minus 15s or minus 30s if I count 15s from the start as well)

  video duration examples :

  video 1 - 00:25:19
  
  video 2 - 00:15:34
  
  video 3 - 00:19:21
  
  video 4 - 00:22:49
  
  etc.

• converting jpg to .mp4 by ffmpeg

  5 juillet 2015, par Sam

  I have 320 jpg (320x574) images which I recorded with 2000 fps. I want to make a .mp4 video of them. I have run below codes in cmd (win7) and when I run the code it is working and gives me the MP4 file and I can see the video, but this attention note pops up in the cmd :

  Frame rate very high for a muxer not efficiently supporting it

  and asked me to use other muxer or -vsync 2.

  ffmpeg -f image2 -i Path/To/File/filename%d.jpg -r 2000 -pix_fmt yuv420p    path\to\result\test.mp4

  I also tried this code with -vsync 2

   ffmpeg -f image2 -i Path/To/File/filename%d.jpg -r 2000 -pix_fmt yuv420p -vsync 2    path\to\result\test.mp4

  It works, but I am not able to see the video.

  First of all I wonder if the code is right to convert jpg images to MP4 video with 2000 fps ?

  Secondly, what should I do with the attention note ?

  I really appreciate any help.

• Revision 3606b78108 : Modified test for auto key frame detection. The existing test was triggering a

  16 avril 2015, par paulwilkins

  Changed Paths :
   Modify /vp9/encoder/vp9_firstpass.c

  
  
  Modified test for auto key frame detection.

  The existing test was triggering a lot of false positives on some types
  of animated material with very plain backgrounds. These were triggering
  code designed to catch key frames in letter box format clips.

  This patch tightens up the criteria and imposes a minimum requirement
  on the % blocks coded intra in the first pass and the ratio between the
  % coded intra and the modified inter % after discounting neutral (flat)
  blocks that are coded equally well either way.

  On a particular problem animation clip this change eliminated a large
  number of false positives including some cases where the old code
  selected kf several times in a row. Marginal false negatives are less
  damaging typically to compression and in the problem clip there are now
  a couple of cases where "visual" scene cuts are ignored because of well
  correlated content across the scene cut.

  Replaced some magic numbers related to this with #defines and added
  explanatory comments.

  Change-Id : Ia3d304ac60eb7e4323e3817eaf83b4752cd63ecf