Recherche avancée

Sur d’autres sites (3410)

• Why does ffmpeg return a different framecount than ffprobe for the same file ?

  5 mars 2018, par Greg

  I’m trying to count the number of frames in a video but ffmpeg and ffprobe are giving me two different answers.

  $ time ffprobe -v error -count_frames -select_streams v:0 -show_entries stream=nb_read_frames -of default=nokey=1:noprint_wrappers=1 myvideo.mp4
  
  2858
  
  
  
  real    0m2.987s
  
  user    0m2.740s
  
  sys     0m0.172s

  When I check the same file with ffmpeg I get 2 more frames...

  $ time ffmpeg -y -i myvideo.mp4 -vcodec copy -acodec copy -f null /dev/null 2>&1 | grep 'frame=' | awk '{print $2}'
  
  2860
  
  
  
  real    0m0.127s
  
  user    0m0.080s
  
  sys     0m0.032s

  I used ffprobe to output all of the frames and count the number of "[FRAME]"s in the resultant output...

  ffprobe -i myvideo.mp4 -show_frames -v error | grep -o '\[FRAME\]' | wc -l
  
  2858

  Which as you can see shows the number ffprobe thought there were.

  Obviously I would prefer to use ffmpeg here because it is significantly faster than ffprobe and I am dealing with thousands of videos that need parsing and indexing. However the failure isn’t consistent across multiple videos ; sometimes it’s 1 out, other times it’s 2 or more...

  Unfortunately, I have been counting frames for the past two years using the ffmpeg method, so I have a significant library of videos to reprocess now ... he gulps... I guess its a good way to verify the readability of the files on the cluster... even so, its going to take probably a few weeks to recalculate all of the existing video frame sizes.

• ffmpeg : remove dead call to av_parser_change()

  21 mars 2018, par James Almer

  ffmpeg : remove dead call to av_parser_change()
  It's been a noop for years, and it's been argued that in-band headers
  
  should not be forcedly removed without the user's explicit request.
  Also, as the FIXME line stated, this is a job for a bitstream filter
  
  like extract_extradata, remove_extradata, dump_extradata, and
  
  filter_units.
  Signed-off-by : James Almer <jamrial@gmail.com>
  

  • [DH] fftools/ffmpeg.c
  • [DH] fftools/ffmpeg.h

• is there any functional build of ffmpeg to android

  11 mai 2018, par Rafael Lima

  I’ve searching the last 3 days for a usable API for android access ffmpeg.
  Since FFMpeg group doesn’t release an official lib for android I found several paralel projects trying to build it.

  So it brings me to my nightmare that is called compile.

  i’ve followed all these tutorials : https://trac.ffmpeg.org/wiki/CompilationGuide/Android

  And others found in different places. but none of them build

  NONE OF THEM IS LESS THAN 3 YEARS OLD

  Sorry for the caps, but it is frustrating... no ffmpeg build projects I found deal with nkd above 14 and google doesn’t keep in archive nkds older than that, so even if i agree with get all outdated libraries source i cant reproduce de compiler i cant download the same ndk...

  The only api i manage to download with a functional build of ffmpeg probably was compiled without some codecs, because on my tests i can only handle few types of videos

  ===============================================================

  The question is, does anyone know an actual, stable, project for building ffmpeg to android ?

  I’m even willing to pay in order to get a working version of it