Fastest way to extract frames using ffmpeg

Question

Hi I need to extract frames from videos using ffmpeg   Is there a faster way to do it than this   ffmpeg -i file mpg -r 1 1  filename 03d jpg

User · Answer

If you know exactly which frames to extract, eg 1, 200, 400, 600, 800, 1000, try using:

select='eq(n\,1)+eq(n\,200)+eq(n\,400)+eq(n\,600)+eq(n\,800)+eq(n\,1000)' \
       -vsync vfr -q:v 2

I'm using this with a pipe to Imagemagick's montage to get 10 frames preview from any videos. Obviously the frame numbers you'll need to figure out using ffprobe

ffmpeg -i myVideo.mov -vf \
    select='eq(n\,1)+eq(n\,200)+eq(n\,400)+eq(n\,600)+eq(n\,800)+eq(n\,1000)',scale=320:-1 \
    -vsync vfr -q:v 2 -f image2pipe -vcodec ppm - \
  | montage -tile x1 -geometry "1x1+0+0<" -quality 100 -frame 1 - output.png

.

Little explanation:

In ffmpeg expressions + stands for OR and * for AND
\, is simply escaping the , character
Without -vsync vfr -q:v 2 it doesn't seem to work but I don't know why - anyone?

User · Answer

This worked for me ffmpeg -i file mp4 -vf fps 1  d jpg

User · Answer

I tried it  3600 frame in 32 seconds  your method is really slow  You should try this   ffmpeg -i file mpg -s 240x135 -vf fps 1  d jpg

User · Answer

Output one image every minute  named img001 jpg  img002 jpg  img003 jpg  etc  The  03d dictates that the ordinal number of each output image will be formatted using 3 digits  ffmpeg -i myvideo avi -vf fps 1 60 img 03d jpg  Change the fps 1 60 to fps 1 30 to capture a image every 30 seconds  Similarly if you want to capture a image every 5 seconds then change fps 1 60 to fps 1 5 SOURCE  https   trac ffmpeg org wiki Create a thumbnail image every X seconds of the video

User · Answer

In my case I need frames at least every second  I used the  seek to  approach above but wondered if I could parallelize the task   I used the N processes with FIFO approach here  https   unix stackexchange com questions 103920 parallelize-a-bash-for-loop 216475 216475  open sem      mkfifo  tmp pipe-     exec 3 lt  gt  tmp pipe-     rm  tmp pipe-     local i  1   for   i gt 0 i--    do     printf  s 000  gt  amp 3   done   run with lock        local x     read -u 3 -n 3 x  amp  amp    0  x      exit  x                     printf    3d      gt  amp 3       amp    N 16 open sem  N time for i in  0  39    do run with lock ffmpeg -ss  echo  i  -i  tmp input GOPR1456 MP4  -frames v 1  tmp output period down  i jpg   amp  done   Essentially I forked the process with  amp  but limited the number of concurrent threads to N   This improved the  seek to  approach from 26 seconds to 16 seconds in my case   The only problem is the main thread does not exit cleanly back to the terminal since stdout gets flooded

User · Answer

If the JPEG encoding step is too performance intensive  you could always store the frames uncompressed as BMP images   ffmpeg -i file mpg -r 1 1  filename 03d bmp   This also has the advantage of not incurring more quality loss through quantization by transcoding to JPEG   PNG is also lossless but tends to take much longer than JPEG to encode

User · Answer

Came across this question  so here s a quick comparison  Compare these two different ways to extract one frame per minute from a video 38m07s long   time ffmpeg -i input mp4 -filter v fps fps 1 60 ffmpeg  0d bmp   1m36 029s  This takes long because ffmpeg parses the entire video file to get the desired frames   time for i in  0  39    do ffmpeg -accurate seek -ss  echo  i 60 0   bc  -i input mp4   -frames v 1 period down  i bmp   done   0m4 689s  This is about 20 times faster  We use fast seeking to go to the desired time index and extract a frame  then call ffmpeg several times for every time index  Note that -accurate seek is the default   and make sure you add -ss before the input video -i option   Note that it s better to use -filter v -fps fps     instead of -r as the latter may be inaccurate  Although the ticket is marked as fixed  I still did experience some issues  so better play it safe

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