9
6
I'm trying to extract key frames from a video clip. I tried the following command, but it extracts all frames.
ffmpeg -vf select="eq(pict_type\,PICT_TYPE_I)" -i 2.flv -vsync 2 -s 73x41 -r 30 -f image2 thumbnails-%%02d.jpeg
9
6
I'm trying to extract key frames from a video clip. I tried the following command, but it extracts all frames.
ffmpeg -vf select="eq(pict_type\,PICT_TYPE_I)" -i 2.flv -vsync 2 -s 73x41 -r 30 -f image2 thumbnails-%%02d.jpeg
19
You can make this simpler using -skip_frame
without the need for select
video filter:
ffmpeg -skip_frame nokey -i 2.flv -vsync 0 -r 30 -f image2 thumbnails-%02d.jpeg
12
Example using the select
and scale
filters:
ffmpeg -i 2.flv -vf "select=eq(pict_type\,I),scale=73x41" \
-vsync vfr -qscale:v 2 thumbnails-%02d.jpeg
A few tips:
Filters should not come before the -i
option, as they're an output option. I don't know where exactly you got the command from, but PICT_TYPE_I
does not exist – it should be I
.
In the scale
filter you can replace 73
or 41
to have the filter automatically calculate the width or height to preserve aspect ratio: such as scale=73:-1
or scale=-1:41
. This prevents stretching or squishing that can result from "forced" scaling.
Output quality can be controlled with -qscale:v
(or the alias -q:v
). Effective range is a linear scale of 2 to 31 and a lower value is a higher quality.
That your ffmpeg
allows a filter before the input tells me it could be outdated. Download a recent static build for your operating system, or build it yourself according to the compilation guides if the above does not work.
1If your goal is to extract the key frames losslessly, you can try the following: ffmpeg -i 2.flv -vf "select=eq(pict_type\,I)" -vsync vfr frame-%02d.png
– Peltier – 2015-03-07T14:11:56.277
0
if this errors:
Option vf (set video filters) cannot be applied to input url 1508.mp4 -- you are trying to apply an input option to an output file or vice versa. Move this option before the file it belongs to. Error parsing options for input file 1508.mp4. Error opening input files: Invalid argument
you can do this:
ffmpeg -i 263.mp4 -vf select=eq(pict_type\,PICT_TYPE_I) -vsync 2 -s 480x320 -r 24 -f image2 thumbnails-%05d.jpeg
==--------------------------------------------
“-i” Parameters in advance
2Amazing, takes less than 10s on a 20min video compared to more than 3 minutes with select filter ! – mad – 2018-04-08T15:23:18.223
Make sure to use
-threads 1
, compared to the default-threads auto
it makes acropdetect
filter graph (ffmpeg -threads 1 -skip_frame nokey -i input.mkv -filter:v select='not(mod(n\,20))',cropdetect -an -f null /dev/null
) 2x as fast on my system (60s down to 30s)! – genpfault – 2019-02-09T03:36:50.457I would not use skip_frame nokey. Have you even checked the output? On my files and build (aug 2019) I get improper time stamps, as in nokey gives me the preceding frame before the I frame, while the nonfiltered/all frames show the I frame at a later time stamp. – JasonXA – 2019-11-21T04:57:37.193