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How can I convert a video file to a sequence of images, for example one frame every N seconds. Can mplayer or ffmpeg do this? I have used MPlayer to grab screenshots manually but I would like to automate this for a long video.

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8 Answers 8

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It's very simple with ffmpeg, and it can output one frame every N seconds without extra scripting. To export as an image sequence just use myimage_%04d.png or similar as the output. The %0xd bit is converted to a zero-padded integer x digits long - the example I gave gets output as

  • myimage_0000.png,

  • myimage_0001.png,

  • myimage_0002.png

    etc..

You can use lots of still image formats, png, jpeg, tga, whatever (see ffmpeg -formats for a full list).

Ok so now we know how to export the movie as a sequence of images, but say we don't want to export every single frame?

The trick is to simply change the frame rate of the output to whatever we want using the -r n option where n is the number of frames per second. 1 frame per second would be -r 1, one frame every four seconds would be -r 0.25, one frame every ten seconds would be -r 0.1 and so on.

So to put it all together, this is how it would look to save one frame of input.mov every four seconds to output_0000.png, output_0001.png etc.:

ffmpeg -i input.mov -r 0.25 output_%04d.png

Note that the -r 0.25 option goes after the -i input.mov part, because it's controlling the frame rate of the output. If you put it before the input it would treat the input file as if it had the specified frame rate.

Change the %xd to however many digits you need, e.g. if the command would create more than 10,000 frames change the %04d to %05d. This also works for input files that are image sequence. Read more here.

Windows users: On the command line use %

example: ffmpeg -i inputFile.mp4 -r 1 outputFile_%02d.png

In CMD and BAT Scripts use %%

example: ffmpeg -i inputFile.mp4 -r 1 outputFile %%02d.png

So double %% in scripts, and single % on the interactive command line. Getting it wrong in either situation will generate an error.

Edit Worth checking out the discussion of file types in the comments below. There are advantages and disadvantages with each:

  • jpeg much smaller file sizes, lossy, only 8-bit colour, no alpha.
  • png lossless, large files, slow. 8-bit colour supports alpha.
  • tiff lossless, even larger files, fast, supports up to 16 colour and alpha.

To specify the file format, just use the required extension in the output file, e.g. myimage_%04d.jpg, myimage_%04d.png or myimage_%04d.tiff

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  • 1
    What should I put into -r if I want to export every frame? If I know the video's FPS, I guess I input that, but what if I don't? Apr 23, 2015 at 0:10
  • 7
    Don't use the -r flag at all. Then FFMPEG will use the input file's frame rate.
    – stib
    Apr 23, 2015 at 0:42
  • 3
    Note that you'll really want to use jpegs for this, unless you're sure png's are what you want. In my case, jpegs were about 50kb each, and pngs were about 2MB.
    – mlissner
    Oct 28, 2015 at 2:14
  • 10
    the advantage of pngs is lossless compression, so if you're using the image sequence as an intermediate and don't mind the extra size then that's when you might use png.
    – stib
    May 11, 2016 at 7:43
  • 4
    Tip: make sure the -r 1 goes AFTER the input file, otherwise it doesn't have the intended effect.
    – Simon E.
    Sep 23, 2019 at 9:10
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mplayer -vo jpeg -sstep 5 file.avi

will save a frame as a jpeg file every 5 seconds.

However, it will not stop at the end of the file, it will continue producing copies of the last frame. To avoid this, find the duration of the video in seconds, using another player, or with mplayer:

mplayer -vo null -ao null -frames 0 -identify file.avi

and look for a line like "ID_LENGTH=147.00".

Subtract 2 from the length, and use this value for the -endposoption. For example, for a 147 second video:

mplayer -vo jpeg -sstep 5 -endpos 145 file.avi
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  • this sounds like an mplayer bug. nice workaround. Apr 29, 2010 at 17:04
  • Could you at least mention on which operating system are you using this command? Apr 23, 2015 at 0:06
  • It was 5 years ago, but it was probably the latest Ubuntu Desktop at the time, Ubuntu 10.4 .
    – Liam
    Apr 23, 2015 at 22:27
  • How can I choose steps shorter than 1s. It does only accept integers.
    – fcpenha
    Mar 2, 2016 at 22:52
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    Nowadays, mpv --vo=image --sstep=5 movie.mkv works great without the aforementioned bug (mpv is a fork of mplayer) using mpv 0.27.0 on Debian.
    – Adam Katz
    Dec 2, 2017 at 0:44
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With ffmpeg, you can do the following:

ffmpeg -ss 4 -i input.avi -s 320x240 -frames:v 1 output.jpg

This command generates a 320×240 sized JPG thumbnail at the 4th second in the video. Put this in a script that changes the time and file name and you're done.

More info: Create a thumbnail image every X seconds of the video

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  • 2
    This seems to do what I want, but with one problem. It will process the file from the start on each iteration, getting exponentially slow.
    – Liam
    Apr 27, 2010 at 14:42
  • @Liam - Does it help if you leave the offset time alone (set it at 1) and use the -ss position flag to seek further into the file instead? -ss Seek to given time position in seconds. hh:mm:ss[.xxx] syntax is also supported
    – Nifle
    Apr 29, 2010 at 7:53
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    @liam: put the -ss before the -i so that the seek happens before the input video gets decoded. this should speed it up. source Apr 29, 2010 at 17:03
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    There's a better, much faster way to do it with ffmpeg. See my answer below.
    – stib
    Mar 15, 2014 at 9:47
  • stib's solution is the best IMO.
    – Griffin
    Jun 2, 2014 at 7:48
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If you are after a kind of contact sheet and if you are working with a Unix-like OS, you can use this elaborate script, called to the point Video Contact Sheet *NIX, short vcs.

In the background it also uses ffmpeg (by default) or mplayer, hence can handle a lot of video formats. It automates the process of capturing still images from the movie and compose these to an image with some header and footer. You can choose e.g. how many captures you want or alternatively the time differences between them.

For a interval of 10 minutes, the invocation is like that:

vcs -i 10m input.avi

Check the full list of commandline options for some other tweaks.

Here is an example contact sheet, taken from the homepage:

enter image description here

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With VLC 1.1.0 and above, you can use the scene video filter:

vlc C:\video\to\process.mp4 --rate=1 --video-filter=scene --vout=dummy --start-time=10 --stop-time=11 --scene-format=png --scene-ratio=24 --scene-prefix=snap --scene-path=C:\path\for\snapshots\ vlc://quit

The above saves 1 out of every 24 frames (--scene-ratio=24), starting at 00:00:10 and ending at 00:00:11.

Just tested and confirmed this works with VLC 2.0.3 on a fresh Windows 8 installation (I have no additional video plugins or software).

Full documentation: http://wiki.videolan.org/How_to_create_thumbnails

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VirtualDub can do this for you

File -> Export -> Image sequence

enter image description here

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  • Will this save every frame as an image?
    – Liam
    Apr 27, 2010 at 15:32
  • yes, every frame.
    – Shevek
    Apr 27, 2010 at 16:25
  • I need to skip most frames, outputting all frames will use up too much storage space. I need just one frame every few seconds.
    – Liam
    Apr 28, 2010 at 9:56
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You could also try this

from the VLC command line...

vlc "C:\YOUR\file\path\file.avi" -V image --image-out-prefix=capname --image-out-ratio=60

file.avi is the video you want to capture from, capname is the prefix of the saved images, you might want to play around with the ratio (60 means that 1 out of 60 images is captured) You can add more commands, for example --image-out-format jpeg will save your caps as jpegs instead of of pngs, --snapshot-path lets you choose where to save your caps.

Source of above

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  • I got this message: The command line options couldn't be loaded, check that they are valid.
    – Liam
    Apr 28, 2010 at 9:45
  • On Ubuntu, I got this message: unknown option or missing mandatory argument `--image-out-prefix=capname'
    – Liam
    Apr 28, 2010 at 9:54
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You can skip frames in VirtualDub. Just use "Decimate By" option located at Video -> Frame Rate menu. For example if you set "Decimate By 100" then use File -> Export -> Image sequence, it will save only every 100th frame.

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