How to capture first X frames every X seconds into a PNG with FFmpeg?
I am new to using the command line. It is pretty cool and exciting to learn, but I am stuck.
I have a video where, for example, I want to capture the first 8 frames every 5 seconds into an image.
I've written this command:
ffmpeg -i video.mp4 -vf fps=8/20 out%04d.png
I see it captures 8 frames every 20 seconds, and not the first 8 frames. Is there a way I could specify this in the command?
video ffmpeg mp4 screenshot
asked Dec 30 '18 at 1:06
AFGAFG
11
add a comment |
I am new to using the command line. It is pretty cool and exciting to learn, but I am stuck.
I have a video where, for example, I want to capture the first 8 frames every 5 seconds into an image.
I've written this command:
ffmpeg -i video.mp4 -vf fps=8/20 out%04d.png
I see it captures 8 frames every 20 seconds, and not the first 8 frames. Is there a way I could specify this in the command?
video ffmpeg mp4 screenshot
asked Dec 30 '18 at 1:06
AFGAFG
11
I was trying to get the direct video link from my Dropbox folder instead of downloading. I was using the wrong link, but I figured it out!
– AFG
Dec 30 '18 at 16:52
add a comment |
I am new to using the command line. It is pretty cool and exciting to learn, but I am stuck.
I have a video where, for example, I want to capture the first 8 frames every 5 seconds into an image.
I've written this command:
ffmpeg -i video.mp4 -vf fps=8/20 out%04d.png
I see it captures 8 frames every 20 seconds, and not the first 8 frames. Is there a way I could specify this in the command?
video ffmpeg mp4 screenshot
asked Dec 30 '18 at 1:06
AFGAFG
11
I am new to using the command line. It is pretty cool and exciting to learn, but I am stuck.
I have a video where, for example, I want to capture the first 8 frames every 5 seconds into an image.
I've written this command:
ffmpeg -i video.mp4 -vf fps=8/20 out%04d.png
I see it captures 8 frames every 20 seconds, and not the first 8 frames. Is there a way I could specify this in the command?
video ffmpeg mp4 screenshot
video ffmpeg mp4 screenshot
asked Dec 30 '18 at 1:06
AFGAFG
11
asked Dec 30 '18 at 1:06
AFGAFG
11
edited Dec 30 '18 at 16:51
AFG
asked Dec 30 '18 at 1:06
AFGAFG
11
asked Dec 30 '18 at 1:06
AFGAFG
11
asked Dec 30 '18 at 1:06
AFGAFG
11
11
I was trying to get the direct video link from my Dropbox folder instead of downloading. I was using the wrong link, but I figured it out!
– AFG
Dec 30 '18 at 16:52
add a comment |
I was trying to get the direct video link from my Dropbox folder instead of downloading. I was using the wrong link, but I figured it out!
– AFG
Dec 30 '18 at 16:52
I was trying to get the direct video link from my Dropbox folder instead of downloading. I was using the wrong link, but I figured it out!
– AFG
Dec 30 '18 at 16:52
I was trying to get the direct video link from my Dropbox folder instead of downloading. I was using the wrong link, but I figured it out!
– AFG
Dec 30 '18 at 16:52
add a comment |
2 Answers
2
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oldest
votes
You can use the select filter to select frames that match an expression. If the expression evaluates to a nonzero number or true, it'll select those frames. For example, if your filter is -vf select="between(n, 0, 7)", it'd select the first eight frames. The frame number is n, and it starts at zero.
Combining this with the mod (modulo) operator, you can select the first eight frames of every group of, say, 24 frames, so every second for a video of 24 fps:
ffmpeg -i input.mp4 -vf "select=between(mod(n, 24), 0, 7), setpts=N/24/TB" output.mp4
The setpts filter is needed to adjust the timestamps of the frames so that you don't have gaps in your video.
To get the first eight frames every five seconds, multiply the 24 by 5:
ffmpeg -i input.mp4 -vf "select=between(mod(n, 120), 0, 7), setpts=N/24/TB" output.mp4
To output everything into PNGs, change the output from output.mp4 to output-%04d.png — you'll get sequentially numbered PNGs.
answered Dec 30 '18 at 15:34
slhckslhck
161k47446468
add a comment |
This is a generalized version of the select filter to pick 8 frames every 5 seconds.
ffmpeg -i in.mp4 -vf "select='if(not(floor(mod(t,5)))*lt(ld(1),1),st(1,1)+st(2,n)+st(3,t));if(eq(ld(1),1)*lt(n,ld(2)+8),1,if(trunc(t-ld(3)),st(1,0)))'" -vsync 0 out%d.png
This will work for videos with any frame-rate, constant or variable.
Change the 5 in mod(t,5) for the interval, in seconds. And the 8 in ld(2)+8 for the number of frames to select.
answered Dec 30 '18 at 20:16
GyanGyan
14.9k21845
Pretty complex expression. Had to translate that to pseudocode to figure out what was going on.
– slhck
Dec 30 '18 at 22:00
add a comment |
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2 Answers
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2 Answers
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You can use the select filter to select frames that match an expression. If the expression evaluates to a nonzero number or true, it'll select those frames. For example, if your filter is -vf select="between(n, 0, 7)", it'd select the first eight frames. The frame number is n, and it starts at zero.
Combining this with the mod (modulo) operator, you can select the first eight frames of every group of, say, 24 frames, so every second for a video of 24 fps:
ffmpeg -i input.mp4 -vf "select=between(mod(n, 24), 0, 7), setpts=N/24/TB" output.mp4
The setpts filter is needed to adjust the timestamps of the frames so that you don't have gaps in your video.
To get the first eight frames every five seconds, multiply the 24 by 5:
ffmpeg -i input.mp4 -vf "select=between(mod(n, 120), 0, 7), setpts=N/24/TB" output.mp4
To output everything into PNGs, change the output from output.mp4 to output-%04d.png — you'll get sequentially numbered PNGs.
answered Dec 30 '18 at 15:34
slhckslhck
161k47446468
add a comment |
You can use the select filter to select frames that match an expression. If the expression evaluates to a nonzero number or true, it'll select those frames. For example, if your filter is -vf select="between(n, 0, 7)", it'd select the first eight frames. The frame number is n, and it starts at zero.
Combining this with the mod (modulo) operator, you can select the first eight frames of every group of, say, 24 frames, so every second for a video of 24 fps:
ffmpeg -i input.mp4 -vf "select=between(mod(n, 24), 0, 7), setpts=N/24/TB" output.mp4
The setpts filter is needed to adjust the timestamps of the frames so that you don't have gaps in your video.
To get the first eight frames every five seconds, multiply the 24 by 5:
ffmpeg -i input.mp4 -vf "select=between(mod(n, 120), 0, 7), setpts=N/24/TB" output.mp4
To output everything into PNGs, change the output from output.mp4 to output-%04d.png — you'll get sequentially numbered PNGs.
answered Dec 30 '18 at 15:34
slhckslhck
161k47446468
add a comment |
You can use the select filter to select frames that match an expression. If the expression evaluates to a nonzero number or true, it'll select those frames. For example, if your filter is -vf select="between(n, 0, 7)", it'd select the first eight frames. The frame number is n, and it starts at zero.
Combining this with the mod (modulo) operator, you can select the first eight frames of every group of, say, 24 frames, so every second for a video of 24 fps:
ffmpeg -i input.mp4 -vf "select=between(mod(n, 24), 0, 7), setpts=N/24/TB" output.mp4
The setpts filter is needed to adjust the timestamps of the frames so that you don't have gaps in your video.
To get the first eight frames every five seconds, multiply the 24 by 5:
ffmpeg -i input.mp4 -vf "select=between(mod(n, 120), 0, 7), setpts=N/24/TB" output.mp4
To output everything into PNGs, change the output from output.mp4 to output-%04d.png — you'll get sequentially numbered PNGs.
answered Dec 30 '18 at 15:34
slhckslhck
161k47446468
You can use the select filter to select frames that match an expression. If the expression evaluates to a nonzero number or true, it'll select those frames. For example, if your filter is -vf select="between(n, 0, 7)", it'd select the first eight frames. The frame number is n, and it starts at zero.
Combining this with the mod (modulo) operator, you can select the first eight frames of every group of, say, 24 frames, so every second for a video of 24 fps:
ffmpeg -i input.mp4 -vf "select=between(mod(n, 24), 0, 7), setpts=N/24/TB" output.mp4
The setpts filter is needed to adjust the timestamps of the frames so that you don't have gaps in your video.
To get the first eight frames every five seconds, multiply the 24 by 5:
ffmpeg -i input.mp4 -vf "select=between(mod(n, 120), 0, 7), setpts=N/24/TB" output.mp4
To output everything into PNGs, change the output from output.mp4 to output-%04d.png — you'll get sequentially numbered PNGs.
answered Dec 30 '18 at 15:34
slhckslhck
161k47446468
answered Dec 30 '18 at 15:34
slhckslhck
161k47446468
answered Dec 30 '18 at 15:34
slhckslhck
161k47446468
answered Dec 30 '18 at 15:34
slhckslhck
161k47446468
161k47446468
add a comment |
add a comment |
This is a generalized version of the select filter to pick 8 frames every 5 seconds.
ffmpeg -i in.mp4 -vf "select='if(not(floor(mod(t,5)))*lt(ld(1),1),st(1,1)+st(2,n)+st(3,t));if(eq(ld(1),1)*lt(n,ld(2)+8),1,if(trunc(t-ld(3)),st(1,0)))'" -vsync 0 out%d.png
This will work for videos with any frame-rate, constant or variable.
Change the 5 in mod(t,5) for the interval, in seconds. And the 8 in ld(2)+8 for the number of frames to select.
answered Dec 30 '18 at 20:16
GyanGyan
14.9k21845
Pretty complex expression. Had to translate that to pseudocode to figure out what was going on.
– slhck
Dec 30 '18 at 22:00
add a comment |
This is a generalized version of the select filter to pick 8 frames every 5 seconds.
ffmpeg -i in.mp4 -vf "select='if(not(floor(mod(t,5)))*lt(ld(1),1),st(1,1)+st(2,n)+st(3,t));if(eq(ld(1),1)*lt(n,ld(2)+8),1,if(trunc(t-ld(3)),st(1,0)))'" -vsync 0 out%d.png
This will work for videos with any frame-rate, constant or variable.
Change the 5 in mod(t,5) for the interval, in seconds. And the 8 in ld(2)+8 for the number of frames to select.
answered Dec 30 '18 at 20:16
GyanGyan
14.9k21845
Pretty complex expression. Had to translate that to pseudocode to figure out what was going on.
– slhck
Dec 30 '18 at 22:00
add a comment |
This is a generalized version of the select filter to pick 8 frames every 5 seconds.
ffmpeg -i in.mp4 -vf "select='if(not(floor(mod(t,5)))*lt(ld(1),1),st(1,1)+st(2,n)+st(3,t));if(eq(ld(1),1)*lt(n,ld(2)+8),1,if(trunc(t-ld(3)),st(1,0)))'" -vsync 0 out%d.png
This will work for videos with any frame-rate, constant or variable.
Change the 5 in mod(t,5) for the interval, in seconds. And the 8 in ld(2)+8 for the number of frames to select.
answered Dec 30 '18 at 20:16
GyanGyan
14.9k21845
This is a generalized version of the select filter to pick 8 frames every 5 seconds.
ffmpeg -i in.mp4 -vf "select='if(not(floor(mod(t,5)))*lt(ld(1),1),st(1,1)+st(2,n)+st(3,t));if(eq(ld(1),1)*lt(n,ld(2)+8),1,if(trunc(t-ld(3)),st(1,0)))'" -vsync 0 out%d.png
This will work for videos with any frame-rate, constant or variable.
Change the 5 in mod(t,5) for the interval, in seconds. And the 8 in ld(2)+8 for the number of frames to select.
answered Dec 30 '18 at 20:16
GyanGyan
14.9k21845
answered Dec 30 '18 at 20:16
GyanGyan
14.9k21845
answered Dec 30 '18 at 20:16
GyanGyan
14.9k21845
answered Dec 30 '18 at 20:16
GyanGyan
14.9k21845
14.9k21845
Pretty complex expression. Had to translate that to pseudocode to figure out what was going on.
– slhck
Dec 30 '18 at 22:00
add a comment |
Pretty complex expression. Had to translate that to pseudocode to figure out what was going on.
– slhck
Dec 30 '18 at 22:00
Pretty complex expression. Had to translate that to pseudocode to figure out what was going on.
– slhck
Dec 30 '18 at 22:00
Pretty complex expression. Had to translate that to pseudocode to figure out what was going on.
– slhck
Dec 30 '18 at 22:00
add a comment |
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I was trying to get the direct video link from my Dropbox folder instead of downloading. I was using the wrong link, but I figured it out!
– AFG
Dec 30 '18 at 16:52