How to capture multiple screenshot from online video stream using ffmpeg with specific seek time

1
votes

I'm using ffmpeg to take screenshot from online video stream. I want to seek multiple timeline. I've used the following command to capture 1 screenshot by seek command: ffmpeg -ss 00:02:10 -i "stream-url" -frames:v 1 out1.jpg

How I can take multiple screenshot via multiple seek time. I've searched for the solution but no success.

I've used the following command to take multiple screenshot as follows: ffmpeg -noaccurate_seek -ss 00:01:10 -i "stream-url" -map 0:v:0 -vframes 1 -f mpeg "thumb/output_01.jpg" -ss 00:02:10 -i "stream-url" -map 1:v:0 -vframes 1 -f mpeg "thumb/output_02.jpg"

Is there any way to generate screenshots from same input via seek command? How to make it more faster? How to skip multiple input(-i param)? I've also tried with other commands but those are more slower. Can anyone help me?

1
ffmpeg

1 Answers

3
votes

There's no easy way I know to specify a number of arbitrary seek points from which to extract frames (similar question here).

However, seeking is very fast with the way you specified. Instead of constructing a complex command, you could just download the YouTube video using youtube-dl (if you haven't done that already) and generate the commands like this:

ffmpeg -ss 00:01:10 -i input -frames:v 1 out1.jpg
ffmpeg -ss 00:02:05 -i input -frames:v 1 out2.jpg
ffmpeg -ss 00:03:20 -i input -frames:v 1 out3.jpg

Note that exporting JPG might lead to low quality. Using PNG is preferred; you will get lossless frames that you can handle with another program later (e.g. to resize or compress).

If you want to get frames from regular intervals, use the fps filter to drop the framerate:

ffmpeg -i input -filter:v fps=1/60 out%02d.jpg

This will output a frame every minute (1/60 frames per second = 1 frame per minute), with two zero-padded digits as output numbers. You could additionally offset the start by providing a -ss option before the input file.