Making a Video of a Single Window | Hacker News Reader

Making a Video of a Single Window

tratt.net

77 pointsltratt38 comments

On Linux you can just use "SimpleScreenRecorder". It allows recording video of a single window (with audio from mic). I use it at work to create demos. My video demos are better than most others' because the video does not contain the whole screen (unlike many other demos) and my videos are accompanied by audio narration so demo can be watched independently later. Mac users often ask me how I create my demo videos.

I've lived through decades of running into software with names like "Easy Driver Finder", "Quick PDF joiner", "Simple Disk Partitioner" and such, which so often turn out to be crap/non-free/unusable trial version/malware. This has conditioned me to automatically dismiss things named in this fashion. Though I suspect this is mainly an issue in the Windows world.

I don't fault the author of SimpleScreenRecorder at all. Objectively it's the perfect name for the tool. I just realized how sad this is that my mind went straight to "Oh, sounds like one of those shit apps".

This one looks really good though!

> I've lived through decades of running into software with names like "Easy Driver Finder", "Quick PDF joiner", "Simple Disk Partitioner" and such, which so often turn out to be crap/non-free/unusable trial version/malware.

I have a few friends who use windows. They live in this weird world where everything they call "free" is a trap. They are usually very impressed when I show them repositories and flathub.

This looks like a nice tool, thanks. Although worth noting it only records a screen region, so if you move the window it won't follow it.

Nice! If I understand correctly, this script assumes that the window will remain in the same place until the end of the recording, right? I'm not saying that's wrong. Specially if you know that the window won't move, then it's a good solution

Or you can just use OBS which makes all this really easy ^^.

But it was nice to learn about hk !

OBS is awful if all your work is about "screen recording".

take a look at simplescreenrecorder. it just works and i can record, save and upload a file in as much time as it takes for the recording.

this takes almost no resources while OBS is a resource hog, unless you are streaming, there is absolutely no reason to use OBS.

OBS can record an actual window, rather than an area on the screen. That is, you can move the window or cover it while recording, and you will only get the window contents.

But yeh, it's heavy. I tend to use peek for quick ones.

I use SimpleScreenRecorder (which is also mentioned in the footnote of the article). It really is simple to use and light weight.

I used to manually select area to record (with border outside the window to record) until I searched and found a solution using ffmpeg to add the border. So, now I just use the select window option. I also use Auto-Editor (https://github.com/WyattBlue/auto-editor) to prune silent portions.

I find the resource -hogging of obs really goes away once you start using hardware encoding. Not available on old cards, but the performance overhead is minimal.

i am using dell latitude E7440 laptop and it does not have a dedicated graphics card. i have tried using "OBS" but it was "too painful" to get working

I'm all for using and reusing old hardware as long as it makes sense, but complaining about something being a resource hog on a 9 year old laptop with 8GB of ddr3 is nonsensical.

So I should switch to anew laptp, spend a thousand dollars because my current machine won't run obs. It will run other software like simple screen recorder just fine but no. Its the user who is wrong for owning old/affordable machines. Great.

At least up to 8th gen intel igpu OBS is unusable

>OBS is a resource hog

I'm confused, as it is super lightweight.

Most of its resource usage is from video encoding. You can lower the quality, exchange bitrate for cpu while keeping the quality, or even use hardware encoding.

> unless you are streaming, there is absolutely no reason to use OBS.

Not true in my experience. Simplescreenrecorder was not capable of recording (without streaming) full screen opengl games with sound at acceptable quality last time I tried it, OBS is the only thing I've found that will do this apart from hardware based recorders. To be fair, the last time I tried simplescreenrecorder was several years ago, perhaps it has improved in the meantime.

VLC has a feature for this as well. That's my go-to since it's usually already on my machine no matter which I'm using

Why is that the case? I only do screen recordings and it's a fantastic tool for it.

I haven't used SSR before, but I'm not even seeing a meter for adjusting your microphone volume.

Ffmpeg can capture a single window on Windows, weirdly I can't find an equally simple way of doing it on Linux.

ffmpeg -f gdigrab -framerate 30 -i title=Calculator output.mkv

https://trac.ffmpeg.org/wiki/Capture/Desktop

On Linux I use the following shell-function, can't remember the source of it though, probably somewhere on Stack Overflow:

    $ which capture_window
    
    capture_window () {
     save_dir="$(mktemp -d)"
     filename="$save_dir/$(date +%Y-%m-%d_%H-%M_%S).mp4"
     ffmpeg -f x11grab -framerate 25 $(xwininfo | gawk 'match($0, /-geometry ([0-9]+x[0-9]+).([0-9]+).([0-9]+)/, a)\
          { print "-video_size " a[1] " -i +" a[2] "," a[3] }') $filename
     echo "Saved as \"$filename\""
    }

Here's a link to an article where they provide a shell script to easily do it:

https://tratt.net/laurie/blog/2022/making_a_video_of_a_singl...

Pipewire allows this relatively easily

Correct me if I'm wrong, but Pipewire would allow applications to implement this functionality "relatively easily", but it doesn't actually provide any end-user tooling itself for this, right?

Any gstreamer program should work as long as you have pipewire gst plugin installed (including building your own gst pipeline). Note that pipewire needs to be either supported by the program for video capture, or you need to use compositor that exposes every window as a pipewire video source.

If you're looking to record terminals, https://asciinema.org/

Kazam has the option to record a single window. It can also optionally capture microphone and speakers audio and mouse.

created a webapp for this exact purpose:

https://screencap.video

Unfortunately, doesn't seem to work...

    Uncaught (in promise) DOMException: MediaRecorder constructor: video/webm;codecs=h264 indicates an unsupported codec screencap.video:123
    Uncaught TypeError: mediaRecorder is undefined

Mozilla/5.0 (X11; Linux x86_64; rv:103.0) Gecko/20100101 Firefox/103.0

this is built in on Mac

It’s not, unless I’ve missed something. You can capture an image of a single window (direct from the compositor), but not video.

What you can do is select a region of a screen to video capture with cmd+shift+5. But that’s capturing from the framebuffer, so it captures whatever’s below the rounded corners as well (and doesn’t capture the window shadow).

QuickTime can record a window... low computational overhead, and built-in.

Also when you move or resize the window? Or can you just set the fixed frame for screen recording to a selected window's initial frame?

Can it? File / New screen recording just gets me the same cmd+shift+5 interface.

"capture selected window" or just press space

But that’s just a screenshot. You can’t do that with video right?

With both.. it's the same interface

You can't record _videos_ of a specific window though. You can only record a fixed region of the screen or the whole screen. "Capture selected window" only deals with screenshots, not with video.

QuickTime + iMovie gets you what you need for anything short of full-on professional videos.

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