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| layout | title | subtitle | description | categories | cover | date |
|---|---|---|---|---|---|---|
| post | Lossless screen recording | Never waste resources with OBS again | Recording your screen (or monitors) with ffmpeg for a high-quality lossless video that uses very little system resources | minimalism | /assets/ffmpeg-lossless.png | 2018-08-12 17:15:20 |
I've been trying off and on for the past few weeks to figure out how to record my 1920x1080 monitor. The recording is going to be some music videos for a friend. Originally, it was just going to be a single background image for the whole video then I had the idea of using cava in a transparent terminal on top of the background. This didn't work at all because it actually kept freezing when I tried to record it. So I tried switching to ncmpcpp visualiser. This still had horrible lag. So I've been puzzling over how to use ffmpeg to losslessly record my second monitor. I finally figured it out and have pasted the command below.
ffmpeg -video_size 1920x1080 -framerate 30 -f x11grab -draw_mouse 0 -i :0.0+1366,0 -c:v libx264 -crf 0 -preset ultrafast output.mkv
This is the exact command I used; I'll modify it so you know what to edit for your use-case 😉
ffmpeg -video_size <target-resolution> -framerate 30 -f x11grab -i :0.0+<width-of-unused-monitor>,0 -c:v libx264 -crf 0 -preset ultrafast <filename>.mkv
If you do not want the cursor recorded, add -draw_mouse 0 directly after x11grab like I did in the first command.
My video was 470mb for a ~13 minute video. If you're going to archive the recording or are concerned about file size, re-encode it losslessly but with a slower preset. As the initial recording was lossless and the re-encode is lossless too, there will be no absolutely no loss is quality . . . anywhere. I also highly recommend using this as a general purpose screen recorder if you have a low-end system. Previously, I was using OBS and the lag in the video was incredible but with ffmpeg, it's smooth as butter. The command for re-encoding is below:
ffmpeg -i output.mkv -c:v libx264 -crf 0 -preset veryslow output-smaller.mkv
