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+---
+title: "Using ffmpeg to combine videos side by side"
+permalink: /using-ffmpeg-to-combine-video-side-by-side.html
+date: 2023-11-04T09:04:28+02:00
+layout: post
+type: note
+draft: false
+---
+
+I had a 4 webm videos (each 492x451) that I wanted to combine to be played side
+by side and I tried [iMovie](https://support.apple.com/imovie) and
+[Kdenlive](https://kdenlive.org/) and failed to do it in an easy way. I needed
+this for Github readme file so it also needed to be a GIF.
+
+The following is the [ffmpeg](https://ffmpeg.org/) version of it.
+
+```sh
+ffmpeg -y \
+  -i 01.webm \
+  -i 02.webm \
+  -i 03.webm \
+  -i 04.webm \
+  -filter_complex "\
+        [0:v] trim=duration=8, setpts=PTS-STARTPTS, scale=492x451, fps=6 [a0]; \
+        [1:v] trim=duration=8, setpts=PTS-STARTPTS, scale=492x451, fps=6 [a1]; \
+        [2:v] trim=duration=8, setpts=PTS-STARTPTS, scale=492x451, fps=6 [a2]; \
+        [3:v] trim=duration=8, setpts=PTS-STARTPTS, scale=492x451, fps=6 [a3]; \
+        [a0][a1][a2][a3] xstack=inputs=4:layout=0_0|w0_0|w0+w1_0|w0+w1+w2_0, scale=1000:-1 [v]" \
+  -map "[v]" \
+  -crf 23 \
+  -preset veryfast \
+  trigraphs.gif
+```
+
+- This will produce `trigraphs.gif` that is also scaled to max 1000px in width
+  (refer to `scale=1000:-1`).
+- The important part for 4x1 stack is `xstack=inputs=4:layout=0_0|w0_0|w0+w1_0|w0+w1+w2_0`.
+- This will also cap frame rate to 6 (refer to `fps=6`) since that is enough and
+  this makes playback of GIFs smoother in a browser.
+
+![Result](./assets/notes/trigraphs.gif){:loading="lazy"}