Add note about stripping streams with ffmpeg

notes/ffmpeg-remove-stream.md

@@ -0,0 +1,19 @@
+---
+title: Strip audio / subtitle stream with ffmpeg
+tags:
+  - Media
+emoji: 🎵
+link: https://stackoverflow.com/a/38162168
+---
+
+```bash
+ls -1 *.mp4 | xargs -I{} ffmpeg -y -i {} -map 0 -map -0:a:0 -c copy /path/to/out/{}
+```
+
+`-map -0:a:0` removes the 0th audio stream.
+
+
+- v - video, such as `-map -0:v`
+- a - audio, such as `-map -0:a`
+- s - subtitles, such as `-map -0:s`
+- d - data, such as `-map -0:d`