add ffpmeg notes

active/software_ffmpeg/ffmpeg.md

@@ -1,5 +1,47 @@
 # FFMPEG
 
+## Slow down a gif
+
+```bash
+ffmpeg \
+-r 100 \
+-i "solid-snake-mgs.gif" \
+-vf " minterpolate=50,split[g][p]; [p]palettegen[p]; [g][p]paletteuse" out.gif
+```
+
+## Combine images into a gif
+
+```bash
+ffmpeg \
+-f image2 \
+-framerate 3 \
+-i frame_%d.jpeg video.gif
+```
+
+## Compression
+
+```bash
+ffmpeg \
+-hwaccel vaapi \
+-vaapi_device /dev/dri/renderD128 \
+-hwaccel_output_format vaapi \
+-i input.mp4 \
+-c:v hevc_vaapi \
+-rc_mode 1 \
+-qp 25 \
+output.mp4
+
+ffmpeg \
+-hwaccel vaapi \
+-vaapi_device /dev/dri/renderD128 \
+-hwaccel_output_format vaapi \
+-i input.mp4 \
+-c:v h264_vaapi \
+-b:v 0 \
+-maxrate 10M \
+output.mp4
+```
+
 ## DVD Ripping
 
 ```bash