Add FFMPEG cheat sheet to this repo rather than linking to my website.

README.md

@@ -19,6 +19,8 @@ Here's an example visualization of inviscid flow over an airfoil from a simulati
 
 [Creating an Animation](Tutorials/creating-an-annimation.md)
 
+[FFMPEG Cheat Sheet](Tutorials/FFMPEG-cheat-sheet.md)
+
 ### Remote Visualization
 
 [Interactive Visualization on Phoenix](Tutorials/interactive-visualization-on-Phoenix.md)

Tutorials/FFMPEG-cheat-sheet.md

@@ -0,0 +1,75 @@
+# FFMPEG Cheat Sheet
+This file details a set of common things you may want to do with FFMPEG.
+
+## Create a video from a sequence of PNG images
+The following command can be used to make a .mp4 video from a series of images padded with zeros (`pic.00001.png`, `pic.0002.png`, ...).
+
+```
+ffmpeg -r 30 -f image2 -i pic.%04d.png -vcodec libx264 -crf 25  -pix_fmt yuv420p test.mp4
+```
+
+The inputs are:
+* `-r` is the framerate
+* `-crf` is the quality, lower means better quality
+* `-S` (optional) video resolution in pixes
+* `-pix_fmt` specifies the pixel format
+
+## Playing one video after another
+The following command can be used to play a sequence of videos with the same width and height.
+```
+ffmpeg -f concat -i videos.txt -c copy joinedVideo.mp4
+```
+The file `videos.txt` contains an ordered list of videos with the following syntax: 
+```
+file '/directory/Video1.mp4'
+file '/directory/Video2.mp4'
+```
+## Stacking videos
+The following command can be used to vertically stack two videos with the same width.
+```
+ffmpeg -i 1.mp4 -i 2.mp4 -filter_complex vstack out.mp4
+```
+The following command can be used to horizontally stack two videos with the same height.
+```
+ffmpeg -i 1.mp4 -i 2.mp4 -filter_complex hstack out.mp4
+```
+`N` videos can be stacked using the following.
+```
+ffmpeg -i 1.mp4 -i 2.mp4 -i 3.mp4 -filter_complex hstack=N out.mp4
+```
+A 2x2 array of compatible videos can be created using
+```
+ffmpeg -i input0 -i input1 -i input2 -i input3 -filter_complex "[0:v][1:v][2:v][3:v]xstack=inputs=4:layout=0_0|w0_0|0_h0|w0_h0[v]" -map "[v]" output.mp4
+```
+
+## Dealing with an odd number of pixels
+Adding `-vf "pad=ceil(iw/2)*2:ceil(ih/2)*2"` to your FFMPEG command as shown below allows you to create a video from PNGs that are not an even number of pixels in height and/or width.
+```
+ffmpeg -r 30 -f image2 -i pic.%04d.png -vcodec libx264 -vf "pad=ceil(iw/2)*2:ceil(ih/2)*2" -crf 25  -pix_fmt yuv420p test.mp4
+```
+
+## Adding an .mp3 to a video
+The following command can be used to add sound to video.
+```
+ffmpeg -r 30 -f image2 -i pic.%04d.png -i MP3FILE.mp3 -vcodec libx264 -b 4M -vpre normal -acodec copy test.mp4
+```
+The inputs are:
+* `-i MP3FILE.mp3` is the name of the audio file
+* `-acodec copy` copies the audio from the input to the output stream
+
+## Converting a video to .mp4
+The following command can be used to convert a video to .mp4.
+```
+ffmpeg  -i INPUT.avi -vcodec libx264 -crf 25 OUTPUT.mp4
+```
+
+## Cropping a video
+The following command can be used to crop a video
+```
+ffmpeg -i input.mp4 -vf "crop=w:h:x:y" output.mp4
+```
+where the inputs are
+* `-vf` indicates the usage of a video filter
+* `crop` is the name of the filter
+* `w:h` is the width and height of the output video<
+* `x:y` is the coordinate from which the video will be

Tutorials/creating-an-annimation.md

@@ -67,4 +67,4 @@ The inputs are:
 
 - `-pix_format` specifies the pixel format
 
-For additional details on the basics of FFMPEG, see the FFMPEG Cheat Sheet tab [Here](https://benwilfong.com)
+For additional details on the basics of FFMPEG, see the [FFMPEG Cheat Sheet](FFMPEG-cheat-sheet.md).