Add ffmpeg filtergraphs

1 files changed, 12 insertions, 0 deletions

diff --git a/ffmpeg.md b/ffmpeg.md
index 663471e..31a69bb 100644
--- a/ffmpeg.md
+++ b/ffmpeg.md
@@ -36,3 +36,15 @@ For the transpose parameter you can pass:
 ## Record sound
 
     ffmpeg -f alsa -i default out.flac
+
+## Fitlering
+
+### Filtergraph
+
+* A filtergraph is a `;`-separated list of filterchains.
+* A filterchain is a `,`-separated list of filters.
+* A filter is
+
+    [in1] ... [ink] filter_name=option1=val1:...:optionn=valn [out1] ... [outm]
+
+* Use `-filter_complex` if more than one input or output stream.