Add bitrate conversion

1 files changed, 8 insertions, 1 deletions

diff --git a/ffmpeg.md b/ffmpeg.md
index b87ab63..033c5e4 100644
--- a/ffmpeg.md
+++ b/ffmpeg.md
@@ -11,12 +11,19 @@ Works for audio, too.
     ffmpeg -i in.mp4 -codec:v copy -codec:a copy -ss START_TIME -t DURATION out.mp4
     ffmpeg -ss START_TIME -t DURATION -i in.mp4 -codec:v copy -codec:a copy out.mp4
 
-## Resize
+## Quality
+
+### Resize
 
     ffmpeg -i in.mp4 -s 720x480 out.mp4
     # -1 means to automatically preserve aspect ratio
     ffmpeg -i in.mp4 -filter:v scale=720:-1 out.mp4
 
+### Bitrate
+
+* `-b:a 192k`: specify audio bitrate to 192 kbps
+* `-b:v 2M`: specify video bitrate to 2 mbps
+
 ## Audio/video delay
 
     ffmpeg -i "$input" -itsoffset <offset in seconds> -i "$input" -map 1:v -map 0:a -c:a copy -c:v libx264 "$output"