using correct binary for ffmpeg

Makefile

@@ -10,7 +10,7 @@ build/bin/ffmpeg:
 	mkdir -p build/bin
 	rm -rf build/ffmpeg*
 	cd build; \
-		curl https://johnvansickle.com/ffmpeg/releases/ffmpeg-release-arm64-static.tar.xz | tar x
+		curl https://johnvansickle.com/ffmpeg/releases/ffmpeg-release-amd64-static.tar.xz | tar x
 	mv build/ffmpeg*/ffmpeg build/ffmpeg*/ffprobe build/bin
 
 build/layer.zip: build/bin/ffmpeg

README.md

@@ -4,7 +4,7 @@ This is an AWS Lambda layer containing statically linked `ffmpeg` and `ffprobe`
 
 ## Use within Lambda
 
-You can use a pre-deployed ARN: `arn:aws:lambda:us-east-1:145266761615:layer:ffmpeg:3` or deploy yourself -- edit Makefile to set your deployment bucket etc, then just run `make deploy`.
+You can use a pre-deployed ARN: `arn:aws:lambda:us-east-1:145266761615:layer:ffmpeg:4` or deploy yourself -- edit Makefile to set your deployment bucket etc, then just run `make deploy`.
 
 The binares will be in `/opt/bin/ffmpeg` and `/opt/bin/ffprobe` inside your Lambda container.