Add ffmpeg related scripts

scripts/shell/ffmpeg-get-video-crf-level.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+ffmpeg -i $1 -an -vframes 1 -f null - -v 48 2>&1 | grep -oE "crf=[0-9\.]+"

scripts/shell/ffmpeg-get-video-duration.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+ffmpeg -i $1 2>&1 | grep "Duration" | awk -F, '{print $1}' | xargs