Create script to two-pass render a video file to a target sizemain

pass in the input, output, and target size to the script.

Sizes are in the form of: 100M, 1G, 1500k

1 files changed, 59 insertions, 0 deletions

diff --git a/two-pass.sh b/two-pass.sh
new file mode 100755
index 0000000..e9e3e15
--- /dev/null
+++ b/two-pass.sh
@@ -0,0 +1,59 @@
+#!/usr/bin/env bash
+set -x
+INPUT=$1 # input file
+OUTPUT=$2 # target file
+SIZE=$3 # [0-9]+[GgMmKk]
+TEMP=$(mktemp)
+DURATION=$(mediainfo --Inform="Video;%Duration%" $INPUT)
+durS=$(($DURATION/1000))
+if [[ "$SIZE" =~ [0-9]+[Gg] ]]; then
+    gb=${SIZE/[Gg]/}
+    kb=$(($gb * 8 * 1024 * 1024))
+fi
+if [[ "$SIZE" =~ [0-9]+[Mm] ]]; then
+    mb=${SIZE/[Mm]/}
+    kb=$(($mb * 8 * 1024)) # doing 1M = 1000K just to build in some overhead
+fi
+if [[ "$SIZE" =~ [0-9]+[Kk] ]]; then
+    k=${SIZE/[Kk]/}
+    kb=$((k * 8))
+
+fi
+if [ ! $kb ]; then
+    echo "unable to calculate bitrate"
+    exit
+fi
+audiosize=$((160*durS))
+target=$(($kb-$audiosize))
+bitrate=$(($target/$durS))
+
+
+ffmpeg -i $1 \
+       -y \
+       -f mp4 \
+       -g 15 \
+       -movflags +faststart \
+       -preset ultrafast \
+       -threads 9 \
+       -c:v libx264 \
+       -b:v ${bitrate}k \
+       -pass 1 \
+       -an \
+       -passlogfile $TEMP \
+       /dev/null
+
+ffmpeg -i $1 \
+       -y \
+       -b:a 160k \
+       -c:a aac \
+       -ac 2 \
+       -f mp4 \
+       -g 15 \
+       -movflags +faststart \
+       -preset ultrafast \
+       -threads 9 \
+       -c:v libx264 \
+       -b:v ${bitrate}k \
+       -pass 2 \
+       -passlogfile $TEMP \
+       $2