FFmpeg scripts: Multiple Bitrate transcoding for adaptive streaming with FFmpeg.

ffmpeg_abr_transcode.sh

#!/bin/sh
#
# ffmpeg_abr_transcode.sh
#     FFmpeg scripts: Multiple Bitrate transcoding for adaptive streaming with FFmpeg.
#
# (c) 2023 LiveInstantly, LLC. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# NOTE:
#  - This script is fixed for 30fps input video.
#  - 'High' profile video encoding is with 128kbps audio and other profiles are with 64kbps audio. 
#  - The encode spec file is as follows:
# 
# The encode spec file is a text file with multiple lines, and each line must have 3 elements with comma-separated:
#   video-width,video-hight,video-bitrate,vieo-profile
# An example of encode spec file (text file):
#  1920,1080,6000,high
#  1920,1080,4700,high
#  1280,720,3400,high
#  960,540,2250,main
#  960,540,1500,main
#  640,360,1000,main
#  640,360,650,main
#  320,180,400,baseline
#

file=$1
basename=$2
specfile=$3

print_usage() {
        echo ""
        echo "`basename $0`: ffmpeg GOP aligned encoding"
        echo "Usage: `basename $0` [filename] [output file basename]"
        echo "    [filename]:                   Input video file path and name."
        echo "    [output file basename]        Output base filename."
        echo "    [encode spec file]            Encode Spec filename."
        echo ""
        exit 1
}

if [ "x$1" = "x" ]; then
        echo "Error: No input video file path given."
        print_usage
fi
if [ "x$2" = "x" ]; then
        echo "Error: No output file basename given."
        print_usage
fi
if [ "x$3" = "x" ]; then
        echo "Error: No encode spec file given."
        print_usage
fi
if [ ! -f "$3" ]; then
        echo "Error: a given encode spec file not found."
        print_usage
fi

options="ffmpeg -threads 0"
options="${options} -i ${file}"
options="${options} -pix_fmt yuv420p"
options="${options} -r 30"
count=0

while read line
do
        width=`echo ${line} | sed 's/^\([^,]*\),\([^,]*\),\([^,]*\),\([^,]*\)$/\1/'`
        height=`echo ${line} | sed 's/^\([^,]*\),\([^,]*\),\([^,]*\),\([^,]*\)$/\2/'`
        bitrate=`echo ${line} | sed 's/^\([^,]*\),\([^,]*\),\([^,]*\),\([^,]*\)$/\3/'`
        profile=`echo ${line} | sed 's/^\([^,]*\),\([^,]*\),\([^,]*\),\([^,]*\)$/\4/'`
        bufsize=`expr ${bitrate} \* 2`
        bitrate_str=`printf "%04d" ${bitrate}`

        # Map for Video Encoding
        options="${options} -map 0:v:0 -c:v libx264"
        options="${options} -preset medium -tune film"
        options="${options} -b:v ${bitrate}k -profile:v ${profile}"
        options="${options} -minrate:v ${bitrate}k"
        options="${options} -maxrate:v ${bitrate}k"
        options="${options} -bufsize:v ${bufsize}k"
        options="${options} -vf:v scale=${width}:${height}"
        options="${options} -g 60 -x264opts no-scenecut -sc_threshold 0 -vsync 1"
        #options="${options} -g 60 -x264opts keyint=60:keyint_min=60:no-scenecut -sc_threshold 0 -vsync 1"
        options="${options} -map 0:a:0 -c:a aac"
        if [ "x${profile}" = "xhigh" ]; then
                options="${options} -b:a 128k -ac:a 2 -ar:a 48000"
        else
                options="${options} -b:a 64k -ac:a 2 -ar:a 48000"
        fi
        options="${options} -af:a aresample=async=1:min_hard_comp=0.100000:first_pts=0"
        options="${options} ${basename}_${bitrate_str}_${width}x${height}.mp4"

        count=`expr ${count} \+ 1`
done < $3

echo ${options}
exec ${options}