How to Hardsub Sinhala subtitles on Linux using FFmpeg

The process of burning subtitles to a video is called "Subtitle Hard-subbing" or "Subtitle Hard-coding". This is very useful when you want to watch movies with Sinhala subtitles on TVs without Unicode support. This will basically paint subtitles on relevant frames.

Before doing this remember, you can't separate subtitle from a hard-subbed video. So, always keep the original video and subtitle file. This process is not equal to the "Mux" option in mkvtoonix.

To make everything smooth, I made this simple Python script to do this. (I'm not a Python expert. So, pardon me if this code is shit.)

	#!/usr/bin/python3
	#
	# - This script can be used to hardsub Sinhala subtitle files.
	# - If your input video is in H.265 output will be created in H.264.
	#
	# - You need to have following packages installed on your system to use this.
	# - python3
	# - ffmpeg
	# - mediainfo
	#
	#
	import sys
	import getopt
	import subprocess
	import io
	from pathlib import Path
	def main(argv):
	inputFile = ""
	subFile = ""
	outputPath = ""
	try:
	opts, args = getopt.getopt(
	argv, "hi:s:o:", ["input=", "subtitle=", "outputpath="])
	except getopt.GetoptError:
	print('si_hardsub -i <inputfile> -s <subtitle>')
	sys.exit(2)
	for opt, arg in opts:
	if opt == '-h':
	print('si_hardsub -i <inputfile> -s <subtitle>')
	sys.exit()
	elif opt in ("-i", "--input"):
	inputFile = arg
	elif opt in ("-s", "--subtitle"):
	subFile = str(arg)
	elif opt in ("-o", "--outputpath"):
	outputPath = str(arg)
	if (inputFile == "" or subFile == ""):
	print('si_hardsub -i <inputFile> -s <subtitle>')
	sys.exit(2)
	# copy sub file to temp
	bashCommand = ["cp", subFile, "/tmp"]
	process = subprocess.Popen(bashCommand, stdout=subprocess.PIPE)
	process.wait()
	#remove temp file
	bashCommand = ["rm", "/tmp/input.ass"]
	process = subprocess.Popen(bashCommand, stdout=subprocess.PIPE)
	process.wait()
	# create subtitle file
	outputPathAuto = Path(subFile).resolve().parent
	subFile = "/tmp/" + Path(subFile).resolve().name
	convertedSubFile = "/tmp/input.ass"
	bashCommand = ["ffmpeg", "-i", subFile, convertedSubFile]
	process = subprocess.Popen(bashCommand, stdout=subprocess.PIPE)
	process.wait()
	# Optional : Resize font size [START]
	content = Path(convertedSubFile).read_text()
	content = content.replace(
	"Style: Default,Arial,16", "Style: Default,Arial,21")
	with io.open(convertedSubFile, 'w', encoding='utf8') as subFile:
	subFile.write(content)
	# Optional: Resize font size[END]
	# Get media info
	bashCommand = ["mediainfo", inputFile]
	process = subprocess.Popen(bashCommand, stdout=subprocess.PIPE)
	mediainfo, err = process.communicate()
	process.wait()
	if (outputPath == ""):
	outputFile = str(outputPathAuto) + "/converted_" + \
	Path(inputFile).resolve().stem + ".mp4"
	else:
	outputFile = str(outputPath) + "converted_" + \
	Path(inputFile).resolve().stem + ".mp4"
	if ("HEVC" in str(mediainfo)):
	bashCommand = ['ffmpeg', '-i', inputFile, '-bsf:v', 'h264_mp4toannexb', '-sn', '-map', '0:0', '-map',
	'0:1', '-vcodec', 'libx264', '-vf', 'ass=/tmp/input.ass', outputFile]
	else:
	bashCommand = ['ffmpeg', '-i', inputFile,
	'-vf', 'ass=/tmp/input.ass', outputFile]
	process = subprocess.Popen(bashCommand, stdout=subprocess.PIPE)
	process.wait()
	if __name__ == "__main__":
	main(sys.argv[1:])

view raw si_hardsub.py hosted with ❤ by GitHub

You can run this script as below,

1) First give executable permission to the script.
sudo chmod +x si_hardsub.py
2) Then run it. ./si_hardsub.py -i test.mp4 -s test.srt