!!!Only for timcodes with frame expressions!!!

ttml2srt3.py

'''The simplest of all TTML to SRT subtitle converters, might not work in every case but it works for me'''
from xmltodict import parse
import json

def zfillseconds(input):
	secondsP1, secondsP2 = input.split(',')
	secondsP1 = secondsP1.zfill(2)
	while len(secondsP2) != 3:
		secondsP2 += '0'
	
	return secondsP1 + ',' + secondsP2
	
	
def convert2srt(content, framerate = None):
	tojson = parse(content)
	p = tojson['tt']['body']['div']['p']
	
	if not framerate:
		framerate = int(tojson['tt']['@ttp:frameRate'])
	

	data = []
	for element in p:
		
		time_stamp_begin = element['@begin']
		time_stamp_end = element['@end']
		
		full_seconds_begin = int(time_stamp_begin.split(':')[2])
		frames_begin = int(time_stamp_begin.split(':')[3])
		seconds_from_frames_begin = float(f'{frames_begin/framerate:0.03f}')
		all_seconds_begin = full_seconds_begin + seconds_from_frames_begin
		seconds_srt_begin = zfillseconds(str(all_seconds_begin).replace('.',','))
		srt_time_stamp_begin = time_stamp_begin[:-5] + seconds_srt_begin
		
		full_seconds_end = int(time_stamp_end.split(':')[2])
		frames_end = int(time_stamp_end.split(':')[3])
		seconds_from_frames_end = float(f'{frames_end/framerate:0.03f}')
		all_seconds_end = full_seconds_end + seconds_from_frames_end
		seconds_srt_end = zfillseconds(str(all_seconds_end).replace('.',','))
		srt_time_stamp_end = time_stamp_end[:-5] + seconds_srt_end
		if not '#text' in element:
			element['#text'] = ''
		data.append((srt_time_stamp_begin, srt_time_stamp_end, element['#text']))
	
	
	srt_lines = []
	for idx, (begin, end, text) in enumerate(data):
		if begin != data[idx-1][0]:
			srt_lines.append('\n' + str(idx+1))
			srt_lines.append(begin +' --> ' + end )
			srt_lines.append(text)
		else:
			srt_lines.append(text)		
		#~ break
		
	return '\n'.join(srt_lines)
	
	#~ print(json.dumps(tt))




if __name__ == '__main__':
	with open('subtitle.tt','r', encoding = 'utf-8-sig') as f:
		print(convert2srt(f.read()))