srtUtils.py

# ==================================================================================
# Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.

# Permission is hereby granted, free of charge, to any person obtaining a copy of this
# software and associated documentation files (the "Software"), to deal in the Software
# without restriction, including without limitation the rights to use, copy, modify,
# merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
# INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
# PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
# ==================================================================================
#
# srtUtils.py
# by: Rob Dachowski
# For questions or feedback, please contact robdac@amazon.com
# 
# Purpose: The program provides a number of utility functions for creating SubRip Subtitle files (.SRT)
#
# Change Log:
#          6/29/2018: Initial version
#
# ==================================================================================

import json
import boto3
import re
import codecs
from audioUtils import *



# ==================================================================================
# Function: newPhrase
# Purpose: simply create a phrase tuple
# Parameters: 
#                 None
# ==================================================================================
def newPhrase():
	return { 'start_time': '', 'end_time': '', 'words' : [] }


	
# ==================================================================================
# Function: getTimeCode
# Purpose: Format and return a string that contains the converted number of seconds into SRT format
# Parameters: 
#                 seconds - the duration in seconds to convert to HH:MM:SS,mmm 
# ==================================================================================	
	# Format and return a string that contains the converted number of seconds into SRT format
def getTimeCode(seconds):
	t_hund = int(seconds % 1 * 1000)
	t_seconds = int(seconds)
	t_secs = ((float(t_seconds) / 60) % 1) * 60
	t_mins = int(t_seconds / 60)
	return str("%02d:%02d:%02d,%03d" % (00, t_mins, int(t_secs), t_hund))
	

# ==================================================================================
# Function: writeTranscriptToSRT
# Purpose: Function to get the phrases from the transcript and write it out to an SRT file
# Parameters: 
#                 transcript - the JSON output from Amazon Transcribe
#                 sourceLangCode - the language code for the original content (e.g. English = "EN")
#                 srtFileName - the name of the SRT file (e.g. "mySRT.SRT")
# ==================================================================================	
def writeTranscriptToSRT(transcript, sourceLangCode, srtFileName):
	# Write the SRT file for the original language
	print("\n==> Creating SRT from transcript")
	phrases = getPhrasesFromTranscript(transcript)
	writeSRT(phrases, srtFileName)
	

# ==================================================================================
# Function: writeTranscriptToSRT
# Purpose: Based on the JSON transcript provided by Amazon Transcribe, get the phrases from the translation 
#          and write it out to an SRT file
# Parameters: 
#                 transcript - the JSON output from Amazon Transcribe
#                 sourceLangCode - the language code for the original content (e.g. English = "EN")
#                 targetLangCode - the language code for the translated content (e.g. Spanich = "ES")
#                 srtFileName - the name of the SRT file (e.g. "mySRT.SRT")
# ==================================================================================
def writeTranslationToSRT(transcript, sourceLangCode, targetLangCode, srtFileName, region, avOutput):
	# First get the translation
	print("\n\n==> Translating from " + sourceLangCode + " to " + targetLangCode)
	translation = translateTranscript(transcript, sourceLangCode, targetLangCode, region)
	#print("\n\n==> Translation: " + str(translation))
		
	# Now create phrases from the translation
	textToTranslate = unicode(translation["TranslatedText"])
	phrases = getPhrasesFromTranslation(textToTranslate, targetLangCode)
	writeSRT(phrases, srtFileName)
	

# ==================================================================================
# Function: getPhrasesFromTranslation
# Purpose: Based on the JSON translation provided by Amazon Translate, get the phrases from the translation 
#          and write it out to an SRT file.  Note that since we are using a block of translated text rather than
#          a JSON structure with the timing for the start and end of each word as in the output of Transcribe,
#          we will need to calculate the start and end-time for each phrase
# Parameters: 
#                 translation - the JSON output from Amazon Translate
#                 targetLangCode - the language code for the translated content (e.g. Spanich = "ES")
# ==================================================================================	
def getPhrasesFromTranslation(translation, targetLangCode):

	# Now create phrases from the translation
	words = translation.split()
	
	#print(words) #debug statement
	
	#set up some variables for the first pass
	phrase =  newPhrase()
	phrases = []
	nPhrase = True
	x = 0
	c = 0
	seconds = 0

	print "==> Creating phrases from translation..."

	for word in words:

		# if it is a new phrase, then get the start_time of the first item
		if nPhrase == True:
			phrase["start_time"] = getTimeCode(seconds)
			nPhrase = False
			c += 1
				
		# Append the word to the phrase...
		phrase["words"].append(word)
		x += 1
		
		
		# now add the phrase to the phrases, generate a new phrase, etc.
		if x == 10:
		
			# For Translations, we now need to calculate the end time for the phrase
			psecs = getSecondsFromTranslation(getPhraseText(phrase), targetLangCode, "phraseAudio" + str(c) + ".mp3") 
			seconds += psecs
			phrase["end_time"] = getTimeCode(seconds)
		
			#print c, phrase
			phrases.append(phrase)
			phrase = newPhrase()
			nPhrase = True
			#seconds += .001
			x = 0
			
		# This if statement is to address a defect in the SubtitleClip.   If the Subtitles end up being
		# a different duration than the content, MoviePy will sometimes fail with unexpected errors while
		# processing the subclip.   This is limiting it to something less than the total duration for our example
		# however, you may need to modify or eliminate this line depending on your content.
		if c == 30:
			break
			
	return phrases
	

# ==================================================================================
# Function: getPhrasesFromTranscript
# Purpose: Based on the JSON transcript provided by Amazon Transcribe, get the phrases from the translation 
#          and write it out to an SRT file
# Parameters: 
#                 transcript - the JSON output from Amazon Transcribe
# ==================================================================================
def getPhrasesFromTranscript(transcript):

	# This function is intended to be called with the JSON structure output from the Transcribe service.  However,
	# if you only have the translation of the transcript, then you should call getPhrasesFromTranslation instead

	# Now create phrases from the translation
	ts = json.loads(transcript)
	items = ts['results']['items']
	#print(items)
	
	#set up some variables for the first pass
	phrase =  newPhrase()
	phrases = []
	nPhrase = True
	x = 0
	c = 0

	print "==> Creating phrases from transcript..."

	for item in items:

		# if it is a new phrase, then get the start_time of the first item
		if nPhrase == True:
			if item["type"] == "pronunciation":
				phrase["start_time"] = getTimeCode(float(item["start_time"]))
				nPhrase = False
			c+= 1
		else:	
			# get the end_time if the item is a pronuciation and store it
			# We need to determine if this pronunciation or puncuation here
			# Punctuation doesn't contain timing information, so we'll want
			# to set the end_time to whatever the last word in the phrase is.
			if item["type"] == "pronunciation":
				phrase["end_time"] = getTimeCode(float(item["end_time"]))
				
		# in either case, append the word to the phrase...
		phrase["words"].append(item['alternatives'][0]["content"])
		x += 1
		
		# now add the phrase to the phrases, generate a new phrase, etc.
		if x == 10:
			#print c, phrase
			phrases.append(phrase)
			phrase = newPhrase()
			nPhrase = True
			x = 0
			
	return phrases
	



# ==================================================================================
# Function: translateTranscript
# Purpose: Based on the JSON transcript provided by Amazon Transcribe, get the JSON response of translated text
# Parameters: 
#                 transcript - the JSON output from Amazon Transcribe
#                 sourceLangCode - the language code for the original content (e.g. English = "EN")
#                 targetLangCode - the language code for the translated content (e.g. Spanich = "ES")
#                 region - the AWS region in which to run the Translation (e.g. "us-east-1")
# ==================================================================================
def translateTranscript(transcript, sourceLangCode, targetLangCode, region):
	# Get the translation in the target language.  We want to do this first so that the translation is in the full context
	# of what is said vs. 1 phrase at a time.  This really matters in some lanaguages

	# stringify the transcript
	ts = json.loads(transcript)

	# pull out the transcript text and put it in the txt variable
	txt = ts["results"]["transcripts"][0]["transcript"]
		
	#set up the Amazon Translate client
	translate = boto3.client(service_name='translate', region_name=region, use_ssl=True)
	
	# call Translate  with the text, source language code, and target language code.  The result is a JSON structure containing the 
	# translated text
	translation = translate.translate_text(Text=txt,SourceLanguageCode=sourceLangCode, TargetLanguageCode=targetLangCode)
	
	return translation
	
	

# ==================================================================================
# Function: writeSRT
# Purpose: Iterate through the phrases and write them to the SRT file
# Parameters: 
#                 phrases - the array of JSON tuples containing the phrases to show up as subtitles
#                 filename - the name of the SRT output file (e.g. "mySRT.srt")
# ==================================================================================
def writeSRT(phrases, filename):
	print "==> Writing phrases to disk..."

	# open the files
	e = codecs.open(filename,"w+", "utf-8")
	x = 1
	
	for phrase in phrases:

		# determine how many words are in the phrase
		length = len(phrase["words"])
		
		# write out the phrase number
		e.write(str(x) + "\n")
		x += 1
		
		# write out the start and end time
		e.write(phrase["start_time"] + " --> " + phrase["end_time"] + "\n")
					
		# write out the full phase.  Use spacing if it is a word, or punctuation without spacing
		out = getPhraseText(phrase)

		# write out the srt file
		e.write(out + "\n\n")
		

		#print out
		
	e.close()
	

# ==================================================================================
# Function: getPhraseText
# Purpose: For a given phrase, return the string of words including punctuation
# Parameters: 
#                 phrase - the array of JSON tuples containing the words to show up as subtitles
# ==================================================================================

def getPhraseText(phrase):

	length = len(phrase["words"])
		
	out = ""
	for i in range(0, length):
		if re.match('[a-zA-Z0-9]', phrase["words"][i]):
			if i > 0:
				out += " " + phrase["words"][i]
			else:
				out += phrase["words"][i]
		else:
			out += phrase["words"][i]
			
	return out