How to Convert Subtitle File to have Only ONE Sentence Per Subtitle?
I have re-coded to rely on the pysrt package, as requested, and a smigeon of re.
The idea is to build a dictionary based on start_times.
If the start time exists, data is added to the entry for that time but the end_time is updated at the same time, so the end time advances with the text.
If no start time exists, it is simply a new dictionary entry.
The start time is only advanced once we know that a sentence has been completed.
So in essence, we start to build a sentence with a fixed start time. The sentence continues to be built, by adding more text and updating the end time, until the sentence finishes. Here we advance the start time using the current record, which we know to be a new sentence.
Sub-title entries with multiple sentences are broken up, with start and end times calculated using the pysrt character_per_second entry for the entire sub-title entry, before it was broken up.
Finally, a new sub-title file is written to disk from the entries in the dictionary.
Obviously, with only a single file to play with, I may well be missing some sub-title layout humps in the road, but at least it gives you a working starting point.
The code is commented throughout, so most things should be clear, as to how and why.
Edit:
I have refined the checking for existing dictionary start times and altered the method used to decide if a sentence has ended i.e. put the full stops back into the text, after splitting.
The second video you mentioned does have sub-titles that are slightly off, to begin with, notice that there are no milli-second values at all.
The following code does a fair job on the second video and a good job on the first.
Edit 2: Added contiguous full-stops and html <> tag removal
Edit 3: It turns out that pysrt removes the html tags from the calculation for characters per second. I have now done so as well, which means that the <html> formatting can be retained within the sub-titles.
Edit 4: This version copes with full stops in mathematical and chemical formulae, plus ip numbers etc. Basically places where a full stop doesn't mean a full stop. It also allows for sentences which end in ? and !
import pysrt
import re
abbreviations = ['Dr.','Mr.','Mrs.','Ms.','etc.','Jr.','e.g.'] # You get the idea!
abbrev_replace = ['Dr','Mr','Mrs','Ms','etc','Jr','eg']
subs = pysrt.open('new.srt')
subs_dict = {} # Dictionary to accumulate new sub-titles (start_time:[end_time,sentence])
start_sentence = True # Toggle this at the start and end of sentences
# regex to remove html tags from the character count
tags = re.compile(r'<.*?>')
# regex to split on ".", "?" or "!" ONLY if it is preceded by something else
# which is not a digit and is not a space. (Not perfect but close enough)
# Note: ? and ! can be an issue in some languages (e.g. french) where both ? and !
# are traditionally preceded by a space ! rather than!
end_of_sentence = re.compile(r'([^\s\0-9][\.\?\!])')
# End of sentence characters
eos_chars = set([".","?","!"])
for sub in subs:
if start_sentence:
start_time = sub.start
start_sentence = False
text = sub.text
#Remove multiple full-stops e.g. "and ....."
text = re.sub('\.+', '.', text)
# Optional
for idx, abr in enumerate(abbreviations):
if abr in text:
text = text.replace(abr,abbrev_replace[idx])
# A test could also be made for initials in names i.e. John E. Rotten - showing my age there ;)
multi = re.split(end_of_sentence,text.strip())
cps = sub.characters_per_second
# Test for a sub-title with multiple sentences
if len(multi) > 1:
# regex end_of_sentence breaks sentence start and sentence end into 2 parts
# we need to put them back together again.
# hence the odd range because the joined end part is then deleted
for cnt in range(divmod(len(multi),2)[0]): # e.g. len=3 give 0 | 5 gives 0,1 | 7 gives 0,1,2
multi[cnt] = multi[cnt] + multi[cnt+1]
del multi[cnt+1]
for part in multi:
if len(part): # Avoid blank parts
pass
else:
continue
# Convert start time to seconds
h,m,s,milli = re.split(':|,',str(start_time))
s_time = (3600*int(h))+(60*int(m))+int(s)+(int(milli)/1000)
# test for existing data
try:
existing_data = subs_dict[str(start_time)]
end_time = str(existing_data[0])
h,m,s,milli = re.split(':|,',str(existing_data[0]))
e_time = (3600*int(h))+(60*int(m))+int(s)+(int(milli)/1000)
except:
existing_data = []
e_time = s_time
# End time is the start time or existing end time + the time taken to say the current words
# based on the calculated number of characters per second
# use regex "tags" to remove any html tags from the character count.
e_time = e_time + len(tags.sub('',part)) / cps
# Convert start to a timestamp
s,milli = divmod(s_time,1)
m,s = divmod(int(s),60)
h,m = divmod(m,60)
start_time = "{:02d}:{:02d}:{:02d},{:03d}".format(h,m,s,round(milli*1000))
# Convert end to a timestamp
s,milli = divmod(e_time,1)
m,s = divmod(int(s),60)
h,m = divmod(m,60)
end_time = "{:02d}:{:02d}:{:02d},{:03d}".format(h,m,s,round(milli*1000))
# if text already exists add the current text to the existing text
# if not use the current text to write/rewrite the dictionary entry
if existing_data:
new_text = existing_data[1] + " " + part
else:
new_text = part
subs_dict[str(start_time)] = [end_time,new_text]
# if sentence ends re-set the current start time to the end time just calculated
if any(x in eos_chars for x in part):
start_sentence = True
start_time = end_time
print ("Split",start_time,"-->",end_time,)
print (new_text)
print('\n')
else:
start_sentence = False
else: # This is Not a multi-part sub-title
end_time = str(sub.end)
# Check for an existing dictionary entry for this start time
try:
existing_data = subs_dict[str(start_time)]
except:
existing_data = []
# if it already exists add the current text to the existing text
# if not use the current text
if existing_data:
new_text = existing_data[1] + " " + text
else:
new_text = text
# Create or Update the dictionary entry for this start time
# with the updated text and the current end time
subs_dict[str(start_time)] = [end_time,new_text]
if any(x in eos_chars for x in text):
start_sentence = True
print ("Single",start_time,"-->",end_time,)
print (new_text)
print('\n')
else:
start_sentence = False
# Generate the new sub-title file from the dictionary
idx=0
outfile = open('video_new.srt','w')
for key, text in subs_dict.items():
idx+=1
outfile.write(str(idx)+"\n")
outfile.write(key+" --> "+text[0]+"\n")
outfile.write(text[1]+"\n\n")
outfile.close()
The output after passing through the above code for your video.srt file is as follows:
1
00:00:13,100 --> 00:00:27,280
Dr Martin Luther King, Jr, in a 1968 speech where he reflects
upon the Civil Rights Movement, states, "In the end, we will remember not the words of our enemies but the silence of our friends."
2
00:00:27,280 --> 00:00:29,800
As a teacher, I've internalized this message.
3
00:00:29,800 --> 00:00:39,701
Every day, all around us, we see the consequences of silence manifest themselves in the form of discrimination, violence, genocide and war.
4
00:00:39,701 --> 00:00:46,178
In the classroom, I challenge my students to explore the silences in their own lives through poetry.
5
00:00:46,178 --> 00:00:54,740
We work together to fill those spaces, to recognize them, to name them, to understand that they don't
have to be sources of shame.
6
00:00:54,740 --> 00:01:14,408
In an effort to create a culture within my classroom where students feel safe sharing the intimacies of their own silences, I have four core principles posted on the board that sits in the front of my class, which every student signs
at the beginning of the year: read critically, write consciously, speak clearly, tell your truth.
7
00:01:14,408 --> 00:01:18,871
And I find myself thinking a lot about that last point, tell your truth.
8
00:01:18,871 --> 00:01:28,848
And I realized that if I was going to ask my students to speak up, I was going to have to tell my truth and be honest with them about the times where I failed to do so.
9
00:01:28,848 --> 00:01:44,479
So I tell them that growing up, as a kid in a Catholic family in New Orleans, during Lent I was always taught that the most meaningful thing one could do was to give something up, sacrifice something you typically indulge in to prove to God you understand his sanctity.
10
00:01:44,479 --> 00:01:50,183
I've given up soda, McDonald's, French fries, French kisses, and everything in between.
11
00:01:50,183 --> 00:01:54,071
But one year, I gave up speaking.
12
00:01:54,071 --> 00:02:03,286
I figured the most valuable thing I could sacrifice was my own voice, but it was like I hadn't realized that I had given that up a long time ago.
13
00:02:03,286 --> 00:02:23,167
I spent so much of my life telling people the things they wanted to hear instead of the things they needed to, told myself I wasn't meant to be anyone's conscience because I still had to figure out being my own, so sometimes I just wouldn't say anything, appeasing ignorance with my silence, unaware that validation doesn't need words to endorse its existence.
14
00:02:23,167 --> 00:02:29,000
When Christian was beat up for being gay, I put my hands in my pocket and walked with my head
down as if I didn't even notice.
15
00:02:29,000 --> 00:02:39,502
I couldn't use my locker for weeks
because the bolt on the lock reminded me of the one I had put on my lips when the homeless man on the corner looked at me with eyes up merely searching for an affirmation that he was worth seeing.
16
00:02:39,502 --> 00:02:43,170
I was more concerned with
touching the screen on my Apple than actually feeding him one.
17
00:02:43,170 --> 00:02:46,049
When the woman at the fundraising gala said "I'm so proud of you.
18
00:02:46,049 --> 00:02:53,699
It must be so hard teaching
those poor, unintelligent kids," I bit my lip, because apparently
we needed her money more than my students needed their dignity.
19
00:02:53,699 --> 00:03:02,878
We spend so much time listening to the things people are saying that we rarely pay attention to the things they don't.
20
00:03:02,878 --> 00:03:06,139
Silence is the residue of fear.
21
00:03:06,139 --> 00:03:09,615
It is feeling your flaws gut-wrench guillotine your tongue.
22
00:03:09,615 --> 00:03:13,429
It is the air retreating from your chest because it doesn't feel safe in your lungs.
23
00:03:13,429 --> 00:03:15,186
Silence is Rwandan genocide.
24
00:03:15,186 --> 00:03:16,423
Silence is Katrina.
25
00:03:16,553 --> 00:03:19,661
It is what you hear when there
aren't enough body bags left.
26
00:03:19,661 --> 00:03:22,062
It is the sound after the noose is already tied.
27
00:03:22,062 --> 00:03:22,870
It is charring.
28
00:03:22,870 --> 00:03:23,620
It is chains.
29
00:03:23,620 --> 00:03:24,543
It is privilege.
30
00:03:24,543 --> 00:03:25,178
It is pain.
31
00:03:25,409 --> 00:03:28,897
There is no time to pick your battles when your battles have already picked you.
32
00:03:28,897 --> 00:03:31,960
I will not let silence wrap itself around my indecision.
33
00:03:31,960 --> 00:03:36,287
I will tell Christian that he is a lion, a sanctuary of bravery and brilliance.
34
00:03:36,287 --> 00:03:42,340
I will ask that homeless man what his name is and how his day was, because sometimes all people want to be is human.
35
00:03:42,340 --> 00:03:51,665
I will tell that woman that my students can talk about transcendentalism like their last name was Thoreau, and just because you watched
one episode of "The Wire" doesn't mean you know anything about my kids.
36
00:03:51,665 --> 00:04:03,825
So this year, instead of giving something up, I will live every day as if there were a microphone tucked under my tongue, a stage on the underside of my inhibition.
37
00:04:03,825 --> 00:04:10,207
Because who has to have a soapbox when all you've ever needed is your voice?
38
00:04:10,207 --> 00:04:12,712
Thank you.
39
00:04:12,712 --> 00:00:00,000
(Applause)
It may not be what you are after but rather than calculate the times, why not take them directly out of the subtitle file itself.
I mocked this up as an example. It isn't perfect by a long shot but it may help.
import re
#Pre-process file to remove blank lines, line numbers and timestamp --> chars
with open('video.srt','r') as f:
lines = f.readlines()
with open('video.tmp','w') as f:
for line in lines:
line = line.strip()
if line.strip():
if line.strip().isnumeric():
continue
else:
line = line.replace(' --> ', ' ')
line = line+" "
f.write(line)
# Process pre-processed file
with open('video.tmp','r') as f:
lines = f.readlines()
outfile = open('new_video.srt','w')
idx = 0
# Define the regex options we will need
#regex to look for the time stamps in each sentence using the first and last only
timestamps = re.compile('\d{1,2}(?::\d{2}){1,2}(?:,)\d{3}')
#regex to remove html tags from length calculations
tags = re.compile(r'<.*?>')
#re.split('([^\s\0-9]\.)',a)
# This is to cope with text that contains mathematical, chemical formulae, ip addresses etc
# where "." does not mean full-stop (end of sentence)
# This is used to split on a "." only if it is NOT preceded by space or a number
# this should catch most things but will fail to split the sentence if it genuinely
# ends with a number followed by a full-stop.
end_of_sentence = re.compile(r'([^\s\0-9]\.)')
#sentences = str(lines).split('.')
sentences = re.split(end_of_sentence,str(lines))
# Because the sentences where split on "x." we now have to add that back
# so we concatenate every other list item with the previous one.
idx = 0
joined =[]
while idx < (len(sentences) -1) :
joined.append(sentences[idx]+sentences[idx+1])
idx += 2
sentences = joined
previous_timings =["00:00:00,000","00:00:00,000"]
previous_sentence = ""
#Dictionary of timestamps that will require post-processing
registry = {}
loop = 0
for sentence in sentences:
print(sentence)
timings = timestamps.findall(sentence)
idx+=1
outfile.write(str(idx)+"\n")
if timings:
#There are timestamps in the sentence
previous_timings = timings
loop = 0
start_time = timings[0]
end_time = timings[-1]
# Revert list item to a string
sentence = ''.join(sentence)
# Remove timestamps from the text
sentence = ''.join(re.sub(timestamps,' ', sentence))
# Get rid of multiple spaces and \ characters
sentence = ' '.join(sentence.split())
sentence = sentence.replace(' ', ' ')
sentence = sentence.replace("\\'", "'")
previous_sentence = sentence
print("Starts at", start_time)
print(sentence)
print("Ends at", end_time,'\n')
outfile.write(start_time+" --> "+end_time+"\n")
outfile.write(sentence+"\n\n")
else:
# There are no timestamps in the sentence therefore this must
# be a separate sentence cut adrift from an existing timestamp
# We will have to estimate its start and end times using data
# from the last time stamp we know of
start_time = previous_timings[0]
reg_end_time = previous_timings[-1]
# Convert timestamp to seconds
h,m,s,milli = re.split(':|,',start_time)
s_time = (3600*int(h))+(60*int(m))+int(s)+(int(milli)/1000)
# Guess the timing for the previous sentence and add it
# but only for the first adrift sentence as the start time will be adjusted
# This number may well vary depending on the cadence of the speaker
if loop == 0:
registry[reg_end_time] = reg_end_time
#s_time += 0.06 * len(previous_sentence)
s_time += 0.06 * len(tags.sub('',previous_sentence))
# Guess the end time
e_time = s_time + (0.06 * len(tags.sub('',previous_sentence)))
# Convert start to a timestamp
s,milli = divmod(s_time,1)
m,s = divmod(int(s),60)
h,m = divmod(m,60)
start_time = "{:02d}:{:02d}:{:02d},{:03d}".format(h,m,s,round(milli*1000))
# Convert end to a timestamp
s,milli = divmod(e_time,1)
m,s = divmod(int(s),60)
h,m = divmod(m,60)
end_time = "{:02d}:{:02d}:{:02d},{:03d}".format(h,m,s,round(milli*1000))
#Register new end time for previous sentence
if loop == 0:
loop = 1
registry[reg_end_time] = start_time
print("Starts at", start_time)
print(sentence)
print("Ends at", end_time,'\n')
outfile.write(start_time+" --> "+end_time+"\n")
outfile.write(sentence+"\n\n")
try:
# re-set the previous start time in case the following sentence
# was cut adrift from its time stamp as well
previous_timings[0] = end_time
except:
pass
outfile.close()
#Post processing
if registry:
outfile = open('new_video.srt','r')
text = outfile.read()
new_text = text
# Run through registered end times and replace them
# if not the video player will not display the subtitles
# correctly because they overlap in time
for key, end in registry.items():
new_text = new_text.replace(key, end, 1)
print("replacing", key, "with", end)
outfile.close()
outfile = open('new_video.srt','w')
outfile.write(new_text)
outfile.close()
Edit:
Happily, I persevered with this code because I was intrigued by the problem.
Whilst I appreciate that it is hackey and doesn't use the pysrt subtitle module, just re, I believe that, in this instance, it does a fair job.
I have commented the edited code, so hopefully it will be clear what I am doing and why.
The regx is looking for timestamp patterns 0:00:0,000, 00:00:00,000, 0:00:00,000 etc i.e.
\d{1,2}(?::\d{2}){1,2}(?:,)\d{3}
1 or 2 decimals followed by : plus 2 decimals followed by : plus 1 or 2 decimals followed by :, followed by 3 decimals
If a concatenated sentence has multiple start and end times within it, for the whole sentence we only require the first, the sentence start time, and the last, the sentence end time. I hope that is clear.
Edit 2 This version copes with full stops in mathematical and chemical formulae, plus ip numbers etc. Basically places where a full stop doesn't mean a full stop.
