merge-srt/merge_srt.py

296 lines
11 KiB
Python

import sys
import shlex
class SRTMerger:
def __init__(self, srt1_filename, srt2_filename, commands_filename, output_filename):
self.errors = []
self.srt1 = self.parse_srt(srt1_filename)
self.srt2 = self.parse_srt(srt2_filename)
self.commands = self.read_commands(commands_filename)
self.output = []
self.output_filename = output_filename
def parse_srt(self, filename):
entries = []
try:
with open(filename, 'r', encoding='utf-8-sig') as f:
content = f.read().strip()
except IOError as e:
self.errors.append(f"Error reading {filename}: {e}")
return entries
blocks = content.split('\n\n')
for block_number, block in enumerate(blocks, start=1):
lines = block.split('\n')
if len(lines) < 3:
self.errors.append(f"Block {block_number} in {filename} has less than 3 lines.")
continue
try:
timestamp_line = lines[1]
text = '\n'.join(lines[2:]).strip()
entries.append({
'timestamp': timestamp_line,
'text': text,
})
except Exception as e:
self.errors.append(f"Error parsing block {block_number} in {filename}: {e}")
return entries
def read_commands(self, filename):
commands = []
try:
with open(filename, 'r', encoding='utf-8') as f:
lines = f.readlines()
except IOError as e:
self.errors.append(f"Error reading {filename}: {e}")
return commands
supported = {
'COPY': self.parse_copy,
'MAP': self.parse_map,
'SYNC': self.parse_sync,
'PUT': self.parse_put,
}
for line_number, line in enumerate(lines, start=1):
parts = SRTMerger.split_line(line)
if not parts:
continue
command = parts[0].upper()
if command not in supported:
self.errors.append(f"Line {line_number}: unknown command '{command}'.")
continue
parsed = supported[command](parts)
if parsed is None:
self.errors.append(f"Line {line_number}: invalid {command} command.")
else:
commands.append(parsed)
return commands
@staticmethod
def split_line(line):
line = line.strip()
parts = []
for part in shlex.split(line, comments = True):
parts.append(part)
return parts
def parse_copy(self, parts):
if len(parts) != 3:
return None
try:
source = int(parts[1])
if source not in (1, 2):
return None
if '-' in parts[2]:
start, end = map(int, parts[2].split('-'))
else:
start = end = int(parts[2])
if start > end:
return None
except (ValueError, AttributeError, TypeError):
return None
return ('COPY', source, start, end)
def parse_map(self, parts):
if len(parts) not in (4, 5):
return None
try:
text_source = int(parts[1])
if text_source not in (1, 2):
return None
if len(parts) == 4:
# New syntax: textstart-textend
range_str = parts[2]
start_end = range_str.split('-')
if len(start_end) != 2:
return None
text_start = int(start_end[0])
text_end = int(start_end[1])
if text_start < 1 or text_end < text_start:
return None
count = text_end - text_start + 1
time_start = int(parts[3])
else:
# Original syntax: textstart, timestart, count
text_start = int(parts[2])
time_start = int(parts[3])
count = int(parts[4])
if text_start < 1 or time_start < 1 or count < 1:
return None
# Common checks
if time_start < 1 or count < 1:
return None
except (ValueError, AttributeError, TypeError):
return None
return ('MAP', text_source, text_start, time_start, count)
def parse_sync(self, parts):
if len(parts) != 4:
return None
try:
text_source = int(parts[1])
if text_source not in (1, 2):
return None
text_index = int(parts[2])
time_index = int(parts[3])
if text_index < 2 or time_index < 1:
return None
except (ValueError, AttributeError, TypeError):
return None
return ('SYNC', text_source, text_index, time_index)
def parse_put(self, parts):
if len(parts) != 4:
return None
try:
source = int(parts[1])
if source not in (1, 2):
return None
index = int(parts[2])
if index < 1:
return None
text = parts[3]
except (ValueError, TypeError) as e:
return None
return ('PUT', source, index, text)
def process_commands(self):
supported = {
'COPY': self.handle_copy,
'MAP': self.handle_map,
'SYNC': self.handle_sync,
'PUT': self.handle_put,
}
for cmd in self.commands:
supported[cmd[0]](*cmd[1:])
def handle_copy(self, source, start, end):
source_list = self.srt1 if source == 1 else self.srt2
start_idx, end_idx = start - 1, end - 1
if start_idx < 0 or end_idx >= len(source_list) or start_idx > end_idx:
self.errors.append(f"Invalid COPY command: source {source}, range {start}-{end}.")
return
self.output.extend(source_list[start_idx:end_idx + 1])
def handle_map(self, text_source, text_start, time_start, count):
time_source = text_source
text_list = self.srt1 if text_source == 1 else self.srt2
time_list = self.srt2 if time_source == 1 else self.srt1
text_start_idx = text_start - 1
time_start_idx = time_start - 1
if (text_start_idx < 0 or text_start_idx + count > len(text_list) or
time_start_idx < 0 or time_start_idx + count > len(time_list)):
self.errors.append(f"Invalid MAP command: source {text_source}, text start {text_start}, time start {time_start}, count {count}.")
return
for i in range(count):
text_entry = text_list[text_start_idx + i]
time_entry = time_list[time_start_idx + i]
self.output.append({
'timestamp': time_entry['timestamp'],
'text': text_entry['text'],
})
def handle_sync(self, text_source, text_index, time_index):
text_list = self.srt1 if text_source == 1 else self.srt2
time_list = self.srt2 if text_source == 1 else self.srt1
text_start_idx = text_index - 1
time_start_idx = time_index - 1
prev_text_idx = text_start_idx - 1
if (text_start_idx < 0 or text_start_idx >= len(text_list) or
time_start_idx < 1 or prev_text_idx < 0 or time_start_idx >= len(time_list)):
self.errors.append(f"Invalid SYNC command: text index {text_index} must be >=2 and <= {len(text_list)}, time index {time_index} must be >=1 and <= {len(time_list)}.")
return
text_entry = text_list[text_start_idx]
time_entry = time_list[time_start_idx]
prev_text_entry = text_list[prev_text_idx]
delta = self.compute_delta(prev_text_entry['timestamp'], text_entry['timestamp'])
new_ts = self.add_delta_to_timestamp(time_entry['timestamp'], delta)
self.output.append({
'timestamp': new_ts,
'text': text_entry['text'],
})
def handle_put(self, source, index, text):
source_list = self.srt1 if source == 1 else self.srt2
index_idx = index - 1
if index_idx < 0 or index_idx >= len(source_list):
self.errors.append(f"Invalid PUT command: source {source}, index {index} is out of bounds.")
return
entry = source_list[index_idx]
new_entry = {
'timestamp': entry['timestamp'],
'text': text,
}
self.output.append(new_entry)
def write_output(self):
if self.output_filename == '-':
out = sys.stdout
else:
try:
out = open(self.output_filename, 'w', encoding='utf-8')
except IOError as e:
print(f"Error writing to {self.output_filename}: {e}", file=sys.stderr)
return
try:
for i, entry in enumerate(self.output, start=1):
out.write(f"{i}\n{entry['timestamp']}\n{entry['text'].strip()}\n\n")
finally:
if out is not sys.stdout:
out.close()
@staticmethod
def parse_timestamp(ts_str):
start_str, end_str = ts_str.split(' --> ')
def parse_part(part):
parts = part.split(':')
hours = int(parts[0])
minutes = int(parts[1])
sec_ms = parts[2].split(',')
seconds = int(sec_ms[0])
ms = int(sec_ms[1])
return hours * 3600000 + minutes * 60000 + seconds * 1000 + ms
return parse_part(start_str), parse_part(end_str)
@staticmethod
def compute_delta(prev_ts_str, curr_ts_str):
prev_start, _ = SRTMerger.parse_timestamp(prev_ts_str)
curr_start, _ = SRTMerger.parse_timestamp(curr_ts_str)
return curr_start - prev_start
@staticmethod
def format_time(ms):
total_seconds = ms // 1000
ms_part = ms % 1000
hours = total_seconds // 3600
minutes = (total_seconds // 60) % 60
seconds = total_seconds % 60
return hours, minutes, seconds, ms_part
@staticmethod
def format_timestamp(start_ms, end_ms):
def format_part(h, m, s, ms):
return f"{h:02}:{m:02}:{s:02},{ms:03}"
start_h, start_m, start_s, start_ms_part = SRTMerger.format_time(start_ms)
end_h, end_m, end_s, end_ms_part = SRTMerger.format_time(end_ms)
return f"{format_part(start_h, start_m, start_s, start_ms_part)} --> {format_part(end_h, end_m, end_s, end_ms_part)}"
@staticmethod
def add_delta_to_timestamp(ts_str, delta):
start, end = SRTMerger.parse_timestamp(ts_str)
return SRTMerger.format_timestamp(start + delta, end + delta)
if __name__ == '__main__':
if len(sys.argv) != 5:
print("Usage: python merge_srt.py <srt1> <srt2> <commands> <output>", file=sys.stderr)
sys.exit(1)
srt1_filename, srt2_filename, commands_filename, output_filename = sys.argv[1:5]
merger = SRTMerger(srt1_filename, srt2_filename, commands_filename, output_filename)
if merger.errors:
for error in merger.errors:
print(error, file=sys.stderr)
sys.exit(1)
merger.process_commands()
if merger.errors:
for error in merger.errors:
print(error, file=sys.stderr)
sys.exit(1)
merger.write_output()