Implement Parallel Processing for Performance Improvement

[Shadows97]

The current processing of audio and video files in PySubtitle is sequential, which can be slow for large files. Implementing parallel processing can significantly improve performance.

Tasks:

• Investigate and implement parallel processing techniques for audio extraction and speech recognition.
• Ensure that the parallel processing implementation is thread-safe and efficient.
• Update the documentation to include information on performance improvements.

[hcm444]

concurrent.futures is probably an easy way

[Shadows97]

Yes but have already add it on your last pull req. It will be good if each new addition to the code is made on a branch associated with the issue concerned. This allows better visibility