SUMMARY

When trying to transcribe any sound using the installed transcribe plugin, the plugin crashes after a short while with a Python backtrace in the logs.


STEPS TO REPRODUCE
1. Start KdenLive
2. Add a Sound file and select it
3. Click Transcribe
4. Wait
5. See Logs

OBSERVED RESULT
```
/home/d0/.var/app/org.kde.kdenlive/data/kdenlive/venv/lib/python3.12/site-packages/whisper/transcribe.py:124: UserWarning: Performing inference on CPU when CUDA is available
  warnings.warn("Performing inference on CPU when CUDA is available")
Traceback (most recent call last):
  File "/app/share/kdenlive/scripts/whisper/whispertotext.py", line 192, in <module>
    sys.exit(main())
             ^^^^^^
  File "/app/share/kdenlive/scripts/whisper/whispertotext.py", line 174, in main
    result = run_whisper(source, model, device, task, jobArgs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/share/kdenlive/scripts/whisper/whispertotext.py", line 126, in run_whisper
    result = loadedModel.transcribe(source, **transcribe_kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/d0/.var/app/org.kde.kdenlive/data/kdenlive/venv/lib/python3.12/site-packages/whisper/transcribe.py", line 155, in transcribe
    tokenizer = get_tokenizer(
                ^^^^^^^^^^^^^^
  File "/home/d0/.var/app/org.kde.kdenlive/data/kdenlive/venv/lib/python3.12/site-packages/whisper/tokenizer.py", line 380, in get_tokenizer
    raise ValueError(f"Unsupported language: {language}")
ValueError: Unsupported language: language
```


EXPECTED RESULT

Loading bar should load and display transcription after a while

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Kubuntu 24.04
KDE Plasma Version: 6.3.2
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION

Since I am an avid Python-dev I can also found the culpit: https://github.com/KDE/kdenlive/blob/965d9ffad5e0848bf0d6657df32489c555124d86/data/scripts/whisper/whispertotext.py#L166

On line 166 you do
    language = args.language
Then on line 172
   jobArgs = f"language={language} "

There are two problems here:

[1] The value of args.language isn't simply "English", it already contains the variable name, so it is "language=English". When you then set jobArgs i nline 172 jobArgs doesn't become "language=English" but "language=language=English" which is obviously wrong

[2] The Whisper API doesn't expect the string "English" it expects an ISO-639-1 language code (e.g. "en" for English or "de" for German). This means there needs to be a mapping function somewhere

Adding the following below line 166 makes it work for me:

    # Take the latter part of "language=English" by splitting at the equals sign
    language = language.split("=")[1]

    # Map Language to two-letter ISO-639-1 code
    LANGUAGE_TO_ISO = {
            "English" : "en",
            "German" : "de",
            # More needs to be added here
            }
    language = LANGUAGE_TO_ISO.get(language)

Please note that this may not be usable in production, since this will fail if language doesn't contain "=". For a production code it would probably be better to fix this upstream in the part that sends the language string and make it send a propper ISO-639-1 two letter code from the start. But those who just need it to work and have that issue could edit the file...