Update vad.py with more sane speech_pad_ms: int = 4000

[montvid]

In all my tests speech_pad_ms: int = 400 was too small. All other VAD numbers were good. Making speech_pad_ms: int = 4000 2x the min_silence_duration_ms: int = 2000 fixed all my problems. Maybe someone forgot to add another 0?

Here it is doubled too:
https://github.com/jhj0517/Whisper-WebUI/blob/master/configs/default_parameters.yaml
vad:
vad_filter: false
threshold: 0.5
min_speech_duration_ms: 250
max_speech_duration_s: 9999
min_silence_duration_ms: 1000
speech_pad_ms: 2000

[MahmoudAshraf97]

Hello, it doesn't make sense to pad 4s on each side when most silences are less than that, the padding here is to account for slight segment boundaries inacccuracies i.e. not to cut a word in the middle, if 4000 works the best for you, then I guess turning the VAD off completely might be a better solution.
Anyways, I'm not in favor of changing the default value, users have the option to change it if their own use cases need it

[montvid]

Thank you for the explanation. I checked my transcription and indeed it has sometimes 1 word or 1 sentence missing. A major headache how to adjust the VAD :(