VS 2022 Subtitle Editor Waveform View Inactive

[GilesUK]

Help! The subtitle editor in Visual Studio 2022 no longer shows the waveform view for videos I'm editing. It only shows the video frame view, which makes creating subtitles manually very difficult. The waveform view button is greyed out and doesn't work. Why is this?
My current workaround is to save the video as a WAV file and then import the WAV file into a new project (to the voice track). Sometimes it shows the waveform view of the WAV file, other times it's just a row of black rectangles.
I've noticed that the "speech to text / voice detection" section is also hidden when no waveform view is available. It seems to be available or hidden randomly, even in the same session.
I'm using Visual Studio 2022 Ultimate, update 25.1.0.472 on a Windows 10 computer 64 bit.
What am I doing wrong? Any help would be greatly appreciated. Thanks.

[lata]

GilesUK
And welcome to the forums
Just tested VS 2022 with no problems, I was using a MTS ( digital Dolby) and MP4 (LPCM Audio) and ( Mpeg Audio) video files, all showed the wave form below the preview screen
Can you check the properties of the video files you are using to make sure they do contain an audio stream

Post updated
To the right of the wave form view is an icon / button to switch between Video and Audio view

click image for larger view

[GilesUK]

Hi. Thanks for your reply. Yes, that "Waveform view" button is grey/inactive and the "Speech to Text"/"Voice Detection" section is not showing. They used to work OK, but recently (maybe following up automatic update?) they no longer work.
Yes, all the videos (1280x720 pixels, 25fps, 10Mbps, MP4 files) contain audio streams.