This commit adds a conversion from stereo to mono in the
`read_audio_data` function of `common-whisper.cpp`.
The motivation for this change is prior to Commit
7d3da68f79 ("examples : use miniaudio for
direct decoding flac, mp3, ogg and wav (#2759)", there was a step that
read stereo int16 data -> pcm16 (448512 samples), and then converted to
mono (224256 samples), and then also convert to stereo in `pcmf32s.
The middle step here seems to have been missed when rewriting the code to
use Miniaudio and caused issues then transcribing stereo audio files.
For example, currently using the audio sample in the linked issue the
output is:
```console
[00:00:00.000 --> 00:00:03.000] (speaker 1) Sous-titres réalisés para la communauté d'Amara.org
```
And with the change in this commit the output is:
```
[00:00:00.000 --> 00:00:01.500] (speaker 1) *sonnerie de téléphone*
[00:00:01.500 --> 00:00:07.000] (speaker 1) Salut jeune homme !
[00:00:07.000 --> 00:00:08.500] (speaker 0) C'est vrai que je te dérange ?
[00:00:08.500 --> 00:00:10.500] (speaker 1) Ah pas du tout, pas du tout, pas du tout !
[00:00:10.500 --> 00:00:12.500] (speaker 1) J'étais en train de...
[00:00:12.500 --> 00:00:14.500] (speaker 1) de préparer un courrier
```
Resolves: https://github.com/ggml-org/whisper.cpp/issues/3092
* ggml : remove MSVC warnings pragmas
This commit removes the MSVC-specific pragmas as these are now handled
in CMakeLists.txt.
* whisper : remove MSVC warning pragmas
This commit removes the MSVC-specific pragmas. These are now handled in
the CMakeLists.txt file.
