[PATCH v6 0/1] MR2263: evr: Fix crash when clear input type for the mixer

[Tingzhong Luo (＠tzluo)]

In the implementation of
[`evr_disconnect()`](https://gitlab.winehq.org/wine/wine/-/blob/wine-8.2/dlls/evr/evr.c#L325-333),
it will try to clear types of mixer by pass null to 
`IMFTransform_SetInputType()`:

```c
static void evr_disconnect(struct strmbase_renderer *iface)
{
    struct evr *filter = impl_from_strmbase_renderer(iface);

if (filter->mixer)
        IMFTransform_SetInputType(filter->mixer, 0, NULL, 0);
    evr_set_input_type(filter, NULL);
    evr_release_services(filter);
}

```

This null ptr (`media_type`) will be pass to
[`video_mixer_collect_output_types()`](https://gitlab.winehq.org/wine/wine/-/blob/wine-8.2/dlls/evr/mixer.c#L869)
and cause a [crash](https://gitlab.winehq.org/wine/wine/-/blob/wine-8.2/dlls/evr/mixer.c#L663):

```c
static HRESULT WINAPI video_mixer_transform_SetInputType(IMFTransform *iface, DWORD id, IMFMediaType *media_type, DWORD flags)
{
...
    if (!mixer->device_manager)
        hr = MF_E_NOT_INITIALIZED;
    else
    {
        if (SUCCEEDED(hr = video_mixer_get_processor_service(mixer, &service)))
        {
            if (SUCCEEDED(hr = video_mixer_init_dxva_videodesc(media_type, &video_desc)))
...
```

In this patch, `video_mixer_transform_SetInputType()` will only clear types when
got a NULL `media_type` and return `S_OK`.

--
  v6: evr: Fix crash when clear input type for the mixer

https://gitlab.winehq.org/wine/wine/-/merge_requests/2263