[PATCH v4 2/3] mfsrcsnk: Allow NULL for time_format.

[Brendan McGrath]

From: Brendan McGrath

Allow the value of pguidTimeFormat to be NULL on a call to
IMFMediaSource::Start. Currently, if NULL is used, Wine crashes with
a SIGSEGV.

MS documentation states:
This parameter can be NULL. If the value is NULL, it is equivalent to GUID_NULL.

https://learn.microsoft.com/en-us/windows/win32/api/mfidl/nf-mfidl-imfmedias...
---
 dlls/mfsrcsnk/media_source.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/dlls/mfsrcsnk/media_source.c b/dlls/mfsrcsnk/media_source.c
index 1e7918562fd..d7f20e511c8 100644
--- a/dlls/mfsrcsnk/media_source.c
+++ b/dlls/mfsrcsnk/media_source.c
@@ -1262,6 +1262,9 @@ static HRESULT WINAPI media_source_Start(IMFMediaSource *iface, IMFPresentationD
     TRACE("source %p, descriptor %p, format %s, position %s\n", source, descriptor,
             debugstr_guid(format), debugstr_propvar(position));

+    if (!format)
+        format = &GUID_NULL;
+
     EnterCriticalSection(&source->cs);

if (source->state == SOURCE_SHUTDOWN)