Win video capture: Fix capture format and frame buffer mismatch

media/capture/video/win/video_capture_device_win.cc

Index: media/capture/video/win/video_capture_device_win.cc
diff --git a/media/capture/video/win/video_capture_device_win.cc b/media/capture/video/win/video_capture_device_win.cc
index 249bfedf58505eaab9222685a26f5c4e288afe50..3487d1e20a6d2bd4492f2cee4625a9420e0832a4 100644
--- a/media/capture/video/win/video_capture_device_win.cc
+++ b/media/capture/video/win/video_capture_device_win.cc
@@ -457,6 +457,11 @@ void VideoCaptureDeviceWin::TakePhoto(TakePhotoCallback callback) {
 void VideoCaptureDeviceWin::FrameReceived(const uint8_t* buffer,
                                           int length,
                                           base::TimeDelta timestamp) {
+  if (static_cast<size_t>(length) < capture_format_.ImageAllocationSize()) {
+    DLOG(WARNING) << "Media sample buffer with insufficient size.";
+    return;

[mcasas, 2016/09/29 20:43:31]

With this we will just be ignoring the incoming frame,
never doing anything about it and capturing nothing. 
I suggest adding the condition to the lines around [1],
so the start of that method reads:

  const int length = sample->GetActualDataLength();
  if (length <= 0 ||
      static_cast<size_t>(length) < resulting_format_.ImageAllocationSize()) {
    DLOG(WARNING) << "Wrong media sample length";
    return S_FALSE;
  }

  uint8_t* buffer = nullptr;
  if (FAILED(sample->GetPointer(&buffer)))
    return S_FALSE;

so we can inform Win DirectShow that something
wrong has happened, and we don't do unnecessary
work :)

Actually I wrote this and just noticed that SinkInputPin's
fills in |resulting_format_| but does not propagate this
information, and that's probably the root cause of this
crash. Notwithstanding my recommended code, you
should also extend SinkFilterObserver::FrameReceived()
signature to have a const VideoCaptureFormat& as
a parameter, send |resulting_format_| to
VideoCaptureDeviceWin::FrameReceived() and there
forward it instead of the hoped-for |capture_format_|.

[1]
https://cs.chromium.org/chromium/src/media/capture/video/win/sink_input_pin_w...
[2]
https://cs.chromium.org/chromium/src/media/capture/video/win/sink_filter_obse...

+  }
+
   if (first_ref_time_.is_null())
     first_ref_time_ = base::TimeTicks::Now();