Win video capture: Fix capture format and frame buffer mismatch

media/capture/video/win/video_capture_device_win.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/capture/video/win/video_capture_device_win.h"
 
 #include <ks.h>
 #include <ksmedia.h>
 
 #include <algorithm>
@@ skipping 439 matching lines @@
   // SampleGrabber filter to a PIN_CATEGORY_STILL of |capture_filter_|. This
   // way, however, is not widespread and proves too cumbersome, so we just grab
   // the next captured frame instead.
   take_photo_callbacks_.push(std::move(callback));
 }
 
 // Implements SinkFilterObserver::SinkFilterObserver.
 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();
 
   // There is a chance that the platform does not provide us with the timestamp,
   // in which case, we use reference time to calculate a timestamp.
   if (timestamp == media::kNoTimestamp)
     timestamp = base::TimeTicks::Now() - first_ref_time_;
 
   client_->OnIncomingCapturedData(buffer, length, capture_format_, 0,
                                   base::TimeTicks::Now(), timestamp);
@@ skipping 119 matching lines @@
 void VideoCaptureDeviceWin::SetErrorState(
     const tracked_objects::Location& from_here,
     const std::string& reason,
     HRESULT hr) {
   DCHECK(thread_checker_.CalledOnValidThread());
   DLOG_IF_FAILED_WITH_HRESULT(reason, hr);
   state_ = kError;
   client_->OnError(from_here, reason);
 }
 }  // namespace media