Mac VideoCapture: Support for Blackmagic DeckLink device & capabilities enumeration, using SDK.

media/video/capture/mac/video_capture_device_decklink_mac.mm

+// Copyright 2014 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/video/capture/mac/video_capture_device_decklink_mac.h"
+
+#include "base/logging.h"
+#include "base/memory/ref_counted.h"
+#include "base/strings/sys_string_conversions.h"
+#include "third_party/decklink/mac/include/DeckLinkAPI.h"
+
+namespace {
+
+// DeckLink SDK uses ScopedComPtr-style APIs. Chrome ScopedComPtr is only
+// available for Windows builds. This is a verbatim knock-off of the needed
+// parts of base::win::ScopedComPtr<> for ref counting.
+template <class T>
+class ScopedDeckLinkPtr : public scoped_refptr<T> {
+ public:
+  using scoped_refptr<T>::ptr_;
+
+  T** Receive() {
+    DCHECK(!ptr_) << "Object leak. Pointer must be NULL";
+    return &ptr_;
+  }
+
+  void** ReceiveVoid() {
+    return reinterpret_cast<void**>(Receive());
+  }
+
+  void Release() {
+    if (ptr_ != NULL) {
+      ptr_->Release();
+      ptr_ = NULL;
+    }
+  }
+};
+
+}  // namespace
+
+namespace media {
+
+std::string JoinDeviceNameAndFormat(CFStringRef name, CFStringRef format) {
+  return base::SysCFStringRefToUTF8(name) + " - " +
+      base::SysCFStringRefToUTF8(format);
+}
+
+//static
+void VideoCaptureDeviceDeckLinkMac::EnumerateDevices(
+    VideoCaptureDevice::Names* device_names) {
+  scoped_refptr<IDeckLinkIterator> decklink_iter(
+      CreateDeckLinkIteratorInstance());
+  // At this point, not being able to create a DeckLink iterator means that
+  // there are no Blackmagic DeckLink devices in the system, don't print error.

[perkj_chrome, 2014/09/15 09:13:16]

What do you mean by" don't print error." ?

[mcasas, 2014/09/22 08:39:09]

Rewritten. What I meant is that l.55 is a DVLOG_IF() and not
an DPLOG(ERROR, ...)

+  DVLOG_IF(1, !decklink_iter) << "Could not create DeckLink iterator";
+  if (!decklink_iter)
+    return;
+
+  ScopedDeckLinkPtr<IDeckLink> decklink;
+  while (decklink_iter->Next(decklink.Receive()) == S_OK) {
+    ScopedDeckLinkPtr<IDeckLink> decklink_local;
+    decklink_local.swap(decklink);
+
+    CFStringRef device_model_name = NULL;
+    HRESULT hr = decklink_local->GetModelName(&device_model_name);
+    DVLOG_IF(1, hr != S_OK) << "Error reading Blackmagic device model name";
+    CFStringRef device_display_name = NULL;
+    hr = decklink_local->GetDisplayName(&device_display_name);
+    DVLOG_IF(1, hr != S_OK) << "Error reading Blackmagic device display name";
+    DVLOG_IF(1, hr == S_OK) << "Blackmagic device found with name: " <<
+        base::SysCFStringRefToUTF8(device_display_name);
+
+    if (!device_model_name && !device_display_name)
+      continue;
+
+    ScopedDeckLinkPtr<IDeckLinkInput> decklink_input;
+    if (decklink_local->QueryInterface(IID_IDeckLinkInput,
+        decklink_input.ReceiveVoid()) != S_OK) {
+      DLOG(ERROR) << "Error Blackmagic querying input interface.";
+      return;
+    }
+
+    ScopedDeckLinkPtr<IDeckLinkDisplayModeIterator> display_mode_iter;
+    if (decklink_input->GetDisplayModeIterator(display_mode_iter.Receive()) !=
+        S_OK) {
+      continue;
+    }
+
+    ScopedDeckLinkPtr<IDeckLinkDisplayMode> display_mode;
+    while (display_mode_iter->Next(display_mode.Receive()) == S_OK) {
+      CFStringRef format_name = NULL;
+      if (display_mode->GetName(&format_name) == S_OK) {
+        VideoCaptureDevice::Name name(
+            JoinDeviceNameAndFormat(device_display_name, format_name),
+            JoinDeviceNameAndFormat(device_model_name, format_name),
+            VideoCaptureDevice::Name::DECKLINK,
+            VideoCaptureDevice::Name::OTHER_TRANSPORT);
+        device_names->push_back(name);
+        DVLOG(1) << "Blackmagic camera enumerated: " << name.name();
+      }
+      display_mode.Release();
+    }
+  }
+}
+
+// static
+void VideoCaptureDeviceDeckLinkMac::EnumerateDeviceCapabilities(
+    const VideoCaptureDevice::Name& device,
+    VideoCaptureFormats* supported_formats) {
+  scoped_refptr<IDeckLinkIterator> decklink_iter(
+      CreateDeckLinkIteratorInstance());
+  DLOG_IF(ERROR, !decklink_iter) << "Error creating DeckLink iterator";
+  if (!decklink_iter)
+    return;
+
+  ScopedDeckLinkPtr<IDeckLink> decklink;
+  while (decklink_iter->Next(decklink.Receive()) == S_OK) {
+    ScopedDeckLinkPtr<IDeckLink> decklink_local;
+    decklink_local.swap(decklink);
+
+    ScopedDeckLinkPtr<IDeckLinkInput> decklink_input;
+    if (decklink_local->QueryInterface(IID_IDeckLinkInput,
+        decklink_input.ReceiveVoid()) != S_OK) {

[perkj_chrome, 2014/09/15 09:13:16]

4 more spaces right? 

[mcasas, 2014/09/22 08:39:09]

Done.

+      DLOG(ERROR) << "Error Blackmagic querying input interface.";
+      return;
+    }
+
+    ScopedDeckLinkPtr<IDeckLinkDisplayModeIterator> display_mode_iter;
+    if (decklink_input->GetDisplayModeIterator(display_mode_iter.Receive()) !=
+        S_OK) {
+      continue;
+    }
+
+    CFStringRef device_model_name = NULL;
+    if (decklink_local->GetModelName(&device_model_name) != S_OK)
+      continue;
+
+    ScopedDeckLinkPtr<IDeckLinkDisplayMode> display_mode;
+    while (display_mode_iter->Next(display_mode.Receive()) == S_OK) {
+      CFStringRef format_name = NULL;
+      if (display_mode->GetName(&format_name) == S_OK && device.id() !=

[perkj_chrome, 2014/09/15 09:13:16]

nit : prever to move device.id() != to the next line for readability.

[mcasas, 2014/09/22 08:39:09]

Would love to but then I'd have to break the next line and gets even
more confusing :(

+          JoinDeviceNameAndFormat(device_model_name, format_name)) {
+        display_mode.Release();
+        continue;
+      }
+
+      // IDeckLinkDisplayMode does not have information on pixel format, this
+      // is only available on capture.
+      media::VideoPixelFormat pixel_format = media::PIXEL_FORMAT_UNKNOWN;
+      BMDTimeValue time_value, time_scale;
+      float frame_rate = 0.0f;
+      if (display_mode->GetFrameRate(&time_value, &time_scale) == S_OK &&
+          time_value > 0) {
+        frame_rate = static_cast<float>(time_scale) / time_value;
+      }
+      media::VideoCaptureFormat format(
+          gfx::Size(display_mode->GetWidth(), display_mode->GetHeight()),
+          frame_rate,
+          pixel_format);
+      supported_formats->push_back(format);
+      DVLOG(2) << device.name() << " " << format.ToString();
+      display_mode.Release();
+    }
+    return;
+  }
+}
+
+VideoCaptureDeviceDeckLinkMac::VideoCaptureDeviceDeckLinkMac(
+    const Name& device_name) {}
+
+VideoCaptureDeviceDeckLinkMac::~VideoCaptureDeviceDeckLinkMac() {}
+
+void VideoCaptureDeviceDeckLinkMac::AllocateAndStart(
+    const VideoCaptureParams& params,
+    scoped_ptr<VideoCaptureDevice::Client> client) {
+  NOTIMPLEMENTED();
+}
+
+void VideoCaptureDeviceDeckLinkMac::StopAndDeAllocate() {
+  NOTIMPLEMENTED();
+}
+
+} // namespace media