modules/desktop_capture/desktop_capturer_differ_wrapper.cc - src - Git at Google

 /*
  *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */

 #include "modules/desktop_capture/desktop_capturer_differ_wrapper.h"

 #include <stdint.h>
 #include <string.h>

 #include <utility>

 #include "modules/desktop_capture/desktop_geometry.h"
 #include "modules/desktop_capture/desktop_region.h"
 #include "modules/desktop_capture/differ_block.h"
 #include "rtc_base/checks.h"
 #include "rtc_base/time_utils.h"

 namespace webrtc {

 namespace {

 // Returns true if (0, 0) - (`width`, `height`) vector in `old_buffer` and
 // `new_buffer` are equal. `width` should be less than 32
 // (defined by kBlockSize), otherwise BlockDifference() should be used.
 bool PartialBlockDifference(const uint8_t* old_buffer,
                             const uint8_t* new_buffer,
                             int width,
                             int height,
                             int stride) {
   RTC_DCHECK_LT(width, kBlockSize);
   const int width_bytes = width * DesktopFrame::kBytesPerPixel;
   for (int i = 0; i < height; i++) {
     if (memcmp(old_buffer, new_buffer, width_bytes) != 0) {
       return true;
     }
     old_buffer += stride;
     new_buffer += stride;
   }
   return false;
 }

 // Compares columns in the range of [`left`, `right`), in a row in the
 // range of [`top`, `top` + `height`), starts from `old_buffer` and
 // `new_buffer`, and outputs updated regions into `output`. `stride` is the
 // DesktopFrame::stride().
 void CompareRow(const uint8_t* old_buffer,
                 const uint8_t* new_buffer,
                 const int left,
                 const int right,
                 const int top,
                 const int bottom,
                 const int stride,
                 DesktopRegion* const output) {
   const int block_x_offset = kBlockSize * DesktopFrame::kBytesPerPixel;
   const int width = right - left;
   const int height = bottom - top;
   const int block_count = (width - 1) / kBlockSize;
   const int last_block_width = width - block_count * kBlockSize;
   RTC_DCHECK_GT(last_block_width, 0);
   RTC_DCHECK_LE(last_block_width, kBlockSize);

   // The first block-column in a continuous dirty area in current block-row.
   int first_dirty_x_block = -1;

   // We always need to add dirty area into `output` in the last block, so handle
   // it separatedly.
   for (int x = 0; x < block_count; x++) {
     if (BlockDifference(old_buffer, new_buffer, height, stride)) {
       if (first_dirty_x_block == -1) {
         // This is the first dirty block in a continuous dirty area.
         first_dirty_x_block = x;
       }
     } else if (first_dirty_x_block != -1) {
       // The block on the left is the last dirty block in a continuous
       // dirty area.
       output->AddRect(
           DesktopRect::MakeLTRB(first_dirty_x_block * kBlockSize + left, top,
                                 x * kBlockSize + left, bottom));
       first_dirty_x_block = -1;
     }
     old_buffer += block_x_offset;
     new_buffer += block_x_offset;
   }

   bool last_block_diff;
   if (last_block_width < kBlockSize) {
     // The last one is a partial vector.
     last_block_diff = PartialBlockDifference(old_buffer, new_buffer,
                                              last_block_width, height, stride);
   } else {
     last_block_diff = BlockDifference(old_buffer, new_buffer, height, stride);
   }
   if (last_block_diff) {
     if (first_dirty_x_block == -1) {
       first_dirty_x_block = block_count;
     }
     output->AddRect(DesktopRect::MakeLTRB(
         first_dirty_x_block * kBlockSize + left, top, right, bottom));
   } else if (first_dirty_x_block != -1) {
     output->AddRect(
         DesktopRect::MakeLTRB(first_dirty_x_block * kBlockSize + left, top,
                               block_count * kBlockSize + left, bottom));
   }
 }

 // Compares `rect` area in `old_frame` and `new_frame`, and outputs dirty
 // regions into `output`.
 void CompareFrames(const DesktopFrame& old_frame,
                    const DesktopFrame& new_frame,
                    DesktopRect rect,
                    DesktopRegion* const output) {
   RTC_DCHECK(old_frame.size().equals(new_frame.size()));
   RTC_DCHECK_EQ(old_frame.stride(), new_frame.stride());
   rect.IntersectWith(DesktopRect::MakeSize(old_frame.size()));

   const int y_block_count = (rect.height() - 1) / kBlockSize;
   const int last_y_block_height = rect.height() - y_block_count * kBlockSize;
   // Offset from the start of one block-row to the next.
   const int block_y_stride = old_frame.stride() * kBlockSize;
   const uint8_t* prev_block_row_start =
       old_frame.GetFrameDataAtPos(rect.top_left());
   const uint8_t* curr_block_row_start =
       new_frame.GetFrameDataAtPos(rect.top_left());

   int top = rect.top();
   // The last row may have a different height, so we handle it separately.
   for (int y = 0; y < y_block_count; y++) {
     CompareRow(prev_block_row_start, curr_block_row_start, rect.left(),
                rect.right(), top, top + kBlockSize, old_frame.stride(), output);
     top += kBlockSize;
     prev_block_row_start += block_y_stride;
     curr_block_row_start += block_y_stride;
   }
   CompareRow(prev_block_row_start, curr_block_row_start, rect.left(),
              rect.right(), top, top + last_y_block_height, old_frame.stride(),
              output);
 }

 }  // namespace

 DesktopCapturerDifferWrapper::DesktopCapturerDifferWrapper(
     std::unique_ptr<DesktopCapturer> base_capturer)
     : base_capturer_(std::move(base_capturer)) {
   RTC_DCHECK(base_capturer_);
 }

 DesktopCapturerDifferWrapper::~DesktopCapturerDifferWrapper() {}

 void DesktopCapturerDifferWrapper::Start(DesktopCapturer::Callback* callback) {
   callback_ = callback;
   base_capturer_->Start(this);
 }

 void DesktopCapturerDifferWrapper::SetSharedMemoryFactory(
     std::unique_ptr<SharedMemoryFactory> shared_memory_factory) {
   base_capturer_->SetSharedMemoryFactory(std::move(shared_memory_factory));
 }

 void DesktopCapturerDifferWrapper::CaptureFrame() {
   base_capturer_->CaptureFrame();
 }

 void DesktopCapturerDifferWrapper::SetExcludedWindow(WindowId window) {
   base_capturer_->SetExcludedWindow(window);
 }

 bool DesktopCapturerDifferWrapper::GetSourceList(SourceList* sources) {
   return base_capturer_->GetSourceList(sources);
 }

 bool DesktopCapturerDifferWrapper::SelectSource(SourceId id) {
   return base_capturer_->SelectSource(id);
 }

 bool DesktopCapturerDifferWrapper::FocusOnSelectedSource() {
   return base_capturer_->FocusOnSelectedSource();
 }

 bool DesktopCapturerDifferWrapper::IsOccluded(const DesktopVector& pos) {
   return base_capturer_->IsOccluded(pos);
 }

 #if defined(WEBRTC_USE_GIO)
 DesktopCaptureMetadata DesktopCapturerDifferWrapper::GetMetadata() {
   return base_capturer_->GetMetadata();
 }
 #endif  // defined(WEBRTC_USE_GIO)

 void DesktopCapturerDifferWrapper::OnCaptureResult(
     Result result,
     std::unique_ptr<DesktopFrame> input_frame) {
   int64_t start_time_nanos = rtc::TimeNanos();
   if (!input_frame) {
     callback_->OnCaptureResult(result, nullptr);
     return;
   }
   RTC_DCHECK(result == Result::SUCCESS);

   std::unique_ptr<SharedDesktopFrame> frame =
       SharedDesktopFrame::Wrap(std::move(input_frame));
   if (last_frame_ && (last_frame_->size().width() != frame->size().width() ||
                       last_frame_->size().height() != frame->size().height() ||
                       last_frame_->stride() != frame->stride())) {
     last_frame_.reset();
   }

   if (last_frame_) {
     DesktopRegion hints;
     hints.Swap(frame->mutable_updated_region());
     for (DesktopRegion::Iterator it(hints); !it.IsAtEnd(); it.Advance()) {
       CompareFrames(*last_frame_, *frame, it.rect(),
                     frame->mutable_updated_region());
     }
   } else {
     frame->mutable_updated_region()->SetRect(
         DesktopRect::MakeSize(frame->size()));
   }
   last_frame_ = frame->Share();

   frame->set_capture_time_ms(frame->capture_time_ms() +
                              (rtc::TimeNanos() - start_time_nanos) /
                                  rtc::kNumNanosecsPerMillisec);
   callback_->OnCaptureResult(result, std::move(frame));
 }

 }  // namespace webrtc
	/*
	* Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
	*
	* Use of this source code is governed by a BSD-style license
	* that can be found in the LICENSE file in the root of the source
	* tree. An additional intellectual property rights grant can be found
	* in the file PATENTS. All contributing project authors may
	* be found in the AUTHORS file in the root of the source tree.
	*/

	#include "modules/desktop_capture/desktop_capturer_differ_wrapper.h"

	#include <stdint.h>
	#include <string.h>

	#include <utility>

	#include "modules/desktop_capture/desktop_geometry.h"
	#include "modules/desktop_capture/desktop_region.h"
	#include "modules/desktop_capture/differ_block.h"
	#include "rtc_base/checks.h"
	#include "rtc_base/time_utils.h"

	namespace webrtc {

	namespace {

	// Returns true if (0, 0) - (`width`, `height`) vector in `old_buffer` and
	// `new_buffer` are equal. `width` should be less than 32
	// (defined by kBlockSize), otherwise BlockDifference() should be used.
	bool PartialBlockDifference(const uint8_t* old_buffer,
	const uint8_t* new_buffer,
	int width,
	int height,
	int stride) {
	RTC_DCHECK_LT(width, kBlockSize);
	const int width_bytes = width * DesktopFrame::kBytesPerPixel;
	for (int i = 0; i < height; i++) {
	if (memcmp(old_buffer, new_buffer, width_bytes) != 0) {
	return true;
	}
	old_buffer += stride;
	new_buffer += stride;
	}
	return false;
	}

	// Compares columns in the range of [`left`, `right`), in a row in the
	// range of [`top`, `top` + `height`), starts from `old_buffer` and
	// `new_buffer`, and outputs updated regions into `output`. `stride` is the
	// DesktopFrame::stride().
	void CompareRow(const uint8_t* old_buffer,
	const uint8_t* new_buffer,
	const int left,
	const int right,
	const int top,
	const int bottom,
	const int stride,
	DesktopRegion* const output) {
	const int block_x_offset = kBlockSize * DesktopFrame::kBytesPerPixel;
	const int width = right - left;
	const int height = bottom - top;
	const int block_count = (width - 1) / kBlockSize;
	const int last_block_width = width - block_count * kBlockSize;
	RTC_DCHECK_GT(last_block_width, 0);
	RTC_DCHECK_LE(last_block_width, kBlockSize);

	// The first block-column in a continuous dirty area in current block-row.
	int first_dirty_x_block = -1;

	// We always need to add dirty area into `output` in the last block, so handle
	// it separatedly.
	for (int x = 0; x < block_count; x++) {
	if (BlockDifference(old_buffer, new_buffer, height, stride)) {
	if (first_dirty_x_block == -1) {
	// This is the first dirty block in a continuous dirty area.
	first_dirty_x_block = x;
	}
	} else if (first_dirty_x_block != -1) {
	// The block on the left is the last dirty block in a continuous
	// dirty area.
	output->AddRect(
	DesktopRect::MakeLTRB(first_dirty_x_block * kBlockSize + left, top,
	x * kBlockSize + left, bottom));
	first_dirty_x_block = -1;
	}
	old_buffer += block_x_offset;
	new_buffer += block_x_offset;
	}

	bool last_block_diff;
	if (last_block_width < kBlockSize) {
	// The last one is a partial vector.
	last_block_diff = PartialBlockDifference(old_buffer, new_buffer,
	last_block_width, height, stride);
	} else {
	last_block_diff = BlockDifference(old_buffer, new_buffer, height, stride);
	}
	if (last_block_diff) {
	if (first_dirty_x_block == -1) {
	first_dirty_x_block = block_count;
	}
	output->AddRect(DesktopRect::MakeLTRB(
	first_dirty_x_block * kBlockSize + left, top, right, bottom));
	} else if (first_dirty_x_block != -1) {
	output->AddRect(
	DesktopRect::MakeLTRB(first_dirty_x_block * kBlockSize + left, top,
	block_count * kBlockSize + left, bottom));
	}
	}

	// Compares `rect` area in `old_frame` and `new_frame`, and outputs dirty
	// regions into `output`.
	void CompareFrames(const DesktopFrame& old_frame,
	const DesktopFrame& new_frame,
	DesktopRect rect,
	DesktopRegion* const output) {
	RTC_DCHECK(old_frame.size().equals(new_frame.size()));
	RTC_DCHECK_EQ(old_frame.stride(), new_frame.stride());
	rect.IntersectWith(DesktopRect::MakeSize(old_frame.size()));

	const int y_block_count = (rect.height() - 1) / kBlockSize;
	const int last_y_block_height = rect.height() - y_block_count * kBlockSize;
	// Offset from the start of one block-row to the next.
	const int block_y_stride = old_frame.stride() * kBlockSize;
	const uint8_t* prev_block_row_start =
	old_frame.GetFrameDataAtPos(rect.top_left());
	const uint8_t* curr_block_row_start =
	new_frame.GetFrameDataAtPos(rect.top_left());

	int top = rect.top();
	// The last row may have a different height, so we handle it separately.
	for (int y = 0; y < y_block_count; y++) {
	CompareRow(prev_block_row_start, curr_block_row_start, rect.left(),
	rect.right(), top, top + kBlockSize, old_frame.stride(), output);
	top += kBlockSize;
	prev_block_row_start += block_y_stride;
	curr_block_row_start += block_y_stride;
	}
	CompareRow(prev_block_row_start, curr_block_row_start, rect.left(),
	rect.right(), top, top + last_y_block_height, old_frame.stride(),
	output);
	}

	} // namespace

	DesktopCapturerDifferWrapper::DesktopCapturerDifferWrapper(
	std::unique_ptr<DesktopCapturer> base_capturer)
	: base_capturer_(std::move(base_capturer)) {
	RTC_DCHECK(base_capturer_);
	}

	DesktopCapturerDifferWrapper::~DesktopCapturerDifferWrapper() {}

	void DesktopCapturerDifferWrapper::Start(DesktopCapturer::Callback* callback) {
	callback_ = callback;
	base_capturer_->Start(this);
	}

	void DesktopCapturerDifferWrapper::SetSharedMemoryFactory(
	std::unique_ptr<SharedMemoryFactory> shared_memory_factory) {
	base_capturer_->SetSharedMemoryFactory(std::move(shared_memory_factory));
	}

	void DesktopCapturerDifferWrapper::CaptureFrame() {
	base_capturer_->CaptureFrame();
	}

	void DesktopCapturerDifferWrapper::SetExcludedWindow(WindowId window) {
	base_capturer_->SetExcludedWindow(window);
	}

	bool DesktopCapturerDifferWrapper::GetSourceList(SourceList* sources) {
	return base_capturer_->GetSourceList(sources);
	}

	bool DesktopCapturerDifferWrapper::SelectSource(SourceId id) {
	return base_capturer_->SelectSource(id);
	}

	bool DesktopCapturerDifferWrapper::FocusOnSelectedSource() {
	return base_capturer_->FocusOnSelectedSource();
	}

	bool DesktopCapturerDifferWrapper::IsOccluded(const DesktopVector& pos) {
	return base_capturer_->IsOccluded(pos);
	}

	#if defined(WEBRTC_USE_GIO)
	DesktopCaptureMetadata DesktopCapturerDifferWrapper::GetMetadata() {
	return base_capturer_->GetMetadata();
	}
	#endif // defined(WEBRTC_USE_GIO)

	void DesktopCapturerDifferWrapper::OnCaptureResult(
	Result result,
	std::unique_ptr<DesktopFrame> input_frame) {
	int64_t start_time_nanos = rtc::TimeNanos();
	if (!input_frame) {
	callback_->OnCaptureResult(result, nullptr);
	return;
	}
	RTC_DCHECK(result == Result::SUCCESS);

	std::unique_ptr<SharedDesktopFrame> frame =
	SharedDesktopFrame::Wrap(std::move(input_frame));
	if (last_frame_ && (last_frame_->size().width() != frame->size().width() \|\|
	last_frame_->size().height() != frame->size().height() \|\|
	last_frame_->stride() != frame->stride())) {
	last_frame_.reset();
	}

	if (last_frame_) {
	DesktopRegion hints;
	hints.Swap(frame->mutable_updated_region());
	for (DesktopRegion::Iterator it(hints); !it.IsAtEnd(); it.Advance()) {
	CompareFrames(last_frame_, frame, it.rect(),
	frame->mutable_updated_region());
	}
	} else {
	frame->mutable_updated_region()->SetRect(
	DesktopRect::MakeSize(frame->size()));
	}
	last_frame_ = frame->Share();

	frame->set_capture_time_ms(frame->capture_time_ms() +
	(rtc::TimeNanos() - start_time_nanos) /
	rtc::kNumNanosecsPerMillisec);
	callback_->OnCaptureResult(result, std::move(frame));
	}

	} // namespace webrtc