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Unified Diff: media/capture/video/video_capture_system.cc

Issue 2805533002: Reland [Mojo Video Capture] Introduce abstraction VideoCaptureSystem (Closed)
Patch Set: Fix race condition in tests Created 3 years, 8 months ago
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Index: media/capture/video/video_capture_system.cc
diff --git a/media/capture/video/video_capture_system.cc b/media/capture/video/video_capture_system.cc
new file mode 100644
index 0000000000000000000000000000000000000000..7df5e54ea2acd8b878e90a6f0b8d76d723755841
--- /dev/null
+++ b/media/capture/video/video_capture_system.cc
@@ -0,0 +1,126 @@
+// Copyright 2017 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/video_capture_system.h"
+
+#include "media/base/bind_to_current_loop.h"
+
+namespace {
+
+// Compares two VideoCaptureFormat by checking smallest frame_size area, then
+// by _largest_ frame_rate. Used to order a VideoCaptureFormats vector so that
+// the first entry for a given resolution has the largest frame rate, as needed
+// by the ConsolidateCaptureFormats() method.
+bool IsCaptureFormatSmaller(const media::VideoCaptureFormat& format1,
+ const media::VideoCaptureFormat& format2) {
+ DCHECK(format1.frame_size.GetCheckedArea().IsValid());
+ DCHECK(format2.frame_size.GetCheckedArea().IsValid());
+ if (format1.frame_size.GetCheckedArea().ValueOrDefault(0) ==
+ format2.frame_size.GetCheckedArea().ValueOrDefault(0)) {
+ return format1.frame_rate > format2.frame_rate;
+ }
+ return format1.frame_size.GetCheckedArea().ValueOrDefault(0) <
+ format2.frame_size.GetCheckedArea().ValueOrDefault(0);
+}
+
+bool IsCaptureFormatSizeEqual(const media::VideoCaptureFormat& format1,
+ const media::VideoCaptureFormat& format2) {
+ DCHECK(format1.frame_size.GetCheckedArea().IsValid());
+ DCHECK(format2.frame_size.GetCheckedArea().IsValid());
+ return format1.frame_size.GetCheckedArea().ValueOrDefault(0) ==
+ format2.frame_size.GetCheckedArea().ValueOrDefault(0);
+}
+
+// This function receives a list of capture formats, removes duplicated
+// resolutions while keeping the highest frame rate for each, and forcing I420
+// pixel format.
+void ConsolidateCaptureFormats(media::VideoCaptureFormats* formats) {
+ if (formats->empty())
+ return;
+ std::sort(formats->begin(), formats->end(), IsCaptureFormatSmaller);
+ // Due to the ordering imposed, the largest frame_rate is kept while removing
+ // duplicated resolutions.
+ media::VideoCaptureFormats::iterator last =
+ std::unique(formats->begin(), formats->end(), IsCaptureFormatSizeEqual);
+ formats->erase(last, formats->end());
+ // Mark all formats as I420, since this is what the renderer side will get
+ // anyhow: the actual pixel format is decided at the device level.
+ // Don't do this for Y16 format as it is handled separatelly.
+ for (auto& format : *formats) {
+ if (format.pixel_format != media::PIXEL_FORMAT_Y16)
+ format.pixel_format = media::PIXEL_FORMAT_I420;
+ }
+}
+
+} // anonymous namespace
+
+namespace media {
+
+VideoCaptureSystem::VideoCaptureSystem(
+ std::unique_ptr<VideoCaptureDeviceFactory> factory)
+ : factory_(std::move(factory)) {
+ thread_checker_.DetachFromThread();
+}
+
+VideoCaptureSystem::~VideoCaptureSystem() = default;
+
+void VideoCaptureSystem::GetDeviceInfosAsync(
+ const DeviceInfoCallback& result_callback) {
+ DCHECK(thread_checker_.CalledOnValidThread());
+ // Use of Unretained() is safe assuming that |result_callback| has ownership
+ // of |this|.
+ factory_->EnumerateDeviceDescriptors(media::BindToCurrentLoop(
+ base::Bind(&VideoCaptureSystem::OnDescriptorsReceived,
+ base::Unretained(this), result_callback)));
+}
+
+// Creates a VideoCaptureDevice object. Returns NULL if something goes wrong.
+std::unique_ptr<VideoCaptureDevice> VideoCaptureSystem::CreateDevice(
+ const std::string& device_id) {
+ DCHECK(thread_checker_.CalledOnValidThread());
+ const VideoCaptureDeviceInfo* device_info = LookupDeviceInfoFromId(device_id);
+ if (!device_info)
+ return nullptr;
+ return factory_->CreateDevice(device_info->descriptor);
+}
+
+void VideoCaptureSystem::OnDescriptorsReceived(
+ const DeviceInfoCallback& result_callback,
+ std::unique_ptr<VideoCaptureDeviceDescriptors> descriptors) {
+ DCHECK(thread_checker_.CalledOnValidThread());
+ // For devices for which we already have an entry in |devices_info_cache_|,
+ // we do not want to query the |factory_| for supported formats again. We
+ // simply copy them from |devices_info_cache_|.
+ std::vector<VideoCaptureDeviceInfo> new_devices_info_cache;
+ new_devices_info_cache.reserve(descriptors->size());
+ for (const auto& descriptor : *descriptors) {
+ if (auto* cached_info = LookupDeviceInfoFromId(descriptor.device_id)) {
+ new_devices_info_cache.push_back(*cached_info);
+ } else {
+ // Query for supported formats in order to create the entry.
+ VideoCaptureDeviceInfo device_info(descriptor);
+ factory_->GetSupportedFormats(descriptor, &device_info.supported_formats);
+ ConsolidateCaptureFormats(&device_info.supported_formats);
+ new_devices_info_cache.push_back(device_info);
+ }
+ }
+
+ devices_info_cache_.swap(new_devices_info_cache);
+ result_callback.Run(devices_info_cache_);
+}
+
+const VideoCaptureDeviceInfo* VideoCaptureSystem::LookupDeviceInfoFromId(
+ const std::string& device_id) {
+ DCHECK(thread_checker_.CalledOnValidThread());
+ auto iter = std::find_if(
+ devices_info_cache_.begin(), devices_info_cache_.end(),
+ [&device_id](const media::VideoCaptureDeviceInfo& device_info) {
+ return device_info.descriptor.device_id == device_id;
+ });
+ if (iter == devices_info_cache_.end())
+ return nullptr;
+ return &(*iter);
+}
+
+} // namespace media

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