media/capture: Adding WebmMuxer class and unittests

media/filters/webm_muxer_unittest.cc

+// Copyright 2015 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 "base/bind.h"
+#include "base/location.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/run_loop.h"
+#include "media/filters/webm_muxer.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using ::testing::_;
+using ::testing::AtLeast;
+using ::testing::Mock;
+using ::testing::WithArgs;
+
+namespace media {
+
+// Dummy interface class to be able to MOCK its only function below.
+class EventHandlerInterface {
+ public:
+  virtual void WriteCallback(const char* data, int len) {}
+  virtual ~EventHandlerInterface() {}
+};
+
+// Mock reference counted class to EXPECT calls to WriteCallback().
+class MockWebmMuxerEventHandler
+   : public base::RefCounted<MockWebmMuxerEventHandler>,
+     public EventHandlerInterface {
+ public:
+  MockWebmMuxerEventHandler() {}
+
+  MOCK_METHOD2(WriteCallback, void(const char* data, int len));
+
+ private:
+  friend class base::RefCounted<MockWebmMuxerEventHandler>;
+  ~MockWebmMuxerEventHandler() override {}
+
+  DISALLOW_COPY_AND_ASSIGN(MockWebmMuxerEventHandler);
+};
+
+class WebmMuxerTest : public testing::Test {
+ public:
+  void SaveEncodedDataLen(int len) {
+    last_encoded_length_ = len;
+    accumulated_position_ += len;
+  }
+
+ protected:
+  WebmMuxerTest()
+      : loop_(new base::MessageLoop()),
+        mock_handler_(new MockWebmMuxerEventHandler()),
+        webm_muxer_(new WebmMuxer(
+            base::Bind(&MockWebmMuxerEventHandler::WriteCallback,
+                       mock_handler_))),
+        last_encoded_length_(0),
+        accumulated_position_(0) {}
+
+  void SetUp() override {
+    EXPECT_EQ(webm_muxer_->Position(), 0);
+    EXPECT_FALSE(webm_muxer_->Seekable());
+    EXPECT_EQ(webm_muxer_->segment_->mode(), mkvmuxer::Segment::kLive);
+  }
+
+  const scoped_ptr<base::MessageLoop> loop_;
+  const scoped_refptr<MockWebmMuxerEventHandler> mock_handler_;
+  const scoped_ptr<WebmMuxer> webm_muxer_;
+
+  uint32_t last_encoded_length_, accumulated_position_;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(WebmMuxerTest);
+};
+
+// Checks that the WriteCallback is called with appropriate params when
+// WebmMuxer::Write() method is called.
+TEST_F(WebmMuxerTest, Write) {
+  const char encoded_data[] = "abcdefghijklmnopqrstuvwxyz";
+  const int encoded_len = arraysize(encoded_data);
+
+  EXPECT_CALL(*mock_handler_.get(),
+              WriteCallback(encoded_data, encoded_len)).Times(1);
+  webm_muxer_->Write(encoded_data, encoded_len);
+  base::RunLoop().RunUntilIdle();
+
+  EXPECT_EQ(webm_muxer_->Position(), encoded_len);
+  Mock::VerifyAndClearExpectations(mock_handler_.get());
+}
+
+// Checks that the WriteCallback is called with appropriate params when
+// WebmMuxer::OnEncodedVideo() method is called.
+TEST_F(WebmMuxerTest, OnEncodedVideo) {
+  const std::string encoded_data("abcdefghijklmnopqrstuvwxyz");
+
+  EXPECT_CALL(*mock_handler_.get(), WriteCallback(_, _))
+      .Times(AtLeast(1))
+      .WillRepeatedly(WithArgs<1>(
+          Invoke(this, &WebmMuxerTest::SaveEncodedDataLen)));
+  webm_muxer_->OnEncodedVideo(0 /* track_index */,
+                              encoded_data,
+                              base::TimeTicks::Now(),
+                              false /* keyframe */,
+                              gfx::Size(320, 240) /* frame_size */,
+                              30.0f  /* frame_rate */);
+  base::RunLoop().RunUntilIdle();
+
+  // First time around WriteCallback() is pinged a number of times to write the
+  // Matroska header, but at the end it dumps |encoded_data|.
+  EXPECT_EQ(last_encoded_length_, encoded_data.length());
+  EXPECT_EQ(webm_muxer_->Position(), accumulated_position_);
+  EXPECT_GE(webm_muxer_->Position(), last_encoded_length_);
+  const uint32_t begin_of_second_block = accumulated_position_;
+
+  EXPECT_CALL(*mock_handler_.get(), WriteCallback(_, _))
+      .Times(AtLeast(1))
+      .WillRepeatedly(WithArgs<1>(
+          Invoke(this, &WebmMuxerTest::SaveEncodedDataLen)));
+  webm_muxer_->OnEncodedVideo(0 /* track_index */,
+                              encoded_data,
+                              base::TimeTicks::Now(),
+                              false /* keyframe */,
+                              gfx::Size(320, 240) /* frame_size */,
+                              30.0f  /* frame_rate */);
+  base::RunLoop().RunUntilIdle();
+
+  // The second time around the callbacks should include a SimpleBlock header,
+  // namely the track index, a timestamp and a flags byte, for a total of 6B.
+  EXPECT_EQ(last_encoded_length_, encoded_data.length());
+  EXPECT_EQ(webm_muxer_->Position(), accumulated_position_);
+  const uint32_t kSimpleBlockSize = 6u;
+  EXPECT_EQ(begin_of_second_block + kSimpleBlockSize + encoded_data.length(),
+            accumulated_position_);
+
+  Mock::VerifyAndClearExpectations(mock_handler_.get());
+}

[miu, 2015/07/16 01:46:26]

Consider writing a test that encodes multiple tracks.  I'm not sure it's valid
to call Segment::AddFrame() until all video tracks have been added.

[mcasas, 2015/07/17 17:45:07]

It is possible, I think Segment seems to output then a new Track info header,
even if in the middle of the stream. From the unofficial doc [1].
"All tracks shall be described in one (or more, but preferably only one)
TRACKS element."
Any ideas on how to test it? :)
(Short of compiling the whole libwebm and demuxing everything...)

[1] http://www.matroska.org/files/matroska.pdf

[miu, 2015/07/17 22:23:18]

Weird.  I guess no need to test that you can't do something the library let's
you do.

Note, however, if you take my advice on making AddVideoTrack() public, this
should be a non-issue.  ;-)

+
+}  // namespace media