Remove the silly notion of MIME types from media code.

This was one of the first things I checked into Chromium and I've been wanting to remove it for a long, long time now.

BUG=28206
TEST=media_unittests

Review URL: http://codereview.chromium.org/6623087

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@77468 0039d316-1c4b-4281-b951-d872f2087c98

28 files changed, 97 insertions, 279 deletions

diff --git a/media/base/composite_filter.cc b/media/base/composite_filter.cc
index 7d26035..3e7b60c 100644
--- a/media/base/composite_filter.cc
+++ b/media/base/composite_filter.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -69,10 +69,6 @@ bool CompositeFilter::AddFilter(scoped_refptr<Filter> filter) {
   return true;
 }
 
-const char* CompositeFilter::major_mime_type() const {
-  return "";
-}
-
 void CompositeFilter::set_host(FilterHost* host) {
   DCHECK_EQ(message_loop_, MessageLoop::current());
   DCHECK(host);
diff --git a/media/base/composite_filter.h b/media/base/composite_filter.h
index daac421..5fa8531 100644
--- a/media/base/composite_filter.h
+++ b/media/base/composite_filter.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -25,7 +25,6 @@ class CompositeFilter : public Filter {
   bool AddFilter(scoped_refptr<Filter> filter);
 
   // media::Filter methods.
-  virtual const char* major_mime_type() const;
   virtual void set_host(FilterHost* host);
   virtual FilterHost* host();
   virtual void Play(FilterCallback* play_callback);
diff --git a/media/base/filters.cc b/media/base/filters.cc
index eff50b4..1328dd1 100644
--- a/media/base/filters.cc
+++ b/media/base/filters.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -12,10 +12,6 @@ Filter::Filter() : host_(NULL) {}
 
 Filter::~Filter() {}
 
-const char* Filter::major_mime_type() const {
-  return "";
-}
-
 void Filter::set_host(FilterHost* host) {
   DCHECK(host);
   DCHECK(!host_);
@@ -74,22 +70,6 @@ bool DataSource::IsUrlSupported(const std::string& url) {
   return true;
 }
 
-const char* AudioDecoder::major_mime_type() const {
-  return mime_type::kMajorTypeAudio;
-}
-
-const char* AudioRenderer::major_mime_type() const {
-  return mime_type::kMajorTypeAudio;
-}
-
-const char* VideoDecoder::major_mime_type() const {
-  return mime_type::kMajorTypeVideo;
-}
-
-const char* VideoRenderer::major_mime_type() const {
-  return mime_type::kMajorTypeVideo;
-}
-
 void* DemuxerStream::QueryInterface(const char* interface_id) {
   return NULL;
 }
diff --git a/media/base/filters.h b/media/base/filters.h
index 06f44c2..11bf526 100644
--- a/media/base/filters.h
+++ b/media/base/filters.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -53,9 +53,6 @@ class Filter : public base::RefCountedThreadSafe<Filter> {
  public:
   Filter();
 
-  // Return the major mime type for this filter.
-  virtual const char* major_mime_type() const;
-
   // Sets the private member |host_|. This is the first method called by
   // the FilterHost after a filter is created.  The host holds a strong
   // reference to the filter.  The reference held by the host is guaranteed
@@ -156,6 +153,12 @@ class Demuxer : public Filter {
 
 class DemuxerStream : public base::RefCountedThreadSafe<DemuxerStream> {
  public:
+  enum Type {
+    UNKNOWN,
+    AUDIO,
+    VIDEO,
+  };
+
   // Schedules a read.  When the |read_callback| is called, the downstream
   // filter takes ownership of the buffer by AddRef()'ing the buffer.
   //
@@ -173,6 +176,9 @@ class DemuxerStream : public base::RefCountedThreadSafe<DemuxerStream> {
     return (NULL != i);
   };
 
+  // Returns the type of stream.
+  virtual Type type() = 0;
+
   // Returns the media format of this stream.
   virtual const MediaFormat& media_format() = 0;
 
@@ -194,8 +200,6 @@ class DemuxerStream : public base::RefCountedThreadSafe<DemuxerStream> {
 
 class VideoDecoder : public Filter {
  public:
-  virtual const char* major_mime_type() const;
-
   // Initialize a VideoDecoder with the given DemuxerStream, executing the
   // callback upon completion.
   // stats_callback is used to update global pipeline statistics.
@@ -238,8 +242,6 @@ class VideoDecoder : public Filter {
 
 class AudioDecoder : public Filter {
  public:
-  virtual const char* major_mime_type() const;
-
   // Initialize a AudioDecoder with the given DemuxerStream, executing the
   // callback upon completion.
   // stats_callback is used to update global pipeline statistics.
@@ -277,8 +279,6 @@ class AudioDecoder : public Filter {
 
 class VideoRenderer : public Filter {
  public:
-  virtual const char* major_mime_type() const;
-
   // Initialize a VideoRenderer with the given VideoDecoder, executing the
   // callback upon completion.
   virtual void Initialize(VideoDecoder* decoder, FilterCallback* callback,
@@ -292,8 +292,6 @@ class VideoRenderer : public Filter {
 
 class AudioRenderer : public Filter {
  public:
-  virtual const char* major_mime_type() const;
-
   // Initialize a AudioRenderer with the given AudioDecoder, executing the
   // callback upon completion.
   virtual void Initialize(AudioDecoder* decoder, FilterCallback* callback) = 0;
diff --git a/media/base/media_format.cc b/media/base/media_format.cc
index 80c60e0..45df6b6 100644
--- a/media/base/media_format.cc
+++ b/media/base/media_format.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -6,52 +6,6 @@
 
 namespace media {
 
-namespace mime_type {
-
-// Represents a URL, typically used to create a DataSourceInterface.
-// Expected keys:
-//   kURL             String          The URL
-const char kURL[]                           = "text/x-url";
-
-// Represents a generic byte stream, typically from a DataSourceInterface.
-// Expected keys:
-//   None
-const char kApplicationOctetStream[]        = "application/octet-stream";
-
-// Represents encoded audio data, typically from an DemuxerStreamInterface.
-// Expected keys:
-//   None
-const char kMPEGAudio[]                     = "audio/mpeg";
-const char kAACAudio[]                      = "audio/aac";
-
-// Represents encoded video data, typically from a DemuxerStreamInterface.
-// Expected keys:
-//   None
-const char kH264AnnexB[]                    = "video/x-h264-annex-b";
-
-// Represents decoded audio data, typically from an AudioDecoderInterface.
-// Expected keys:
-//   kChannels        Integer         Number of audio channels
-//   kSampleRate      Integer         Audio sample rate (i.e., 44100)
-//   kSampleBits      Integer         Audio bits-per-sample (i.e., 16)
-const char kUncompressedAudio[]             = "audio/x-uncompressed";
-
-// Represents decoded video data, typically from a VideoDecoderInterface.
-// Other information, such as surface format (i.e., YV12), stride and planes are
-// included with the buffer itself and is not part of the MediaFormat.
-// Expected keys:
-//   kWidth           Integer         Display width of the surface
-//   kHeight          Integer         Display height of the surface
-const char kUncompressedVideo[]             = "video/x-uncompressed";
-
-// Major types of media types begin with the prefix "audio/" or "video/".
-const char kMajorTypeVideo[]                = "video/";
-const char kMajorTypeAudio[]                = "audio/";
-
-}  // namespace mime_type
-
-// Common keys.
-const char MediaFormat::kMimeType[]         = "MimeType";
 const char MediaFormat::kURL[]              = "URL";
 const char MediaFormat::kSurfaceFormat[]    = "SurfaceFormat";
 const char MediaFormat::kSurfaceType[]      = "SurfaceType";
@@ -60,10 +14,8 @@ const char MediaFormat::kSampleBits[]       = "SampleBits";
 const char MediaFormat::kChannels[]         = "Channels";
 const char MediaFormat::kWidth[]            = "Width";
 const char MediaFormat::kHeight[]           = "Height";
-const char MediaFormat::kFFmpegCodecID[]    = "FFmpegCodecID";
 
-MediaFormat::MediaFormat() {
-}
+MediaFormat::MediaFormat() {}
 
 MediaFormat::~MediaFormat() {
   Clear();
diff --git a/media/base/media_format.h b/media/base/media_format.h
index 7b53d63..781afd4 100644
--- a/media/base/media_format.h
+++ b/media/base/media_format.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -12,40 +12,16 @@
 
 namespace media {
 
-// Common MIME types.
-namespace mime_type {
-extern const char kURL[];
-extern const char kApplicationOctetStream[];
-extern const char kMPEGAudio[];
-extern const char kAACAudio[];
-extern const char kH264AnnexB[];
-extern const char kUncompressedAudio[];
-extern const char kUncompressedVideo[];
-extern const char kUncompressedVideoEglImage[];
-extern const char kMajorTypeAudio[];
-extern const char kMajorTypeVideo[];
-}  // namespace mime_type
-
 // MediaFormat is used to describe the output of a Filter to determine whether
 // a downstream filter can accept the output from an upstream filter.
-// In general, every MediaFormat contains a MIME type describing its output as
-// well as additional key-values describing additional details.
-//
-// For example, an audio decoder could output audio/x-uncompressed and include
-// additional key-values such as the number of channels and the sample rate.
-// An audio renderer would use this information to properly initialize the
-// audio hardware before playback started.
 //
-// It's also perfectly acceptable to create your own MIME types and standards
-// to allow communication between two filters that goes beyond the basics
-// described here.  For example, you could write a video decoder that outputs
-// a MIME type video/x-special for which your video renderer knows it's some
-// special form of decompressed video output that regular video renderers
-// couldn't handle.
+// For example, an audio decoder could output key-values for the number of
+// channels and the sample rate.  A downstream audio renderer would use this
+// information to properly initialize the audio hardware before playback
+// started.
 class MediaFormat {
  public:
   // Common keys.
-  static const char kMimeType[];
   static const char kURL[];
   static const char kSurfaceType[];
   static const char kSurfaceFormat[];
@@ -54,7 +30,6 @@ class MediaFormat {
   static const char kChannels[];
   static const char kWidth[];
   static const char kHeight[];
-  static const char kFFmpegCodecID[];
 
   MediaFormat();
   ~MediaFormat();
diff --git a/media/base/mock_filters.h b/media/base/mock_filters.h
index e54e5da..dd391ac 100644
--- a/media/base/mock_filters.h
+++ b/media/base/mock_filters.h
@@ -119,6 +119,7 @@ class MockDemuxerStream : public DemuxerStream {
   MockDemuxerStream();
 
   // DemuxerStream implementation.
+  MOCK_METHOD0(type, Type());
   MOCK_METHOD0(media_format, const MediaFormat&());
   MOCK_METHOD1(Read, void(Callback1<Buffer*>::Type* read_callback));
   MOCK_METHOD1(QueryInterface, void*(const char* interface_id));
diff --git a/media/base/pipeline.h b/media/base/pipeline.h
index 0b87d29..8e7a8db 100644
--- a/media/base/pipeline.h
+++ b/media/base/pipeline.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -121,11 +121,11 @@ class Pipeline : public base::RefCountedThreadSafe<Pipeline> {
   // Returns true if there has been network activity.
   virtual bool IsNetworkActive() const = 0;
 
-  // If the |major_mime_type| exists in the pipeline and is being rendered, this
-  // method will return true.  Types are defined in media/base/media_foramt.h.
-  // For example, to determine if a pipeline contains video:
-  //   bool has_video = pipeline->IsRendered(mime_type::kMajorTypeVideo);
-  virtual bool IsRendered(const std::string& major_mime_type) const = 0;
+  // Returns true if the media has audio.
+  virtual bool HasAudio() const = 0;
+
+  // Returns true if the media has video.
+  virtual bool HasVideo() const = 0;
 
   // Gets the current playback rate of the pipeline.  When the pipeline is
   // started, the playback rate will be 0.0f.  A rate of 1.0f indicates
diff --git a/media/base/pipeline_impl.cc b/media/base/pipeline_impl.cc
index 9bce38c..d4009c8 100644
--- a/media/base/pipeline_impl.cc
+++ b/media/base/pipeline_impl.cc
@@ -135,11 +135,14 @@ bool PipelineImpl::IsNetworkActive() const {
   return network_activity_;
 }
 
-bool PipelineImpl::IsRendered(const std::string& major_mime_type) const {
+bool PipelineImpl::HasAudio() const {
   base::AutoLock auto_lock(lock_);
-  bool is_rendered = (rendered_mime_types_.find(major_mime_type) !=
-                      rendered_mime_types_.end());
-  return is_rendered;
+  return has_audio_;
+}
+
+bool PipelineImpl::HasVideo() const {
+  base::AutoLock auto_lock(lock_);
+  return has_video_;
 }
 
 float PipelineImpl::GetPlaybackRate() const {
@@ -321,10 +324,11 @@ void PipelineImpl::ResetState() {
   volume_           = 1.0f;
   playback_rate_    = 0.0f;
   error_            = PIPELINE_OK;
+  has_audio_        = false;
+  has_video_        = false;
   waiting_for_clock_update_ = false;
   audio_disabled_   = false;
   clock_->SetTime(kZero);
-  rendered_mime_types_.clear();
 }
 
 void PipelineImpl::set_state(State next_state) {
@@ -509,18 +513,6 @@ void PipelineImpl::DisableAudioRenderer() {
       NewRunnableMethod(this, &PipelineImpl::DisableAudioRendererTask));
 }
 
-void PipelineImpl::InsertRenderedMimeType(const std::string& major_mime_type) {
-  DCHECK(IsRunning());
-  base::AutoLock auto_lock(lock_);
-  rendered_mime_types_.insert(major_mime_type);
-}
-
-bool PipelineImpl::HasRenderedMimeTypes() const {
-  DCHECK(IsRunning());
-  base::AutoLock auto_lock(lock_);
-  return !rendered_mime_types_.empty();
-}
-
 // Called from any thread.
 void PipelineImpl::OnFilterInitialize() {
   // Continue the initialize task by proceeding to the next stage.
@@ -627,7 +619,8 @@ void PipelineImpl::InitializeTask() {
     set_state(kInitAudioRenderer);
     // Returns false if there's no audio stream.
     if (InitializeAudioRenderer(pipeline_init_state_->audio_decoder_)) {
-      InsertRenderedMimeType(mime_type::kMajorTypeAudio);
+      base::AutoLock auto_lock(lock_);
+      has_audio_ = true;
       return;
     }
   }
@@ -644,13 +637,14 @@ void PipelineImpl::InitializeTask() {
   if (state_ == kInitVideoDecoder) {
     set_state(kInitVideoRenderer);
     if (InitializeVideoRenderer(pipeline_init_state_->video_decoder_)) {
-      InsertRenderedMimeType(mime_type::kMajorTypeVideo);
+      base::AutoLock auto_lock(lock_);
+      has_video_ = true;
       return;
     }
   }
 
   if (state_ == kInitVideoRenderer) {
-    if (!IsPipelineOk() || !HasRenderedMimeTypes()) {
+    if (!IsPipelineOk() || !(HasAudio() || HasVideo())) {
       SetError(PIPELINE_ERROR_COULD_NOT_RENDER);
       return;
     }
@@ -856,11 +850,8 @@ void PipelineImpl::NotifyNetworkEventTask() {
 void PipelineImpl::DisableAudioRendererTask() {
   DCHECK_EQ(MessageLoop::current(), message_loop_);
 
-  // |rendered_mime_types_| is read through public methods so we need to lock
-  // this variable.
   base::AutoLock auto_lock(lock_);
-  rendered_mime_types_.erase(mime_type::kMajorTypeAudio);
-
+  has_audio_ = false;
   audio_disabled_ = true;
 
   // Notify all filters of disabled audio renderer. If the filter isn't
@@ -929,9 +920,7 @@ void PipelineImpl::FilterStateTransitionTask() {
     base::AutoLock auto_lock(lock_);
     // We use audio stream to update the clock. So if there is such a stream,
     // we pause the clock until we receive a valid timestamp.
-    waiting_for_clock_update_ =
-        rendered_mime_types_.find(mime_type::kMajorTypeAudio) !=
-        rendered_mime_types_.end();
+    waiting_for_clock_update_ = has_audio_;
     if (!waiting_for_clock_update_)
       clock_->Play();
 
@@ -1073,7 +1062,7 @@ bool PipelineImpl::InitializeAudioDecoder(
   DCHECK(IsPipelineOk());
 
   scoped_refptr<DemuxerStream> stream =
-      FindDemuxerStream(demuxer, mime_type::kMajorTypeAudio);
+      FindDemuxerStream(demuxer, DemuxerStream::AUDIO);
 
   if (!stream)
     return false;
@@ -1103,7 +1092,7 @@ bool PipelineImpl::InitializeVideoDecoder(
   DCHECK(IsPipelineOk());
 
   scoped_refptr<DemuxerStream> stream =
-      FindDemuxerStream(demuxer, mime_type::kMajorTypeVideo);
+      FindDemuxerStream(demuxer, DemuxerStream::VIDEO);
 
   if (!stream)
     return false;
@@ -1175,15 +1164,13 @@ bool PipelineImpl::InitializeVideoRenderer(
 
 scoped_refptr<DemuxerStream> PipelineImpl::FindDemuxerStream(
     const scoped_refptr<Demuxer>& demuxer,
-    std::string major_mime_type) {
+    DemuxerStream::Type type) {
   DCHECK(demuxer);
 
   const int num_outputs = demuxer->GetNumberOfStreams();
   for (int i = 0; i < num_outputs; ++i) {
     std::string value;
-    if (demuxer->GetStream(i)->media_format().GetAsString(
-        MediaFormat::kMimeType, &value) &&
-        !value.compare(0, major_mime_type.length(), major_mime_type)) {
+    if (demuxer->GetStream(i)->type() == type) {
       return demuxer->GetStream(i);
     }
   }
diff --git a/media/base/pipeline_impl.h b/media/base/pipeline_impl.h
index e817eed..fa4b5d1 100644
--- a/media/base/pipeline_impl.h
+++ b/media/base/pipeline_impl.h
@@ -78,7 +78,8 @@ class PipelineImpl : public Pipeline, public FilterHost {
   virtual bool IsRunning() const;
   virtual bool IsInitialized() const;
   virtual bool IsNetworkActive() const;
-  virtual bool IsRendered(const std::string& major_mime_type) const;
+  virtual bool HasAudio() const;
+  virtual bool HasVideo() const;
   virtual float GetPlaybackRate() const;
   virtual void SetPlaybackRate(float playback_rate);
   virtual float GetVolume() const;
@@ -172,13 +173,6 @@ class PipelineImpl : public Pipeline, public FilterHost {
   virtual void SetCurrentReadPosition(int64 offset);
   virtual int64 GetCurrentReadPosition();
 
-  // Method called during initialization to insert a mime type into the
-  // |rendered_mime_types_| set.
-  void InsertRenderedMimeType(const std::string& major_mime_type);
-
-  // Method called during initialization to determine if we rendered anything.
-  bool HasRenderedMimeTypes() const;
-
   // Callback executed by filters upon completing initialization.
   void OnFilterInitialize();
 
@@ -267,10 +261,11 @@ class PipelineImpl : public Pipeline, public FilterHost {
   bool InitializeAudioRenderer(const scoped_refptr<AudioDecoder>& decoder);
   bool InitializeVideoRenderer(const scoped_refptr<VideoDecoder>& decoder);
 
-  // Helper to find the demuxer of |major_mime_type| from Demuxer.
+  // Returns a reference to the DemuxerStream of the requested type if it
+  // exists, NULL otherwise.
   scoped_refptr<DemuxerStream> FindDemuxerStream(
       const scoped_refptr<Demuxer>& demuxer,
-      std::string major_mime_type);
+      DemuxerStream::Type type);
 
   // Kicks off destroying filters. Called by StopTask() and ErrorChangedTask().
   // When we start to tear down the pipeline, we will consider two cases:
@@ -359,9 +354,9 @@ class PipelineImpl : public Pipeline, public FilterHost {
   // reset the pipeline state, and restore this to PIPELINE_OK.
   PipelineError error_;
 
-  // Vector of major mime types that have been rendered by this pipeline.
-  typedef std::set<std::string> RenderedMimeTypesSet;
-  RenderedMimeTypesSet rendered_mime_types_;
+  // Whether the media contains rendered audio and video streams.
+  bool has_audio_;
+  bool has_video_;
 
   // The following data members are only accessed by tasks posted to
   // |message_loop_|.
diff --git a/media/base/pipeline_impl_unittest.cc b/media/base/pipeline_impl_unittest.cc
index 0762cb35..b583879 100644
--- a/media/base/pipeline_impl_unittest.cc
+++ b/media/base/pipeline_impl_unittest.cc
@@ -79,9 +79,6 @@ class PipelineImplTest : public ::testing::Test {
                                 &CallbackHelper::OnStop));
     message_loop_.RunAllPending();
 
-    // Free allocated media formats (if any).
-    STLDeleteElements(&stream_media_formats_);
-
     mocks_.reset();
   }
 
@@ -125,19 +122,11 @@ class PipelineImplTest : public ::testing::Test {
     }
   }
 
-  // Create a stream with an associated media format.
-  StrictMock<MockDemuxerStream>* CreateStream(const std::string& mime_type) {
+  StrictMock<MockDemuxerStream>* CreateStream(DemuxerStream::Type type) {
     StrictMock<MockDemuxerStream>* stream =
         new StrictMock<MockDemuxerStream>();
-
-    // Sets the mime type of this stream's media format, which is usually
-    // checked to determine the type of decoder to create.
-    MediaFormat* media_format = new MediaFormat();
-    media_format->SetAsString(MediaFormat::kMimeType, mime_type);
-    EXPECT_CALL(*stream, media_format())
-        .WillRepeatedly(ReturnRef(*media_format));
-    stream_media_formats_.push_back(media_format);
-
+    EXPECT_CALL(*stream, type())
+        .WillRepeatedly(Return(type));
     return stream;
   }
 
@@ -209,11 +198,11 @@ class PipelineImplTest : public ::testing::Test {
   }
 
   void CreateAudioStream() {
-    audio_stream_ = CreateStream("audio/x-foo");
+    audio_stream_ = CreateStream(DemuxerStream::AUDIO);
   }
 
   void CreateVideoStream() {
-    video_stream_ = CreateStream("video/x-foo");
+    video_stream_ = CreateStream(DemuxerStream::VIDEO);
   }
 
   MockDemuxerStream* audio_stream() {
@@ -269,9 +258,6 @@ class PipelineImplTest : public ::testing::Test {
   scoped_refptr<StrictMock<MockDemuxerStream> > audio_stream_;
   scoped_refptr<StrictMock<MockDemuxerStream> > video_stream_;
 
-  typedef std::vector<MediaFormat*> MediaFormatVector;
-  MediaFormatVector stream_media_formats_;
-
  private:
   DISALLOW_COPY_AND_ASSIGN(PipelineImplTest);
 };
@@ -291,9 +277,8 @@ TEST_F(PipelineImplTest, NotStarted) {
 
   EXPECT_FALSE(pipeline_->IsRunning());
   EXPECT_FALSE(pipeline_->IsInitialized());
-  EXPECT_FALSE(pipeline_->IsRendered(""));
-  EXPECT_FALSE(pipeline_->IsRendered(mime_type::kMajorTypeAudio));
-  EXPECT_FALSE(pipeline_->IsRendered(mime_type::kMajorTypeVideo));
+  EXPECT_FALSE(pipeline_->HasAudio());
+  EXPECT_FALSE(pipeline_->HasVideo());
 
   // Setting should still work.
   EXPECT_EQ(0.0f, pipeline_->GetPlaybackRate());
@@ -424,8 +409,8 @@ TEST_F(PipelineImplTest, AudioStream) {
   InitializePipeline();
   EXPECT_TRUE(pipeline_->IsInitialized());
   EXPECT_EQ(PIPELINE_OK, pipeline_->GetError());
-  EXPECT_TRUE(pipeline_->IsRendered(media::mime_type::kMajorTypeAudio));
-  EXPECT_FALSE(pipeline_->IsRendered(media::mime_type::kMajorTypeVideo));
+  EXPECT_TRUE(pipeline_->HasAudio());
+  EXPECT_FALSE(pipeline_->HasVideo());
 }
 
 TEST_F(PipelineImplTest, VideoStream) {
@@ -441,8 +426,8 @@ TEST_F(PipelineImplTest, VideoStream) {
   InitializePipeline();
   EXPECT_TRUE(pipeline_->IsInitialized());
   EXPECT_EQ(PIPELINE_OK, pipeline_->GetError());
-  EXPECT_FALSE(pipeline_->IsRendered(media::mime_type::kMajorTypeAudio));
-  EXPECT_TRUE(pipeline_->IsRendered(media::mime_type::kMajorTypeVideo));
+  EXPECT_FALSE(pipeline_->HasAudio());
+  EXPECT_TRUE(pipeline_->HasVideo());
 }
 
 TEST_F(PipelineImplTest, AudioVideoStream) {
@@ -462,8 +447,8 @@ TEST_F(PipelineImplTest, AudioVideoStream) {
   InitializePipeline();
   EXPECT_TRUE(pipeline_->IsInitialized());
   EXPECT_EQ(PIPELINE_OK, pipeline_->GetError());
-  EXPECT_TRUE(pipeline_->IsRendered(media::mime_type::kMajorTypeAudio));
-  EXPECT_TRUE(pipeline_->IsRendered(media::mime_type::kMajorTypeVideo));
+  EXPECT_TRUE(pipeline_->HasAudio());
+  EXPECT_TRUE(pipeline_->HasVideo());
 }
 
 TEST_F(PipelineImplTest, Seek) {
@@ -618,8 +603,8 @@ TEST_F(PipelineImplTest, DisableAudioRenderer) {
   InitializePipeline();
   EXPECT_TRUE(pipeline_->IsInitialized());
   EXPECT_EQ(PIPELINE_OK, pipeline_->GetError());
-  EXPECT_TRUE(pipeline_->IsRendered(mime_type::kMajorTypeAudio));
-  EXPECT_TRUE(pipeline_->IsRendered(mime_type::kMajorTypeVideo));
+  EXPECT_TRUE(pipeline_->HasAudio());
+  EXPECT_TRUE(pipeline_->HasVideo());
 
   EXPECT_CALL(*mocks_->audio_renderer(), SetPlaybackRate(1.0f))
       .WillOnce(DisableAudioRenderer(mocks_->audio_renderer()));
@@ -676,8 +661,8 @@ TEST_F(PipelineImplTest, DisableAudioRendererDuringInit) {
   InitializePipeline();
   EXPECT_TRUE(pipeline_->IsInitialized());
   EXPECT_EQ(PIPELINE_OK, pipeline_->GetError());
-  EXPECT_FALSE(pipeline_->IsRendered(mime_type::kMajorTypeAudio));
-  EXPECT_TRUE(pipeline_->IsRendered(mime_type::kMajorTypeVideo));
+  EXPECT_FALSE(pipeline_->HasAudio());
+  EXPECT_TRUE(pipeline_->HasVideo());
 
   // Verify that ended event is fired when video ends.
   EXPECT_CALL(*mocks_->video_renderer(), HasEnded())
diff --git a/media/ffmpeg/ffmpeg_common.cc b/media/ffmpeg/ffmpeg_common.cc
index 08228fd..244d2729 100644
--- a/media/ffmpeg/ffmpeg_common.cc
+++ b/media/ffmpeg/ffmpeg_common.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -6,11 +6,6 @@
 
 namespace media {
 
-namespace mime_type {
-
-const char kFFmpegAudio[] = "audio/x-ffmpeg";
-const char kFFmpegVideo[] = "video/x-ffmpeg";
-
-}  // namespace mime_type
+// TODO(scherkus): combine ffmpeg_common.h with ffmpeg_util.h
 
 }  // namespace media
diff --git a/media/ffmpeg/ffmpeg_common.h b/media/ffmpeg/ffmpeg_common.h
index 4250233..714a6a1 100644
--- a/media/ffmpeg/ffmpeg_common.h
+++ b/media/ffmpeg/ffmpeg_common.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -48,15 +48,6 @@ class ScopedPtrAVFreePacket {
   }
 };
 
-
-// FFmpeg MIME types.
-namespace mime_type {
-
-extern const char kFFmpegAudio[];
-extern const char kFFmpegVideo[];
-
-}  // namespace mime_type
-
 }  // namespace media
 
 #endif  // MEDIA_FFMPEG_FFMPEG_COMMON_H_
diff --git a/media/filters/audio_renderer_base.cc b/media/filters/audio_renderer_base.cc
index 9d7783f..4dec0a4 100644
--- a/media/filters/audio_renderer_base.cc
+++ b/media/filters/audio_renderer_base.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -259,12 +259,9 @@ bool AudioRendererBase::ParseMediaFormat(const MediaFormat& media_format,
                                          int* sample_rate_out,
                                          int* sample_bits_out) {
   // TODO(scherkus): might be handy to support NULL parameters.
-  std::string mime_type;
-  return media_format.GetAsString(MediaFormat::kMimeType, &mime_type) &&
-      media_format.GetAsInteger(MediaFormat::kChannels, channels_out) &&
+  return media_format.GetAsInteger(MediaFormat::kChannels, channels_out) &&
       media_format.GetAsInteger(MediaFormat::kSampleRate, sample_rate_out) &&
-      media_format.GetAsInteger(MediaFormat::kSampleBits, sample_bits_out) &&
-      mime_type.compare(mime_type::kUncompressedAudio) == 0;
+      media_format.GetAsInteger(MediaFormat::kSampleBits, sample_bits_out);
 }
 
 void AudioRendererBase::SetPlaybackRate(float playback_rate) {
diff --git a/media/filters/audio_renderer_base_unittest.cc b/media/filters/audio_renderer_base_unittest.cc
index ae8e515..c1af178 100644
--- a/media/filters/audio_renderer_base_unittest.cc
+++ b/media/filters/audio_renderer_base_unittest.cc
@@ -58,8 +58,6 @@ class AudioRendererBaseTest : public ::testing::Test {
         .WillRepeatedly(Invoke(this, &AudioRendererBaseTest::EnqueueCallback));
 
     // Sets the essential media format keys for this decoder.
-    decoder_media_format_.SetAsString(MediaFormat::kMimeType,
-                                      mime_type::kUncompressedAudio);
     decoder_media_format_.SetAsInteger(MediaFormat::kChannels, 1);
     decoder_media_format_.SetAsInteger(MediaFormat::kSampleRate, 44100);
     decoder_media_format_.SetAsInteger(MediaFormat::kSampleBits, 16);
diff --git a/media/filters/decoder_base.h b/media/filters/decoder_base.h
index 2d660c9..086aa96 100644
--- a/media/filters/decoder_base.h
+++ b/media/filters/decoder_base.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -221,8 +221,6 @@ class DecoderBase : public Decoder {
     if (!*success) {
       this->host()->SetError(PIPELINE_ERROR_DECODE);
     } else {
-      // TODO(scherkus): subclass shouldn't mutate superclass media format.
-      DCHECK(!media_format_.empty()) << "Subclass did not set media_format_";
       state_ = kInitialized;
     }
   }
diff --git a/media/filters/decoder_base_unittest.cc b/media/filters/decoder_base_unittest.cc
index f0d4117..296bd13c7 100644
--- a/media/filters/decoder_base_unittest.cc
+++ b/media/filters/decoder_base_unittest.cc
@@ -62,7 +62,6 @@ class MockDecoderImpl : public DecoderBase<
  public:
   explicit MockDecoderImpl(MessageLoop* message_loop)
       : DecoderBase<MockDecoder, MockDecoderOutput>(message_loop) {
-    media_format_.SetAsString(MediaFormat::kMimeType, "mock");
   }
 
   virtual ~MockDecoderImpl() {}
diff --git a/media/filters/ffmpeg_audio_decoder.cc b/media/filters/ffmpeg_audio_decoder.cc
index 254222d..b01977b 100644
--- a/media/filters/ffmpeg_audio_decoder.cc
+++ b/media/filters/ffmpeg_audio_decoder.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -81,8 +81,6 @@ void FFmpegAudioDecoder::DoInitialize(DemuxerStream* demuxer_stream,
       av_get_bits_per_sample_fmt(codec_context_->sample_fmt));
   media_format_.SetAsInteger(MediaFormat::kSampleRate,
       codec_context_->sample_rate);
-  media_format_.SetAsString(MediaFormat::kMimeType,
-      mime_type::kUncompressedAudio);
 
   // Prepare the output buffer.
   output_buffer_.reset(static_cast<uint8*>(av_malloc(kOutputBufferSize)));
diff --git a/media/filters/ffmpeg_demuxer.cc b/media/filters/ffmpeg_demuxer.cc
index d482c83..cd1a132 100644
--- a/media/filters/ffmpeg_demuxer.cc
+++ b/media/filters/ffmpeg_demuxer.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -59,22 +59,17 @@ FFmpegDemuxerStream::FFmpegDemuxerStream(FFmpegDemuxer* demuxer,
                                          AVStream* stream)
     : demuxer_(demuxer),
       stream_(stream),
+      type_(UNKNOWN),
       stopped_(false) {
   DCHECK(demuxer_);
 
   // Determine our media format.
   switch (stream->codec->codec_type) {
     case CODEC_TYPE_AUDIO:
-      media_format_.SetAsString(MediaFormat::kMimeType,
-                                mime_type::kFFmpegAudio);
-      media_format_.SetAsInteger(MediaFormat::kFFmpegCodecID,
-                                 stream->codec->codec_id);
+      type_ = AUDIO;
       break;
     case CODEC_TYPE_VIDEO:
-      media_format_.SetAsString(MediaFormat::kMimeType,
-                                mime_type::kFFmpegVideo);
-      media_format_.SetAsInteger(MediaFormat::kFFmpegCodecID,
-                                 stream->codec->codec_id);
+      type_ = VIDEO;
       break;
     default:
       NOTREACHED();
@@ -154,6 +149,10 @@ base::TimeDelta FFmpegDemuxerStream::duration() {
   return duration_;
 }
 
+DemuxerStream::Type FFmpegDemuxerStream::type() {
+  return type_;
+}
+
 const MediaFormat& FFmpegDemuxerStream::media_format() {
   return media_format_;
 }
diff --git a/media/filters/ffmpeg_demuxer.h b/media/filters/ffmpeg_demuxer.h
index 2123563..2ab78ae 100644
--- a/media/filters/ffmpeg_demuxer.h
+++ b/media/filters/ffmpeg_demuxer.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -72,6 +72,7 @@ class FFmpegDemuxerStream : public DemuxerStream, public AVStreamProvider {
   virtual base::TimeDelta duration();
 
   // DemuxerStream implementation.
+  virtual Type type();
   virtual const MediaFormat& media_format();
   virtual void Read(Callback1<Buffer*>::Type* read_callback);
   // Bitstream converter to convert input packet.
@@ -80,8 +81,6 @@ class FFmpegDemuxerStream : public DemuxerStream, public AVStreamProvider {
   // AVStreamProvider implementation.
   virtual AVStream* GetAVStream();
 
-
-
  protected:
   virtual void* QueryInterface(const char* interface_id);
 
@@ -101,6 +100,7 @@ class FFmpegDemuxerStream : public DemuxerStream, public AVStreamProvider {
 
   FFmpegDemuxer* demuxer_;
   AVStream* stream_;
+  Type type_;
   MediaFormat media_format_;
   base::TimeDelta duration_;
   bool discontinuous_;
diff --git a/media/filters/ffmpeg_demuxer_unittest.cc b/media/filters/ffmpeg_demuxer_unittest.cc
index c492493..50ebb1e 100644
--- a/media/filters/ffmpeg_demuxer_unittest.cc
+++ b/media/filters/ffmpeg_demuxer_unittest.cc
@@ -234,10 +234,7 @@ TEST_F(FFmpegDemuxerTest, Initialize_Successful) {
   scoped_refptr<DemuxerStream> stream = demuxer_->GetStream(DS_STREAM_VIDEO);
   AVStreamProvider* av_stream_provider = NULL;
   ASSERT_TRUE(stream);
-  std::string mime_type;
-  EXPECT_TRUE(
-      stream->media_format().GetAsString(MediaFormat::kMimeType, &mime_type));
-  EXPECT_STREQ(mime_type::kFFmpegVideo, mime_type.c_str());
+  EXPECT_EQ(DemuxerStream::VIDEO, stream->type());
   EXPECT_TRUE(stream->QueryInterface(&av_stream_provider));
   EXPECT_TRUE(av_stream_provider);
   EXPECT_EQ(&streams_[AV_STREAM_VIDEO], av_stream_provider->GetAVStream());
@@ -246,9 +243,7 @@ TEST_F(FFmpegDemuxerTest, Initialize_Successful) {
   stream = demuxer_->GetStream(DS_STREAM_AUDIO);
   av_stream_provider = NULL;
   ASSERT_TRUE(stream);
-  EXPECT_TRUE(stream->media_format().GetAsString(MediaFormat::kMimeType,
-              &mime_type));
-  EXPECT_STREQ(mime_type::kFFmpegAudio, mime_type.c_str());
+  EXPECT_EQ(DemuxerStream::AUDIO, stream->type());
   EXPECT_TRUE(stream->QueryInterface(&av_stream_provider));
   EXPECT_TRUE(av_stream_provider);
   EXPECT_EQ(&streams_[AV_STREAM_AUDIO], av_stream_provider->GetAVStream());
diff --git a/media/filters/ffmpeg_video_decoder.cc b/media/filters/ffmpeg_video_decoder.cc
index 378f410..698423b 100644
--- a/media/filters/ffmpeg_video_decoder.cc
+++ b/media/filters/ffmpeg_video_decoder.cc
@@ -110,8 +110,6 @@ void FFmpegVideoDecoder::OnInitializeComplete(const VideoCodecInfo& info) {
   AutoCallbackRunner done_runner(initialize_callback_.release());
 
   if (info.success) {
-    media_format_.SetAsString(MediaFormat::kMimeType,
-                              mime_type::kUncompressedVideo);
     media_format_.SetAsInteger(MediaFormat::kWidth,
                                info.stream_info.surface_width);
     media_format_.SetAsInteger(MediaFormat::kHeight,
diff --git a/media/filters/ffmpeg_video_decoder_unittest.cc b/media/filters/ffmpeg_video_decoder_unittest.cc
index 0ddcdf9..2b3fc9b 100644
--- a/media/filters/ffmpeg_video_decoder_unittest.cc
+++ b/media/filters/ffmpeg_video_decoder_unittest.cc
@@ -133,9 +133,6 @@ ACTION_P(EngineSeek, engine) {
 class FFmpegVideoDecoderTest : public testing::Test {
  protected:
   FFmpegVideoDecoderTest() {
-    MediaFormat media_format;
-    media_format.SetAsString(MediaFormat::kMimeType, mime_type::kFFmpegVideo);
-
     // Create an FFmpegVideoDecoder, and MockVideoDecodeEngine.
     //
     // TODO(ajwong): Break the test's dependency on FFmpegVideoDecoder.
@@ -265,11 +262,8 @@ TEST_F(FFmpegVideoDecoderTest, Initialize_Successful) {
   // Test that the output media format is an uncompressed video surface that
   // matches the dimensions specified by FFmpeg.
   const MediaFormat& media_format = decoder_->media_format();
-  std::string mime_type;
   int width = 0;
   int height = 0;
-  EXPECT_TRUE(media_format.GetAsString(MediaFormat::kMimeType, &mime_type));
-  EXPECT_STREQ(mime_type::kUncompressedVideo, mime_type.c_str());
   EXPECT_TRUE(media_format.GetAsInteger(MediaFormat::kWidth, &width));
   EXPECT_EQ(kWidth, width);
   EXPECT_TRUE(media_format.GetAsInteger(MediaFormat::kHeight, &height));
diff --git a/media/filters/file_data_source.cc b/media/filters/file_data_source.cc
index 64c61fb..9fd93a5 100644
--- a/media/filters/file_data_source.cc
+++ b/media/filters/file_data_source.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -41,8 +41,6 @@ void FileDataSource::Initialize(const std::string& url,
     callback->Run();
     return;
   }
-  media_format_.SetAsString(MediaFormat::kMimeType,
-                            mime_type::kApplicationOctetStream);
   media_format_.SetAsString(MediaFormat::kURL, url);
   host()->SetTotalBytes(file_size_);
   host()->SetBufferedBytes(file_size_);
diff --git a/media/filters/omx_video_decoder.cc b/media/filters/omx_video_decoder.cc
index 73816f9..c8962a3 100644
--- a/media/filters/omx_video_decoder.cc
+++ b/media/filters/omx_video_decoder.cc
@@ -102,8 +102,6 @@ void OmxVideoDecoder::OnInitializeComplete(const VideoCodecInfo& info) {
   AutoCallbackRunner done_runner(initialize_callback_.release());
 
   if (info.success) {
-    media_format_.SetAsString(MediaFormat::kMimeType,
-                              mime_type::kUncompressedVideo);
     media_format_.SetAsInteger(MediaFormat::kWidth,
                                info.stream_info.surface_width);
     media_format_.SetAsInteger(MediaFormat::kHeight,
diff --git a/media/filters/video_renderer_base.cc b/media/filters/video_renderer_base.cc
index 9ed236b..493de69 100644
--- a/media/filters/video_renderer_base.cc
+++ b/media/filters/video_renderer_base.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -49,12 +49,6 @@ bool VideoRendererBase::ParseMediaFormat(
     VideoFrame::SurfaceType* surface_type_out,
     VideoFrame::Format* surface_format_out,
     int* width_out, int* height_out) {
-  std::string mime_type;
-  if (!media_format.GetAsString(MediaFormat::kMimeType, &mime_type))
-    return false;
-  if (mime_type.compare(mime_type::kUncompressedVideo) != 0)
-    return false;
-
   int surface_type;
   if (!media_format.GetAsInteger(MediaFormat::kSurfaceType, &surface_type))
     return false;
diff --git a/media/filters/video_renderer_base_unittest.cc b/media/filters/video_renderer_base_unittest.cc
index aa5cad1..60861f9 100644
--- a/media/filters/video_renderer_base_unittest.cc
+++ b/media/filters/video_renderer_base_unittest.cc
@@ -58,8 +58,6 @@ class VideoRendererBaseTest : public ::testing::Test {
         .WillRepeatedly(Invoke(this, &VideoRendererBaseTest::EnqueueCallback));
 
     // Sets the essential media format keys for this decoder.
-    decoder_media_format_.SetAsString(MediaFormat::kMimeType,
-                                      mime_type::kUncompressedVideo);
     decoder_media_format_.SetAsInteger(MediaFormat::kSurfaceType,
                                        VideoFrame::TYPE_SYSTEM_MEMORY);
     decoder_media_format_.SetAsInteger(MediaFormat::kSurfaceFormat,
diff --git a/media/tools/player_x11/player_x11.cc b/media/tools/player_x11/player_x11.cc
index 2e75994..39504ff 100644
--- a/media/tools/player_x11/player_x11.cc
+++ b/media/tools/player_x11/player_x11.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -266,7 +266,7 @@ int main(int argc, char** argv) {
     g_running = true;
 
     // Check if video is present.
-    audio_only = !pipeline->IsRendered(media::mime_type::kMajorTypeVideo);
+    audio_only = !pipeline->HasVideo();
 
     message_loop.PostTask(FROM_HERE,
         NewRunnableFunction(PeriodicalUpdate, pipeline,