Implement software fallback for PPB_VideoDecoder.

ppapi/examples/video_decode/video_decode.cc

Index: ppapi/examples/video_decode/video_decode.cc
diff --git a/ppapi/examples/video_decode/video_decode.cc b/ppapi/examples/video_decode/video_decode.cc
index de9bb8df2c0c417ecb1c1a45cf5a4e2a58ec10e0..0e47dcfe194eb44809d27d933866aa98b061c181 100644
--- a/ppapi/examples/video_decode/video_decode.cc
+++ b/ppapi/examples/video_decode/video_decode.cc
@@ -20,7 +20,12 @@
 #include "ppapi/cpp/rect.h"
 #include "ppapi/cpp/var.h"
 #include "ppapi/cpp/video_decoder.h"
+
+// VP8 is more likely to work on different versions of Chrome. Undefine this
+// to decode H264.
+#define USE_VP8_TESTDATA_INSTEAD_OF_H264
 #include "ppapi/examples/video_decode/testdata.h"
+
 #include "ppapi/lib/gl/include/GLES2/gl2.h"
 #include "ppapi/lib/gl/include/GLES2/gl2ext.h"
 #include "ppapi/utility/completion_callback_factory.h"
@@ -56,6 +61,7 @@ class MyInstance : public pp::Instance, public pp::Graphics3DClient {
   // pp::Instance implementation.
   virtual void DidChangeView(const pp::Rect& position,
                              const pp::Rect& clip_ignored);
+  virtual bool HandleInputEvent(const pp::InputEvent& event);
 
   // pp::Graphics3DClient implementation.
   virtual void Graphics3DContextLost() {
@@ -139,12 +145,12 @@ class Decoder {
   int id() const { return id_; }
   bool decoding() const { return !flushing_ && !resetting_; }
 
-  void Seek(int frame);
+  void Reset();
   void RecyclePicture(const PP_VideoPicture& picture);
 
  private:
   void InitializeDone(int32_t result);
-  void Start(int frame);
+  void Start();
   void DecodeNextFrame();
   void DecodeDone(int32_t result);
   void PictureReady(int32_t result, PP_VideoPicture picture);
@@ -159,11 +165,29 @@ class Decoder {
 
   size_t encoded_data_next_pos_to_decode_;
   int next_picture_id_;
-  int seek_frame_;
   bool flushing_;
   bool resetting_;
 };
 
+#if defined USE_VP8_TESTDATA_INSTEAD_OF_H264
+
+// VP8 is stored in an IVF container.
+// Helpful description: http://wiki.multimedia.cx/index.php?title=IVF
+
+static void GetNextFrame(size_t* start_pos, size_t* end_pos) {
+  size_t current_pos = *start_pos;
+  if (current_pos == 0)
+    current_pos = 32;  // Skip stream header.
+  uint32_t frame_size = kData[current_pos] + (kData[current_pos + 1] << 8) +
+                        (kData[current_pos + 2] << 16) +
+                        (kData[current_pos + 3] << 24);
+  current_pos += 12;  // Skip frame header.
+  *start_pos = current_pos;
+  *end_pos = current_pos + frame_size;
+}
+
+#else  // !USE_VP8_TESTDATA_INSTEAD_OF_H264
+
 // Returns true if the current position is at the start of a NAL unit.
 static bool LookingAtNAL(const unsigned char* encoded, size_t pos) {
   // H264 frames start with 0, 0, 0, 1 in our test data.
@@ -171,7 +195,6 @@ static bool LookingAtNAL(const unsigned char* encoded, size_t pos) {
          encoded[pos + 2] == 0 && encoded[pos + 3] == 1;
 }
 
-// Find the start and end of the next frame.
 static void GetNextFrame(size_t* start_pos, size_t* end_pos) {
   assert(LookingAtNAL(kData, *start_pos));
   *end_pos = *start_pos;
@@ -181,6 +204,8 @@ static void GetNextFrame(size_t* start_pos, size_t* end_pos) {
   }
 }
 
+#endif  // USE_VP8_TESTDATA_INSTEAD_OF_H264
+
 Decoder::Decoder(MyInstance* instance,
                  int id,
                  const pp::Graphics3D& graphics_3d)
@@ -190,14 +215,19 @@ Decoder::Decoder(MyInstance* instance,
       callback_factory_(this),
       encoded_data_next_pos_to_decode_(0),
       next_picture_id_(0),
-      seek_frame_(0),
       flushing_(false),
       resetting_(false) {
+// TODO(bbudge) Remove this for final patch.
+#if defined USE_VP8_TESTDATA_INSTEAD_OF_H264
+  const PP_VideoProfile kBitstreamProfile = PP_VIDEOPROFILE_VP8MAIN;
+#else
+  const PP_VideoProfile kBitstreamProfile = PP_VIDEOPROFILE_H264MAIN;
+#endif
+
   assert(!decoder_->is_null());
-  const PP_VideoProfile profile = PP_VIDEOPROFILE_H264MAIN;
   decoder_->Initialize(graphics_3d,
-                       profile,
-                       PP_FALSE /* allow_software_fallback */,
+                       kBitstreamProfile,
+                       PP_TRUE /* allow_software_fallback */,
                        callback_factory_.NewCallback(&Decoder::InitializeDone));
 }
 
@@ -209,18 +239,13 @@ void Decoder::InitializeDone(int32_t result) {
   assert(decoder_);
   assert(result == PP_OK);
   assert(decoding());
-  Start(0);
+  Start();
 }
 
-void Decoder::Start(int frame) {
+void Decoder::Start() {
   assert(decoder_);
 
-  // Skip to |frame|.
-  size_t start_pos = 0;
-  size_t end_pos = 0;
-  for (int i = 0; i < frame; i++)
-    GetNextFrame(&start_pos, &end_pos);
-  encoded_data_next_pos_to_decode_ = end_pos;
+  encoded_data_next_pos_to_decode_ = 0;
 
   // Register callback to get the first picture. We call GetPicture again in
   // PictureReady to continuously receive pictures as they're decoded.
@@ -231,9 +256,8 @@ void Decoder::Start(int frame) {
   DecodeNextFrame();
 }
 
-void Decoder::Seek(int frame) {
+void Decoder::Reset() {
   assert(decoder_);
-  seek_frame_ = frame;
   resetting_ = true;
   decoder_->Reset(callback_factory_.NewCallback(&Decoder::ResetDone));
 }
@@ -299,6 +323,8 @@ void Decoder::ResetDone(int32_t result) {
   assert(decoder_);
   assert(result == PP_OK);
   resetting_ = false;
+
+  Start();
 }
 
 MyInstance::MyInstance(PP_Instance instance, pp::Module* module)
@@ -353,6 +379,25 @@ void MyInstance::DidChangeView(const pp::Rect& position,
   InitializeDecoders();
 }
 
+bool MyInstance::HandleInputEvent(const pp::InputEvent& event) {
+  switch (event.GetType()) {
+    case PP_INPUTEVENT_TYPE_MOUSEDOWN: {
+      pp::MouseInputEvent mouse_event(event);
+      // Reset all decoders on mouse down.
+      if (mouse_event.GetButton() == PP_INPUTEVENT_MOUSEBUTTON_LEFT) {
+        for (size_t i = 0; i < video_decoders_.size(); i++) {
+          if (video_decoders_[i]->decoding())
+            video_decoders_[i]->Reset();
+        }
+      }
+      return true;
+    }
+
+    default:
+      return false;
+  }
+}
+
 void MyInstance::InitializeDecoders() {
   assert(video_decoders_.empty());
   // Create two decoders with ids 0 and 1.