Make sure the first VP8 frame for VDA is key frame.

Sometimes WebRTC gives video decoder an old frame after Reset.
VDA will fail if the first frame is not a key frame.
RTCVideoDecoder should return error and skip the frame when
this happens.

BUG=170345
TEST=Try http://apprtc.appspot.com/?debug=loopback on Chromebook Daisy.

Review URL: https://chromiumcodereview.appspot.com/23034002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@217985 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 45 insertions, 1 deletions

diff --git a/content/renderer/media/rtc_video_decoder.cc b/content/renderer/media/rtc_video_decoder.cc
index 27030f6..c048b6b 100644
--- a/content/renderer/media/rtc_video_decoder.cc
+++ b/content/renderer/media/rtc_video_decoder.cc
@@ -195,8 +195,17 @@ int32_t RTCVideoDecoder::Decode(
     // Return an error to request a key frame.
     return WEBRTC_VIDEO_CODEC_ERROR;
   }
-  if (inputImage._frameType == webrtc::kKeyFrame)
+  if (inputImage._frameType == webrtc::kKeyFrame) {
+    DVLOG(2) << "Got key frame. size=" << inputImage._encodedWidth << "x"
+             << inputImage._encodedHeight;
     frame_size_.SetSize(inputImage._encodedWidth, inputImage._encodedHeight);
+  } else if (IsFirstBufferAfterReset(next_bitstream_buffer_id_,
+                                     reset_bitstream_buffer_id_)) {
+    // TODO(wuchengli): VDA should handle it. Remove this when
+    // http://crosbug.com/p/21913 is fixed.
+    DVLOG(1) << "The first frame should be a key frame. Drop this.";
+    return WEBRTC_VIDEO_CODEC_ERROR;
+  }
 
   // Create buffer metadata.
   BufferData buffer_data(next_bitstream_buffer_id_,
@@ -526,6 +535,12 @@ bool RTCVideoDecoder::IsBufferAfterReset(int32 id_buffer, int32 id_reset) {
   return diff < ID_HALF;
 }
 
+bool RTCVideoDecoder::IsFirstBufferAfterReset(int32 id_buffer, int32 id_reset) {
+  if (id_reset == ID_INVALID)
+    return id_buffer == 0;
+  return id_buffer == ((id_reset + 1) & ID_LAST);
+}
+
 void RTCVideoDecoder::SaveToDecodeBuffers_Locked(
     const webrtc::EncodedImage& input_image,
     scoped_ptr<SHMBuffer> shm_buffer,
diff --git a/content/renderer/media/rtc_video_decoder.h b/content/renderer/media/rtc_video_decoder.h
index 7a2686e..13adf37 100644
--- a/content/renderer/media/rtc_video_decoder.h
+++ b/content/renderer/media/rtc_video_decoder.h
@@ -110,6 +110,7 @@ class CONTENT_EXPORT RTCVideoDecoder
   };
 
   FRIEND_TEST_ALL_PREFIXES(RTCVideoDecoderTest, IsBufferAfterReset);
+  FRIEND_TEST_ALL_PREFIXES(RTCVideoDecoderTest, IsFirstBufferAfterReset);
 
   // The meessage loop of |factories| will be saved to |vda_loop_proxy_|.
   RTCVideoDecoder(
@@ -126,6 +127,10 @@ class CONTENT_EXPORT RTCVideoDecoder
   // This handles the wraparound.
   bool IsBufferAfterReset(int32 id_buffer, int32 id_reset);
 
+  // Returns true if bitstream buffer |id_buffer| is the first buffer after
+  // |id_reset|.
+  bool IsFirstBufferAfterReset(int32 id_buffer, int32 id_reset);
+
   // Saves a WebRTC buffer in |decode_buffers_| for decode.
   void SaveToDecodeBuffers_Locked(const webrtc::EncodedImage& input_image,
                                   scoped_ptr<SHMBuffer> shm_buffer,
diff --git a/content/renderer/media/rtc_video_decoder_unittest.cc b/content/renderer/media/rtc_video_decoder_unittest.cc
index 3355b6a..ba27a5767 100644
--- a/content/renderer/media/rtc_video_decoder_unittest.cc
+++ b/content/renderer/media/rtc_video_decoder_unittest.cc
@@ -192,4 +192,28 @@ TEST_F(RTCVideoDecoderTest, IsBufferAfterReset) {
                                                 RTCVideoDecoder::ID_LAST));
 }
 
+TEST_F(RTCVideoDecoderTest, IsFirstBufferAfterReset) {
+  EXPECT_TRUE(
+      rtc_decoder_->IsFirstBufferAfterReset(0, RTCVideoDecoder::ID_INVALID));
+  EXPECT_FALSE(
+      rtc_decoder_->IsFirstBufferAfterReset(1, RTCVideoDecoder::ID_INVALID));
+  EXPECT_FALSE(rtc_decoder_->IsFirstBufferAfterReset(0, 0));
+  EXPECT_TRUE(rtc_decoder_->IsFirstBufferAfterReset(1, 0));
+  EXPECT_FALSE(rtc_decoder_->IsFirstBufferAfterReset(2, 0));
+
+  EXPECT_FALSE(rtc_decoder_->IsFirstBufferAfterReset(RTCVideoDecoder::ID_HALF,
+                                                     RTCVideoDecoder::ID_HALF));
+  EXPECT_TRUE(rtc_decoder_->IsFirstBufferAfterReset(
+      RTCVideoDecoder::ID_HALF + 1, RTCVideoDecoder::ID_HALF));
+  EXPECT_FALSE(rtc_decoder_->IsFirstBufferAfterReset(
+      RTCVideoDecoder::ID_HALF + 2, RTCVideoDecoder::ID_HALF));
+
+  EXPECT_FALSE(rtc_decoder_->IsFirstBufferAfterReset(RTCVideoDecoder::ID_LAST,
+                                                     RTCVideoDecoder::ID_LAST));
+  EXPECT_TRUE(
+      rtc_decoder_->IsFirstBufferAfterReset(0, RTCVideoDecoder::ID_LAST));
+  EXPECT_FALSE(
+      rtc_decoder_->IsFirstBufferAfterReset(1, RTCVideoDecoder::ID_LAST));
+}
+
 }  // content