Bug 1358662 - Implement keyframe and framesize VPXDecoder helpers. r=jya

Encapsulate code from WebMDemuxer to query keyframe and frame
resolution inside VPXDecoder, so we have a clean wrapper for
all the libvpx functions we use.

MozReview-Commit-ID: ASRRhNl0A41

--HG--
extra : rebase_source : a1421462f6fc66a2abd965782ec408a8bcf7fe1f

dom/media/platforms/agnostic/VPXDecoder.cpp

@@ -124,16 +124,8 @@ VPXDecoder::ProcessDecode(MediaRawData* aSample)
   MOZ_ASSERT(mTaskQueue->IsCurrentThreadIn());
 
 #if defined(DEBUG)
-  vpx_codec_stream_info_t si;
-  PodZero(&si);
-  si.sz = sizeof(si);
-  if (mCodec == Codec::VP8) {
-    vpx_codec_peek_stream_info(vpx_codec_vp8_dx(), aSample->Data(), aSample->Size(), &si);
-  } else if (mCodec == Codec::VP9) {
-    vpx_codec_peek_stream_info(vpx_codec_vp9_dx(), aSample->Data(), aSample->Size(), &si);
-  }
-  NS_ASSERTION(bool(si.is_kf) == aSample->mKeyframe,
-               "VPX Decode Keyframe error sample->mKeyframe and si.si_kf out of sync");
+  NS_ASSERTION(IsKeyframe(*aSample, mCodec) == aSample->mKeyframe,
+               "VPX Decode Keyframe error sample->mKeyframe and sample data out of sync");
 #endif
 
   if (vpx_codec_err_t r = vpx_codec_decode(&mVPX, aSample->Data(), aSample->Size(), nullptr, 0)) {
@@ -314,5 +306,37 @@ VPXDecoder::IsVP9(const nsACString& aMimeType)
   return IsVPX(aMimeType, VPXDecoder::VP9);
 }
 
+/* static */
+bool
+VPXDecoder::IsKeyframe(Span<const uint8_t> aBuffer, Codec aCodec)
+{
+  vpx_codec_stream_info_t si;
+  if (aCodec == Codec::VP8) {
+    vpx_codec_peek_stream_info(vpx_codec_vp8_dx(), aBuffer.Elements(), aBuffer.Length(), &si);
+    return bool(si.is_kf);
+  } else if (aCodec == Codec::VP9) {
+    vpx_codec_peek_stream_info(vpx_codec_vp9_dx(), aBuffer.Elements(), aBuffer.Length(), &si);
+    return bool(si.is_kf);
+  }
+
+  return false;
+}
+
+/* static */
+nsIntSize
+VPXDecoder::GetFrameSize(Span<const uint8_t> aBuffer, Codec aCodec)
+{
+  vpx_codec_stream_info_t si;
+  PodZero(&si);
+  si.sz = sizeof(si);
+
+  if (aCodec == Codec::VP8) {
+    vpx_codec_peek_stream_info(vpx_codec_vp8_dx(), aBuffer.Elements(), aBuffer.Length(), &si);
+  } else if (aCodec == Codec::VP9) {
+    vpx_codec_peek_stream_info(vpx_codec_vp9_dx(), aBuffer.Elements(), aBuffer.Length(), &si);
+  }
+
+  return nsIntSize(si.w, si.h);
+}
 } // namespace mozilla
 #undef LOG

dom/media/platforms/agnostic/VPXDecoder.h

@@ -7,6 +7,7 @@
 #define VPXDecoder_h_
 
 #include "PlatformDecoderModule.h"
+#include "mozilla/Span.h"
 
 #include <stdint.h>
 #define VPX_DONT_DEFINE_STDINT_TYPES
@@ -45,6 +46,12 @@ public:
   static bool IsVP8(const nsACString& aMimeType);
   static bool IsVP9(const nsACString& aMimeType);
 
+  // Return true if a sample is a keyframe for the specified codec.
+  static bool IsKeyframe(Span<const uint8_t> aBuffer, Codec aCodec);
+
+  // Return the frame dimensions for a sample for the specified codec.
+  static nsIntSize GetFrameSize(Span<const uint8_t> aBuffer, Codec aCodec);
+
 private:
   ~VPXDecoder();
   RefPtr<DecodePromise> ProcessDecode(MediaRawData* aSample);