Begin refactor of AVDA to support zero-copy.

content/common/gpu/media/android_copying_backing_strategy.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 "content/common/gpu/media/android_copying_backing_strategy.h"
+
+#include "base/bind.h"
+#include "base/logging.h"
+#include "base/trace_event/trace_event.h"
+#include "content/common/gpu/media/avda_return_on_failure.h"
+#include "gpu/command_buffer/service/gles2_cmd_copy_texture_chromium.h"
+#include "gpu/command_buffer/service/gles2_cmd_decoder.h"
+#include "media/base/limits.h"
+#include "media/video/picture.h"
+#include "ui/gl/android/surface_texture.h"
+#include "ui/gl/gl_bindings.h"
+
+namespace content {
+
+// TODO(liberato): It is unclear if we have an issue with deadlock during
+// playback if we lower this.  Previously (crbug.com/176036), a deadlock
+// could occur during preroll.  More recent tests have shown some
+// instability with kNumPictureBuffers==2 with similar symptoms
+// during playback.  crbug.com/:531588 .
+enum { kNumPictureBuffers = media::limits::kMaxVideoFrames + 1 };
+
+AndroidCopyingBackingStrategy::AndroidCopyingBackingStrategy()
+    : state_provider_(nullptr) {}
+
+AndroidCopyingBackingStrategy::~AndroidCopyingBackingStrategy() {}
+
+void AndroidCopyingBackingStrategy::SetStateProvider(
+    AndroidVideoDecodeAcceleratorStateProvider* state_provider) {
+  state_provider_ = state_provider;
+}
+
+void AndroidCopyingBackingStrategy::Cleanup() {
+  DCHECK(state_provider_->ThreadChecker().CalledOnValidThread());
+  if (copier_)
+    copier_->Destroy();
+}
+
+uint32 AndroidCopyingBackingStrategy::GetNumPictureBuffers() const {
+  return kNumPictureBuffers;
+}
+
+uint32 AndroidCopyingBackingStrategy::GetTextureTarget() const {
+  return GL_TEXTURE_2D;
+}
+
+void AndroidCopyingBackingStrategy::AssignCurrentSurfaceToPictureBuffer(
+    int32 codec_buf_index,
+    const media::PictureBuffer& picture_buffer) {
+  // Make sure that the decoder is available.
+  RETURN_ON_FAILURE(state_provider_, state_provider_->GetGlDecoder(),
+                    "Failed to get gles2 decoder instance.", ILLEGAL_STATE);
+
+  // Render the codec buffer into |surface_texture_|, and switch it to be
+  // the front buffer.
+  // This ignores the emitted ByteBuffer and instead relies on rendering to
+  // the codec's SurfaceTexture and then copying from that texture to the
+  // client's PictureBuffer's texture.  This means that each picture's data
+  // is written three times: once to the ByteBuffer, once to the
+  // SurfaceTexture, and once to the client's texture.  It would be nicer to
+  // either:
+  // 1) Render directly to the client's texture from MediaCodec (one write);
+  //    or
+  // 2) Upload the ByteBuffer to the client's texture (two writes).
+  // Unfortunately neither is possible:
+  // 1) MediaCodec's use of SurfaceTexture is a singleton, and the texture
+  //    written to can't change during the codec's lifetime.  b/11990461
+  // 2) The ByteBuffer is likely to contain the pixels in a vendor-specific,
+  //    opaque/non-standard format.  It's not possible to negotiate the
+  //    decoder to emit a specific colorspace, even using HW CSC.  b/10706245
+  // So, we live with these two extra copies per picture :(
+  {
+    TRACE_EVENT0("media", "AVDA::ReleaseOutputBuffer");
+    state_provider_->GetMediaCodec()->ReleaseOutputBuffer(codec_buf_index,
+                                                          true);
+  }
+
+  gfx::SurfaceTexture* surface_texture = state_provider_->GetSurfaceTexture();
+  {
+    TRACE_EVENT0("media", "AVDA::UpdateTexImage");
+    surface_texture->UpdateTexImage();
+  }
+
+  float transfrom_matrix[16];
+  surface_texture->GetTransformMatrix(transfrom_matrix);
+
+  uint32 picture_buffer_texture_id = picture_buffer.texture_id();
+
+  // Defer initializing the CopyTextureCHROMIUMResourceManager until it is
+  // needed because it takes 10s of milliseconds to initialize.
+  if (!copier_) {
+    copier_.reset(new gpu::CopyTextureCHROMIUMResourceManager());
+    copier_->Initialize(state_provider_->GetGlDecoder());
+  }
+
+  // Here, we copy |surface_texture_id_| to the picture buffer instead of
+  // setting new texture to |surface_texture_| by calling attachToGLContext()
+  // because:
+  // 1. Once we call detachFrameGLContext(), it deletes the texture previous
+  //    attached.
+  // 2. SurfaceTexture requires us to apply a transform matrix when we show
+  //    the texture.
+  // TODO(hkuang): get the StreamTexture transform matrix in GPU process
+  // instead of using default matrix crbug.com/226218.
+  const static GLfloat default_matrix[16] = {1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f,

[DaleCurtis, 2015/09/14 18:46:20]

static const? Rename to kDefaultMatrix?

[liberato (no reviews please), 2015/09/14 22:34:52]

done, as kIdentityMatrix.

+                                             0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f,
+                                             0.0f, 0.0f, 0.0f, 1.0f};
+  copier_->DoCopyTextureWithTransform(
+      state_provider_->GetGlDecoder(), GL_TEXTURE_EXTERNAL_OES,
+      state_provider_->GetSurfaceTextureId(), picture_buffer_texture_id,
+      state_provider_->GetSize().width(), state_provider_->GetSize().height(),
+      false, false, false, default_matrix);
+}
+
+}  // namespace content