Begin refactor of AVDA to support zero-copy.

content/common/gpu/media/android_copying_backing_strategy.cc

+// Copyright (c) 2013 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/message_loop/message_loop.h"
+#include "base/metrics/histogram.h"
+#include "content/common/gpu/gpu_channel.h"
+#include "content/common/gpu/media/avda_return_on_failure.h"
+#include "gpu/command_buffer/service/gles2_cmd_decoder.h"
+#include "media/base/bitstream_buffer.h"
+#include "media/base/limits.h"
+#include "media/base/video_decoder_config.h"
+#include "media/video/picture.h"
+#include "ui/gl/android/surface_texture.h"
+#include "ui/gl/gl_bindings.h"
+
+namespace content {
+
+// TODO(dwkang): We only need kMaxVideoFrames to pass media stack's prerolling
+// phase, but 1 is added due to crbug.com/176036. This should be tuned when we
+// have actual use case.
+enum { kNumPictureBuffers = media::limits::kMaxVideoFrames + 1 };
+
+AndroidCopyingBackingStrategy::AndroidCopyingBackingStrategy()
+    : state_provider_(nullptr) {
+}
+
+AndroidCopyingBackingStrategy::~AndroidCopyingBackingStrategy() {
+}
+
+void AndroidCopyingBackingStrategy::SetStateProvider(
+    AndroidVideoDecodeAccelerator::StateProvider* 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 :(
+    state_provider_->GetMediaCodec()->ReleaseOutputBuffer(codec_buf_index,
+        true);
+
+    gfx::SurfaceTexture* surface_texture = state_provider_->GetSurfaceTexture();
+    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, 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(),
+            GetTextureTarget(), picture_buffer_texture_id,
+            GL_RGBA, GL_UNSIGNED_BYTE,
+            state_provider_->GetSize().width(),
+            state_provider_->GetSize().height(),
+            false, false, false, nullptr, default_matrix);
+}
+
+}  // namespace content