Add accelerated VP9 decode infrastructure and an implementation for VA-API.

content/common/gpu/media/vp9_decoder.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 "base/logging.h"
+#include "content/common/gpu/media/vp9_decoder.h"
+#include "media/base/limits.h"
+
+namespace content {
+
+VP9Decoder::VP9Accelerator::VP9Accelerator() {}
+
+VP9Decoder::VP9Accelerator::~VP9Accelerator() {}
+
+VP9Decoder::VP9Decoder(VP9Accelerator* accelerator)
+    : state_(kNeedStreamMetadata), accelerator_(accelerator) {
+  DCHECK(accelerator_);
+  ref_frames_.resize(media::kVp9NumRefFrames);
+}
+
+VP9Decoder::~VP9Decoder() {}
+
+void VP9Decoder::SetStream(const uint8_t* ptr, size_t size) {
+  DCHECK(ptr);
+  DCHECK(size);
+
+  DVLOG(4) << "New input stream at: " << (void*)ptr << " size: " << size;
+  parser_.SetStream(ptr, size);
+}
+
+bool VP9Decoder::Flush() {
+  DVLOG(2) << "Decoder flush";
+  Reset();
+  return true;
+}
+
+void VP9Decoder::Reset() {
+  curr_frame_hdr_ = nullptr;
+  for (auto& ref_frame : ref_frames_)
+    ref_frame = nullptr;
+
+  if (state_ == kDecoding)
+    state_ = kAfterReset;
+}
+
+VP9Decoder::DecodeResult VP9Decoder::Decode() {
+  while (1) {
+    // Read a new frame header if one is not awaiting decoding already.
+    if (!curr_frame_hdr_) {
+      scoped_ptr<media::Vp9FrameHeader> hdr(new media::Vp9FrameHeader());
+      media::Vp9Parser::Result res = parser_.ParseNextFrame(hdr.get());
+      switch (res) {
+        case media::Vp9Parser::kOk:
+          curr_frame_hdr_.reset(hdr.release());
+          break;
+
+        case media::Vp9Parser::kEOStream:
+          return kRanOutOfStreamData;
+
+        case media::Vp9Parser::kInvalidStream:
+          DVLOG(1) << "Error parsing stream";
+          return kDecodeError;

[kcwu, 2015/09/02 10:09:45]

Should we update |state_| as well for all errors?

[Pawel Osciak, 2015/09/08 06:43:48]

Yes, was missing some cleanup.

+      }
+    }
+
+    // If the frame header instructs us to additionally display any of the
+    // previously-decoded frames, do so now.
+    if (curr_frame_hdr_->show_existing_frame) {
+      size_t frame_to_show = curr_frame_hdr_->frame_to_show;
+      if (frame_to_show >= ref_frames_.size() || !ref_frames_[frame_to_show]) {
+        DVLOG(1) << "Request to show an invalid frame";
+        return kDecodeError;
+      }
+
+      if (!accelerator_->OutputPicture(ref_frames_[frame_to_show]))
+        return kDecodeError;
+    }

[kcwu, 2015/09/02 10:09:45]

continue; here?

[Pawel Osciak, 2015/09/08 06:43:48]

I treat this as a critical error.

+
+    if (curr_frame_hdr_->IsKeyframe()) {
+      gfx::Size new_pic_size(curr_frame_hdr_->width, curr_frame_hdr_->height);
+      if (new_pic_size.IsEmpty())

[kcwu, 2015/09/02 10:09:44]

How about DCHECK?
IIUC, the parser never return frames with zero dimension.

[Pawel Osciak, 2015/09/08 06:43:48]

Misread the code, true, this is not needed.

+        return kDecodeError;
+
+      if (new_pic_size != pic_size_) {
+        DVLOG(1) << "New resolution: " << new_pic_size.ToString();
+        pic_size_ = new_pic_size;
+
+        for (auto& ref_frame : ref_frames_)
+          ref_frame = nullptr;
+
+        return kAllocateNewSurfaces;
+      }
+
+      state_ = kDecoding;
+    } else {

[kcwu, 2015/09/02 10:09:45]

Theoretically the parser may return frames with resolution change for
non-keyframe. Should we handle them or at least give warning?

[Pawel Osciak, 2015/09/08 06:43:48]

Good point, this is new in VP9.

+      if (state_ != kDecoding) {
+        // Need a resume point.
+        curr_frame_hdr_.reset();
+        continue;
+      }
+    }
+
+    scoped_refptr<VP9Picture> pic = accelerator_->CreateVP9Picture();
+    if (!pic)
+      return kRanOutOfSurfaces;
+
+    pic->frame_hdr.reset(curr_frame_hdr_.release());
+
+    if (!DecodeAndOutputPicture(pic))
+      return kDecodeError;
+  }
+}
+
+void VP9Decoder::RefreshReferenceFrames(const scoped_refptr<VP9Picture>& pic) {
+  for (size_t i = 0; i < media::kVp9NumRefFrames; ++i) {
+    if (pic->frame_hdr->IsKeyframe() || pic->frame_hdr->RefreshFlag(i))

[kcwu, 2015/09/02 10:09:45]

RefreshFlag should be enough.
How about
DCHECK_IMPLIES(pic->frame_hdr->IsKeyframe(), pic->frame_hdr->RefreshFlag(i));

[Pawel Osciak, 2015/09/08 06:43:48]

Correct, I had moved changing refresh flags to another location, but then
decided to keep it, but didn't change this. Thanks for the idea with
DCHECK_IMPLIES.

+      ref_frames_[i] = pic;
+  }
+}
+
+bool VP9Decoder::DecodeAndOutputPicture(scoped_refptr<VP9Picture> pic) {
+  DCHECK(!pic_size_.IsEmpty());
+
+  media::Vp9FrameHeader* frame_hdr = pic->frame_hdr.get();
+  DCHECK(frame_hdr);
+
+  if (frame_hdr->width == 0 || frame_hdr->height == 0) {

[kcwu, 2015/09/02 10:09:45]

DCHECK instead?

[Pawel Osciak, 2015/09/08 06:43:48]

Acknowledged.

+    frame_hdr->width = pic_size_.width();
+    frame_hdr->height = pic_size_.height();
+  }
+
+  if (!accelerator_->SubmitDecode(pic, parser_.GetSegmentation(),
+                                  parser_.GetLoopFilter(), ref_frames_))
+    return false;
+
+  if (frame_hdr->show_frame) {
+    if (!accelerator_->OutputPicture(pic))
+      return false;
+  }
+
+  RefreshReferenceFrames(pic);
+  return true;
+}
+
+gfx::Size VP9Decoder::GetPicSize() const {
+  return pic_size_;
+}
+
+size_t VP9Decoder::GetRequiredNumOfPictures() const {
+  const size_t kPicsInPipeline = media::limits::kMaxVideoFrames + 2;
+  return media::kVp9NumRefFrames + kPicsInPipeline;

[kcwu, 2015/09/02 10:09:44]

I don't understand these numbers from variable names. Could you give brief
comments? And what is 2?

[Pawel Osciak, 2015/09/08 06:43:48]

We should ideally have the media::limits::kMaxVideoFrames term in higher levels,
but it's not done right now. I'll change this a bit.

+}
+
+}  // namespace content