blob: 0fe244c3767067b63a26a379c2e9701ad9bfac7b [file] [log] [blame]
// Copyright 2014 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 "media/blink/video_frame_compositor.h"
#include "base/bind.h"
#include "base/message_loop/message_loop.h"
#include "base/time/default_tick_clock.h"
#include "base/trace_event/trace_event.h"
#include "media/base/video_frame.h"
namespace media {
// Amount of time to wait between UpdateCurrentFrame() callbacks before starting
// background rendering to keep the Render() callbacks moving.
const int kBackgroundRenderingTimeoutMs = 250;
VideoFrameCompositor::VideoFrameCompositor(
const scoped_refptr<base::SingleThreadTaskRunner>& compositor_task_runner,
const base::Callback<void(gfx::Size)>& natural_size_changed_cb,
const base::Callback<void(bool)>& opacity_changed_cb)
: compositor_task_runner_(compositor_task_runner),
tick_clock_(new base::DefaultTickClock()),
natural_size_changed_cb_(natural_size_changed_cb),
opacity_changed_cb_(opacity_changed_cb),
background_rendering_enabled_(true),
background_rendering_timer_(
FROM_HERE,
base::TimeDelta::FromMilliseconds(kBackgroundRenderingTimeoutMs),
base::Bind(&VideoFrameCompositor::BackgroundRender,
base::Unretained(this)),
// Task is not repeating, CallRender() will reset the task as needed.
false),
client_(nullptr),
rendering_(false),
rendered_last_frame_(false),
is_background_rendering_(false),
new_background_frame_(false),
// Assume 60Hz before the first UpdateCurrentFrame() call.
last_interval_(base::TimeDelta::FromSecondsD(1.0 / 60)),
callback_(nullptr) {
background_rendering_timer_.SetTaskRunner(compositor_task_runner_);
}
VideoFrameCompositor::~VideoFrameCompositor() {
DCHECK(compositor_task_runner_->BelongsToCurrentThread());
DCHECK(!callback_);
DCHECK(!rendering_);
if (client_)
client_->StopUsingProvider();
}
void VideoFrameCompositor::OnRendererStateUpdate(bool new_state) {
DCHECK(compositor_task_runner_->BelongsToCurrentThread());
DCHECK_NE(rendering_, new_state);
rendering_ = new_state;
if (rendering_) {
// Always start playback in background rendering mode, if |client_| kicks
// in right away it's okay.
BackgroundRender();
} else if (background_rendering_enabled_) {
background_rendering_timer_.Stop();
} else {
DCHECK(!background_rendering_timer_.IsRunning());
}
if (!client_)
return;
if (rendering_)
client_->StartRendering();
else
client_->StopRendering();
}
void VideoFrameCompositor::SetVideoFrameProviderClient(
cc::VideoFrameProvider::Client* client) {
DCHECK(compositor_task_runner_->BelongsToCurrentThread());
if (client_)
client_->StopUsingProvider();
client_ = client;
// |client_| may now be null, so verify before calling it.
if (rendering_ && client_)
client_->StartRendering();
}
scoped_refptr<VideoFrame> VideoFrameCompositor::GetCurrentFrame() {
DCHECK(compositor_task_runner_->BelongsToCurrentThread());
return current_frame_;
}
void VideoFrameCompositor::PutCurrentFrame() {
DCHECK(compositor_task_runner_->BelongsToCurrentThread());
rendered_last_frame_ = true;
}
bool VideoFrameCompositor::UpdateCurrentFrame(base::TimeTicks deadline_min,
base::TimeTicks deadline_max) {
DCHECK(compositor_task_runner_->BelongsToCurrentThread());
return CallRender(deadline_min, deadline_max, false);
}
bool VideoFrameCompositor::HasCurrentFrame() {
DCHECK(compositor_task_runner_->BelongsToCurrentThread());
return current_frame_;
}
void VideoFrameCompositor::Start(RenderCallback* callback) {
TRACE_EVENT0("media", "VideoFrameCompositor::Start");
// Called from the media thread, so acquire the callback under lock before
// returning in case a Stop() call comes in before the PostTask is processed.
base::AutoLock lock(callback_lock_);
DCHECK(!callback_);
callback_ = callback;
compositor_task_runner_->PostTask(
FROM_HERE, base::Bind(&VideoFrameCompositor::OnRendererStateUpdate,
base::Unretained(this), true));
}
void VideoFrameCompositor::Stop() {
TRACE_EVENT0("media", "VideoFrameCompositor::Stop");
// Called from the media thread, so release the callback under lock before
// returning to avoid a pending UpdateCurrentFrame() call occurring before
// the PostTask is processed.
base::AutoLock lock(callback_lock_);
DCHECK(callback_);
callback_ = nullptr;
compositor_task_runner_->PostTask(
FROM_HERE, base::Bind(&VideoFrameCompositor::OnRendererStateUpdate,
base::Unretained(this), false));
}
void VideoFrameCompositor::PaintFrameUsingOldRenderingPath(
const scoped_refptr<VideoFrame>& frame) {
if (!compositor_task_runner_->BelongsToCurrentThread()) {
compositor_task_runner_->PostTask(
FROM_HERE,
base::Bind(&VideoFrameCompositor::PaintFrameUsingOldRenderingPath,
base::Unretained(this), frame));
return;
}
if (ProcessNewFrame(frame) && client_)
client_->DidReceiveFrame();
}
scoped_refptr<VideoFrame>
VideoFrameCompositor::GetCurrentFrameAndUpdateIfStale() {
DCHECK(compositor_task_runner_->BelongsToCurrentThread());
if (client_ || !rendering_ || !is_background_rendering_)
return current_frame_;
DCHECK(!last_background_render_.is_null());
const base::TimeTicks now = tick_clock_->NowTicks();
const base::TimeDelta interval = now - last_background_render_;
// Cap updates to 250Hz which should be more than enough for everyone.
if (interval < base::TimeDelta::FromMilliseconds(4))
return current_frame_;
// Update the interval based on the time between calls and call background
// render which will give this information to the client.
last_interval_ = interval;
BackgroundRender();
return current_frame_;
}
base::TimeDelta VideoFrameCompositor::GetCurrentFrameTimestamp() const {
// When the VFC is stopped, |callback_| is cleared; this synchronously
// prevents CallRender() from invoking ProcessNewFrame(), and so
// |current_frame_| won't change again until after Start(). (Assuming that
// PaintFrameUsingOldRenderingPath() is not also called while stopped.)
if (!current_frame_)
return base::TimeDelta();
return current_frame_->timestamp();
}
bool VideoFrameCompositor::ProcessNewFrame(
const scoped_refptr<VideoFrame>& frame) {
DCHECK(compositor_task_runner_->BelongsToCurrentThread());
if (frame == current_frame_)
return false;
// Set the flag indicating that the current frame is unrendered, if we get a
// subsequent PutCurrentFrame() call it will mark it as rendered.
rendered_last_frame_ = false;
if (!current_frame_ ||
current_frame_->natural_size() != frame->natural_size()) {
natural_size_changed_cb_.Run(frame->natural_size());
}
if (!current_frame_ ||
IsOpaque(current_frame_->format()) != IsOpaque(frame->format()))
opacity_changed_cb_.Run(IsOpaque(frame->format()));
current_frame_ = frame;
return true;
}
void VideoFrameCompositor::BackgroundRender() {
DCHECK(compositor_task_runner_->BelongsToCurrentThread());
const base::TimeTicks now = tick_clock_->NowTicks();
last_background_render_ = now;
bool new_frame = CallRender(now, now + last_interval_, true);
if (new_frame && client_)
client_->DidReceiveFrame();
}
bool VideoFrameCompositor::CallRender(base::TimeTicks deadline_min,
base::TimeTicks deadline_max,
bool background_rendering) {
DCHECK(compositor_task_runner_->BelongsToCurrentThread());
base::AutoLock lock(callback_lock_);
if (!callback_) {
// Even if we no longer have a callback, return true if we have a frame
// which |client_| hasn't seen before.
return !rendered_last_frame_ && current_frame_;
}
DCHECK(rendering_);
// If the previous frame was never rendered and we're not in background
// rendering mode (nor have just exited it), let the client know.
if (!rendered_last_frame_ && current_frame_ && !background_rendering &&
!is_background_rendering_) {
callback_->OnFrameDropped();
}
const bool new_frame = ProcessNewFrame(
callback_->Render(deadline_min, deadline_max, background_rendering));
// We may create a new frame here with background rendering, but the provider
// has no way of knowing that a new frame had been processed, so keep track of
// the new frame, and return true on the next call to |CallRender|.
const bool had_new_background_frame = new_background_frame_;
new_background_frame_ = background_rendering && new_frame;
is_background_rendering_ = background_rendering;
last_interval_ = deadline_max - deadline_min;
// Restart the background rendering timer whether we're background rendering
// or not; in either case we should wait for |kBackgroundRenderingTimeoutMs|.
if (background_rendering_enabled_)
background_rendering_timer_.Reset();
return new_frame || had_new_background_frame;
}
} // namespace media