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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | |
xhwang
2015/04/28 23:12:06
2015
DaleCurtis
2015/04/29 00:54:07
Done.
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2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #include "media/base/null_video_sink.h" | |
6 | |
7 #include "base/bind.h" | |
8 #include "base/callback_helpers.h" | |
9 #include "base/location.h" | |
10 #include "base/single_thread_task_runner.h" | |
11 | |
12 namespace media { | |
13 | |
14 NullVideoSink::NullVideoSink( | |
15 bool clockless, | |
16 base::TimeDelta interval, | |
17 const NewFrameCB& new_frame_cb, | |
18 const scoped_refptr<base::SingleThreadTaskRunner>& task_runner) | |
19 : clockless_(clockless), | |
20 interval_(interval), | |
21 new_frame_cb_(new_frame_cb), | |
22 task_runner_(task_runner), | |
23 started_(false), | |
24 callback_(nullptr), | |
25 tick_clock_(&default_tick_clock_) { | |
26 } | |
27 | |
28 NullVideoSink::~NullVideoSink() { | |
29 DCHECK(!started_); | |
30 } | |
31 | |
32 void NullVideoSink::Start(RenderCallback* callback) { | |
33 DCHECK(task_runner_->BelongsToCurrentThread()); | |
34 DCHECK(!started_); | |
35 callback_ = callback; | |
36 started_ = true; | |
37 last_now_ = current_render_time_ = tick_clock_->NowTicks(); | |
38 cancelable_worker_.Reset( | |
39 base::Bind(&NullVideoSink::CallRender, base::Unretained(this))); | |
40 task_runner_->PostTask(FROM_HERE, cancelable_worker_.callback()); | |
41 } | |
42 | |
43 void NullVideoSink::Stop() { | |
44 DCHECK(task_runner_->BelongsToCurrentThread()); | |
45 cancelable_worker_.Cancel(); | |
46 started_ = false; | |
47 if (!stop_cb_.is_null()) | |
48 base::ResetAndReturn(&stop_cb_).Run(); | |
49 } | |
50 | |
51 void NullVideoSink::CallRender() { | |
52 DCHECK(task_runner_->BelongsToCurrentThread()); | |
53 DCHECK(started_); | |
54 | |
55 const base::TimeTicks end_of_interval = current_render_time_ + interval_; | |
56 DVLOG(2) << "NullVideoSink::Render(" << current_render_time_.ToInternalValue() | |
xhwang
2015/04/28 23:12:06
s/Render/CallRender? This doesn't necessarily trig
DaleCurtis
2015/04/29 00:54:07
Just going to remove, it was really for debugging
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57 << ", " << end_of_interval.ToInternalValue() << ")"; | |
58 | |
59 if (current_render_time_ > pause_end_time_) { | |
60 scoped_refptr<VideoFrame> new_frame = | |
61 callback_->Render(current_render_time_, end_of_interval); | |
62 const bool is_new_frame = new_frame != last_frame_; | |
63 last_frame_ = new_frame; | |
64 if (is_new_frame) | |
65 new_frame_cb_.Run(new_frame); | |
66 } | |
67 | |
68 current_render_time_ += interval_; | |
69 | |
70 if (clockless_) { | |
71 task_runner_->PostTask(FROM_HERE, cancelable_worker_.callback()); | |
72 return; | |
73 } | |
74 | |
75 // Recompute now to compensate for the cost of Render(). | |
76 const base::TimeTicks now = tick_clock_->NowTicks(); | |
77 base::TimeDelta delay = current_render_time_ - now; | |
78 | |
79 // If we're behind, find the next nearest on time interval. | |
80 if (delay < base::TimeDelta()) | |
81 delay += interval_ * (-delay / interval_ + 1); | |
xhwang
2015/04/28 23:12:06
IIUIC, this translates to:
delay += interval_ *
DaleCurtis
2015/04/29 00:54:07
That's not quite true since this is integer math a
xhwang
2015/04/29 03:49:13
Ah, I see. Sorry for my ignorance :)
Just an extr
DaleCurtis
2015/04/29 04:26:48
It could go either way, since delay is 0, we may n
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82 current_render_time_ = now + delay; | |
83 | |
84 // The tick clock is frozen in this case, so clamp delay to the interval time. | |
85 // We still want the interval passed to Render() to grow, but we also don't | |
86 // want the delay used here to increase slowly over time. | |
87 if (last_now_ == now && delay > interval_) | |
88 delay = interval_; | |
89 last_now_ = now; | |
90 | |
91 task_runner_->PostDelayedTask(FROM_HERE, cancelable_worker_.callback(), | |
92 delay); | |
93 } | |
94 | |
95 void NullVideoSink::PaintFrameUsingOldRenderingPath( | |
96 const scoped_refptr<VideoFrame>& frame) { | |
97 new_frame_cb_.Run(frame); | |
98 } | |
99 | |
100 } // namespace media | |
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