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1 // Copyright 2015 The Chromium Authors. All rights reserved. | |
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/capture/webm_muxer.h" | |
6 | |
7 #include <limits> | |
8 | |
9 namespace media { | |
10 | |
11 // Template to +1 a non-negative Natural number to make a strictly positive one. | |
12 template <typename NonNegativeNaturalType> | |
13 class PositiveInteger{ | |
14 public: | |
15 explicit PositiveInteger(NonNegativeNaturalType value) | |
16 : value_(value + static_cast<NonNegativeNaturalType>(1)) { | |
17 static_assert(std::numeric_limits<NonNegativeNaturalType>::is_integer && | |
18 !std::numeric_limits<NonNegativeNaturalType>::is_signed, | |
19 "NonNegativeNaturalType must be an unsigned integer type"); | |
20 } | |
21 NonNegativeNaturalType Value() const { return value_; } | |
22 | |
23 private: | |
24 const NonNegativeNaturalType value_; | |
25 | |
26 DISALLOW_IMPLICIT_CONSTRUCTORS(PositiveInteger); | |
27 }; | |
28 | |
29 WebmMuxer::WebmMuxer(const WriteDataCB& write_data_callback) | |
30 : write_data_callback_(write_data_callback), | |
31 position_(0), | |
32 segment_(new mkvmuxer::Segment()) { | |
33 DVLOG(2) << __FUNCTION__; | |
34 DCHECK(thread_checker_.CalledOnValidThread()); | |
35 segment_->Init(this); | |
36 segment_->set_mode(mkvmuxer::Segment::kLive); | |
37 segment_->OutputCues(false); | |
38 | |
39 mkvmuxer::SegmentInfo* const info = segment_->GetSegmentInfo(); | |
40 info->set_writing_app("Chrome"); | |
41 info->set_muxing_app("Chrome"); | |
42 } | |
43 | |
44 WebmMuxer::~WebmMuxer() { | |
45 DCHECK(thread_checker_.CalledOnValidThread()); | |
46 DVLOG(2) << __FUNCTION__; | |
47 segment_->Finalize(); | |
48 } | |
49 | |
50 void WebmMuxer::OnEncodedVideo(uint32_t track_number, | |
51 const std::string& encoded_data, | |
52 const base::TimeDelta& timedelta_us, | |
53 bool keyframe, | |
54 const gfx::Size& frame_size, | |
55 double frame_rate) { | |
56 DVLOG(2) << __FUNCTION__; | |
57 DCHECK(thread_checker_.CalledOnValidThread()); | |
58 | |
59 // |track_number|, a caller-side identifier, cannot be zero (!), see | |
60 // http://www.matroska.org/technical/specs/index.html#Tracks | |
61 const PositiveInteger<uint32_t> nonzero_track_number(track_number); | |
62 | |
63 // Add the video track the first time we see it. | |
64 if (!segment_->GetTrackByNumber(nonzero_track_number.Value())) | |
65 AddVideoTrack(nonzero_track_number.Value(), frame_size, frame_rate); | |
66 DCHECK(segment_->GetTrackByNumber(nonzero_track_number.Value())); | |
67 | |
68 segment_->AddFrame(reinterpret_cast<const uint8_t*>(encoded_data.data()), | |
69 encoded_data.size(), | |
70 nonzero_track_number.Value(), | |
71 timedelta_us.InMicroseconds(), | |
72 keyframe); | |
73 } | |
74 | |
75 bool WebmMuxer::AddVideoTrack(uint32_t track_number, | |
76 const gfx::Size& frame_size, | |
77 double frame_rate) { | |
78 DVLOG(2) << "AddVideoTrack: " << frame_size.ToString() << "@" | |
79 << frame_rate << "fps, number: " << track_number; | |
80 DCHECK(thread_checker_.CalledOnValidThread()); | |
81 DCHECK_GT(track_number, 0u) << "Track number must be (strictly) positive."; | |
82 | |
83 segment_->AddVideoTrack(frame_size.width(), | |
84 frame_size.height(), | |
85 track_number); | |
86 mkvmuxer::VideoTrack* const video_track = | |
87 reinterpret_cast<mkvmuxer::VideoTrack*>( | |
88 segment_->GetTrackByNumber(track_number)); | |
89 DCHECK(video_track); | |
90 video_track->set_codec_id(mkvmuxer::Tracks::kVp8CodecId); | |
91 DCHECK_EQ(video_track->crop_right(), 0ull); | |
92 DCHECK_EQ(video_track->crop_left(), 0ull); | |
93 DCHECK_EQ(video_track->crop_top(), 0ull); | |
94 DCHECK_EQ(video_track->crop_bottom(), 0ull); | |
95 | |
96 video_track->set_frame_rate(frame_rate); | |
97 video_track->set_default_duration(base::Time::kMicrosecondsPerSecond / | |
98 frame_rate); | |
99 // Change segment's timestamps to microseconds instead of milliseconds: | |
100 // http://matroska.org/technical/specs/index.html#TimecodeScale | |
101 segment_->GetSegmentInfo()->set_timecode_scale(1000000000ull); | |
miu
2015/07/17 22:23:18
IIUC, this be 1000 instead? Better yet: base::Tim
mcasas
2015/07/18 00:05:22
Yeah, done.
| |
102 return true; | |
103 } | |
104 | |
105 mkvmuxer::int32 WebmMuxer::Write(const void* buf, mkvmuxer::uint32 len) { | |
106 DVLOG(3) << __FUNCTION__ << " length=" << len; | |
107 DCHECK(thread_checker_.CalledOnValidThread()); | |
108 write_data_callback_.Run(static_cast<const char*>(buf), len); | |
109 position_ += len; | |
110 return 0; | |
111 } | |
112 | |
113 mkvmuxer::int64 WebmMuxer::Position() const { | |
114 return position_.ValueOrDie(); | |
115 } | |
116 | |
117 mkvmuxer::int32 WebmMuxer::Position(mkvmuxer::int64 position) { | |
118 // The stream is not Seekable() so indicate we cannot set the position. | |
119 return -1; | |
120 } | |
121 | |
122 bool WebmMuxer::Seekable() const { | |
123 return false; | |
124 } | |
125 | |
126 void WebmMuxer::ElementStartNotify(mkvmuxer::uint64 element_id, | |
127 mkvmuxer::int64 position) { | |
128 // This method gets pinged before items are sent to |write_data_callback_|. | |
129 DCHECK_GE(position, position_.ValueOrDefault(0)) | |
130 << "Can't go back in a Live Mkv stream."; | |
131 } | |
132 | |
133 } // namespace media | |
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