1 /*
2 * Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
3 *
4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree.
9 *
10 */
11
12 #include "modules/video_coding/codecs/h264/include/h264.h"
13
14 #include <memory>
15 #include <string>
16
17 #include "absl/container/inlined_vector.h"
18 #include "absl/types/optional.h"
19 #include "api/video_codecs/sdp_video_format.h"
20 #include "media/base/media_constants.h"
21 #include "rtc_base/trace_event.h"
22
23 #if defined(WEBRTC_USE_H264)
24 #include "modules/video_coding/codecs/h264/h264_decoder_impl.h"
25 #include "modules/video_coding/codecs/h264/h264_encoder_impl.h"
26 #endif
27
28 #include "rtc_base/checks.h"
29 #include "rtc_base/logging.h"
30
31 namespace webrtc {
32
33 namespace {
34
35 #if defined(WEBRTC_USE_H264)
36 bool g_rtc_use_h264 = true;
37 #endif
38
39 // If H.264 OpenH264/FFmpeg codec is supported.
IsH264CodecSupported()40 bool IsH264CodecSupported() {
41 #if defined(WEBRTC_USE_H264)
42 return g_rtc_use_h264;
43 #else
44 return false;
45 #endif
46 }
47
48 constexpr ScalabilityMode kSupportedScalabilityModes[] = {
49 ScalabilityMode::kL1T1, ScalabilityMode::kL1T2, ScalabilityMode::kL1T3};
50
51 } // namespace
52
CreateH264Format(H264Profile profile,H264Level level,const std::string & packetization_mode,bool add_scalability_modes)53 SdpVideoFormat CreateH264Format(H264Profile profile,
54 H264Level level,
55 const std::string& packetization_mode,
56 bool add_scalability_modes) {
57 const absl::optional<std::string> profile_string =
58 H264ProfileLevelIdToString(H264ProfileLevelId(profile, level));
59 RTC_CHECK(profile_string);
60 absl::InlinedVector<ScalabilityMode, kScalabilityModeCount> scalability_modes;
61 if (add_scalability_modes) {
62 for (const auto scalability_mode : kSupportedScalabilityModes) {
63 scalability_modes.push_back(scalability_mode);
64 }
65 }
66 return SdpVideoFormat(
67 cricket::kH264CodecName,
68 {{cricket::kH264FmtpProfileLevelId, *profile_string},
69 {cricket::kH264FmtpLevelAsymmetryAllowed, "1"},
70 {cricket::kH264FmtpPacketizationMode, packetization_mode}},
71 scalability_modes);
72 }
73
DisableRtcUseH264()74 void DisableRtcUseH264() {
75 #if defined(WEBRTC_USE_H264)
76 g_rtc_use_h264 = false;
77 #endif
78 }
79
SupportedH264Codecs(bool add_scalability_modes)80 std::vector<SdpVideoFormat> SupportedH264Codecs(bool add_scalability_modes) {
81 TRACE_EVENT0("webrtc", __func__);
82 if (!IsH264CodecSupported())
83 return std::vector<SdpVideoFormat>();
84 // We only support encoding Constrained Baseline Profile (CBP), but the
85 // decoder supports more profiles. We can list all profiles here that are
86 // supported by the decoder and that are also supersets of CBP, i.e. the
87 // decoder for that profile is required to be able to decode CBP. This means
88 // we can encode and send CBP even though we negotiated a potentially
89 // higher profile. See the H264 spec for more information.
90 //
91 // We support both packetization modes 0 (mandatory) and 1 (optional,
92 // preferred).
93 return {CreateH264Format(H264Profile::kProfileBaseline, H264Level::kLevel3_1,
94 "1", add_scalability_modes),
95 CreateH264Format(H264Profile::kProfileBaseline, H264Level::kLevel3_1,
96 "0", add_scalability_modes),
97 CreateH264Format(H264Profile::kProfileConstrainedBaseline,
98 H264Level::kLevel3_1, "1", add_scalability_modes),
99 CreateH264Format(H264Profile::kProfileConstrainedBaseline,
100 H264Level::kLevel3_1, "0", add_scalability_modes),
101 CreateH264Format(H264Profile::kProfileMain, H264Level::kLevel3_1, "1",
102 add_scalability_modes),
103 CreateH264Format(H264Profile::kProfileMain, H264Level::kLevel3_1, "0",
104 add_scalability_modes)};
105 }
106
SupportedH264DecoderCodecs()107 std::vector<SdpVideoFormat> SupportedH264DecoderCodecs() {
108 TRACE_EVENT0("webrtc", __func__);
109 if (!IsH264CodecSupported())
110 return std::vector<SdpVideoFormat>();
111
112 std::vector<SdpVideoFormat> supportedCodecs = SupportedH264Codecs();
113
114 // OpenH264 doesn't yet support High Predictive 4:4:4 encoding but it does
115 // support decoding.
116 supportedCodecs.push_back(CreateH264Format(
117 H264Profile::kProfilePredictiveHigh444, H264Level::kLevel3_1, "1"));
118 supportedCodecs.push_back(CreateH264Format(
119 H264Profile::kProfilePredictiveHigh444, H264Level::kLevel3_1, "0"));
120
121 return supportedCodecs;
122 }
123
Create(const cricket::VideoCodec & codec)124 std::unique_ptr<H264Encoder> H264Encoder::Create(
125 const cricket::VideoCodec& codec) {
126 RTC_DCHECK(H264Encoder::IsSupported());
127 #if defined(WEBRTC_USE_H264)
128 RTC_CHECK(g_rtc_use_h264);
129 RTC_LOG(LS_INFO) << "Creating H264EncoderImpl.";
130 return std::make_unique<H264EncoderImpl>(codec);
131 #else
132 RTC_DCHECK_NOTREACHED();
133 return nullptr;
134 #endif
135 }
136
IsSupported()137 bool H264Encoder::IsSupported() {
138 return IsH264CodecSupported();
139 }
140
SupportsScalabilityMode(ScalabilityMode scalability_mode)141 bool H264Encoder::SupportsScalabilityMode(ScalabilityMode scalability_mode) {
142 for (const auto& entry : kSupportedScalabilityModes) {
143 if (entry == scalability_mode) {
144 return true;
145 }
146 }
147 return false;
148 }
149
Create()150 std::unique_ptr<H264Decoder> H264Decoder::Create() {
151 RTC_DCHECK(H264Decoder::IsSupported());
152 #if defined(WEBRTC_USE_H264)
153 RTC_CHECK(g_rtc_use_h264);
154 RTC_LOG(LS_INFO) << "Creating H264DecoderImpl.";
155 return std::make_unique<H264DecoderImpl>();
156 #else
157 RTC_DCHECK_NOTREACHED();
158 return nullptr;
159 #endif
160 }
161
IsSupported()162 bool H264Decoder::IsSupported() {
163 return IsH264CodecSupported();
164 }
165
166 } // namespace webrtc
167