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1 /* | 1 /* |
2 * Copyright (c) 2016 The WebRTC project authors. All Rights Reserved. | 2 * Copyright (c) 2016 The WebRTC project authors. All Rights Reserved. |
3 * | 3 * |
4 * Use of this source code is governed by a BSD-style license | 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 | 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 | 6 * tree. An additional intellectual property rights grant can be found |
7 * in the file PATENTS. All contributing project authors may | 7 * in the file PATENTS. All contributing project authors may |
8 * be found in the AUTHORS file in the root of the source tree. | 8 * be found in the AUTHORS file in the root of the source tree. |
9 */ | 9 */ |
10 | 10 |
11 #include "webrtc/common_video/h264/pps_parser.h" | 11 #include "webrtc/common_video/h264/pps_parser.h" |
12 | 12 |
13 #include <memory> | |
14 | |
15 #include "webrtc/common_video/h264/h264_common.h" | 13 #include "webrtc/common_video/h264/h264_common.h" |
16 #include "webrtc/base/bitbuffer.h" | 14 #include "webrtc/base/bitbuffer.h" |
17 #include "webrtc/base/buffer.h" | 15 #include "webrtc/base/buffer.h" |
18 #include "webrtc/base/logging.h" | 16 #include "webrtc/base/logging.h" |
19 | 17 |
20 #define RETURN_EMPTY_ON_FAIL(x) \ | 18 #define RETURN_EMPTY_ON_FAIL(x) \ |
21 if (!(x)) { \ | 19 if (!(x)) { \ |
22 return rtc::Optional<PpsParser::PpsState>(); \ | 20 return rtc::Optional<PpsParser::PpsState>(); \ |
23 } | 21 } |
24 | 22 |
25 namespace webrtc { | 23 namespace webrtc { |
26 | 24 |
27 // General note: this is based off the 02/2014 version of the H.264 standard. | 25 // General note: this is based off the 02/2014 version of the H.264 standard. |
28 // You can find it on this page: | 26 // You can find it on this page: |
29 // http://www.itu.int/rec/T-REC-H.264 | 27 // http://www.itu.int/rec/T-REC-H.264 |
30 | 28 |
31 rtc::Optional<PpsParser::PpsState> PpsParser::ParsePps(const uint8_t* data, | 29 rtc::Optional<PpsParser::PpsState> PpsParser::ParsePps(const uint8_t* data, |
32 size_t length) { | 30 size_t length) { |
33 // First, parse out rbsp, which is basically the source buffer minus emulation | 31 // First, parse out rbsp, which is basically the source buffer minus emulation |
34 // bytes (the last byte of a 0x00 0x00 0x03 sequence). RBSP is defined in | 32 // bytes (the last byte of a 0x00 0x00 0x03 sequence). RBSP is defined in |
35 // section 7.3.1 of the H.264 standard. | 33 // section 7.3.1 of the H.264 standard. |
36 std::unique_ptr<rtc::Buffer> unpacked_buffer = H264::ParseRbsp(data, length); | 34 std::unique_ptr<rtc::Buffer> unpacked_buffer = H264::ParseRbsp(data, length); |
37 rtc::BitBuffer bit_buffer(unpacked_buffer->data(), unpacked_buffer->size()); | 35 rtc::BitBuffer bit_buffer(unpacked_buffer->data(), unpacked_buffer->size()); |
38 return ParseInternal(&bit_buffer); | 36 return ParseInternal(&bit_buffer); |
39 } | 37 } |
40 | 38 |
41 rtc::Optional<uint32_t> PpsParser::ParsePpsIdFromSlice(const uint8_t* data, | |
42 size_t length) { | |
43 std::unique_ptr<rtc::Buffer> slice_rbsp(H264::ParseRbsp(data, length)); | |
44 rtc::BitBuffer slice_reader(slice_rbsp->data(), slice_rbsp->size()); | |
45 | |
46 uint32_t golomb_tmp; | |
47 // first_mb_in_slice: ue(v) | |
48 if (!slice_reader.ReadExponentialGolomb(&golomb_tmp)) | |
49 return rtc::Optional<uint32_t>(); | |
50 // slice_type: ue(v) | |
51 if (!slice_reader.ReadExponentialGolomb(&golomb_tmp)) | |
52 return rtc::Optional<uint32_t>(); | |
53 // pic_parameter_set_id: ue(v) | |
54 uint32_t slice_pps_id; | |
55 if (!slice_reader.ReadExponentialGolomb(&slice_pps_id)) | |
56 return rtc::Optional<uint32_t>(); | |
57 return rtc::Optional<uint32_t>(slice_pps_id); | |
58 } | |
59 | |
60 rtc::Optional<PpsParser::PpsState> PpsParser::ParseInternal( | 39 rtc::Optional<PpsParser::PpsState> PpsParser::ParseInternal( |
61 rtc::BitBuffer* bit_buffer) { | 40 rtc::BitBuffer* bit_buffer) { |
62 PpsState pps; | 41 PpsState pps; |
63 | 42 |
64 uint32_t bits_tmp; | 43 uint32_t bits_tmp; |
65 uint32_t golomb_ignored; | 44 uint32_t golomb_ignored; |
66 // pic_parameter_set_id: ue(v) | 45 // pic_parameter_set_id: ue(v) |
67 RETURN_EMPTY_ON_FAIL(bit_buffer->ReadExponentialGolomb(&pps.id)); | 46 RETURN_EMPTY_ON_FAIL(bit_buffer->ReadExponentialGolomb(&golomb_ignored)); |
68 // seq_parameter_set_id: ue(v) | 47 // seq_parameter_set_id: ue(v) |
69 RETURN_EMPTY_ON_FAIL(bit_buffer->ReadExponentialGolomb(&pps.sps_id)); | 48 RETURN_EMPTY_ON_FAIL(bit_buffer->ReadExponentialGolomb(&golomb_ignored)); |
70 // entropy_coding_mode_flag: u(1) | 49 // entropy_coding_mode_flag: u(1) |
71 uint32_t entropy_coding_mode_flag; | 50 uint32_t entropy_coding_mode_flag; |
72 RETURN_EMPTY_ON_FAIL(bit_buffer->ReadBits(&entropy_coding_mode_flag, 1)); | 51 RETURN_EMPTY_ON_FAIL(bit_buffer->ReadBits(&entropy_coding_mode_flag, 1)); |
73 // TODO(pbos): Implement CABAC support if spotted in the wild. | 52 // TODO(pbos): Implement CABAC support if spotted in the wild. |
74 RTC_CHECK(entropy_coding_mode_flag == 0) | 53 RTC_CHECK(entropy_coding_mode_flag == 0) |
75 << "Don't know how to parse CABAC streams."; | 54 << "Don't know how to parse CABAC streams."; |
76 // bottom_field_pic_order_in_frame_present_flag: u(1) | 55 // bottom_field_pic_order_in_frame_present_flag: u(1) |
77 uint32_t bottom_field_pic_order_in_frame_present_flag; | 56 uint32_t bottom_field_pic_order_in_frame_present_flag; |
78 RETURN_EMPTY_ON_FAIL( | 57 RETURN_EMPTY_ON_FAIL( |
79 bit_buffer->ReadBits(&bottom_field_pic_order_in_frame_present_flag, 1)); | 58 bit_buffer->ReadBits(&bottom_field_pic_order_in_frame_present_flag, 1)); |
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160 // constrained_intra_pred_flag: u(1) | 139 // constrained_intra_pred_flag: u(1) |
161 RETURN_EMPTY_ON_FAIL(bit_buffer->ReadBits(&bits_tmp, 2)); | 140 RETURN_EMPTY_ON_FAIL(bit_buffer->ReadBits(&bits_tmp, 2)); |
162 // redundant_pic_cnt_present_flag: u(1) | 141 // redundant_pic_cnt_present_flag: u(1) |
163 RETURN_EMPTY_ON_FAIL( | 142 RETURN_EMPTY_ON_FAIL( |
164 bit_buffer->ReadBits(&pps.redundant_pic_cnt_present_flag, 1)); | 143 bit_buffer->ReadBits(&pps.redundant_pic_cnt_present_flag, 1)); |
165 | 144 |
166 return rtc::Optional<PpsParser::PpsState>(pps); | 145 return rtc::Optional<PpsParser::PpsState>(pps); |
167 } | 146 } |
168 | 147 |
169 } // namespace webrtc | 148 } // namespace webrtc |
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