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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 "base/logging.h" |
| 6 #include "base/memory/scoped_ptr.h" |
| 7 #include "base/stl_util.h" |
| 8 |
| 9 #include "media/base/decrypt_config.h" |
| 10 #include "media/filters/h265_parser.h" |
| 11 |
| 12 namespace media { |
| 13 |
| 14 #define READ_BITS_OR_RETURN(num_bits, out) \ |
| 15 do { \ |
| 16 int _out; \ |
| 17 if (!br_.ReadBits(num_bits, &_out)) { \ |
| 18 DVLOG(1) \ |
| 19 << "Error in stream: unexpected EOS while trying to read " #out; \ |
| 20 return kInvalidStream; \ |
| 21 } \ |
| 22 *out = _out; \ |
| 23 } while (0) |
| 24 |
| 25 #define TRUE_OR_RETURN(a) \ |
| 26 do { \ |
| 27 if (!(a)) { \ |
| 28 DVLOG(1) << "Error in stream: invalid value, expected " << #a; \ |
| 29 return kInvalidStream; \ |
| 30 } \ |
| 31 } while (0) |
| 32 |
| 33 H265NALU::H265NALU() { |
| 34 memset(this, 0, sizeof(*this)); |
| 35 } |
| 36 |
| 37 H265Parser::H265Parser() { |
| 38 Reset(); |
| 39 } |
| 40 |
| 41 H265Parser::~H265Parser() { |
| 42 } |
| 43 |
| 44 void H265Parser::Reset() { |
| 45 stream_ = NULL; |
| 46 bytes_left_ = 0; |
| 47 encrypted_ranges_.clear(); |
| 48 } |
| 49 |
| 50 void H265Parser::SetStream(const uint8* stream, off_t stream_size) { |
| 51 std::vector<SubsampleEntry> subsamples; |
| 52 SetEncryptedStream(stream, stream_size, subsamples); |
| 53 } |
| 54 |
| 55 void H265Parser::SetEncryptedStream( |
| 56 const uint8* stream, off_t stream_size, |
| 57 const std::vector<SubsampleEntry>& subsamples) { |
| 58 DCHECK(stream); |
| 59 DCHECK_GT(stream_size, 0); |
| 60 |
| 61 stream_ = stream; |
| 62 bytes_left_ = stream_size; |
| 63 |
| 64 encrypted_ranges_.clear(); |
| 65 const uint8* start = stream; |
| 66 const uint8* stream_end = stream_ + bytes_left_; |
| 67 for (size_t i = 0; i < subsamples.size() && start < stream_end; ++i) { |
| 68 start += subsamples[i].clear_bytes; |
| 69 |
| 70 const uint8* end = std::min(start + subsamples[i].cypher_bytes, stream_end); |
| 71 encrypted_ranges_.Add(start, end); |
| 72 start = end; |
| 73 } |
| 74 } |
| 75 |
| 76 bool H265Parser::LocateNALU(off_t* nalu_size, off_t* start_code_size) { |
| 77 // Find the start code of next NALU. |
| 78 off_t nalu_start_off = 0; |
| 79 off_t annexb_start_code_size = 0; |
| 80 |
| 81 if (!H264Parser::FindStartCodeInClearRanges(stream_, bytes_left_, |
| 82 encrypted_ranges_, |
| 83 &nalu_start_off, |
| 84 &annexb_start_code_size)) { |
| 85 DVLOG(4) << "Could not find start code, end of stream?"; |
| 86 return false; |
| 87 } |
| 88 |
| 89 // Move the stream to the beginning of the NALU (pointing at the start code). |
| 90 stream_ += nalu_start_off; |
| 91 bytes_left_ -= nalu_start_off; |
| 92 |
| 93 const uint8* nalu_data = stream_ + annexb_start_code_size; |
| 94 off_t max_nalu_data_size = bytes_left_ - annexb_start_code_size; |
| 95 if (max_nalu_data_size <= 0) { |
| 96 DVLOG(3) << "End of stream"; |
| 97 return false; |
| 98 } |
| 99 |
| 100 // Find the start code of next NALU; |
| 101 // if successful, |nalu_size_without_start_code| is the number of bytes from |
| 102 // after previous start code to before this one; |
| 103 // if next start code is not found, it is still a valid NALU since there |
| 104 // are some bytes left after the first start code: all the remaining bytes |
| 105 // belong to the current NALU. |
| 106 off_t next_start_code_size = 0; |
| 107 off_t nalu_size_without_start_code = 0; |
| 108 if (!H264Parser::FindStartCodeInClearRanges(nalu_data, max_nalu_data_size, |
| 109 encrypted_ranges_, |
| 110 &nalu_size_without_start_code, |
| 111 &next_start_code_size)) { |
| 112 nalu_size_without_start_code = max_nalu_data_size; |
| 113 } |
| 114 *nalu_size = nalu_size_without_start_code + annexb_start_code_size; |
| 115 *start_code_size = annexb_start_code_size; |
| 116 return true; |
| 117 } |
| 118 |
| 119 H265Parser::Result H265Parser::AdvanceToNextNALU(H265NALU* nalu) { |
| 120 off_t start_code_size; |
| 121 off_t nalu_size_with_start_code; |
| 122 if (!LocateNALU(&nalu_size_with_start_code, &start_code_size)) { |
| 123 DVLOG(4) << "Could not find next NALU, bytes left in stream: " |
| 124 << bytes_left_; |
| 125 return kEOStream; |
| 126 } |
| 127 |
| 128 nalu->data = stream_ + start_code_size; |
| 129 nalu->size = nalu_size_with_start_code - start_code_size; |
| 130 DVLOG(4) << "NALU found: size=" << nalu_size_with_start_code; |
| 131 |
| 132 // Initialize bit reader at the start of found NALU. |
| 133 if (!br_.Initialize(nalu->data, nalu->size)) |
| 134 return kEOStream; |
| 135 |
| 136 // Move parser state to after this NALU, so next time AdvanceToNextNALU |
| 137 // is called, we will effectively be skipping it; |
| 138 // other parsing functions will use the position saved |
| 139 // in bit reader for parsing, so we don't have to remember it here. |
| 140 stream_ += nalu_size_with_start_code; |
| 141 bytes_left_ -= nalu_size_with_start_code; |
| 142 |
| 143 // Read NALU header, skip the forbidden_zero_bit, but check for it. |
| 144 int data; |
| 145 READ_BITS_OR_RETURN(1, &data); |
| 146 TRUE_OR_RETURN(data == 0); |
| 147 |
| 148 READ_BITS_OR_RETURN(6, &nalu->nal_unit_type); |
| 149 READ_BITS_OR_RETURN(6, &nalu->nuh_layer_id); |
| 150 READ_BITS_OR_RETURN(3, &nalu->nuh_temporal_id_plus1); |
| 151 |
| 152 DVLOG(4) << "NALU type: " << static_cast<int>(nalu->nal_unit_type) |
| 153 << " at: " << reinterpret_cast<const void*>(nalu->data) |
| 154 << " size: " << nalu->size; |
| 155 |
| 156 return kOk; |
| 157 } |
| 158 |
| 159 } // namespace media |
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