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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #include "media/webm/webm_cluster_parser.h" | 5 #include "media/webm/webm_cluster_parser.h" |
6 | 6 |
7 #include <vector> | 7 #include <vector> |
8 | 8 |
9 #include "base/logging.h" | 9 #include "base/logging.h" |
10 #include "base/sys_byteorder.h" | 10 #include "base/sys_byteorder.h" |
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196 if (last_block_timecode_ != -1 && timecode < last_block_timecode_) { | 196 if (last_block_timecode_ != -1 && timecode < last_block_timecode_) { |
197 DVLOG(1) << "Got a block with a timecode before the previous block."; | 197 DVLOG(1) << "Got a block with a timecode before the previous block."; |
198 return false; | 198 return false; |
199 } | 199 } |
200 | 200 |
201 last_block_timecode_ = timecode; | 201 last_block_timecode_ = timecode; |
202 | 202 |
203 base::TimeDelta timestamp = base::TimeDelta::FromMicroseconds( | 203 base::TimeDelta timestamp = base::TimeDelta::FromMicroseconds( |
204 (cluster_timecode_ + timecode) * timecode_multiplier_); | 204 (cluster_timecode_ + timecode) * timecode_multiplier_); |
205 | 205 |
206 // Every encrypted Block has an HMAC and IV prepended to it. Current encrypted | 206 // Every encrypted Block has a signal byte and IV prepended to it. Current |
207 // WebM request for comments specification is here | 207 // encrypted WebM request for comments specification is here |
208 // http://wiki.webmproject.org/encryption/webm-encryption-rfc | 208 // http://wiki.webmproject.org/encryption/webm-encryption-rfc |
209 bool is_track_encrypted = | 209 bool is_track_encrypted = |
210 track_num == video_.track_num() && !video_encryption_key_id_.empty(); | 210 track_num == video_.track_num() && !video_encryption_key_id_.empty(); |
211 | 211 |
212 // If stream is encrypted skip past the HMAC. Encrypted buffers must include | |
213 // the signal byte, the IV (if frame is encrypted) and | |
214 // the frame because the decryptor will verify this data before decryption. | |
215 // The HMAC and IV will be copied into DecryptConfig. | |
216 int offset = (is_track_encrypted) ? kWebMHmacSize : 0; | |
217 | |
218 // The first bit of the flags is set when the block contains only keyframes. | 212 // The first bit of the flags is set when the block contains only keyframes. |
219 // http://www.matroska.org/technical/specs/index.html | 213 // http://www.matroska.org/technical/specs/index.html |
220 bool is_keyframe = (flags & 0x80) != 0; | 214 bool is_keyframe = (flags & 0x80) != 0; |
221 scoped_refptr<StreamParserBuffer> buffer = | 215 scoped_refptr<StreamParserBuffer> buffer = |
222 StreamParserBuffer::CopyFrom(data + offset, size - offset, is_keyframe); | 216 StreamParserBuffer::CopyFrom(data, size, is_keyframe); |
223 | 217 |
224 if (is_track_encrypted) { | 218 if (is_track_encrypted) { |
225 uint8 signal_byte = data[kWebMHmacSize]; | 219 uint8 signal_byte = data[0]; |
226 int data_offset = sizeof(signal_byte); | 220 int data_offset = sizeof(signal_byte); |
227 | 221 |
228 // Setting the DecryptConfig object of the buffer while leaving the | 222 // Setting the DecryptConfig object of the buffer while leaving the |
229 // initialization vector empty will tell the decryptor that the frame is | 223 // initialization vector empty will tell the decryptor that the frame is |
230 // unencrypted but integrity should still be checked. | 224 // unencrypted. |
231 std::string counter_block; | 225 std::string counter_block; |
232 | 226 |
233 if (signal_byte & kWebMFlagEncryptedFrame) { | 227 if (signal_byte & kWebMFlagEncryptedFrame) { |
234 uint64 network_iv; | 228 uint64 network_iv; |
235 memcpy(&network_iv, data + kWebMHmacSize + data_offset, | 229 memcpy(&network_iv, data + data_offset, sizeof(network_iv)); |
236 sizeof(network_iv)); | |
237 const uint64 iv = base::NetToHost64(network_iv); | 230 const uint64 iv = base::NetToHost64(network_iv); |
238 counter_block = GenerateCounterBlock(iv); | 231 counter_block = GenerateCounterBlock(iv); |
239 data_offset += sizeof(iv); | 232 data_offset += sizeof(iv); |
240 } | 233 } |
241 | 234 |
| 235 // TODO(fgalligan): Revisit if DecryptConfig needs to be set on unencrypted |
| 236 // frames after the CDM API is finalized. |
| 237 // Unencrypted frames of potentially encrypted streams currently set |
| 238 // DecryptConfig. |
242 buffer->SetDecryptConfig(scoped_ptr<DecryptConfig>(new DecryptConfig( | 239 buffer->SetDecryptConfig(scoped_ptr<DecryptConfig>(new DecryptConfig( |
243 video_encryption_key_id_, | 240 video_encryption_key_id_, |
244 counter_block, | 241 counter_block, |
245 std::string(reinterpret_cast<const char*>(data), kWebMHmacSize), | |
246 data_offset, | 242 data_offset, |
247 std::vector<SubsampleEntry>()))); | 243 std::vector<SubsampleEntry>()))); |
248 } | 244 } |
249 | 245 |
250 buffer->SetTimestamp(timestamp); | 246 buffer->SetTimestamp(timestamp); |
251 if (cluster_start_time_ == kNoTimestamp()) | 247 if (cluster_start_time_ == kNoTimestamp()) |
252 cluster_start_time_ = timestamp; | 248 cluster_start_time_ = timestamp; |
253 | 249 |
254 if (block_duration >= 0) { | 250 if (block_duration >= 0) { |
255 buffer->SetDuration(base::TimeDelta::FromMicroseconds( | 251 buffer->SetDuration(base::TimeDelta::FromMicroseconds( |
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282 | 278 |
283 buffers_.push_back(buffer); | 279 buffers_.push_back(buffer); |
284 return true; | 280 return true; |
285 } | 281 } |
286 | 282 |
287 void WebMClusterParser::Track::Reset() { | 283 void WebMClusterParser::Track::Reset() { |
288 buffers_.clear(); | 284 buffers_.clear(); |
289 } | 285 } |
290 | 286 |
291 } // namespace media | 287 } // namespace media |
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