| // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef COBALT_MEDIA_BASE_DECRYPT_CONFIG_H_ |
| #define COBALT_MEDIA_BASE_DECRYPT_CONFIG_H_ |
| |
| #include <iosfwd> |
| #include <memory> |
| #include <string> |
| #include <vector> |
| |
| #include "base/basictypes.h" |
| #include "base/optional.h" |
| #include "cobalt/media/base/encryption_pattern.h" |
| #include "cobalt/media/base/media_export.h" |
| #include "cobalt/media/base/subsample_entry.h" |
| #include "starboard/types.h" |
| |
| namespace cobalt { |
| namespace media { |
| |
| // The encryption mode. The definitions are from ISO/IEC 23001-7:2016. |
| // TODO(crbug.com/825041): Merge this with existing media::EncryptionScheme. |
| enum class EncryptionMode { |
| kUnencrypted = 0, |
| kCenc, // 'cenc' subsample encryption using AES-CTR mode. |
| kCbcs, // 'cbcs' pattern encryption using AES-CBC mode. |
| kMaxValue = kCbcs |
| }; |
| |
| // Contains all information that a decryptor needs to decrypt a media sample. |
| class MEDIA_EXPORT DecryptConfig { |
| public: |
| // Keys are always 128 bits. |
| static const int kDecryptionKeySize = 16; |
| |
| // |key_id| is the ID that references the decryption key for this sample. |
| // |iv| is the initialization vector defined by the encrypted format. |
| // Currently |iv| must be 16 bytes as defined by WebM and ISO. It must |
| // be provided. |
| // |subsamples| defines the clear and encrypted portions of the sample as |
| // described above. A decrypted buffer will be equal in size to the sum |
| // of the subsample sizes. |
| // |encryption_pattern| is the pattern used ('cbcs' only). It is optional |
| // as Common encryption of MPEG-2 transport streams v1 (23009-1:2014) |
| // does not specify patterns for cbcs encryption mode. The pattern is |
| // assumed to be 1:9 for video and 1:0 for audio. |
| static std::unique_ptr<DecryptConfig> CreateCencConfig( |
| const std::string& key_id, const std::string& iv, |
| const std::vector<SubsampleEntry>& subsamples); |
| static std::unique_ptr<DecryptConfig> CreateCbcsConfig( |
| const std::string& key_id, const std::string& iv, |
| const std::vector<SubsampleEntry>& subsamples, |
| base::Optional<EncryptionPattern> encryption_pattern); |
| |
| DecryptConfig(const EncryptionMode& encryption_mode, |
| const std::string& key_id, const std::string& iv, |
| const std::vector<SubsampleEntry>& subsamples, |
| base::Optional<EncryptionPattern> encryption_pattern); |
| ~DecryptConfig(); |
| |
| const std::string& key_id() const { return key_id_; } |
| const std::string& iv() const { return iv_; } |
| const std::vector<SubsampleEntry>& subsamples() const { return subsamples_; } |
| const EncryptionMode& encryption_mode() const { return encryption_mode_; } |
| const base::Optional<EncryptionPattern>& encryption_pattern() const { |
| return encryption_pattern_; |
| } |
| |
| // Returns whether this config has EncryptionPattern set or not. |
| bool HasPattern() const; |
| |
| // Returns true if the corresponding decoder buffer requires decryption and |
| // false if that buffer is clear despite the presence of DecryptConfig. |
| bool is_encrypted() const { return !key_id_.empty() && !iv_.empty(); } |
| |
| // Returns true if all fields in |config| match this config. |
| bool Matches(const DecryptConfig& config) const; |
| |
| // Prints to std::ostream. |
| std::ostream& Print(std::ostream& os) const; |
| |
| private: |
| const EncryptionMode encryption_mode_; |
| const std::string key_id_; |
| |
| // Initialization vector. |
| const std::string iv_; |
| |
| // Subsample information. May be empty for some formats, meaning entire frame |
| // (less data ignored by data_offset_) is encrypted. |
| const std::vector<SubsampleEntry> subsamples_; |
| |
| // Only specified if |encryption_mode_| requires a pattern. |
| base::Optional<EncryptionPattern> encryption_pattern_; |
| |
| DISALLOW_COPY_AND_ASSIGN(DecryptConfig); |
| }; |
| |
| } // namespace media |
| } // namespace cobalt |
| |
| inline std::ostream& operator<<(std::ostream& os, |
| const cobalt::media::DecryptConfig& obj) { |
| return obj.Print(os); |
| } |
| |
| #endif // COBALT_MEDIA_BASE_DECRYPT_CONFIG_H_ |