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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MEDIA_BASE_DECRYPT_CONFIG_H_
#define MEDIA_BASE_DECRYPT_CONFIG_H_
#include <stdint.h>
#include <iosfwd>
#include <memory>
#include <string>
#include <vector>
#include "media/base/encryption_pattern.h"
#include "media/base/encryption_scheme.h"
#include "media/base/media_export.h"
#include "media/base/subsample_entry.h"
#include "third_party/abseil-cpp/absl/types/optional.h"
namespace media {
// 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. Tracks other than video are protected
// using whole-block full-sample encryption (pattern 0:0 or unspecified).
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,
absl::optional<EncryptionPattern> encryption_pattern);
DecryptConfig(EncryptionScheme encryption_scheme,
const std::string& key_id,
const std::string& iv,
const std::vector<SubsampleEntry>& subsamples,
absl::optional<EncryptionPattern> encryption_pattern);
DecryptConfig& operator=(const DecryptConfig&) = delete;
~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_; }
EncryptionScheme encryption_scheme() const { return encryption_scheme_; }
const absl::optional<EncryptionPattern>& encryption_pattern() const {
return encryption_pattern_;
}
std::unique_ptr<DecryptConfig> Clone() const;
// Makes a new config which has the same configuration options (mode, pattern)
// while providing a new vector of subsamples and initialization vector.
std::unique_ptr<DecryptConfig> CopyNewSubsamplesIV(
const std::vector<SubsampleEntry>& subsamples,
const std::string& iv);
// Returns whether this config has EncryptionPattern set or not.
bool HasPattern() const;
// 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:
DecryptConfig(const DecryptConfig& other);
const EncryptionScheme encryption_scheme_;
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.
absl::optional<EncryptionPattern> encryption_pattern_;
};
inline std::ostream& operator<<(std::ostream& os,
const media::DecryptConfig& obj) {
return obj.Print(os);
}
} // namespace media
#endif // MEDIA_BASE_DECRYPT_CONFIG_H_
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