Benjamin Wright | 0076529 | 2018-11-30 16:18:26 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2018 The WebRTC project authors. All Rights Reserved. |
| 3 | * |
| 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 |
| 6 | * tree. An additional intellectual property rights grant can be found |
| 7 | * in the file PATENTS. All contributing project authors may |
| 8 | * be found in the AUTHORS file in the root of the source tree. |
| 9 | */ |
| 10 | |
| 11 | #ifndef VIDEO_BUFFERED_FRAME_DECRYPTOR_H_ |
| 12 | #define VIDEO_BUFFERED_FRAME_DECRYPTOR_H_ |
| 13 | |
| 14 | #include <deque> |
| 15 | #include <memory> |
| 16 | |
Steve Anton | 10542f2 | 2019-01-11 09:11:00 -0800 | [diff] [blame] | 17 | #include "api/crypto/crypto_options.h" |
| 18 | #include "api/crypto/frame_decryptor_interface.h" |
Benjamin Wright | 0076529 | 2018-11-30 16:18:26 -0800 | [diff] [blame] | 19 | #include "modules/video_coding/frame_object.h" |
| 20 | |
| 21 | namespace webrtc { |
| 22 | |
| 23 | // This callback is provided during the construction of the |
| 24 | // BufferedFrameDecryptor and is called each time a frame is sucessfully |
| 25 | // decrypted by the buffer. |
| 26 | class OnDecryptedFrameCallback { |
| 27 | public: |
| 28 | virtual ~OnDecryptedFrameCallback() = default; |
| 29 | // Called each time a decrypted frame is returned. |
| 30 | virtual void OnDecryptedFrame( |
| 31 | std::unique_ptr<video_coding::RtpFrameObject> frame) = 0; |
| 32 | }; |
| 33 | |
Benjamin Wright | 52426ed | 2019-03-01 11:01:59 -0800 | [diff] [blame] | 34 | // This callback is called each time there is a status change in the decryption |
| 35 | // stream. For example going from a none state to a first decryption or going |
| 36 | // frome a decryptable state to a non decryptable state. |
| 37 | class OnDecryptionStatusChangeCallback { |
| 38 | public: |
| 39 | virtual ~OnDecryptionStatusChangeCallback() = default; |
| 40 | // Called each time the decryption stream status changes. This call is |
| 41 | // blocking so the caller must relinquish the callback quickly. This status |
| 42 | // must match what is specified in the FrameDecryptorInterface file. Notably |
| 43 | // 0 must indicate success and any positive integer is a failure. |
Benjamin Wright | 2af5dcb | 2019-04-09 20:08:41 +0000 | [diff] [blame] | 44 | virtual void OnDecryptionStatusChange( |
| 45 | FrameDecryptorInterface::Status status) = 0; |
Benjamin Wright | 52426ed | 2019-03-01 11:01:59 -0800 | [diff] [blame] | 46 | }; |
| 47 | |
Benjamin Wright | 0076529 | 2018-11-30 16:18:26 -0800 | [diff] [blame] | 48 | // The BufferedFrameDecryptor is responsible for deciding when to pass |
| 49 | // decrypted received frames onto the OnDecryptedFrameCallback. Frames can be |
| 50 | // delayed when frame encryption is enabled but the key hasn't arrived yet. In |
| 51 | // this case we stash about 1 second of encrypted frames instead of dropping |
| 52 | // them to prevent re-requesting the key frame. This optimization is |
| 53 | // particularly important on low bandwidth networks. Note stashing is only ever |
| 54 | // done if we have never sucessfully decrypted a frame before. After the first |
| 55 | // successful decryption payloads will never be stashed. |
| 56 | class BufferedFrameDecryptor final { |
| 57 | public: |
| 58 | // Constructs a new BufferedFrameDecryptor that can hold |
| 59 | explicit BufferedFrameDecryptor( |
| 60 | OnDecryptedFrameCallback* decrypted_frame_callback, |
Benjamin Wright | a556448 | 2019-04-03 10:44:18 -0700 | [diff] [blame] | 61 | OnDecryptionStatusChangeCallback* decryption_status_change_callback); |
Benjamin Wright | 0076529 | 2018-11-30 16:18:26 -0800 | [diff] [blame] | 62 | ~BufferedFrameDecryptor(); |
| 63 | // This object cannot be copied. |
| 64 | BufferedFrameDecryptor(const BufferedFrameDecryptor&) = delete; |
| 65 | BufferedFrameDecryptor& operator=(const BufferedFrameDecryptor&) = delete; |
Benjamin Wright | a556448 | 2019-04-03 10:44:18 -0700 | [diff] [blame] | 66 | |
| 67 | // Sets a new frame decryptor as the decryptor for the buffered frame |
| 68 | // decryptor. This allows the decryptor to be switched out without resetting |
| 69 | // the video stream. |
| 70 | void SetFrameDecryptor( |
| 71 | rtc::scoped_refptr<FrameDecryptorInterface> frame_decryptor); |
| 72 | |
Benjamin Wright | 0076529 | 2018-11-30 16:18:26 -0800 | [diff] [blame] | 73 | // Determines whether the frame should be stashed, dropped or handed off to |
| 74 | // the OnDecryptedFrameCallback. |
| 75 | void ManageEncryptedFrame( |
| 76 | std::unique_ptr<video_coding::RtpFrameObject> encrypted_frame); |
| 77 | |
| 78 | private: |
| 79 | // Represents what should be done with a given frame. |
| 80 | enum class FrameDecision { kStash, kDecrypted, kDrop }; |
| 81 | |
| 82 | // Attempts to decrypt the frame, if it fails and no prior frames have been |
| 83 | // decrypted it will return kStash. Otherwise fail to decrypts will return |
| 84 | // kDrop. Successful decryptions will always return kDecrypted. |
| 85 | FrameDecision DecryptFrame(video_coding::RtpFrameObject* frame); |
| 86 | // Retries all the stashed frames this is triggered each time a kDecrypted |
| 87 | // event occurs. |
| 88 | void RetryStashedFrames(); |
| 89 | |
| 90 | static const size_t kMaxStashedFrames = 24; |
| 91 | |
Benjamin Wright | 168456c | 2018-12-07 11:31:25 -0800 | [diff] [blame] | 92 | const bool generic_descriptor_auth_experiment_; |
Benjamin Wright | 0076529 | 2018-11-30 16:18:26 -0800 | [diff] [blame] | 93 | bool first_frame_decrypted_ = false; |
Benjamin Wright | 2af5dcb | 2019-04-09 20:08:41 +0000 | [diff] [blame] | 94 | FrameDecryptorInterface::Status last_status_ = |
| 95 | FrameDecryptorInterface::Status::kUnknown; |
Benjamin Wright | a556448 | 2019-04-03 10:44:18 -0700 | [diff] [blame] | 96 | rtc::scoped_refptr<FrameDecryptorInterface> frame_decryptor_; |
Benjamin Wright | 0076529 | 2018-11-30 16:18:26 -0800 | [diff] [blame] | 97 | OnDecryptedFrameCallback* const decrypted_frame_callback_; |
Benjamin Wright | 52426ed | 2019-03-01 11:01:59 -0800 | [diff] [blame] | 98 | OnDecryptionStatusChangeCallback* const decryption_status_change_callback_; |
Benjamin Wright | 0076529 | 2018-11-30 16:18:26 -0800 | [diff] [blame] | 99 | std::deque<std::unique_ptr<video_coding::RtpFrameObject>> stashed_frames_; |
| 100 | }; |
| 101 | |
| 102 | } // namespace webrtc |
| 103 | |
| 104 | #endif // VIDEO_BUFFERED_FRAME_DECRYPTOR_H_ |