112 lines
4.5 KiB
C++
112 lines
4.5 KiB
C++
// Copyright 2018 Google LLC. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file or at
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// https://developers.google.com/open-source/licenses/bsd
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#ifndef PACKAGER_MEDIA_CRYPTO_SUBSAMPLE_GENERATOR_H_
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#define PACKAGER_MEDIA_CRYPTO_SUBSAMPLE_GENERATOR_H_
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#include <memory>
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#include <vector>
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#include <packager/media/base/fourccs.h>
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#include <packager/media/base/stream_info.h>
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#include <packager/status.h>
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namespace shaka {
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namespace media {
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class AV1Parser;
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class VideoSliceHeaderParser;
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class VPxParser;
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struct SubsampleEntry;
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/// Parsing and generating encryption subsamples from bitstreams. Note that the
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/// class can be used to generate subsamples from both audio and video
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/// bitstreams according to relevant specifications. For example, for video
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/// streams, the most notable specifications are Common Encryption v3 spec [1]
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/// and Apple SAMPLE AES spec [2]; for audio streams, they are full sample
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/// encrypted except for Apple SAMPLE AES spec, which usually contains leading
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/// clear bytes.
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/// [1] https://www.iso.org/standard/68042.html
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/// [2] https://apple.co/2Noi43q
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class SubsampleGenerator {
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public:
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/// @param vp9_subsample_encryption determines if subsample encryption or full
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/// sample encryption is used for VP9. Only relevant for VP9 codec.
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explicit SubsampleGenerator(bool vp9_subsample_encryption);
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virtual ~SubsampleGenerator();
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/// Initialize the generator.
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/// @param protection_scheme is the protection scheme to be used for the
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/// encryption. It is used to determine if the protected data should be
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/// block aligned.
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/// @param stream_info contains stream information.
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/// @returns OK on success, an error status otherwise.
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virtual Status Initialize(FourCC protection_scheme,
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const StreamInfo& stream_info);
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/// Generates subsamples from the bitstream. Note that all frames should be
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/// processed by this function even if it is not encrypted as the next
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/// (encrypted) frame may be dependent on the previous clear frames.
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/// @param frame points to the start of the frame.
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/// @param frame_size is the size of the frame.
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/// @param[out] subsamples will contain the output subsamples on success. It
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/// will be empty if the frame should be full sample encrypted.
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/// @returns OK on success, an error status otherwise.
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virtual Status GenerateSubsamples(const uint8_t* frame,
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size_t frame_size,
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std::vector<SubsampleEntry>* subsamples);
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// Testing injections.
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void InjectVpxParserForTesting(std::unique_ptr<VPxParser> vpx_parser);
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void InjectVideoSliceHeaderParserForTesting(
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std::unique_ptr<VideoSliceHeaderParser> header_parser);
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void InjectAV1ParserForTesting(std::unique_ptr<AV1Parser> av1_parser);
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private:
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SubsampleGenerator(const SubsampleGenerator&) = delete;
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SubsampleGenerator& operator=(const SubsampleGenerator&) = delete;
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Status GenerateSubsamplesFromVPxFrame(
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const uint8_t* frame,
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size_t frame_size,
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std::vector<SubsampleEntry>* subsamples);
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Status GenerateSubsamplesFromH26xFrame(
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const uint8_t* frame,
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size_t frame_size,
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std::vector<SubsampleEntry>* subsamples);
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Status GenerateSubsamplesFromAV1Frame(
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const uint8_t* frame,
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size_t frame_size,
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std::vector<SubsampleEntry>* subsamples);
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const bool vp9_subsample_encryption_ = false;
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// Whether the protected portion should be AES block (16 bytes) aligned.
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bool align_protected_data_ = false;
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Codec codec_ = kUnknownCodec;
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// For NAL structured video only, the size of NAL unit length in bytes. Can be
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// 1, 2 or 4 bytes.
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uint8_t nalu_length_size_ = 0;
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// For SAMPLE AES only, 32 bytes for Video and 16 bytes for audio.
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size_t leading_clear_bytes_size_ = 0;
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// For SAMPLE AES only, if the data size is less than this value, none of the
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// bytes are encrypted. The size is 48+1 bytes for video NAL and 32 bytes for
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// audio according to MPEG-2 Stream Encryption Format for HTTP Live Streaming.
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size_t min_protected_data_size_ = 0;
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// VPx parser for VPx streams.
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std::unique_ptr<VPxParser> vpx_parser_;
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// Video slice header parser for NAL strucutred streams.
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std::unique_ptr<VideoSliceHeaderParser> header_parser_;
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// AV1 parser for AV1 streams.
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std::unique_ptr<AV1Parser> av1_parser_;
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};
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} // namespace media
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} // namespace shaka
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#endif // PACKAGER_MEDIA_CRYPTO_SUBSAMPLE_GENERATOR_H_
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