1 // Copyright 2016 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 // Note: ported from Chromium commit head: 7014d6d 5 6 #ifndef SUBSAMPLE_ENTRY_H_ 7 #define SUBSAMPLE_ENTRY_H_ 8 9 #include <stdint.h> 10 11 namespace media { 12 13 // The Common Encryption spec provides for subsample encryption, where portions 14 // of a sample are set in cleartext. A SubsampleEntry specifies the number of 15 // clear and encrypted bytes in each subsample. For decryption, all of the 16 // encrypted bytes in a sample should be considered a single logical stream, 17 // regardless of how they are divided into subsamples, and the clear bytes 18 // should not be considered as part of decryption. This is logically equivalent 19 // to concatenating all 'cypher_bytes' portions of subsamples, decrypting that 20 // result, and then copying each byte from the decrypted block over the 21 // position of the corresponding encrypted byte. 22 struct SubsampleEntry { 23 SubsampleEntry() : clear_bytes(0), cypher_bytes(0) {} 24 SubsampleEntry(uint32_t clear_bytes, uint32_t cypher_bytes) 25 : clear_bytes(clear_bytes), cypher_bytes(cypher_bytes) {} 26 uint32_t clear_bytes; 27 uint32_t cypher_bytes; 28 }; 29 30 } // namespace media 31 32 #endif // SUBSAMPLE_ENTRY_H_ 33
