1 /* 2 * MOV CENC (Common Encryption) writer 3 * Copyright (c) 2015 Eran Kornblau <erankor at gmail dot com> 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22 #ifndef AVFORMAT_MOVENCCENC_H 23 #define AVFORMAT_MOVENCCENC_H 24 25 #include "libavutil/aes_ctr.h" 26 #include "avformat.h" 27 #include "avio.h" 28 29 #define CENC_KID_SIZE (16) 30 31 struct MOVTrack; 32 33 typedef struct { 34 struct AVAESCTR* aes_ctr; 35 uint8_t* auxiliary_info; 36 size_t auxiliary_info_size; 37 size_t auxiliary_info_alloc_size; 38 uint32_t auxiliary_info_entries; 39 40 /* subsample support */ 41 int use_subsamples; 42 uint16_t subsample_count; 43 size_t auxiliary_info_subsample_start; 44 uint8_t* auxiliary_info_sizes; 45 size_t auxiliary_info_sizes_alloc_size; 46 } MOVMuxCencContext; 47 48 /** 49 * Initialize a CENC context 50 * @param key encryption key, must have a length of AES_CTR_KEY_SIZE 51 * @param use_subsamples when enabled parts of a packet can be encrypted, otherwise the whole packet is encrypted 52 */ 53 int ff_mov_cenc_init(MOVMuxCencContext* ctx, uint8_t* encryption_key, int use_subsamples, int bitexact); 54 55 /** 56 * Free a CENC context 57 */ 58 void ff_mov_cenc_free(MOVMuxCencContext* ctx); 59 60 /** 61 * Write a fully encrypted packet 62 */ 63 int ff_mov_cenc_write_packet(MOVMuxCencContext* ctx, AVIOContext *pb, const uint8_t *buf_in, int size); 64 65 /** 66 * Parse AVC NAL units from annex B format, the nal size and type are written in the clear while the body is encrypted 67 */ 68 int ff_mov_cenc_avc_parse_nal_units(MOVMuxCencContext* ctx, AVIOContext *pb, const uint8_t *buf_in, int size); 69 70 /** 71 * Write AVC NAL units that are in MP4 format, the nal size and type are written in the clear while the body is encrypted 72 */ 73 int ff_mov_cenc_avc_write_nal_units(AVFormatContext *s, MOVMuxCencContext* ctx, int nal_length_size, 74 AVIOContext *pb, const uint8_t *buf_in, int size); 75 76 /** 77 * Write the cenc atoms that should reside inside stbl 78 */ 79 void ff_mov_cenc_write_stbl_atoms(MOVMuxCencContext* ctx, AVIOContext *pb); 80 81 /** 82 * Write the sinf atom, contained inside stsd 83 */ 84 int ff_mov_cenc_write_sinf_tag(struct MOVTrack* track, AVIOContext *pb, uint8_t* kid); 85 86 #endif /* AVFORMAT_MOVENCCENC_H */ 87