libavformat/movenccenc.h

   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 #include "cbs.h"
  29
  30 #define CENC_KID_SIZE (16)
  31
  32 struct MOVTrack;
  33
  34 struct MOVMuxCencAV1TGInfo {
  35     uint32_t encrypted_bytes;
  36     uint32_t write_clear_bytes;
  37     uint32_t aux_clear_bytes;
  38 };
  39
  40 typedef struct {
  41     struct AVAESCTR* aes_ctr;
  42     uint8_t* auxiliary_info;
  43     size_t auxiliary_info_size;
  44     size_t auxiliary_info_alloc_size;
  45     uint32_t auxiliary_info_entries;
  46
  47     /* subsample support */
  48     int use_subsamples;
  49     uint16_t subsample_count;
  50     size_t auxiliary_info_subsample_start;
  51     uint8_t* auxiliary_info_sizes;
  52     size_t  auxiliary_info_sizes_alloc_size;
  53
  54     /* AV1 */
  55     struct MOVMuxCencAV1TGInfo *tile_group_sizes;
  56     uint32_t clear_bytes;
  57     int tile_num;
  58     /* CBS */
  59     CodedBitstreamContext *cbc;
  60     CodedBitstreamFragment temporal_unit;
  61 } MOVMuxCencContext;
  62
  63 /**
  64  * Initialize a CENC context
  65  * @param key encryption key, must have a length of AES_CTR_KEY_SIZE
  66  * @param use_subsamples when enabled parts of a packet can be encrypted, otherwise the whole packet is encrypted
  67  */
  68 int ff_mov_cenc_init(MOVMuxCencContext* ctx, uint8_t* encryption_key, int use_subsamples,
  69                      enum AVCodecID codec_id, int bitexact);
  70
  71 /**
  72  * Free a CENC context
  73  */
  74 void ff_mov_cenc_free(MOVMuxCencContext* ctx);
  75
  76 /**
  77  * Write a fully encrypted packet
  78  */
  79 int ff_mov_cenc_write_packet(MOVMuxCencContext* ctx, AVIOContext *pb, const uint8_t *buf_in, int size);
  80
  81 /**
  82  * Parse AVC NAL units from annex B format, the nal size and type are written in the clear while the body is encrypted
  83  */
  84 int ff_mov_cenc_avc_parse_nal_units(MOVMuxCencContext* ctx, AVIOContext *pb, const uint8_t *buf_in, int size);
  85
  86 /**
  87  * Write AVC NAL units that are in MP4 format, the nal size and type are written in the clear while the body is encrypted
  88  */
  89 int ff_mov_cenc_avc_write_nal_units(AVFormatContext *s, MOVMuxCencContext* ctx, int nal_length_size,
  90     AVIOContext *pb, const uint8_t *buf_in, int size);
  91
  92 int ff_mov_cenc_av1_write_obus(AVFormatContext *s, MOVMuxCencContext* ctx,
  93                                AVIOContext *pb, const AVPacket *pkt);
  94
  95 /**
  96  * Clear subsample data. To be called for fragmented output.
  97  */
  98 void ff_mov_cenc_flush(MOVMuxCencContext* ctx);
  99
 100 /**
 101  * Write the cenc atoms that should reside inside stbl
 102  */
 103 void ff_mov_cenc_write_stbl_atoms(MOVMuxCencContext* ctx, AVIOContext *pb, int64_t moof_offset);
 104
 105 /**
 106  * Write the sinf atom, contained inside stsd
 107  */
 108 int ff_mov_cenc_write_sinf_tag(struct MOVTrack* track, AVIOContext *pb, uint8_t* kid);
 109
 110 #endif /* AVFORMAT_MOVENCCENC_H */