[FFmpeg-cvslog] movenc: support cenc (common encryption)
erankor
git at videolan.org
Tue Dec 15 15:36:32 CET 2015
ffmpeg | branch: master | erankor <eran.kornblau at kaltura.com> | Mon Dec 7 12:01:09 2015 +0200| [4469e8ebb2f370794c88aa51d528d1d899d29ddc] | committer: Michael Niedermayer
movenc: support cenc (common encryption)
support writing encrypted mp4 using aes-ctr, conforming to ISO/IEC
23001-7.
3 new parameters were added:
- encryption_scheme - allowed values are none (default) and cenc-aes-ctr
- encryption_key - 128 bit encryption key (hex)
- encryption_kid - 128 bit encryption key identifier (hex)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=4469e8ebb2f370794c88aa51d528d1d899d29ddc
---
Changelog | 1 +
libavformat/Makefile | 2 +-
libavformat/movenc.c | 92 +++++++++-
libavformat/movenc.h | 16 ++
libavformat/movenccenc.c | 415 ++++++++++++++++++++++++++++++++++++++++++++++
libavformat/movenccenc.h | 86 ++++++++++
6 files changed, 604 insertions(+), 8 deletions(-)
diff --git a/Changelog b/Changelog
index 1770068..a3d44b4 100644
--- a/Changelog
+++ b/Changelog
@@ -2,6 +2,7 @@ Entries are sorted chronologically from oldest to youngest within each release,
releases are sorted from youngest to oldest.
version <next>:
+- Common Encryption (CENC) MP4 encoding support
- DXV decoding
- extrastereo filter
- ocr filter
diff --git a/libavformat/Makefile b/libavformat/Makefile
index ddc4c3d..110e9e3 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -264,7 +264,7 @@ OBJS-$(CONFIG_MMF_DEMUXER) += mmf.o
OBJS-$(CONFIG_MMF_MUXER) += mmf.o rawenc.o
OBJS-$(CONFIG_MOV_DEMUXER) += mov.o isom.o mov_chan.o replaygain.o
OBJS-$(CONFIG_MOV_MUXER) += movenc.o isom.o avc.o hevc.o \
- movenchint.o mov_chan.o rtp.o
+ movenchint.o mov_chan.o rtp.o movenccenc.o
OBJS-$(CONFIG_MP2_MUXER) += mp3enc.o rawenc.o id3v2enc.o
OBJS-$(CONFIG_MP3_DEMUXER) += mp3dec.o replaygain.o
OBJS-$(CONFIG_MP3_MUXER) += mp3enc.o rawenc.o id3v2enc.o
diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index e3bab96..3cb3263 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -83,6 +83,9 @@ static const AVOption options[] = {
{ "fragment_index", "Fragment number of the next fragment", offsetof(MOVMuxContext, fragments), AV_OPT_TYPE_INT, {.i64 = 1}, 1, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM},
{ "mov_gamma", "gamma value for gama atom", offsetof(MOVMuxContext, gamma), AV_OPT_TYPE_FLOAT, {.dbl = 0.0 }, 0.0, 10, AV_OPT_FLAG_ENCODING_PARAM},
{ "frag_interleave", "Interleave samples within fragments (max number of consecutive samples, lower is tighter interleaving, but with more overhead)", offsetof(MOVMuxContext, frag_interleave), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
+ { "encryption_scheme", "Configures the encryption scheme, allowed values are none, cenc-aes-ctr", offsetof(MOVMuxContext, encryption_scheme_str), AV_OPT_TYPE_STRING, {.str = NULL}, .flags = AV_OPT_FLAG_ENCODING_PARAM, .unit = "movflags" },
+ { "encryption_key", "The media encryption key (hex)", offsetof(MOVMuxContext, encryption_key), AV_OPT_TYPE_BINARY, .flags = AV_OPT_FLAG_ENCODING_PARAM, .unit = "movflags" },
+ { "encryption_kid", "The media encryption key identifier (hex)", offsetof(MOVMuxContext, encryption_kid), AV_OPT_TYPE_BINARY, .flags = AV_OPT_FLAG_ENCODING_PARAM, .unit = "movflags" },
{ NULL },
};
@@ -891,7 +894,7 @@ static int get_samples_per_packet(MOVTrack *track)
return first_duration;
}
-static int mov_write_audio_tag(AVIOContext *pb, MOVTrack *track)
+static int mov_write_audio_tag(AVIOContext *pb, MOVMuxContext *mov, MOVTrack *track)
{
int64_t pos = avio_tell(pb);
int version = 0;
@@ -912,7 +915,11 @@ static int mov_write_audio_tag(AVIOContext *pb, MOVTrack *track)
}
avio_wb32(pb, 0); /* size */
- avio_wl32(pb, tag); // store it byteswapped
+ if (mov->encryption_scheme != MOV_ENC_NONE) {
+ ffio_wfourcc(pb, "enca");
+ } else {
+ avio_wl32(pb, tag); // store it byteswapped
+ }
avio_wb32(pb, 0); /* Reserved */
avio_wb16(pb, 0); /* Reserved */
avio_wb16(pb, 1); /* Data-reference index, XXX == 1 */
@@ -1000,6 +1007,10 @@ static int mov_write_audio_tag(AVIOContext *pb, MOVTrack *track)
if (track->mode == MODE_MOV && track->enc->codec_type == AVMEDIA_TYPE_AUDIO)
mov_write_chan_tag(pb, track);
+ if (mov->encryption_scheme != MOV_ENC_NONE) {
+ ff_mov_cenc_write_sinf_tag(track, pb, mov->encryption_kid);
+ }
+
return update_size(pb, pos);
}
@@ -1659,7 +1670,11 @@ static int mov_write_video_tag(AVIOContext *pb, MOVMuxContext *mov, MOVTrack *tr
int avid = 0;
avio_wb32(pb, 0); /* size */
- avio_wl32(pb, track->tag); // store it byteswapped
+ if (mov->encryption_scheme != MOV_ENC_NONE) {
+ ffio_wfourcc(pb, "encv");
+ } else {
+ avio_wl32(pb, track->tag); // store it byteswapped
+ }
avio_wb32(pb, 0); /* Reserved */
avio_wb16(pb, 0); /* Reserved */
avio_wb16(pb, 1); /* Data-reference index */
@@ -1750,6 +1765,10 @@ static int mov_write_video_tag(AVIOContext *pb, MOVMuxContext *mov, MOVTrack *tr
mov_write_pasp_tag(pb, track);
}
+ if (mov->encryption_scheme != MOV_ENC_NONE) {
+ ff_mov_cenc_write_sinf_tag(track, pb, mov->encryption_kid);
+ }
+
/* extra padding for avid stsd */
/* https://developer.apple.com/library/mac/documentation/QuickTime/QTFF/QTFFChap2/qtff2.html#//apple_ref/doc/uid/TP40000939-CH204-61112 */
if (avid)
@@ -1848,9 +1867,9 @@ static int mov_write_stsd_tag(AVIOContext *pb, MOVMuxContext *mov, MOVTrack *tra
avio_wb32(pb, 0); /* version & flags */
avio_wb32(pb, 1); /* entry count */
if (track->enc->codec_type == AVMEDIA_TYPE_VIDEO)
- mov_write_video_tag(pb, mov, track);
+ mov_write_video_tag(pb, mov, track);
else if (track->enc->codec_type == AVMEDIA_TYPE_AUDIO)
- mov_write_audio_tag(pb, track);
+ mov_write_audio_tag(pb, mov, track);
else if (track->enc->codec_type == AVMEDIA_TYPE_SUBTITLE)
mov_write_subtitle_tag(pb, track);
else if (track->enc->codec_tag == MKTAG('r','t','p',' '))
@@ -1980,6 +1999,9 @@ static int mov_write_stbl_tag(AVIOContext *pb, MOVMuxContext *mov, MOVTrack *tra
mov_write_stsc_tag(pb, track);
mov_write_stsz_tag(pb, track);
mov_write_stco_tag(pb, track);
+ if (mov->encryption_scheme == MOV_ENC_CENC_AES_CTR) {
+ ff_mov_cenc_write_stbl_atoms(&track->cenc, pb);
+ }
return update_size(pb, pos);
}
@@ -4419,7 +4441,15 @@ int ff_mov_write_packet(AVFormatContext *s, AVPacket *pkt)
&size);
avio_write(pb, reformatted_data, size);
} else {
- size = ff_avc_parse_nal_units(pb, pkt->data, pkt->size);
+ if (mov->encryption_scheme == MOV_ENC_CENC_AES_CTR) {
+ size = ff_mov_cenc_avc_parse_nal_units(&trk->cenc, pb, pkt->data, size);
+ if (size < 0) {
+ ret = size;
+ goto err;
+ }
+ } else {
+ size = ff_avc_parse_nal_units(pb, pkt->data, pkt->size);
+ }
}
} else if (enc->codec_id == AV_CODEC_ID_HEVC && trk->vos_len > 6 &&
(AV_RB24(trk->vos_data) == 1 || AV_RB32(trk->vos_data) == 1)) {
@@ -4440,7 +4470,20 @@ int ff_mov_write_packet(AVFormatContext *s, AVPacket *pkt)
avio_write(pb, pkt->data, size);
#endif
} else {
- avio_write(pb, pkt->data, size);
+ if (mov->encryption_scheme == MOV_ENC_CENC_AES_CTR) {
+ if (enc->codec_id == AV_CODEC_ID_H264 && enc->extradata_size > 4) {
+ int nal_size_length = (enc->extradata[4] & 0x3) + 1;
+ ret = ff_mov_cenc_avc_write_nal_units(s, &trk->cenc, nal_size_length, pb, pkt->data, size);
+ } else {
+ ret = ff_mov_cenc_write_packet(&trk->cenc, pb, pkt->data, size);
+ }
+
+ if (ret) {
+ goto err;
+ }
+ } else {
+ avio_write(pb, pkt->data, size);
+ }
}
if ((enc->codec_id == AV_CODEC_ID_DNXHD ||
@@ -4913,6 +4956,8 @@ static void mov_free(AVFormatContext *s)
if (mov->tracks[i].vos_len)
av_freep(&mov->tracks[i].vos_data);
+
+ ff_mov_cenc_free(&mov->tracks[i].cenc);
}
av_freep(&mov->tracks);
@@ -5123,6 +5168,31 @@ static int mov_write_header(AVFormatContext *s)
if (!mov->tracks)
return AVERROR(ENOMEM);
+ if (mov->encryption_scheme_str != NULL && strcmp(mov->encryption_scheme_str, "none") != 0) {
+ if (strcmp(mov->encryption_scheme_str, "cenc-aes-ctr") == 0) {
+ mov->encryption_scheme = MOV_ENC_CENC_AES_CTR;
+
+ if (mov->encryption_key_len != AES_CTR_KEY_SIZE) {
+ av_log(s, AV_LOG_ERROR, "Invalid encryption key len %d expected %d\n",
+ mov->encryption_key_len, AES_CTR_KEY_SIZE);
+ ret = AVERROR(EINVAL);
+ goto error;
+ }
+
+ if (mov->encryption_kid_len != CENC_KID_SIZE) {
+ av_log(s, AV_LOG_ERROR, "Invalid encryption kid len %d expected %d\n",
+ mov->encryption_kid_len, CENC_KID_SIZE);
+ ret = AVERROR(EINVAL);
+ goto error;
+ }
+ } else {
+ av_log(s, AV_LOG_ERROR, "unsupported encryption scheme %s\n",
+ mov->encryption_scheme_str);
+ ret = AVERROR(EINVAL);
+ goto error;
+ }
+ }
+
for (i = 0; i < s->nb_streams; i++) {
AVStream *st= s->streams[i];
MOVTrack *track= &mov->tracks[i];
@@ -5241,6 +5311,14 @@ static int mov_write_header(AVFormatContext *s)
memcpy(track->vos_data, st->codec->extradata, track->vos_len);
}
}
+
+ if (mov->encryption_scheme == MOV_ENC_CENC_AES_CTR) {
+ ret = ff_mov_cenc_init(&track->cenc, mov->encryption_key,
+ track->enc->codec_id == AV_CODEC_ID_H264, s->flags & AVFMT_FLAG_BITEXACT);
+ if (ret) {
+ goto error;
+ }
+ }
}
for (i = 0; i < s->nb_streams; i++) {
diff --git a/libavformat/movenc.h b/libavformat/movenc.h
index 06adf2b..deb90fe 100644
--- a/libavformat/movenc.h
+++ b/libavformat/movenc.h
@@ -25,6 +25,7 @@
#define AVFORMAT_MOVENC_H
#include "avformat.h"
+#include "movenccenc.h"
#define MOV_FRAG_INFO_ALLOC_INCREMENT 64
#define MOV_INDEX_CLUSTER_SIZE 1024
@@ -149,8 +150,15 @@ typedef struct MOVTrack {
} vc1_info;
void *eac3_priv;
+
+ MOVMuxCencContext cenc;
} MOVTrack;
+typedef enum {
+ MOV_ENC_NONE = 0,
+ MOV_ENC_CENC_AES_CTR,
+} MOVEncryptionScheme;
+
typedef struct MOVMuxContext {
const AVClass *av_class;
int mode;
@@ -193,6 +201,14 @@ typedef struct MOVMuxContext {
int frag_interleave;
int missing_duration_warned;
+
+ char *encryption_scheme_str;
+ MOVEncryptionScheme encryption_scheme;
+ uint8_t *encryption_key;
+ int encryption_key_len;
+ uint8_t *encryption_kid;
+ int encryption_kid_len;
+
} MOVMuxContext;
#define FF_MOV_FLAG_RTP_HINT (1 << 0)
diff --git a/libavformat/movenccenc.c b/libavformat/movenccenc.c
new file mode 100644
index 0000000..b91294f
--- /dev/null
+++ b/libavformat/movenccenc.c
@@ -0,0 +1,415 @@
+/*
+ * MOV CENC (Common Encryption) writer
+ * Copyright (c) 2015 Eran Kornblau <erankor at gmail dot com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include "movenccenc.h"
+#include "libavutil/intreadwrite.h"
+#include "avio_internal.h"
+#include "movenc.h"
+#include "avc.h"
+
+static int auxiliary_info_alloc_size(MOVMuxCencContext* ctx, int size)
+{
+ size_t new_alloc_size;
+
+ if (ctx->auxiliary_info_size + size > ctx->auxiliary_info_alloc_size) {
+ new_alloc_size = FFMAX(ctx->auxiliary_info_size + size, ctx->auxiliary_info_alloc_size * 2);
+ if (av_reallocp(&ctx->auxiliary_info, new_alloc_size)) {
+ return AVERROR(ENOMEM);
+ }
+
+ ctx->auxiliary_info_alloc_size = new_alloc_size;
+ }
+
+ return 0;
+}
+
+static int auxiliary_info_write(MOVMuxCencContext* ctx,
+ const uint8_t *buf_in, int size)
+{
+ int ret;
+
+ ret = auxiliary_info_alloc_size(ctx, size);
+ if (ret) {
+ return ret;
+ }
+ memcpy(ctx->auxiliary_info + ctx->auxiliary_info_size, buf_in, size);
+ ctx->auxiliary_info_size += size;
+
+ return 0;
+}
+
+static int auxiliary_info_add_subsample(MOVMuxCencContext* ctx,
+ uint16_t clear_bytes, uint32_t encrypted_bytes)
+{
+ uint8_t* p;
+ int ret;
+
+ if (!ctx->use_subsamples) {
+ return 0;
+ }
+
+ ret = auxiliary_info_alloc_size(ctx, 6);
+ if (ret) {
+ return ret;
+ }
+
+ p = ctx->auxiliary_info + ctx->auxiliary_info_size;
+
+ AV_WB16(p, clear_bytes);
+ p += sizeof(uint16_t);
+
+ AV_WB32(p, encrypted_bytes);
+
+ ctx->auxiliary_info_size += 6;
+ ctx->subsample_count++;
+
+ return 0;
+}
+
+/**
+ * Encrypt the input buffer and write using avio_write
+ */
+static void mov_cenc_write_encrypted(MOVMuxCencContext* ctx, AVIOContext *pb,
+ const uint8_t *buf_in, int size)
+{
+ uint8_t chunk[4096];
+ const uint8_t* cur_pos = buf_in;
+ int size_left = size;
+ int cur_size;
+
+ while (size_left > 0) {
+ cur_size = FFMIN(size_left, sizeof(chunk));
+ av_aes_ctr_crypt(ctx->aes_ctr, chunk, cur_pos, cur_size);
+ avio_write(pb, chunk, cur_size);
+ cur_pos += cur_size;
+ size_left -= cur_size;
+ }
+}
+
+/**
+ * Start writing a packet
+ */
+static int mov_cenc_start_packet(MOVMuxCencContext* ctx)
+{
+ int ret;
+
+ /* write the iv */
+ ret = auxiliary_info_write(ctx, av_aes_ctr_get_iv(ctx->aes_ctr), AES_CTR_IV_SIZE);
+ if (ret) {
+ return ret;
+ }
+
+ if (!ctx->use_subsamples) {
+ return 0;
+ }
+
+ /* write a zero subsample count */
+ ctx->auxiliary_info_subsample_start = ctx->auxiliary_info_size;
+ ctx->subsample_count = 0;
+ ret = auxiliary_info_write(ctx, (uint8_t*)&ctx->subsample_count, sizeof(ctx->subsample_count));
+ if (ret) {
+ return ret;
+ }
+
+ return 0;
+}
+
+/**
+ * Finalize a packet
+ */
+static int mov_cenc_end_packet(MOVMuxCencContext* ctx)
+{
+ size_t new_alloc_size;
+
+ av_aes_ctr_increment_iv(ctx->aes_ctr);
+
+ if (!ctx->use_subsamples) {
+ ctx->auxiliary_info_entries++;
+ return 0;
+ }
+
+ /* add the auxiliary info entry size*/
+ if (ctx->auxiliary_info_entries >= ctx->auxiliary_info_sizes_alloc_size) {
+ new_alloc_size = ctx->auxiliary_info_entries * 2 + 1;
+ if (av_reallocp(&ctx->auxiliary_info_sizes, new_alloc_size)) {
+ return AVERROR(ENOMEM);
+ }
+
+ ctx->auxiliary_info_sizes_alloc_size = new_alloc_size;
+ }
+ ctx->auxiliary_info_sizes[ctx->auxiliary_info_entries] =
+ AES_CTR_IV_SIZE + ctx->auxiliary_info_size - ctx->auxiliary_info_subsample_start;
+ ctx->auxiliary_info_entries++;
+
+ /* update the subsample count*/
+ AV_WB16(ctx->auxiliary_info + ctx->auxiliary_info_subsample_start, ctx->subsample_count);
+
+ return 0;
+}
+
+int ff_mov_cenc_write_packet(MOVMuxCencContext* ctx, AVIOContext *pb,
+ const uint8_t *buf_in, int size)
+{
+ int ret;
+
+ ret = mov_cenc_start_packet(ctx);
+ if (ret) {
+ return ret;
+ }
+
+ ret = auxiliary_info_add_subsample(ctx, 0, size);
+ if (ret) {
+ return ret;
+ }
+
+ mov_cenc_write_encrypted(ctx, pb, buf_in, size);
+
+ ret = mov_cenc_end_packet(ctx);
+ if (ret) {
+ return ret;
+ }
+
+ return 0;
+}
+
+int ff_mov_cenc_avc_parse_nal_units(MOVMuxCencContext* ctx, AVIOContext *pb,
+ const uint8_t *buf_in, int size)
+{
+ const uint8_t *p = buf_in;
+ const uint8_t *end = p + size;
+ const uint8_t *nal_start, *nal_end;
+ int ret;
+
+ ret = mov_cenc_start_packet(ctx);
+ if (ret) {
+ return ret;
+ }
+
+ size = 0;
+ nal_start = ff_avc_find_startcode(p, end);
+ for (;;) {
+ while (nal_start < end && !*(nal_start++));
+ if (nal_start == end)
+ break;
+
+ nal_end = ff_avc_find_startcode(nal_start, end);
+
+ avio_wb32(pb, nal_end - nal_start);
+ avio_w8(pb, *nal_start);
+ mov_cenc_write_encrypted(ctx, pb, nal_start + 1, nal_end - nal_start - 1);
+
+ auxiliary_info_add_subsample(ctx, 5, nal_end - nal_start - 1);
+
+ size += 4 + nal_end - nal_start;
+ nal_start = nal_end;
+ }
+
+ ret = mov_cenc_end_packet(ctx);
+ if (ret) {
+ return ret;
+ }
+
+ return size;
+}
+
+int ff_mov_cenc_avc_write_nal_units(AVFormatContext *s, MOVMuxCencContext* ctx,
+ int nal_length_size, AVIOContext *pb, const uint8_t *buf_in, int size)
+{
+ int nalsize;
+ int ret;
+ int j;
+
+ ret = mov_cenc_start_packet(ctx);
+ if (ret) {
+ return ret;
+ }
+
+ while (size > 0) {
+ /* parse the nal size */
+ if (size < nal_length_size + 1) {
+ av_log(s, AV_LOG_ERROR, "CENC-AVC: remaining size %d smaller than nal length+type %d\n",
+ size, nal_length_size + 1);
+ return -1;
+ }
+
+ avio_write(pb, buf_in, nal_length_size + 1);
+
+ nalsize = 0;
+ for (j = 0; j < nal_length_size; j++) {
+ nalsize = (nalsize << 8) | *buf_in++;
+ }
+ size -= nal_length_size;
+
+ /* encrypt the nal body */
+ if (nalsize <= 0 || nalsize > size) {
+ av_log(s, AV_LOG_ERROR, "CENC-AVC: nal size %d remaining %d\n", nalsize, size);
+ return -1;
+ }
+
+ mov_cenc_write_encrypted(ctx, pb, buf_in + 1, nalsize - 1);
+ buf_in += nalsize;
+ size -= nalsize;
+
+ auxiliary_info_add_subsample(ctx, nal_length_size + 1, nalsize - 1);
+ }
+
+ ret = mov_cenc_end_packet(ctx);
+ if (ret) {
+ return ret;
+ }
+
+ return 0;
+}
+
+/* TODO: reuse this function from movenc.c */
+static int64_t update_size(AVIOContext *pb, int64_t pos)
+{
+ int64_t curpos = avio_tell(pb);
+ avio_seek(pb, pos, SEEK_SET);
+ avio_wb32(pb, curpos - pos); /* rewrite size */
+ avio_seek(pb, curpos, SEEK_SET);
+
+ return curpos - pos;
+}
+
+static int mov_cenc_write_senc_tag(MOVMuxCencContext* ctx, AVIOContext *pb,
+ int64_t* auxiliary_info_offset)
+{
+ int64_t pos = avio_tell(pb);
+
+ avio_wb32(pb, 0); /* size */
+ ffio_wfourcc(pb, "senc");
+ avio_wb32(pb, ctx->use_subsamples ? 0x02 : 0); /* version & flags */
+ avio_wb32(pb, ctx->auxiliary_info_entries); /* entry count */
+ *auxiliary_info_offset = avio_tell(pb);
+ avio_write(pb, ctx->auxiliary_info, ctx->auxiliary_info_size);
+ return update_size(pb, pos);
+}
+
+static int mov_cenc_write_saio_tag(AVIOContext *pb, int64_t auxiliary_info_offset)
+{
+ int64_t pos = avio_tell(pb);
+ uint8_t version;
+
+ avio_wb32(pb, 0); /* size */
+ ffio_wfourcc(pb, "saio");
+ version = auxiliary_info_offset > 0xffffffff ? 1 : 0;
+ avio_w8(pb, version);
+ avio_wb24(pb, 0); /* flags */
+ avio_wb32(pb, 1); /* entry count */
+ if (version) {
+ avio_wb64(pb, auxiliary_info_offset);
+ } else {
+ avio_wb32(pb, auxiliary_info_offset);
+ }
+ return update_size(pb, pos);
+}
+
+static int mov_cenc_write_saiz_tag(MOVMuxCencContext* ctx, AVIOContext *pb)
+{
+ int64_t pos = avio_tell(pb);
+ avio_wb32(pb, 0); /* size */
+ ffio_wfourcc(pb, "saiz");
+ avio_wb32(pb, 0); /* version & flags */
+ avio_w8(pb, ctx->use_subsamples ? 0 : AES_CTR_IV_SIZE); /* default size*/
+ avio_wb32(pb, ctx->auxiliary_info_entries); /* entry count */
+ if (ctx->use_subsamples) {
+ avio_write(pb, ctx->auxiliary_info_sizes, ctx->auxiliary_info_entries);
+ }
+ return update_size(pb, pos);
+}
+
+void ff_mov_cenc_write_stbl_atoms(MOVMuxCencContext* ctx, AVIOContext *pb)
+{
+ int64_t auxiliary_info_offset;
+
+ mov_cenc_write_senc_tag(ctx, pb, &auxiliary_info_offset);
+ mov_cenc_write_saio_tag(pb, auxiliary_info_offset);
+ mov_cenc_write_saiz_tag(ctx, pb);
+}
+
+static int mov_cenc_write_schi_tag(AVIOContext *pb, uint8_t* kid)
+{
+ int64_t pos = avio_tell(pb);
+ avio_wb32(pb, 0); /* size */
+ ffio_wfourcc(pb, "schi");
+
+ avio_wb32(pb, 32); /* size */
+ ffio_wfourcc(pb, "tenc");
+ avio_wb32(pb, 0); /* version & flags */
+ avio_wb24(pb, 1); /* is encrypted */
+ avio_w8(pb, AES_CTR_IV_SIZE); /* iv size */
+ avio_write(pb, kid, CENC_KID_SIZE);
+
+ return update_size(pb, pos);
+}
+
+int ff_mov_cenc_write_sinf_tag(MOVTrack* track, AVIOContext *pb, uint8_t* kid)
+{
+ int64_t pos = avio_tell(pb);
+ avio_wb32(pb, 0); /* size */
+ ffio_wfourcc(pb, "sinf");
+
+ /* frma */
+ avio_wb32(pb, 12); /* size */
+ ffio_wfourcc(pb, "frma");
+ avio_wl32(pb, track->tag);
+
+ /* schm */
+ avio_wb32(pb, 20); /* size */
+ ffio_wfourcc(pb, "schm");
+ avio_wb32(pb, 0); /* version & flags */
+ ffio_wfourcc(pb, "cenc"); /* scheme type*/
+ avio_wb32(pb, 0x10000); /* scheme version */
+
+ /* schi */
+ mov_cenc_write_schi_tag(pb, kid);
+
+ return update_size(pb, pos);
+}
+
+int ff_mov_cenc_init(MOVMuxCencContext* ctx, uint8_t* encryption_key,
+ int use_subsamples, int bitexact)
+{
+ int ret;
+
+ ctx->aes_ctr = av_aes_ctr_alloc();
+ if (!ctx->aes_ctr) {
+ return AVERROR(ENOMEM);
+ }
+
+ ret = av_aes_ctr_init(ctx->aes_ctr, encryption_key);
+ if (ret != 0) {
+ return ret;
+ }
+
+ if (!bitexact) {
+ av_aes_ctr_set_random_iv(ctx->aes_ctr);
+ }
+
+ ctx->use_subsamples = use_subsamples;
+
+ return 0;
+}
+
+void ff_mov_cenc_free(MOVMuxCencContext* ctx)
+{
+ av_aes_ctr_free(ctx->aes_ctr);
+}
diff --git a/libavformat/movenccenc.h b/libavformat/movenccenc.h
new file mode 100644
index 0000000..6f9e70e
--- /dev/null
+++ b/libavformat/movenccenc.h
@@ -0,0 +1,86 @@
+/*
+ * MOV CENC (Common Encryption) writer
+ * Copyright (c) 2015 Eran Kornblau <erankor at gmail dot com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVFORMAT_MOVENCCENC_H
+#define AVFORMAT_MOVENCCENC_H
+
+#include "libavutil/aes_ctr.h"
+#include "avformat.h"
+#include "avio.h"
+
+#define CENC_KID_SIZE (16)
+
+struct MOVTrack;
+
+typedef struct {
+ struct AVAESCTR* aes_ctr;
+ uint8_t* auxiliary_info;
+ size_t auxiliary_info_size;
+ size_t auxiliary_info_alloc_size;
+ uint32_t auxiliary_info_entries;
+
+ /* subsample support */
+ int use_subsamples;
+ uint16_t subsample_count;
+ size_t auxiliary_info_subsample_start;
+ uint8_t* auxiliary_info_sizes;
+ size_t auxiliary_info_sizes_alloc_size;
+} MOVMuxCencContext;
+
+/**
+ * Initialize a CENC context
+ * @param key encryption key, must have a length of AES_CTR_KEY_SIZE
+ * @param use_subsamples when enabled parts of a packet can be encrypted, otherwise the whole packet is encrypted
+ */
+int ff_mov_cenc_init(MOVMuxCencContext* ctx, uint8_t* encryption_key, int use_subsamples, int bitexact);
+
+/**
+ * Free a CENC context
+ */
+void ff_mov_cenc_free(MOVMuxCencContext* ctx);
+
+/**
+ * Write a fully encrypted packet
+ */
+int ff_mov_cenc_write_packet(MOVMuxCencContext* ctx, AVIOContext *pb, const uint8_t *buf_in, int size);
+
+/**
+ * Parse AVC NAL units from annex B format, the nal size and type are written in the clear while the body is encrypted
+ */
+int ff_mov_cenc_avc_parse_nal_units(MOVMuxCencContext* ctx, AVIOContext *pb, const uint8_t *buf_in, int size);
+
+/**
+ * Write AVC NAL units that are in MP4 format, the nal size and type are written in the clear while the body is encrypted
+ */
+int ff_mov_cenc_avc_write_nal_units(AVFormatContext *s, MOVMuxCencContext* ctx, int nal_length_size,
+ AVIOContext *pb, const uint8_t *buf_in, int size);
+
+/**
+ * Write the cenc atoms that should reside inside stbl
+ */
+void ff_mov_cenc_write_stbl_atoms(MOVMuxCencContext* ctx, AVIOContext *pb);
+
+/**
+ * Write the sinf atom, contained inside stsd
+ */
+int ff_mov_cenc_write_sinf_tag(struct MOVTrack* track, AVIOContext *pb, uint8_t* kid);
+
+#endif /* AVFORMAT_MOVENCCENC_H */
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