On Tue, Jan 2, 2018 at 9:57 AM, Jacob Trimble <modma...@google.com> wrote:
> On Wed, Dec 20, 2017 at 4:31 PM, wm4 <nfx...@googlemail.com> wrote:
>> On Wed, 20 Dec 2017 15:10:43 -0800
>> Jacob Trimble <modmaker-at-google....@ffmpeg.org> wrote:
>>
>>> From 1508d19e9f7acf43d76010ce54d59ff204613601 Mon Sep 17 00:00:00 2001
>>> From: Jacob Trimble <modma...@google.com>
>>> Date: Tue, 5 Dec 2017 14:52:22 -0800
>>> Subject: [PATCH] avcodec/avcodec.h: Add encryption info side data.
>>>
>>> This new side-data will contain info on how a packet is encrypted.
>>> This allows the app to handle packet decryption.
>>>
>>> Signed-off-by: Jacob Trimble <modma...@google.com>
>>> ---
>>
>> Looks generally good to me, a few minor cosmetic comments below.
>>
>>> libavcodec/Makefile | 2 +
>>> libavcodec/avcodec.h | 13 ++++
>>> libavcodec/encryption_info.c | 139
>>> +++++++++++++++++++++++++++++++++++++++++++
>>> libavcodec/encryption_info.h | 121 +++++++++++++++++++++++++++++++++++++
>>> 4 files changed, 275 insertions(+)
>>> create mode 100644 libavcodec/encryption_info.c
>>> create mode 100644 libavcodec/encryption_info.h
>>>
>>> diff --git a/libavcodec/Makefile b/libavcodec/Makefile
>>> index ab7893f560..11ad642c6c 100644
>>> --- a/libavcodec/Makefile
>>> +++ b/libavcodec/Makefile
>>> @@ -10,6 +10,7 @@ HEADERS = ac3_parser.h
>>> \
>>> dirac.h \
>>> dv_profile.h \
>>> dxva2.h \
>>> + encryption_info.h \
>>> jni.h \
>>> mediacodec.h \
>>> qsv.h \
>>> @@ -36,6 +37,7 @@ OBJS = ac3_parser.o
>>> \
>>> dirac.o \
>>> dv_profile.o \
>>> encode.o \
>>> + encryption_info.o \
>>> imgconvert.o \
>>> jni.o \
>>> mathtables.o \
>>> diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
>>> index 5db6a81320..b43638ebc5 100644
>>> --- a/libavcodec/avcodec.h
>>> +++ b/libavcodec/avcodec.h
>>> @@ -1327,6 +1327,19 @@ enum AVPacketSideDataType {
>>> */
>>> AV_PKT_DATA_A53_CC,
>>>
>>> + /**
>>> + * This side data is encryption "initialization data".
>>> + * For MP4 this is the entire 'pssh' box.
>>> + * For WebM this is the key ID.
>>> + */
>>> + AV_PKT_DATA_ENCRYPTION_INIT_DATA,
>>> +
>>> + /**
>>> + * This side data contains encryption info for how to decrypt the
>>> packet.
>>> + * The format is not part of ABI, use av_encryption_info_* methods to
>>> access.
>>> + */
>>> + AV_PKT_DATA_ENCRYPTION_INFO,
>>> +
>>> /**
>>> * The number of side data types.
>>> * This is not part of the public API/ABI in the sense that it may
>>> diff --git a/libavcodec/encryption_info.c b/libavcodec/encryption_info.c
>>> new file mode 100644
>>> index 0000000000..59ee4c41a9
>>> --- /dev/null
>>> +++ b/libavcodec/encryption_info.c
>>> @@ -0,0 +1,139 @@
>>> +/**
>>> + * 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 "encryption_info.h"
>>> +#include "libavutil/avassert.h"
>>> +#include "libavutil/intreadwrite.h"
>>> +
>>> +#define FF_ENCRYPTION_INFO_EXTRA 24
>>> +
>>> +// The format of the side data:
>>> +// u32be scheme
>>> +// u32be crypt_byte_block
>>> +// u32be skip_byte_block
>>> +// u32be key_id_size
>>> +// u32be iv_size
>>> +// u32be subsample_count
>>> +// u8[key_id_size] key_id
>>> +// u8[iv_size] iv
>>> +// {
>>> +// u32be bytes_of_clear_data
>>> +// u32be bytes_of_protected_data
>>> +// }[subsample_count]
>>> +
>>> +AVEncryptionInfo* av_encryption_info_alloc(uint32_t subsample_count,
>>> uint32_t key_id_size, uint32_t iv_size)
>>
>> I think we generally put the "*" to the name, to reflect the actual C
>> syntax. (Here and in other places where pointers are in the function
>> return or argument types.)
>>
>>> +{
>>> + AVEncryptionInfo *info;
>>> +
>>> + info = av_mallocz(sizeof(AVEncryptionInfo));
>>> + if (!info)
>>> + return NULL;
>>> +
>>> + info->key_id = av_mallocz(key_id_size);
>>> + info->key_id_size = key_id_size;
>>> + info->iv = av_mallocz(iv_size);
>>> + info->iv_size = iv_size;
>>> + info->subsamples = av_mallocz_array(sizeof(AVSubsampleEncryptionInfo),
>>> subsample_count);
>>> + info->subsample_count = subsample_count;
>>> +
>>> + // Allow info->subsamples to be NULL if there are no subsamples.
>>> + if (!info->key_id || !info->iv || (!info->subsamples &&
>>> subsample_count)) {
>>> + av_free(info->key_id);
>>> + av_free(info->iv);
>>> + av_free(info->subsamples);
>>
>> Couldn't this just call av_encryption_info_free()?
>>
>>> + av_freep(&info);
>>> + }
>>> +
>>> + return info;
>>> +}
>>> +
>>> +void av_encryption_info_free(AVEncryptionInfo* info)
>>> +{
>>> + if (info) {
>>> + av_free(info->key_id);
>>> + av_free(info->iv);
>>> + av_free(info->subsamples);
>>> + av_free(info);
>>> + }
>>> +}
>>> +
>>> +AVEncryptionInfo* av_encryption_info_copy_side_data(const AVPacket* packet)
>>
>> Could still be called "get" instead of "copy". I get the intention that
>> this returns a copy of the data, but "copy" still sounds like it's
>> being copied somewhere else. But I have no strong feelings about it.
>>
>>> +{
>>> + AVEncryptionInfo *info;
>>> + uint8_t *buffer;
>>> + unsigned int size;
>>> + uint32_t key_id_size, iv_size, subsample_count, i;
>>> +
>>> + buffer = av_packet_get_side_data(packet, AV_PKT_DATA_ENCRYPTION_INFO,
>>> &size);
>>> + if (!buffer)
>>> + return NULL;
>>> +
>>> + key_id_size = AV_RB32(buffer + 12);
>>> + iv_size = AV_RB32(buffer + 16);
>>> + subsample_count = AV_RB32(buffer + 20);
>>> +
>>> + info = av_encryption_info_alloc(subsample_count, key_id_size, iv_size);
>>> + if (!info)
>>> + return NULL;
>>> +
>>> + info->scheme = AV_RB32(buffer);
>>> + info->crypt_byte_block = AV_RB32(buffer + 4);
>>> + info->skip_byte_block = AV_RB32(buffer + 8);
>>> + memcpy(info->key_id, buffer + 24, key_id_size);
>>> + memcpy(info->iv, buffer + key_id_size + 24, iv_size);
>>> +
>>> + buffer += key_id_size + iv_size + 24;
>>> + for (i = 0; i < subsample_count; i++) {
>>> + info->subsamples[i].bytes_of_clear_data = AV_RB32(buffer);
>>> + info->subsamples[i].bytes_of_protected_data = AV_RB32(buffer + 4);
>>> + buffer += 8;
>>> + }
>>> +
>>> + return info;
>>> +}
>>> +
>>> +int av_encryption_info_add_side_data(AVPacket* packet, const
>>> AVEncryptionInfo* info) {
>>
>> We put the "{" on a separate line for functions.
>>
>>> + uint8_t *buffer;
>>> + size_t size;
>>> + uint32_t i;
>>> +
>>> + size = FF_ENCRYPTION_INFO_EXTRA + info->key_id_size + info->iv_size +
>>> + (sizeof(AVSubsampleEncryptionInfo) * info->subsample_count);
>>> + buffer = av_packet_new_side_data(packet, AV_PKT_DATA_ENCRYPTION_INFO,
>>> size);
>>> + if (!buffer)
>>> + return AVERROR(ENOMEM);
>>> +
>>> + AV_WB32(buffer, info->scheme);
>>> + AV_WB32(buffer + 4, info->crypt_byte_block);
>>> + AV_WB32(buffer + 8, info->skip_byte_block);
>>> + AV_WB32(buffer + 12, info->key_id_size);
>>> + AV_WB32(buffer + 16, info->iv_size);
>>> + AV_WB32(buffer + 20, info->subsample_count);
>>> + buffer += 24;
>>> + memcpy(buffer, info->key_id, info->key_id_size);
>>> + buffer += info->key_id_size;
>>> + memcpy(buffer, info->iv, info->iv_size);
>>> + buffer += info->iv_size;
>>> + for (i = 0; i < info->subsample_count; i++) {
>>> + AV_WB32(buffer, info->subsamples[i].bytes_of_clear_data);
>>> + AV_WB32(buffer + 4, info->subsamples[i].bytes_of_protected_data);
>>> + buffer += 8;
>>> + }
>>> +
>>> + return 0;
>>> +}
>>> diff --git a/libavcodec/encryption_info.h b/libavcodec/encryption_info.h
>>> new file mode 100644
>>> index 0000000000..4fc9b6d3f1
>>> --- /dev/null
>>> +++ b/libavcodec/encryption_info.h
>>> @@ -0,0 +1,121 @@
>>> +/**
>>> + * 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 AVUTIL_ENCRYPTION_INFO_H
>>> +#define AVUTIL_ENCRYPTION_INFO_H
>>> +
>>> +#include "avcodec.h"
>>> +
>>> +typedef struct AVSubsampleEncryptionInfo {
>>> + /** The number of bytes that are clear. */
>>> + unsigned int bytes_of_clear_data;
>>> +
>>> + /**
>>> + * The number of bytes that are protected. If using pattern
>>> encryption,
>>> + * the pattern applies to only the protected bytes; if not using
>>> pattern
>>> + * encryption, all these bytes are encrypted.
>>> + */
>>> + unsigned int bytes_of_protected_data;
>>> +} AVSubsampleEncryptionInfo;
>>> +
>>> +/**
>>> + * This describes encryption info for a packet. This contains
>>> frame-specific
>>> + * info for how to decrypt the packet before passing it to the decoder.
>>> + *
>>> + * The size of this struct is not part of the public ABI.
>>> + */
>>> +typedef struct AVEncryptionInfo {
>>> + /** The fourcc encryption scheme. */
>>> + uint32_t scheme;
>>> +
>>> + /**
>>> + * Only used for pattern encryption. This is the number of 16-byte
>>> blocks
>>> + * that are encrypted.
>>> + */
>>> + uint32_t crypt_byte_block;
>>> +
>>> + /**
>>> + * Only used for pattern encryption. This is the number of 16-byte
>>> blocks
>>> + * that are clear.
>>> + */
>>> + uint32_t skip_byte_block;
>>> +
>>> + /**
>>> + * The ID of the key used to encrypt the packet. This should always be
>>> + * 16 bytes long, but may be changed in the future.
>>> + */
>>> + uint8_t *key_id;
>>> + uint32_t key_id_size;
>>> +
>>> + /**
>>> + * The initialization vector. This may have been zero-filled to be the
>>> + * correct block size. This should always be 16 bytes long, but may be
>>> + * changed in the future.
>>> + */
>>> + uint8_t *iv;
>>> + uint32_t iv_size;
>>> +
>>> + /**
>>> + * An array of subsample encryption info specifying how parts of the
>>> sample
>>> + * are encrypted. If there are no subsamples, then the whole sample is
>>> + * encrypted.
>>> + */
>>> + AVSubsampleEncryptionInfo* subsamples;
>>> + uint32_t subsample_count;
>>> +} AVEncryptionInfo;
>>> +
>>> +/**
>>> + * Allocates an AVEncryptionInfo structure and sub-pointers to hold the
>>> given
>>> + * number of subsamples. This will allocate pointers for the key ID, IV,
>>> + * and subsample entries, set the size members, and zero-initialize the
>>> rest.
>>> + *
>>> + * @param subsample_count The number of subsamples.
>>> + * @param key_id_size The number of bytes in the key ID, should be 16.
>>> + * @param key_id_size The number of bytes in the IV, should be 16.
>>> + *
>>> + * @return The new AVEncryptionInfo structure, or NULL on error.
>>> + */
>>> +AVEncryptionInfo* av_encryption_info_alloc(uint32_t subsample_count,
>>> uint32_t key_id_size, uint32_t iv_size);
>>> +
>>> +/**
>>> + * Frees the given encryption info object. This MUST NOT be used to free
>>> the
>>> + * side-data data pointer, that should use normal side-data methods.
>>> + */
>>> +void av_encryption_info_free(AVEncryptionInfo* info);
>>> +
>>> +/**
>>> + * Creates a copy of the AVEncryptionInfo that is contained in the side
>>> data of
>>> + * the given packet. The resulting object should be passed to
>>> + * av_encryption_info_free() when done.
>>> + *
>>> + * This returns NULL if there is a memory error or if the packet isn't
>>> encrypted.
>>> + * To detect if the packet is encrypted, use av_packet_get_side_data.
>>> + *
>>> + * @return The new AVEncryptionInfo structure, or NULL on error.
>>> + */
>>> +AVEncryptionInfo* av_encryption_info_copy_side_data(const AVPacket*
>>> packet);
>>> +
>>> +/**
>>> + * Adds a new side data to the given packet that holds a copy of the given
>>> + * encryption info.
>>> + *
>>> + * @return 0 on success, or a negative error code on error.
>>> + */
>>> +int av_encryption_info_add_side_data(AVPacket* packet, const
>>> AVEncryptionInfo* info);
>>> +
>>> +#endif /* AVUTIL_ENCRYPTION_INFO_H */
>>
>> So as far as the side data management goes, this should be good. No
>> comment about the crypto stuff or the byte array (de)serialization
>> stuff, didn't take a close look at it. The final patch should also
>> include a minor libavutil bump and an doc/APIchanges entry,
>
> Leaving version bump and changelog entry to whoever pushes it, but
> other comments done.
Just noticed the new files were in libavcodec, moved to libavutil.
Can someone please review this so it can be pushed. I have the MP4
implementation ready and I would like to get that reviewed and pushed
as soon as possible.
Thanks.
From 758b2439e779045fbc82ca8cf91c7f71230e440b Mon Sep 17 00:00:00 2001
From: Jacob Trimble <modma...@google.com>
Date: Tue, 5 Dec 2017 14:52:22 -0800
Subject: [PATCH] avcodec/avcodec.h: Add encryption info side data.
This new side-data will contain info on how a packet is encrypted.
This allows the app to handle packet decryption.
Signed-off-by: Jacob Trimble <modma...@google.com>
---
libavcodec/avcodec.h | 13 +++++
libavutil/Makefile | 2 +
libavutil/encryption_info.c | 137 ++++++++++++++++++++++++++++++++++++++++++++
libavutil/encryption_info.h | 121 ++++++++++++++++++++++++++++++++++++++
4 files changed, 273 insertions(+)
create mode 100644 libavutil/encryption_info.c
create mode 100644 libavutil/encryption_info.h
diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index c13deb599f..e766f21ca0 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -1341,6 +1341,19 @@ enum AVPacketSideDataType {
*/
AV_PKT_DATA_A53_CC,
+ /**
+ * This side data is encryption "initialization data".
+ * For MP4 this is the entire 'pssh' box.
+ * For WebM this is the key ID.
+ */
+ AV_PKT_DATA_ENCRYPTION_INIT_DATA,
+
+ /**
+ * This side data contains encryption info for how to decrypt the packet.
+ * The format is not part of ABI, use av_encryption_info_* methods to access.
+ */
+ AV_PKT_DATA_ENCRYPTION_INFO,
+
/**
* The number of side data types.
* This is not part of the public API/ABI in the sense that it may
diff --git a/libavutil/Makefile b/libavutil/Makefile
index 66b894d66e..fed936df7b 100644
--- a/libavutil/Makefile
+++ b/libavutil/Makefile
@@ -24,6 +24,7 @@ HEADERS = adler32.h \
dict.h \
display.h \
downmix_info.h \
+ encryption_info.h \
error.h \
eval.h \
fifo.h \
@@ -107,6 +108,7 @@ OBJS = adler32.o \
dict.o \
display.o \
downmix_info.o \
+ encryption_info.o \
error.o \
eval.o \
fifo.o \
diff --git a/libavutil/encryption_info.c b/libavutil/encryption_info.c
new file mode 100644
index 0000000000..76796b50ee
--- /dev/null
+++ b/libavutil/encryption_info.c
@@ -0,0 +1,137 @@
+/**
+ * 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 "encryption_info.h"
+#include "libavutil/intreadwrite.h"
+
+#define FF_ENCRYPTION_INFO_EXTRA 24
+
+// The format of the side data:
+// u32be scheme
+// u32be crypt_byte_block
+// u32be skip_byte_block
+// u32be key_id_size
+// u32be iv_size
+// u32be subsample_count
+// u8[key_id_size] key_id
+// u8[iv_size] iv
+// {
+// u32be bytes_of_clear_data
+// u32be bytes_of_protected_data
+// }[subsample_count]
+
+AVEncryptionInfo *av_encryption_info_alloc(uint32_t subsample_count, uint32_t key_id_size, uint32_t iv_size)
+{
+ AVEncryptionInfo *info;
+
+ info = av_mallocz(sizeof(AVEncryptionInfo));
+ if (!info)
+ return NULL;
+
+ info->key_id = av_mallocz(key_id_size);
+ info->key_id_size = key_id_size;
+ info->iv = av_mallocz(iv_size);
+ info->iv_size = iv_size;
+ info->subsamples = av_mallocz_array(sizeof(AVSubsampleEncryptionInfo), subsample_count);
+ info->subsample_count = subsample_count;
+
+ // Allow info->subsamples to be NULL if there are no subsamples.
+ if (!info->key_id || !info->iv || (!info->subsamples && subsample_count)) {
+ av_encryption_info_free(info);
+ return NULL;
+ }
+
+ return info;
+}
+
+void av_encryption_info_free(AVEncryptionInfo *info)
+{
+ if (info) {
+ av_free(info->key_id);
+ av_free(info->iv);
+ av_free(info->subsamples);
+ av_free(info);
+ }
+}
+
+AVEncryptionInfo *av_encryption_info_get_side_data(const AVPacket *packet)
+{
+ AVEncryptionInfo *info;
+ uint8_t *buffer;
+ unsigned int size;
+ uint32_t key_id_size, iv_size, subsample_count, i;
+
+ buffer = av_packet_get_side_data(packet, AV_PKT_DATA_ENCRYPTION_INFO, &size);
+ if (!buffer)
+ return NULL;
+
+ key_id_size = AV_RB32(buffer + 12);
+ iv_size = AV_RB32(buffer + 16);
+ subsample_count = AV_RB32(buffer + 20);
+
+ info = av_encryption_info_alloc(subsample_count, key_id_size, iv_size);
+ if (!info)
+ return NULL;
+
+ info->scheme = AV_RB32(buffer);
+ info->crypt_byte_block = AV_RB32(buffer + 4);
+ info->skip_byte_block = AV_RB32(buffer + 8);
+ memcpy(info->key_id, buffer + 24, key_id_size);
+ memcpy(info->iv, buffer + key_id_size + 24, iv_size);
+
+ buffer += key_id_size + iv_size + 24;
+ for (i = 0; i < subsample_count; i++) {
+ info->subsamples[i].bytes_of_clear_data = AV_RB32(buffer);
+ info->subsamples[i].bytes_of_protected_data = AV_RB32(buffer + 4);
+ buffer += 8;
+ }
+
+ return info;
+}
+
+int av_encryption_info_add_side_data(AVPacket *packet, const AVEncryptionInfo *info)
+{
+ uint8_t *buffer;
+ size_t size;
+ uint32_t i;
+
+ size = FF_ENCRYPTION_INFO_EXTRA + info->key_id_size + info->iv_size +
+ (sizeof(AVSubsampleEncryptionInfo) * info->subsample_count);
+ buffer = av_packet_new_side_data(packet, AV_PKT_DATA_ENCRYPTION_INFO, size);
+ if (!buffer)
+ return AVERROR(ENOMEM);
+
+ AV_WB32(buffer, info->scheme);
+ AV_WB32(buffer + 4, info->crypt_byte_block);
+ AV_WB32(buffer + 8, info->skip_byte_block);
+ AV_WB32(buffer + 12, info->key_id_size);
+ AV_WB32(buffer + 16, info->iv_size);
+ AV_WB32(buffer + 20, info->subsample_count);
+ buffer += 24;
+ memcpy(buffer, info->key_id, info->key_id_size);
+ buffer += info->key_id_size;
+ memcpy(buffer, info->iv, info->iv_size);
+ buffer += info->iv_size;
+ for (i = 0; i < info->subsample_count; i++) {
+ AV_WB32(buffer, info->subsamples[i].bytes_of_clear_data);
+ AV_WB32(buffer + 4, info->subsamples[i].bytes_of_protected_data);
+ buffer += 8;
+ }
+
+ return 0;
+}
diff --git a/libavutil/encryption_info.h b/libavutil/encryption_info.h
new file mode 100644
index 0000000000..6c2eee80f6
--- /dev/null
+++ b/libavutil/encryption_info.h
@@ -0,0 +1,121 @@
+/**
+ * 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 AVUTIL_ENCRYPTION_INFO_H
+#define AVUTIL_ENCRYPTION_INFO_H
+
+#include "libavcodec/avcodec.h"
+
+typedef struct AVSubsampleEncryptionInfo {
+ /** The number of bytes that are clear. */
+ unsigned int bytes_of_clear_data;
+
+ /**
+ * The number of bytes that are protected. If using pattern encryption,
+ * the pattern applies to only the protected bytes; if not using pattern
+ * encryption, all these bytes are encrypted.
+ */
+ unsigned int bytes_of_protected_data;
+} AVSubsampleEncryptionInfo;
+
+/**
+ * This describes encryption info for a packet. This contains frame-specific
+ * info for how to decrypt the packet before passing it to the decoder.
+ *
+ * The size of this struct is not part of the public ABI.
+ */
+typedef struct AVEncryptionInfo {
+ /** The fourcc encryption scheme. */
+ uint32_t scheme;
+
+ /**
+ * Only used for pattern encryption. This is the number of 16-byte blocks
+ * that are encrypted.
+ */
+ uint32_t crypt_byte_block;
+
+ /**
+ * Only used for pattern encryption. This is the number of 16-byte blocks
+ * that are clear.
+ */
+ uint32_t skip_byte_block;
+
+ /**
+ * The ID of the key used to encrypt the packet. This should always be
+ * 16 bytes long, but may be changed in the future.
+ */
+ uint8_t *key_id;
+ uint32_t key_id_size;
+
+ /**
+ * The initialization vector. This may have been zero-filled to be the
+ * correct block size. This should always be 16 bytes long, but may be
+ * changed in the future.
+ */
+ uint8_t *iv;
+ uint32_t iv_size;
+
+ /**
+ * An array of subsample encryption info specifying how parts of the sample
+ * are encrypted. If there are no subsamples, then the whole sample is
+ * encrypted.
+ */
+ AVSubsampleEncryptionInfo *subsamples;
+ uint32_t subsample_count;
+} AVEncryptionInfo;
+
+/**
+ * Allocates an AVEncryptionInfo structure and sub-pointers to hold the given
+ * number of subsamples. This will allocate pointers for the key ID, IV,
+ * and subsample entries, set the size members, and zero-initialize the rest.
+ *
+ * @param subsample_count The number of subsamples.
+ * @param key_id_size The number of bytes in the key ID, should be 16.
+ * @param key_id_size The number of bytes in the IV, should be 16.
+ *
+ * @return The new AVEncryptionInfo structure, or NULL on error.
+ */
+AVEncryptionInfo *av_encryption_info_alloc(uint32_t subsample_count, uint32_t key_id_size, uint32_t iv_size);
+
+/**
+ * Frees the given encryption info object. This MUST NOT be used to free the
+ * side-data data pointer, that should use normal side-data methods.
+ */
+void av_encryption_info_free(AVEncryptionInfo *info);
+
+/**
+ * Creates a copy of the AVEncryptionInfo that is contained in the side data of
+ * the given packet. The resulting object should be passed to
+ * av_encryption_info_free() when done.
+ *
+ * This returns NULL if there is a memory error or if the packet isn't encrypted.
+ * To detect if the packet is encrypted, use av_packet_get_side_data.
+ *
+ * @return The new AVEncryptionInfo structure, or NULL on error.
+ */
+AVEncryptionInfo *av_encryption_info_get_side_data(const AVPacket *packet);
+
+/**
+ * Adds a new side data to the given packet that holds a copy of the given
+ * encryption info.
+ *
+ * @return 0 on success, or a negative error code on error.
+ */
+int av_encryption_info_add_side_data(AVPacket *packet, const AVEncryptionInfo *info);
+
+#endif /* AVUTIL_ENCRYPTION_INFO_H */
--
2.16.0.rc0.223.g4a4ac83678-goog
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