For each encrypted stream type a protected block is identified, over which the protection process is performed. A protected block of audio is typically an audio frame; H. CBC occurs within each protected block, and the initialization vector IV must be reset to its original value at the start of each new protected block.
NAL units of type 1 and type 5 must be encrypted to this specification; other NAL unit types must not be encrypted.
Listing shows the format of a NAL unit that contains encrypted data. Each NAL unit is formed with start code emulation prevention applied. The preceding start code is not part of the protected block and is not encrypted. The contiguous data that follows the unencrypted bytes is a protected block. Any protected block with a length of 16 bytes or fewer has no encryption applied; therefore, a NAL unit with length of 48 bytes or fewer is completely unencrypted.
Each byte block of encrypted data is followed by up to nine byte blocks of unencrypted data. To encrypt an H.
NAL types 1 and 5 with lengths greater than 48 bytes must be protected as defined above.
How to make Token authorized AES encrypted HLS stream working in Safari
To decrypt an H. The resulting bitstream can then be processed by a standard H. The ADTS header, which can be 7 or 9 bytes long, plus the first 16 bytes of the frame after it, are unencrypted. The contiguous data section that follows is encrypted. The size, in bytes, of the encrypted section must be an integer multiple of 16 and is possibly zero.
The AAC frame ends with 0 to 15 unencrypted bytes. Start code emulation prevention is not performed on the encrypted frame. An AC-3 protected frame is the full audio frame, a syncframeas shown in Listing The first 16 bytes, starting with the syncframe header, are not encrypted. The AC-3 frame ends with 0 to 15 unencrypted bytes. Start code emulation prevention is not performed on the encrypted part of the frame.
An Enhanced AC-3 protected block is a single syncframe. The IV is reset at the beginning of each audio frame. The audio setup information must be supplied when a stream is encrypted in conformance with this specification. The big-endian setup information format is shown in Listing The setup information must be packed, with no alignment padding. The size of the setup information is 8 bytes plus the size of the format-specific data.
If a non-Apple encoder is used and does not provide a priming value, set to 0x This comprises the syncinfo structure and the initial part of the bsi structure, as defined in 5. Size and BoxHeader. In elementary streams the audio setup information is carried inside an ID3 Private Frame, as defined in ID3 tag version 2.
The owner identifier is com.GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together. Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
Already on GitHub? Sign in to your account. Hardest part about this will be to come up with an AES cipher lib that doesn't weigh KB :D If it does this code should maybe be loaded on-demand - at least that should be an option :D.
I can send You my file version with my changes and my comments. There is hls. I did changes in the previous hls. When You like my changes and put it to Your code, please, make new test distro and share it with me. But I have problem with audio. When I play hls stream not cryptedafter few minutes audio desynch with video.
Audio is playing early then video. I can not find where is the problem This will also install npm which is the dependency management tool around which this build pipeline is made. Check the readme file for details. I want use this hls. I got already something here that does it for MP3, but will want to integrate it with the current architecture.
But now I have BIG problem with stability of playing hls stream. If hls playing will not stable I have to looking for another solution. I want fix the playing issue, because I like this hls. Finally I found the stability issue and I fixed it. How can I put my changes to git? It is only 4 new lines. May I create new issue with describe of issue and solution?HLS is developed by Apple, which forms the biggest use case for the streaming protocol. Indeed, HLS can be used as a streaming protocol for all major browsers, including Chrome and Firefox.
The AES is the only publicly available security algorithm that is used by the NSA for encrypting its top-secret classified information.
Until aboutFlash was the most popular video streaming application. It was supported by all desktop browsers. Because Flash utilized the same runtime across all browsers, it meant that video streamers did not have to create separate workflows for different devices. DRM and encryption were also supported by Flash. Flash was however plagued by security issues. Video playback on Flash was processor-intensive, which caused mobile batteries to drain very fast.
Apple created its own specifications for video streaming, which could be used for both live streaming and for pre-recorded video streaming. Android OS followed suit by blocking flash playback from browsers on Android. In plain vanilla HTML5 video streaming, only a single video file is available for streaming. The download of the complete video file is initiated every time the stream is played. Even if a viewer watches only 2 minutes of a 30 minute video, the full video would be downloaded, causing data wastage at both the server and the user end.
Streaming protocols remove this inefficiency in video streaming. Streaming protocols such as HLS effectively break down a video file into multiple chunks when streaming, and these video files are downloaded over HTTP in succession. HLS streaming uses the same workflow for both live and for on-demand content.
The core idea in multi-bitrate streaming is that multiple renditions of each video, of varying resolution, are encoded. High resolution videos are delivered to large screen devices having high network bandwidth, whereas lower resolution videos are encoded for mobile phones. Encoding for low resolutions also ensures continuous video streaming when the network connection speed drops.
When the user decides to change video resolution, or when the network bandwidth changes, video streams can be manually or automatically switched.However, as we know, Safari handles HLS playlist and key retrieval within the native stack and there is no easy way for developers to intercept the key request and add in Token into the 2nd level HLS Playlist. Here is a proposed solution if you do some magic on your authentication module to make this work. Below is an diagram to illustrate how this solution works:.
Customer sends request to your authentication system with video ID. Azure Media Services will return the top Playlist to the Authentication system. The top playlist looks like this:. Modify the top playlist, so the player Safari in this case will ping proxy server instead of our key services directly, and add token into the playlist.
Here is the way how top playlist is modified:. In the example above, you need to put in an absolute path in URI otherwise, the request will come back Auth server :. Since we changed the playlist to point to our proxy server, the request will come to proxy server 6. Our proxy server will receive the 2nd level playlist request.
And append the token within this 2nd level Playlist. So the returned playlist looks like this:. Since a token is embedded as a parameter, our key service could authorize the request and give player the AES key. Please feel free to reach out if you have any questions! Below is an diagram to illustrate how this solution works: Explanation for each step: 1.
Our key services accept token as parameter in the key request 5.With the increase of piracy, protecting media content is one of the key concerns of many publishers. AES encryption has been present in the HLS specification from the first draft of the protocol, putting content protection high on the priority list. In fact, there are two encryption schemes which are supported by HLS:. With this encryption level, the stream container is not fully encrypted.
Also, how the encrypted samples are encapsulated, depends on the media format of the segment. This method is also often the easiest to achieve using standard streaming servers and tools.
In order to understand this, let's look at what AES-encryption really is. AES is a symmetric encryption algorithm. It was designed to be efficient in both hardware and software. The algorithm is used worldwide and was adopted as the standard encryption algorithm by the U.
Dealing with DRM - Understanding DRM and How to Produce Protected Content
In general, it might be safe to say this level of AES encryption will not be broken soon. The AES encryption itself can be declared safe.
They deem key protection essential and often employ very obscure or complex schemes to retrieve decryption keys. With AES content protection, key retrieval has been kept simplemaking it easy to implement. It also leaves plenty of freedom to make key protection as simple or advanced as possible. The HLS specification mentions only one aspect of key retrieval: the URL from which the key can be loaded should be a part of the manifest file.
Protecting this resource is up to the publisher itself. It does not provide a high level of security as the URL might leak or could be intercepted on the network. This allows the key server to check which user is requesting the key. If the user is not allowed to access the stream, the key will not be returned.
As a result, only users which have proper authentication will receive the decryption key. A user-specific manifest will then contain a link to the decryption key, containing an authentication token. The server can then check the authentication token and determine if the key can be accessed, or not. It is now of course the question how AES encryption can be used in practice.
This tag signals the URL to the decryption key. It should be placed before the first segment, which is encrypted with the given key. There are two extremes in which this tag can occur:. One time on top of the manifest. This means all segments are encrypted with the same decryption key. In case the decryption key is intercepted, the entire stream can be decrypted.
Before each segment with a different URL. This approach allows you to encrypt each segment with a different key. Between these two extremes, you are free to choose your own frequency of refreshing the encryption keys. Below you can find an example manifest which rotates the encryption key every two segments:. Don't hesitate to let us know.
Our team of experts will be glad to help you. Click the button to go to our dedicated AES demo page. Universal Video Player. High Efficiency Streaming Protocol. Your browser does not support the video tag.This article describes some of the methods for controlling encryption for HLS streaming.
For some of the protection schemes, the API supports multiple protection schemes as well as key rotation.
You can encrypt live and on-demand on the fly by using key files. Key files are text files that have a file name that's the same as the name of the stream you're playing and a. The naming convention is similar for an on-demand stream. To protect the stream sample. Similar to the key files that are described in the previous section, you can protect HLS streams by passing key data to a Wowza Streaming Engine server through the server-side API.
You can do this in Wowza Streaming Engine Manager or by using a text editor. The following methods, when added to a server-side module, are called each time a live or on-demand HLS chunk is created, giving you the opportunity to control how that chunk is encrypted:.
Wowza Streaming Engine doesn't include key server delivery features. It has some basic features for AES key delivery; however, these features are provided only for convenience. The following options are available for key delivery. Contact sales wowza. If you need immediate help for an urgent issue, open a support ticket to get help from one of our technical support engineers.Encrypt & Decrypt File AES 128 PHP Demo
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Wowza ClearCaster. Wowza GoCoder app. Wowza Player. Wowza workflows. Start building. Discover SDKs. General examples. Connect a source.This document describes the supported formats muxers and demuxers provided by the libavformat library. The libavformat library provides some generic global options, which can be set on all the muxers and demuxers.
In addition each muxer or demuxer may support so-called private options, which are specific for that component.
Set probing size in bytes, i. A higher value will enable detecting more information in case it is dispersed into the stream, but will increase latency. Must be an integer not lesser than It is by default. Only write platform- build- and time-independent data. This ensures that file and data checksums are reproducible and match between platforms. Its primary use is for regression testing. Stop muxing at the end of the shortest stream.
Specify how many microseconds are analyzed to probe the input. A higher value will enable detecting more accurate information, but will increase latency.
Set error detection flags. Set maximum buffering duration for interleaving. The duration is expressed in microseconds, and defaults to 10 seconds. To ensure all the streams are interleaved correctly, libavformat will wait until it has at least one packet for each stream before actually writing any packets to the output file. When some streams are "sparse" i. This field specifies the maximum difference between the timestamps of the first and the last packet in the muxing queue, above which libavformat will output a packet regardless of whether it has queued a packet for all the streams.
If set to 0, libavformat will continue buffering packets until it has a packet for each stream, regardless of the maximum timestamp difference between the buffered packets.
Shift timestamps to make them non-negative.
Use AES-128 dynamic encryption and the key delivery service
Also note that this affects only leading negative timestamps, and not non-monotonic negative timestamps. When shifting is enabled, all output timestamps are shifted by the same amount. Audio, video, and subtitles desynching and relative timestamp differences are preserved compared to how they would have been without shifting. Default is -1 autowhich means that the underlying protocol will decide, 1 enables it, and has the effect of reducing the latency, 0 disables it and may increase IO throughput in some cases.
Specifying a positive offset means that the corresponding streams are delayed bt the time duration specified in offset. Default value is 0 meaning that no offset is applied. Separator used to separate the fields printed on the command line about the Stream parameters.