Using Amazon CloudFront for SLDP delivery

Live streaming is growing these days and a lot of its use cases require sub-second delay between image capture and its display on user's device.
That includes online chatting, betting and bidding, gaming, security and surveillance - all of them demand real-time picture to make the immediate response.

With the decline of Flash and RTMP as the main way to view live streams, the industry has been looking for new ways to deliver the media close to real-time.

Softvelum has developed SLDP, a last-mile delivery protocol for end-user devices to cover real-time demand. It's key features are:

• Up to two-seconds delay between origin and player.
• Multiple codecs support: it can deliver whatever your end-user platform can play, e.g. H.264, VP8, VP9, H.265/HEVC.
• Adaptive bitrate support for delivering multiple resolutions and qualities.

Nimble Streamer software media server has full support for SLDP and its features. You can read this article to check how Nimble Streamer may take incoming live streams and produce SLDP based on that input.

SLDP playback is supported by SLDP Player. On Android and iOS, it's a native mobile application, while browser payback is covered by HTML5 JavaScript player working in any MSE-enabled browser. All three players can be customized via respective SDKs.

Playback session authorization in Nimble Streamer

Nimble Streamer paywall features provide a lot of ways of controlling the end-user connection including hotlink protection and pay-per-view which give advanced capabilities but require to sign the stream playback URL on your web page. Other features like geo-location and IP-range block, User-Agent and Referrer fields block require to be pre-configured via WMSPanel.

To give more flexibility, Nimble Streamer now supports sessions authorization via external handler to decide which of the connecting users may continue receiving the stream. The workflow is simple:

1. Player client software connects to Nimble Streamer instance via any stream URL.
2. Nimble Streamer keeps the connection and reaches the external handler, sending all details of this new session.
3. Handler returns response to define further behavior of Nimble Streamer.

Each response has its code in header and body:

• Code 200 response means the stream can be played by this client.
• Code 302 makes Nimble Streamer to redirect the client to a specified URL.
• Code 403 means that this user session is forbidden.

The supported protocols are as follows.

• Live streaming: HLS, MPEG-DASH, SLDP, Icecast and MPEG-TS.
• VOD streaming: HLS, MPEG-DASH and Progressive download.
• Cache-aware re-streaming: HLS, MPEG-DASH, HDS, SmoothStreaming and Progressive download.

Here's how you can use this.

Enable feature

To enable this playback authentication feature, you need to click Control -> API setup top menu. Then you may either go to Global push API tab to define setting for all sever or to Servers push API tab to define per-server setting.

Opening either of those you can scroll down to Auth handler URL section.

Auth handler URL field sets up the URL for your handler web application.

Protected apps is a list of applications to be protected with the handler. You can add or remove apps using removal icon and "Add protected app" link. If you don't specify exact names then all applications will be protected.

Concurrency defines a number of simultaneous requests to handler to perform at a time.

Allow by default defines if clients should be allowed in case authorization handler becomes unavailable.

Message for handler

Your handler needs to be a web application available via specified URL.

The following JSON message is sent by Nimble Streamer to this handler in POST request body:

{"host":"<host>", "url":"<stream URL>","ip":"<client IP>","user-agent": <User-Agent header> , "referer": <Referer header>, "session_id": <Nimble session ID> , "session_type": <protocol name>}

You can see the meaning of most fields' from the line above. The session_type field value may be one of the following: "HLS", "DASH", "HDS", "SMOOTH", "PD", "ICECAST", "MPEGTS" and "SLDP".

Response from handler

The handler needs to return a JSON with one of the following bodies.

Allow connection:

{"return_code":200}

This means that current client may start receiving the stream in this session.

Redirection:

{"return_code":302,"redirect_location":"http://127.0.0.1:8081/content/blocked.mp4/playlist.m3u8"}

This response body will make Nimble start streaming another stream instead of the one requested initially, i.e. this is a redirection. This is useful if you'd like to show some stub for un-authorized client or if a requested stream is not yet available.

Forbidden:

{"return_code":403}

This response means this stream is forbidden for this particular client session.

Example

Check an example of playback authorization handler which checks URL and prevents playback of chunklist.m3u8 and redirects to playlist.m3u8.

Another approach: set sessions via native direct API

You can also get sessions data and delete un-wanted connection using direct native HTTP API of Nimble Streamer. Read this article for more details.

Stay tuned for updates and let us know if you have any questions on this feature set.

Related documentation

Nimble Streamer paywall features, SLDP low latency streaming, Live streaming features, VOD features

DVR MP4 thumbnails in Nimble Streamer

Nimble Streamer software media server has it DVR feature set which covers the majority of use cases for streams recording and playback.

DVR setup is described in this article and you're probably already familiar with it. Now, to get snapshots of DVR stream, you may use direct URL described below.

Notice that thumbnails are generated as .mp4 files containing a single keyframe. This allows inserting thumbnail in any modern browser using <video> element.

If you'd like to generate JPG thumbnails, please read this article.

The latest thumbnail can be obtained using the following URL:

http://<server>/<app>/<stream>/dvr_thumbnail.mp4

If you'd like to get specific time spot, add epoch time:

http://<server>/<app>/<stream>/dvr_thumbnail_<utc>.mp4

E.g. http://serverip/live/stream/dvr_thumbnail_1542708934.mp4

This feature is enabled by default and if you'd like to disable it, use this parameter in Nimble Streamer config file:

dvr_thumbnails_enabled = false

MP4 output was chosen over PNG or JPG images due to resources usage. MP4 frame can be extracted and inserted into MP4 container with relatively small amount of CPU and RAM. Still image capture requires frame decoding and encoding into proper format which needs extra resources. Our customers like Nimble Streamer primarily because of its high performance and we'd like to keep it that way.

Take a look at this video tutorial to see MP4 thumbnails in action and get familiar with DVR most useful features.

Read other documentation articles for more details and full description of available options.

You may also find useful the API call for DVR archive export to MP4.

If you have any questions on this or other features, let us know.

Related documentation

Nimble Streamer, Live streaming scenarios, DVR feature set, DVR setup for Nimble Streamer, Usage snapshots

White Paper: Tools for tailor-made streaming

We're excited to announce our latest white paper published at Broadband TV News news web site.

It's called Softvelum: Tools for tailor-made streaming and you can download it by filling out the form on its webpage.


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