PJSIP is an Open Source Embedded SIP protocol stack written in C.

PJSIP

PJSIP is an Open Source Embedded SIP protocol stack written in C.

The development of PJSIP is mainly focused on having a small footprint, modular, and very portable SIP stack for embedded development purposes (although it’s perfectly good for Win32/Linux/MacOS as well). Some of the characteristics of PJSIP:

• it is built on top of PJLIB, and since PJLIB is a very very portable library, basically PJSIP can run on any platforms where PJLIB is ported (including platforms where normally it would be hard to port existing programs to, such as Symbian and some custom OSes).
• it has quite a small footprint, although probably it’s not the smallest SIP stack on the planet (the smallest SIP stack would be a stack that does nothing!),
• it is quite customizable and modular, meaning that features that are not needed won’t get linked into the executable,
• it has pretty good performance (thousands of calls per second), and
• it has quite a lot of SIP features.

A high-level SIP multimedia user agent API is available for both C and Python language.

Links

• PJSIP – SIP Stack Features
• PJSIP – Open Source SIP Stack
• PJSUA – Console Based SIP User Agent
• PJMEDIA – Small footprint media stack
• PJSIP-JNI – A Java wrapper for the PJSIP library
• Open Source VOIP Software

https://www.pjsip.org/

https://github.com/pjsip/pjproject


New: Video codec VP8 & VP9!

PJSIP is a free and open source multimedia communication library written in C language implementing standard based protocols such as SIP, SDP, RTP, STUN, TURN, and ICE. It combines signaling protocol (SIP) with rich multimedia framework and NAT traversal functionality into high level API that is portable and suitable for almost any type of systems ranging from desktops, embedded systems, to mobile handsets.

PJSIP is both compact and feature rich. It supports audio, video, presence, and instant messaging, and has extensive documentation. PJSIP is very portable. On mobile devices, it abstracts system dependent features and in many cases is able to utilize the native multimedia capabilities of the device.

Learning VoIP, RTP and SIP (aka awesome pjsip) @ Medium.com


https://stackoverflow.com/questions/tagged/pjsip


This is interesting
Debugging SIP message traffic with PJSIP History

The Continuing Evolution of Video Codecs

From a LinkedIn discussion in HEVC / H.265.

Sinan Othman, Ph.D. Said:  

The current dominant codec for Internet video is H.264, but there are influential companies dedicated to alternatives. With the advent of 4K (aka Ultra HD), new codecs will be useful. H.265 (aka HEVC) and VP9 could split the market.

While commenting on: 

The Continuing Evolution of Video Codecs

http://www.cedmagazine.com/articles/2014/07/the-continuing-evolution-of-video-codecs

HEVC, H.265, H.264, UHD, UHDTV, VP9, 4K, U;tra HD

Google Finishes Defining Its VP9 Video Codec, Adds it to Chromium

http://thenextweb.com/google/2013/06/17/google-finishes-defining-its-vp9-video-codec-adds-it-to-chromium-ahead-of-chrome-and-youtube-rollout/

Last month, Google revealed that it was planning to finish defining its VP9 video codec on June 17 (today), after which it will start using the next-generation compression technology in Chrome and on YouTube. The company is wasting no time: it has already enabled the free video compression standard by default in the latest Chromium build.

The addition was first noted by developer and Google open-source Chromium evangelist François Beaufort. He points to a Chromium code review with the following short but succinct description: “Remove VP9 flag, and enable VP9 support by default.”

VP9 is the successor to VP8, both of which fall under Google’s WebM project of freeing Web codecs from royalty constraints. Despite the fact that Google unveiled WebM three years ago at its I/O conference, VP8 is still rarely used when compared to H.264, today’s most popular video codec.

As Beaufort explains, the main advantage of VP9 for users is that it’s 50 percent more efficient than H.264, meaning that you’ll use half the bandwidth on average when watching a video on the internet. Yet that doesn’t take H.265 into account, the successor to H.264 that offers comparable video quality at half the number of bits per second and also requires its implementers to pay patent royalties.

Although VP9 transmits video more efficiently than its predecessor, VP8 still saw patent-infringement claims from Nokia, and there’s no reason to assume VP9 won’t as well. Presumably, Google has learned and will make an effort to avoid such problems again, especially given that VP9 is meant to become part of WebRTC, an open project that lets users communicate in real-time via voice and video sans plugins, later this year.

As for its own products, Google has previously said it wants to build VP9 into Chrome, and today’s Chromium integration shows the company is putting its money where its mouth is. Furthermore, YouTube said last month it plans to add support for VP9 once the video codec lands in Chrome.

Chromium is the open source Web browser project that shares much of the same code as Google Chrome, and new features are often added there first. It’s not clear when VP9 will land in Chrome, but we’d wager it’s likely to trickle into the various channels during the next few months and arrive in the stable release by default before the end of the year.