Multimedia

Multimedia

Multimedia 101

Utilizing the right streaming protocol for your business can translate into a more efficient method to increase profits by communicating more effectively. Streaming media usage has grown exponentially over the past few years, utilized not only for entertainment purposes but as a powerful vehicle for organizations to market, sell, and support their products and services, as well as for internal communications and training. Streaming media, provided by a streaming provider, can be broadcast live or through video. In live streaming, the media is broadcast live over the internet, utilizing a camera for the media, an encoder to digitize the content, a media publisher and a content delivery network to distribute and deliver the content. The audience can then view the media live. The iPad and HTML5 have accelerated the demand for understanding and creating the underlying technology of digital video. Besides the inevitable codecs (H264 & VP8), experts are discussing video delivery mechanisms, using indecipherable acronyms like RTMP, CDN and HLS. This blog post will give an overview of the various video streaming methods in plain English and bring the all-round developer and publisher up to date. In a nutshell, there are three widely used ways to stream a video: Progressive Download, RTMP/RTSP Streaming, and Adaptive HTTP Streaming. We'll look at the three in detail here, describing their pros, cons, and various technologies that support each. Please Note: more streaming methods exsit (as multicast and peer to peer), but are not widely.

Progressive Download

Progressive Download is the most widely used video delivery method by far (in part because it's whatYouTube uses). It's also easiest to implement: just put a video on your webserver and point your player to the URL. Once a user hits play, the player immediately starts downloading the file. The player will start video playback as soon as it has enough data to do so, but it will continue to download until it has received the whole file (hence the progressive). Progressive Download is supported by Flash, HTML5 browsers, the iPad/iPhone and Android. On the server side, every regular webhoster supports downloads, as does every CDN (Content Delivery Network; webhosters that specialize in large-scale delivery). In most cases (Flash needs a small server module), it is possible to seek in a player to a not-yet-downloaded part of the video. At that point, the player re-downloads the video, starting at the seek offset instead of at the beginning. We call that feature pseudo-streaming. The simplicity of Progressive Download also has its downsides. For one, bandwidth is wasted on data downloaded but not watched. Consider a user watching a ten minute video. They may leave the page after having watched only one minute of the video, but at that point the other nine minutes have already been downloaded. This means that the publisher has paid to transfer nine times as much data as the user actually watched - an expensive proposition on a large scale. Another downside is the inability to change the quality of the video mid-stream: once the download starts, the video quality is locked. After switching a player to fullscreen, you generally see a blurry video, because it was intended to be watched at a much smaller size. Or, when you watch video on an iPad, your connection may switch from WiFi to 3G. Playback then stutters, because the download speeds are much lower on 3G. In sum, Progressive Download works fine for short clips (a few minutes). For longer videos, the downside starts to impact playback too much. Plus, live streaming is not possible, as there's no downloadable file. RTSP/RTMP Streaming. Because of the downside of Progressive Download, RTMP/RTSP Streaming is widely used by professional media organizations like Hulu. This method uses specialized webservers that only deliver the frames of a video the user is currently watching. No data is downloaded in advance and the data a user has seen is immediately discarded. The most widely accepted solution is RTMP (Real Time Messaging Protocol), the streaming protocol of Flash. It is supported by servers such as FMS and Wowza and most CDNs (but not by regular webhosters). HTML5 does not include a dedicated streaming protocol, nor does the iPad/iPhone. Android has support, for RTSP (Real Time Streaming Protocol). Unfortunately, RTSP is not widely supported by servers and CDNs. This lack of support, especially on the server side, is the biggest drawback of RTMP/RTSP Streaming. Most publishers do not want to maintain expensive, dedicated servers to stream their videos. Additionally, the dedicated protocols (RTMP and RTSP) are often blocked by corporate firewalls. On the plus side, RTMP streaming can change video quality mid-stream. This allows for optimal playback quality in the fullscreen and WiFi/3G scenarios described above. However, if the connection speed drops below the minimum bandwidth needed for the video, playback will be continuously interrupted. Unlike progressive download, users cannot pause a video and wait for enough data to download to ensure smooth playback. In sum, RTMP/RTSP Streaming works great even for long-form or live video. It has specific server and protocol requirements, which makes it less accessible and adds significant complexity and cost as compared to Progressive Download.

RTSP/RTMP Streaming

Because of the downsides of Progressive Download, RTMP/RTSP Streaming is widely used by professional media organizations like Hulu. This method uses specialized webservers that only deliver the frames of a video the user is currently watching. No data is downloaded in advance and data a user has seen is immediately discarded. The preferred solution is RTMP (Real Time Messaging Protocol), the streaming protocol of Flash. It is supported by servers such as FMS and Wowza and most CDNs (but not by regular webhosters). HTML5 does not include a dedicated streaming protocol, nor does the iPad/iPhone. Android has support, for RTSP (Real Time Streaming Protocol). Unfortunately, at this time RTSP is not widely supported by servers and CDNs. This lack of support, especially on the server side, is the biggest drawback of RTMP/RTSP Streaming. Most publishers do not want to maintain expensive, dedicated servers to stream their videos. Additionally, the dedicated protocols (RTMP and RTSP) are often blocked by corporate firewalls. On the plus side, RTMP streaming can change video quality mid-stream. This allows for optimal playback quality in the fullscreen and WiFi/3G scenarios described above. However, if the connection speed drops below the minimum bandwidth needed for the video, playback will be continuously interrupted. Unlike progressive download, users cannot pause a video and wait for enough data to download to ensure smooth playback. In sum, RTMP/RTSP Streaming works great even for long-form or live video. It has specific server and protocol requirements, which makes it less accessible and adds significant complexity and cost as compared to Progressive Download.

Adaptive HTTP

Adaptive HTTP Streaming, a recent addition to the streaming format is a hybrid of the RTMP/RTSP Streaming (bandwidth efficiency, quality switching) and Progressive Download (no special servers or protocol needed). Adaptive HTTP Streaming stores your videos on the server in small fragments (a few seconds each). The player then glues these fragments together into a continuous stream. Adaptive HTTP Streaming is supported by both Flash and the iPad/iPhone. Android supports it as of version 3 and support in HTML5 is currently under development. Since Adaptive HTTP Streaming leverages standard webservers, it is supported by webhosters and CDNs alike. Although Adaptive HTTP Streaming eliminates many of the downsides of RTMP/RTSP Streaming and Progressive Download, it still has issues of its own, the biggest being the lack of standardization. Because it is a new technology, there is no single, widely used implementation. The most popular is currently Apple's HLS (HTTP Live Streaming), which is supported by the iPad/iPhone and Android 3.0. However, both Adobe and Microsoft have competing offerings (Zeri & Smooth) and the MPEG consortium is working on a standard named DASH. It's also worth noting that none of the Adaptive HTTP Streaming implementations work with regular MP4 files. They all require your files to be converted from a regular MP4 into a specific fragmented format. Apple, Microsoft and Adobe each supply a tool for this, but support for these formats doesn't exist in regular video editors and transcoding tools (yet).

In summary, while Adaptive HTTP Streaming will likely become the single video streaming method over time, the technology is still fragmented (no pun intended) and ecosystem support is only beginning to arrive.

In short, utilizing the right streaming protocol for your business can translate into a more efficient method to increase profits by communicating more effectively.

How your internet connection effects your viewing and why type and size matters

When watching a video or live broadcast, the browser needs to be able to receive all video data in a rate which is equal to or higher than the streaming speed. A raw video file as AVI will need an enormous bandwidth; in other words you need to have a high speed internet that will be equal to or greater than the streaming rate of an AVI file. To achieve a decent quality, while keeping the bandwidth relatively low, a video and audio compression is used. For instance, with video compression (H264) and audio compression (CODEC) we can stream a nice quality video in a 320 by 240 pixels window with a 29 frames per seconds. To watch this video live, a user will need a bandwidth of about 350 bps (bits per seconds), which is about half the speed than a DSL line from Verizon or a competitive company can provide. Please note: When your bandwidth (Internet Speed) is lower than the streaming rate of the required bandwidth, your browser will buffer the data and play the movie in delayed time.

When a compression is deployed, the following table should reflect file size and bit rate needed to stream a desired size window.

Video file format:

.avi

Short for audio/video interleaved. Originally developed as a rival to Quicktime format for Windows machines but will be playable on most computers via helpers and plug ins. It can use several compression schemes and is becoming increasingly popular. Most digital video cameras shoot in .avi format

 

.mov

These file types are based on the Quicktime (QT) system. Its designed initially for the Mac platform but is now usable via a plugin and helper application on most other operating systems. You can load the standard quicktime player™ from Apple for free as well as get access to a host of resources. QT has some great compression schemes which often make QT files smaller without loss of quality.

It can also be streamed

 

.mpeg

This format takes it's name from the developing group (motion Pictures Expert Group). Remains an important web video file type due to the range of compression that can be applied. Unlike avi and Qucktime not developed for a particular operating system
http://www.mpeg.org/ can provide more info

 

 

.wmv

Windows Media Video.
Part of Microsoft's windows media format, a comparatively new all singing and dancing media format but as you can guess has Microsoft's resources behind it. It benefits from jumps in compression technology and has the weight of Microsoft behind it. WMV files can be downloaded or streamed. Microsoft have tons of resources at: < br /> http://www.microsoft.com/windows/windowsmedia/default.asp many of which are free to download.
.wmv files can also be streamed

.rm

RealVideo® files.
These are the archetypial streamed video files. Good examples can be seen in action on the BBC news site at http://news.bbc.co.uk/). One of the first and still most popular streamed media format. The basic player can still be downloaded for free at http://www.real.com/. You can also use the files as non streamed format, but they are not so well designed for that

But for more details about creating .rm files visit the Real networks site athttp://www.realnetworks.com/ they have a host of free resources.

 

.flv

The FLV file type is primarily associated with 'Flash' by Adobe Systems Incorporated.

Adobe Flash, initially known as Shockwave Flash and popularly called simply Flash, refers to both the Adobe Flash Player and to the Adobe Flash Professional multimedia authoring program.

The Flash Player, developed and distributed by Adobe Systems (which acquired Macromedia in a merger that was finalized in December 2005), is a client application available in most common Web browsers.

Among other uses, if you obtain a video from YouTube it will likely have the .FLV file extension and be a Flash Video File.

What is Live Web Cast

Live Web cast is when data is streamed from a video camera to a media server. The media server is then feeding the stream to viewers in real time.

Live Web Cast 101

Live Web cast requires a stable and committed bandwidth. To watch a live web cast in a 320 by 240 window with no interruptions, a DSL internet connection with download speed of 350 kbs (kilo bits per seconds) or higher is sufficient.

The web cast server needs to be on a high speed network to accommodate a feed to all potential users; For the example above (Live web cast in a 320 by 240 window and 29 frames per seconds) a server on a 100 mb (mega bit per second) network can support up to 285 clients watching the Live web. A server on a 1000 mb network can accommodate 2850 clients or virewers.

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