General streaming media FAQ
What is streaming video or audio?
Streaming video or audio is video (as on television) or sound (as on the radio) delivered over the Internet via a modem or broadband connection.
Why is it called "streaming"?
It's called "streaming" because the sound and picture data flow in a digital stream from a server computer to your computer, ready to hear or view in real time, without having to download all of the content before you can enjoy it. It comes to you in a stream of digital bits... hence the term "streaming."
What kinds of streaming audio or video are there?
There are 5 main streaming media companies (with their media streams):
- Adobe/Macromedia (with Flash/Shockwave)
- Microsoft (with Windows Media - audio and video)
- Apple (with QuickTime)
- Real Networks (with RealMedia, RealVideo and RealAudio)
- Nullsoft Streaming Video (.nsv) and Shoutcast, IceCast (GNU GPL/Open Source version of Shoutcast), Live365 streaming audio
The first three provide streaming media players for the Mac and Windows platforms. All these companies provide "basic" free players. Some of them also have optional "plus" players that offer extra features - at extra cost.
What difference does it make if content is streamed, rather than downloaded?
Audio and video files can be very large. You would spend many minutes or even hours waiting for them to be downloaded to your computer if they weren't streamed. Streaming media technology allows you to see or hear the content in just a few seconds, instead of having to wait for it. Your only wait is a few seconds for a "buffer" to be built up that helps avoid interruptions caused by Internet traffic problems.
In the majority of cases streaming media is used to maintain control over the distribution of the media files (because it can be difficult to save/rip/download/record/capture streaming video and audio).
Why do I have to choose a streaming "speed" such as 56 kbps, 128 kbps, 300 kbps and so on before I can play an audio or video clip?
Digital content is encoded at different data-delivery rates to accommodate users' Internet connection speeds, which streaming audio/video is quite sensitive to. The faster the speed, the better the clip will look and sound. If you have a 256-kbps DSL broadband connection, a video clip will play only at that maximum rate, even if you chose to play it at 300 kbps. The key to strong streaming: Select a speed your Internet connection can handle so it doesn't lose data, which can create a lousy picture.
What special equipment do I need to watch streaming audio or video?
You only need a computer with an Internet connection (minimum 28.8 Kbps modem; ideally - broadband connection) and capable of playing audio or video, plus player software that can receive and process audio/video streams. You may already have such software on your computer, but if not, it is available as a free download from Real Networks (Real Player), Microsoft (Windows Media Player), Apple (Quicktime Player), Nullsoft (Winamp),....
Is it possible to save/rip/download/record/capture streaming audio/video?
You may use streaming media recording software to record audio and video streams. You may also use streaming audio recording software to record audio streams. Please see Streaming media recording FAQ for more.
How can I tell if I have everything I need to play streaming media?
Most recent computers will have everything needed. If you have speakers/earphones for your computer and you've heard them play sound, chances are you're okay. Generally speaking the faster your online connection (modem, cable, DSL) and computer speed (in megahertz), the higher the quality of the streaming audio or video will be. A 56 Kbps modem is a practical minimum for video.
Can I receive streaming media via Web TV?
Earlier versions of Web TV can't receive streaming media, but some later versions can. You should check your manual or ask the Web TV folks to see if your model supports streaming video/audio.
If I need a streaming player, how do I get one?
Just download it using the links below! Remember, you only need the basic, free version of each player to enjoy streaming content. Some of these companies sell upgraded versions with more features, but all supply a basic, free version too. They usually hide the free one, so don't buy the upgraded version unless you want to. Once you've downloaded the player, it will usually install itself. You may need to reset your browser preferences to use a new player.
Is there any downside to streaming?
There are some potential problems, but we'll tell you how to avoid or minimize them.
- Traffic jams. Streaming requires an Internet connection that's free of bottlenecks or "traffic jams." But the Internet isn't a direct pipeline from the source to you. Streamed content passes through many other computers on its way to your computer via your ISP. If any one of them is carrying too much other traffic, the streamed content may be interrupted and pause. Streamed content is "buffered" to help avoid this, but sometimes it's unavoidable. Usually the delay only lasts a few seconds, and the audio picks up where it stopped. Video is more sensitive to such interruptions.
- A slow computer. Even with a fast computer, if you have too many applications open, it could slow down your media streaming. If you notice things are sluggish, close all unnecessary applications and windows running on your computer. Just keep your Web browser and your media player open. (If you're just listening or watching, you can even close your browser.) In any case, speedy computers are better.
- Noisy phone lines. If you have a phone line that isn't free of noise (humming, crackling), that's not good for streaming (or Web browsing). Disconnect any phones that cause a buzz or hum. Have your phone company check your line to get rid of humming or other line noise. Of course, a cable modem or DSL connection is best for streaming media.
- Firewall. Software and hardware firewalls may block access to streaming media. You or your network administrator should configure your computer properly.
What are PNM, RTSP, MMS, RTMP, RTSPU, RTSPT, MMSU, MMST protocols?
RTSP protocol is the default protocol for streaming Windows Media. RTSP protocol is also used for streaming RealMedia/RealVideo/RealAudio, streaming QuickTime video (.mov, .mp4, .sdp streams).
MMS protocol is used for streaming Windows Media only.
- RTSP using UDP is called RTSPU
- RTSP using TCP is called RTSPT
- MMS using UDP is called MMSU
- MMS using TCP is called MMST
PNM protocol is used for RealMedia/RealVideo/RealAudio streaming only. RTMP protocol is used for Flash audio and video streams only.
Media files can also be streamed through HTTP or other protocols.
The majority of streams are streamed through HTTP, RTSP, MMS and RTMP. PNM protocol is usually not used on the newest servers, but such streams are not very rare.
What is playlist file?
Playlists are powerful and flexible. They allow to schedule content to play in succession. Also with a playlist content distributor can insert advertising or special-interest clips into a presentation after a specific period of time or at a specific point. Windows Media Services and Windows Media Player work together to play the clips in a playlist with minimal buffering time or interruption between clips.
What is server or protocol rollover?
Online content distributor can use metafiles (specially organized simple text files) to provide means of automatically switching to alternate content sources when a media stream cannot be accessed or played for some reason. This is called rollover, and you can use it to specify alternate content on different servers or even different types of servers. The simplest playlists are created by adding multiple ENTRY elements to a metafile.
Concerning Windows Media streaming, you can specify a first alternate on a different Windows Media server. If that content fails to play, the client can rollover to a second alternate on a Web server.
Windows Media Services 9 Series can use RTSP, HTTP, or MMS protocols for streaming. It uses RTSP when trying to connect to Windows Media Player 9 Series or later. If that attempt is unsuccessful, the server uses HTTP to connect to the Player. Earlier versions of the Player do not support RTSP, but they do support MMS protocol. If the server cannot connect to the Player by using MMS or RTSP, then the server tries to connect using HTTP protocol. Windows Media Player automatically tries to rollover to different protocols according to its Windows Media property settings before trying the rollover URLs in the metafile.
What's the difference between a broadcast, a multicast and a webcast?
Broadcasting is the distribution of audio and/or video signals which transmit programs to an audience. The audience may be the general public or a relatively large sub-audience, such as children or young adults. The Internet may bring either radio or TV to the recipient, especially with multicasting allowing the signal and bandwidth to be shared.
Multicast is the delivery of information to a group of destinations simultaneously using the most efficient strategy to deliver the messages over each link of the network only once, creating copies only when the links to the destinations split. Multicast utilizes network infrastructure efficiently by requiring the source to send a network packet only once, even if it needs to be delivered to a large number of receivers. The nodes in the network take care of replicating the packet to reach multiple receivers only where necessary.
A webcast is a media file distributed over the Internet using streaming media technology. As a broadcast may either be live or recorded, similarly, a webcast may either be distributed live or recorded. Essentially, webcasting is "broadcasting" over the Internet. A webcast uses streaming media technology to take a single content source and distribute it to many simultaneous listeners/viewers.
What is Web conferencing?
Web conferencing is used to conduct live meetings or presentations over the Internet. In the early years of the Internet, the term "web conferencing" was often used to refer to group discussions conducted within a message board (via posted text messages) therefore not live, but the term has evolved to refer specifically to "live" or "synchronous" meetings, while the posted message variety of discussion is called a "forum", "message board", or "bulletin board". In a web conference, each participant sits at his/her own computer, and is connected to other participants via the internet. This can be either a downloaded application on each of the attendees computers or a web-based application where the attendees will simply enter a "URL" or website meeting address to enter the live meeting or conference. These web-based applications are used either with Flash or Java technology.
What is webinar?
A webinar is a type of web conference, that tends to be mostly one-way, from the speaker to the audience with limited audience interaction, such as in a Webcast, which is transmission of information in one direction only, like watching a concert on the internet. A webinar however, can be very collaborative, and include polling and question & answer sessions to allow full participation between the audience and the presenter. A webinar is "live" in the sense that information is conveyed according to an agenda, with a starting and ending time. In most cases, the presenter may speak over a standard telephone line, pointing out information being presented on screen, and the audience can respond over their own telephones, preferably a speakerphone. There are a few web conferencing technologies on the market that have incorporated the use of VoIP audio technology, to allow for a truly web-driven presentation, removing the need for any external devices, such as a telephone.
What is podcast?
Podcast is a digital media file, or a related collection of such files, which is distributed over the Internet using syndication feeds (RSS or Atom) for playback on portable media players and personal computers. The term can refer either to the content itself or to the method by which it is syndicated; the latter is also termed podcasting. The host or author of a podcast is often called a podcaster.
The term "podcast" is a portmanteau of the words "iPod" and "broadcast", the Apple iPod being the brand of portable media player for which the first podcasting scripts were developed. These scripts allow podcasts to be automatically transferred to a mobile device after they are downloaded.
Though podcasters' web sites may also offer direct download or streaming of their content, a podcast is distinguished from other digital media formats by its ability to be syndicated, subscribed to, and downloaded automatically when new content is added, using an aggregator or feed reader capable of reading feed formats such as RSS or Atom.
What is codec?
A codec is a device or program capable of performing encoding and decoding on a digital data stream or signal. The word codec may be a combination of any of the following: 'Compressor-Decompressor', 'Coder-Decoder', or 'Compression/Decompression algorithm'.
Embedded media players like Adobe Flash Player use built-in codecs to decompress streaming media data before showing it to a user.
Many multimedia data streams need to contain both audio and video data, and often some form of metadata that permits synchronisation of the audio and video. Each of these three streams may be handled by different programs, processes, or hardware; but for the multimedia data stream to be useful in stored or transmitted form, they must be encapsulated together in a container format.
Compression quality: lossy vs. lossless
Most codecs are lossy. Originally this was in order to make the compressed files small enough to be readily transmitted across non-broadband networks and stored on relatively expensive media, such as non-volatile memory and hard disk as opposed to write-once read-many formats such as CD-ROM and DVD.
There are lossless codecs but for most purposes the slight increase in quality is not worth the increase in data size, which is often considerable. The main exception to this is if the data is to undergo further processing (for example editing) in which case the repeated application of lossy codecs (repeated encoding and subsequent decoding) will almost certainly degrade the quality of the edited file such that it is readily identifiable (visually or audibly or both). Using more than one codec or encoding scheme whilst creating a finished product can also degrade quality significantly (however there are many situations where this is all but unavoidable). The decreasing cost of storage capacity and network bandwidth may obviate the need for lossy codecs for some media over time.
What is DRM (Digital Rights Management)?
DRM (Digital Rights Management) is a secure technology which enables the copyright owner of a piece of intellectual property (such as a music, video, or text file) to specify what a user can do with it. Typically, this is used to offer downloads without having to worry that the user is freely distributing the file over the Web without any compensation to the copyright holder.
After downloading DRM-protected content to your computer, you may have problem playing it with your favorite device. Luckily sometimes you can remove DRM protection with DRM removal software.
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