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Using the Streaming Media Service
Instructions and advice for creatiing and uploading content for the Streaming Media Service.
- 1 About the service
- 2 Obtaining access to the Server
- 3 What is 'Streaming Media'?
- 4 Windows Media Player
- 5 Producing an audio or video material
- 6 Encoding the clip
- 7 Compression settings when encoding
- 8 Choosing the encoding settings
- 9 Transferring the Windows Media File to the streaming server
- 10 Setting access permissions
- 11 How to use Windows Media Player to access the clip
- 12 Using Metafiles to link from a Web page
- 13 Doing more with Metafiles
- 14 Embedding Windows Media Player in a Web page
1 About the service
The Streaming Media service allows approved departmental CFS users to transfer audio/video clips to the streaming server in IT Services. These media files may then be viewed remotely with Windows Media Player and viewed from a Web page. Instructions for doing this are provided below.
2 Obtaining access to the Server
Departments are allocated their own area on the streaming server and access to this area is controlled by either their Departmental IT Contact(s). Requests for an initial allocation on the streaming server should be submitted by Departmental IT Contacts using the web form Requesting FREE Filestore Quota. (NOTE: IT Services will inform this person when the area has been set up on the streaming server and is available to use.)
Departments will be given an initial free allocation of 500MB of disk space on the streaming server. Extra disk space may be purchased using the Requesting CHARGED Filestore Quota web form. There will be a small rental charge and a departmental SAP code must be provided. (See Quota Information for more details.)
The forms can be accessed through the ITS online self service portal.
3 What is 'Streaming Media'?
Streaming Media is the preferred method for delivering audio/video clips over a network. The user may start to view the media files as soon as the data is fed from the streaming server. The common alternative to Streaming Media is "Download and Play", this is when the whole clip must be downloaded to the client machine before it can be viewed and because of the large size of media files this could take some time.
Advantages of Streaming Media
- Quick access time, users can start playing the content almost immediately.
- Allows users to jump to any point in the clip, fast forward, rewind etc without having to download the whole file.
- There is no local copy so users cannot easily distribute the clip further.
- Very efficient for distributing to many users simultaneously.
Disadvantages of Streaming Media
- The file is not available offline i.e. it can't be downloaded and played later.
- User must connect across the network each time they wish to view the file.
- Must meet the minimum connection speed specified by the media file to view it.
- Quality of the viewed file is dictated by the connection speed.
4 Windows Media Player
The streaming server will only stream files in Windows Media format (.wma or .wmv) and Windows Media Player must be available to view these files. This application is installed on all CFS XP clients and is freely available to download for home users from http://www.microsoft.com/windows/windowsmedia/player/default.aspx
5 Producing an audio or video material
The Multimedia Services video team in IT Services provide can provide advice on creating good quality video and audio material. Here are a few basic tips that will make an audio or video clip easier to encode and give a better end result:-
- When shooting video footage try and keep movement to a minimum by using a tripod and avoiding panning shots.
- Lighting is critical, poorly lit shots lose a lot of detail when they are encoded.
- Avoid complex and moving backgrounds.
- Try to avoid background noise when taking audio recordings.
- Material must then be encoded into a suitable format before it is transferred to the streaming server.
Windows Movie Maker software (found on all CFS machines) allows you to edit video material and encode it in a suitable format. It is important that you do not use any audio, video, images or any other material for which you do not either own the Copyright, or for which you have not obtained explicit written permission to use.
You are advised to check Copyright Information which has been provided by the Library and aims to explain how copyright affects the activities of University staff and students.
6 Encoding the clip
Encoding is the process of converting and compressing the information in audio or video clips into a suitable format for streaming. At the University of Leicester the only format supported by the streaming server is Windows Media format and your audio or video clips must therefore be converted into .wma or .wmv format before they are transferred to the streaming server.
You may download Windows Media Encoder to encode your own audio/video clips. Windows Movie Maker software (found on all CFS machines) allows you to edit video material and encode it in a suitable format.
A compression algorithm must also be applied to your media files to reduce their size and make them more manageable across a network. This compression process aims to throw away data that is not needed but please note this will affect the quality of the image and sound.
Before the content is played to the user it will be decompressed using a decompression algorithm. These algorithms are called codecs (short for compressor/decompressor). Please refer to the on-line Help in Windows Media Encoder for information about the codecs available.
7 Compression settings when encoding
The Windows Media Encoder includes many predefined destination, video, and audio settings (profiles) and you can easily set up an encoding session using a predefined profile. However, if you want to customize the settings, then the following paragraphs provide information that may be useful.
Codecs
Use the appropriate codec for the session. For example, when your audio source is voice or primarily voice, use the Windows Media Audio 9 Voice codec. For a screen capture session, use the Windows Media Video 9 Screen codec.
Bit rate
A higher bit rate achieves a better image quality. If the bit rate setting is too low, the codec will drop frames to produce a higher quality image, although this may not be visible to the viewer.
Frame rate
There is a tradeoff between image quality and frame rate, in that as the image quality increases, the frame rate decreases. If maintaining the frame rate is more important, you can decrease the image quality setting.
Image quality (smoothness)
You can adjust the image quality to be smoother or more clear. Increasing the clarity can affect the frame rate, depending on the video. For example, if your video contains a lot of motion, increasing the clarity may decrease the frames rate. In addition, increasing the clarity results in a higher bit rate requirement and may also necessitate increasing the buffer size.
Frame size
The larger the frame size, the higher the bit rate requirement.
Key frames
If you use a longer key frame distance, additional key frames are inserted when necessary; for example, when a scene changes. For low motion content, a setting of 20 seconds is typically appropriate. For higher bit rate content, you should lower the key frame distance.
8 Choosing the encoding settings
If you wish to customise the settings used when encoding the following questions may help you determine what to use:
What will the file be viewed with?
This will determine the type of media file produced. At the moment only files in Windows Media Player format (.wma or .wmv) are supported for streaming. Also, please note that there are different versions of Window Media Player, earlier versions may not necessarily be able to read all the types of encoding (codecs) that the later ones can.
Where will the user view the content?
This is a very important question as where the user views the content will determine how much information they can receive per second (network bandwidth). Users on a Local Area Network (LAN), such as the campus network, can view files encoded to stream at 1000 Kilobits per second (1000Kbps, 1Mbps). For broadband internet connections, use a maximum streaming rate of around 500kbps.
What is most important to get across?
If the original footage must be significantly compressed it is important to decide which part of it will be reduced in quality. For instance with audio visual footage of someone talking it is probably important that what they say comes across clearly, so it is the video component that must be compromised, in addition the audio probably only needs to be in mono rather than stereo.
How many people will watch it at once?
This along with the stream rate will determine the load on the server and the network i.e. a class of 200 looking at a video which is streaming at 1Mbps will cause a load of 200Mbps. This will cause a significant load on the server. The aggregate load for any one session should not exceed 50 Mbps, i.e. a class of 50 viewing a 1Mbps file or a class of 200 viewing a 250Kbps file.
9 Transferring the Windows Media File to the streaming server
When your audio or video clip has been encoded to Windows Media format (.wma or .wmv) it can be converted to a streaming media file by simply changing the file extension to .asf . You must then transfer this file to the streaming server in order to provide access for other users.
To assist with this transfer you can make your department's area accessible from "My Computer" by mapping a network drive to the streaming server.
To do this run Windows Explorer and select the Map Network Drive... option from the Tools menu. The next available drive letter appears in the Drive: box and you should type
\\cfs.le.ac.uk\root\streaming\<department_code>\
in the Folder: box.
See The two-letter code system if you need to check the code for your department.
For example the area on the streaming server for Engineering would be located at \\cfs.le.ac.uk\root\streaming\eg\.
The drive will remain mapped to the streaming server for future sessions, if necessary it can be removed using the Disconnect Network Drive... option.
You may now access the folders in your department's area on the streaming server from "My Computer" when you run Windows Explorer. Initially there should be two sub-folders in your department's area, namely world and campus.
You must copy your Windows Media file (in .asf format) to the appropriate folder depending on the type of access required. Files placed in the "world" folder will by default have world access and may be viewed from anywhere on the Internet, whereas files placed in the "campus" folder may only be viewed if using computers on the campus network.
Note: A file structure can be organised with sub-folders on the streaming server just like any other filestore on CFS.
10 Setting access permissions
By default the files on the streaming server may be viewed by all users, however it is possible to restrict access by CFS username or group. To do this right click on the file you wish to restrict access to and select Properties. Click on the Security tab followed by the Advanced button.
Next click on the check box in the bottom left hand corner labelled "Allow inheritable permissions from parent to propagate to this object", when you do this a dialogue box appears with 3 options "Copy", "Remove" and "Cancel", choose "Copy". Next, remove any entries in the top pane for users you do not wish to view the clip.
See the short video presentation for a demonstration of the procedure for setting access permissions.
NOTE: Make sure you remove the "Windows Media Services Guest Account" which allows ANY user to view the clip.
NOTE: Do not remove access for the following accounts: Administrators, Network Service and System.
To add your own account click on the Add button and type your CFS username into the bottom pane of the window that appears, click on the Check Names button then on OK.
Your username should appear in the list of users. Highlight your username and click on the check box next to "Full Control" and below "Allow", then click on Apply. You have now given yourself Full Control of the file while removing access to the users you removed from the list.
To give more users access to the file, add their usernames in like you did your own, multiple names can be entered seperated by a semi-colon. They will have default permissions to read the file when they are added which is sufficient, or you can give certain users full control like you did yourself. When you have finished click on OK.
11 How to use Windows Media Player to access the clip
To use Windows Media Player to access the clip on the streaming server select the Open URL... option from the File menu and then enter the URL of the clip. The format used for the URL will depend on the location of your clip.
- If the file has been created in the world directory the format used would be mms://streaming1.le.ac.uk/<department_code>/<path to file>
For example: mms://streaming1.le.ac.uk/cc/sms/test1.asf - If the file has been created in the campus directory the format used would be mms://streaming1.le.ac.uk/<department_code_campus>/<path to file>
For example: mms://streaming1.le.ac.uk/cc_campus/sms/test1.asf
12 Using Metafiles to link from a Web page
To access a file on the streaming server directly from a link on a Web page you must create a Windows Media Metafile file. This is a simple text file ending with the extension name .asx and it contains information about the location of the media file. To create a Metafile run Notepad and enter the following text:
To save this file as a Metafile provide it with a .asx extension, for example, mymetafile.asx . This file must be transferred to a Web server. Then to access the Metafile, which will access and play the media file from the streaming server, enter the following HTML code in a Web page <a href="http path to .asx file">Text for the link</a> For example: <a href="http://www.le.ac.uk/its/mymetafile1.asx file">Play My Media</a>
A sample Metafile file can be found at \\cfs.le.ac.uk\root\streaming\xx\world\samples\metafiles\sample.asx
For specific instructions of how to link to a video from a Plone web page, please visit Adding a streaming video to your Plone website.
13 Doing more with Metafiles
Metafiles can do more than simply providing a redirect from a Web link to a media file, they can contain various scripting commands to tell Windows Media Player how to play a particular file. For example it is possible to create a Metafile file to play only a small portion of the media file by specifying a length of time into the file and then a duration time (see below).
The above code in a Metafile would start playing 37 seconds into the clip specified by the path mms://streaming1.le.ac.uk/xx/samples/mediafiles/sample.asf and then play the next 15 seconds of the clip from that point. This file can be found at \\cfs.le.ac.uk\root\streaming\xx\world\samples\metafiles\snippet.asx
It is also possible to play multiple clips one after another by including multiple "entry" sections.
Or you could combine the two to play multiple snippets of a media file.
14 Embedding Windows Media Player in a Web page
It is possible to embed the Windows Media Player in a Web page. However, the procedure involved is beyond the scope of this documentation. If you'd like help embedding a streaming video into a web page or blackboard page then please contact ithelp@le.ac.uk.
For further information about embedding a streaming video into a Web page so that it is compatible with Internet Explorer and other browsers see Using the Windows Media Player Control in a Web Page.
See also How to Embed Windows Media Files which has been provided by MediaCollege, a free educational website that has video, audio and electronic media resources; including some free tutorials.
