The aim of this document is to provide a very basic introduction to the Video Streaming in Nokia devices, for a deeper discussion please refer to the Forum Nokia Audio Video section that contains a lot of information on which this document is based http://www.forum.nokia.com/main/resources/technologies/audiovideo/index…..
In a mobile device you can use the pre-installed video player for two different purposes:

- Video streaming
- Stand alone local video player

The main difference between these two is that in video streaming, the compressed video data is fetched from a server during playback, whereas in the local video viewer, the video is stored locally in the memory of the device or in the memory card.

A video in streaming is often launched through the web browser or through a downloaded definition file (.RAM file), which will launch the device streaming player and open the video URL (rtsp://address/folder/).
Downloading a file first and playing it afterwards is always local playback, because the entire video file has already been stored locally. Progressive downloading means that the entire video clip doesn’t have to be downloaded to start playing it.

In order to create a video clip you have to consider these basic building blocks

When you work on video for mobile devices the compression of the file plays a very important role so you have to consider very deeply the video coding.

Keep always in your mind that a video sequence consists of a series of still images and that video compression methods are based on reducing the redundant and perceptually irrelevant parts of video sequences.
Efficient compression cannot be reached simply by reducing the redundancy of the sequence, this is the reason why video encoders must also discard some non redundant information. When doing this, the encoders take into account the properties of the human visual system and mainly discard the information that is least important for the subjective quality of the image.

In video coding some images sequences can be harder to compress due to movement or texture that have to be rendered, in order to meet a constant bit-rate target, the video encoder controls the frame rate as well as the quality of images.

Codecs

H.263 is a codec used in various multimedia services and it provides a lot of encoding tools and coding complexities for different purposes.
For the wide part of mobile multimedia services the H.263 Profile 0, Level 10 has been defined as a mandatory codec and it’s also the mainstream codec supported in Nokia video players.

MPEG-4 Visual is an optional video codec in several recent multimedia standards and it is widely supported in more recent Nokia devices this codec, also called MPEG-4 Part 2, contains different profiles for different purposes. Nokia platforms support Simple Profile 0.

RealVideo 7 and RealVideo 8 are two proprietary video coding formats developed by Real Networks, the RealPlayer installed on Nokia devices supports the decoding of video in RealVideo 7 and RealVideo 8 formats.
RealVideo 7 is similar to MPEG-4 and H.263 , RealVideo 8 is also similar to the MPEG-4 and H.263 but it is 30% to 40% better than RealVideo 7 due to major differences in the specific techniques used for transform coding.

RealVideo 10 includes enhancements on the encoder side, so it is compatible with all RealVideo 9 capable players. RealNetworks states that RealVideo 10 provides at least the same visual quality as RealVideo 9, using a 30 percent lower bit rate.

File Formats

There is a difference between the video coding format and the video file format. The coding format is related to the action of a specific coding algorithm that codes content information into a code stream. The file format is a way of organizing video and audio code streams so that they can be accessed for local decoding and playback or streamed over a transport channel.
The following list includes some of the most common video file formats today:
Microsoft Audio-Video Interleaved (AVI)Apple QuickTime file format (.mov)MPEG-1 file format (.mpg)3GPP file format (.3gp)3GPP file format (.3gp)MP4 file format (.mp4)

Nokia Platforms

The different Nokia platforms provide different (but often similar) capabilities for the video.

Use this table as a basic reference, you find more info on Forum Nokia.

Streaming

Streaming is the transmission of real-time data, both audio and video, from a server to a client, where the client decodes and plays the data as it is received. Streaming lets the viewer see the content immediately after a short buffering period. One advantage compared to local playback is that no data will be stored permanently to the terminating client. The end user cannot forward or send the content to another user, so the content can be charged each time it is consumed. This is one great advantage for service providers.
If the content is to be served within a particular operator’s service domain only, appropriate authoring guidelines are usually available from the operator or the service provider.

Server products

There are several products that you can use in order to deliver your video on mobile devices: Open Streaming Server is an digital media delivery. Main characteristics are: – Streaming of mp4, 3gp, WMF, QT files – Dynamic Bandwidth adaptation – Load balancing – Content distribution Technology: C++, Java and CORBA http://sourceforge.net/projects/openstreamingQuickTime Streaming Server is Apple’s industrial-strength, standards-based streaming server for delivering media in real time over IP networks. Using the open standard RTP/RTSP streaming protocol, QuickTime Streaming Server provides native streaming of MPEG-4 and 3GPP files http://www.apple.com/quicktime/streamingserver/Helix Server is the only multi-format, cross platform streaming server for delivering the highest quality experience to wired and wireless devices http://www.realnetworks.com/products/media_delivery.html

Terms and meanings

Use this table as a quick reference for the most common terms used in the video streaming on mobile devices