Video And Streaming In Nokia Devices

F O R U M N O K I A

Video And Streaming In Nokia Devices

Version 3.0; November 14, 2005

Video

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Copyright © 2005 Nokia Corporation. All rights reserved.

Nokia and Nokia Connecting People are registered trademarks of Nokia Corporation. Java and all Java-based marks are trademarks or registered trademarks of Sun Microsystems, Inc. Other product and company names mentioned herein may be trademarks or trade names of their respective owners.

Disclaimer

The information in this document is provided “as is,” with no warranties whatsoever, including any warranty of merchantability, fitness for any particular purpose, or any warranty otherwise arising out of any proposal, specification, or sample. Furthermore, information provided in this document is preliminary, and may be changed substantially prior to final release. This document is provided for informational purposes only.

Nokia Corporation disclaims all liability, including liability for infringement of any proprietary rights, relating to implementation of information presented in this document. Nokia Corporation does not warrant or represent that such use will not infringe such rights.

Nokia Corporation retains the right to make changes to this specification at any time, without notice.

License

A license is hereby granted to download and print a copy of this specification for personal use only. No other license to any other intellectual property rights is granted herein.

Video And Streaming In Nokia Devices 2

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Contents

1 Introduction................................................................................................................................................ 6 2 Video Player ................................................................................................................................................ 7 3 Video Coding ............................................................................................................................................... 8

3.1 H.263.............................................................................................................................................................8 3.2 MPEG-4 Visual.............................................................................................................................................9 3.3 RealVideo 7 and RealVideo 8................................................................................................................9 3.4 RealVideo 9 and RealVideo 10 .............................................................................................................9

4 Audio Coding.............................................................................................................................................10 4.1 AMR-NB .....................................................................................................................................................10 4.2 AMR-WB ....................................................................................................................................................10 4.3 RealAudio Voice, RealAudio 7, RealAudio 8, and RealAudio 10..............................................11 4.4 MP3.............................................................................................................................................................11 4.5 AAC..............................................................................................................................................................11 4.6 AAC+ and eAAC+ .....................................................................................................................................11

5 File Formats...............................................................................................................................................12 6 Video Capabilities in Nokia Platforms................................................................................................13

6.1 Series 40 Platform.................................................................................................................................13 6.2 S60 Platform............................................................................................................................................13

6.2.1 S60 1st Edition.......................................................................................................................13 6.2.2 S60 2nd Edition .....................................................................................................................14 6.2.3 S60 3rd Edition ......................................................................................................................15

6.3 Series 80 2nd Edition .............................................................................................................................15 6.3.1 Video Recorder.....................................................................................................................15 6.3.2 RealPlayer ..............................................................................................................................15

6.4 Nokia 7710 Device.................................................................................................................................16 6.4.1 Video Recorder.....................................................................................................................16 6.4.2 RealPlayer ..............................................................................................................................16

7 Streaming ..................................................................................................................................................17 7.1 Streaming Video Creation – Basic Steps ........................................................................................17

7.1.1 3GPP-compatible content authoring tools.................................................................18 7.1.2 Players for PC environment .............................................................................................18

7.2 Network and Bit-Rate Options for Streaming..............................................................................19 7.3 Content Creation with 3GPP Codecs ................................................................................................20

7.3.1 Audio.......................................................................................................................................20 7.3.2 Video .......................................................................................................................................21

7.4 Suggested Video Encoder Configurations .....................................................................................22


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8 Tools for Video Content Creation.........................................................................................................24 8.1 RealMedia Content Creation with RealProducer and Helix Mobile Producer Authoring Tools .....................................................................................................................................................................24

8.1.1 Video encoding....................................................................................................................24 8.1.2 Audio encoding....................................................................................................................24

8.2 Tips and Tricks........................................................................................................................................24 8.2.1 Selectivity for authored sequences...............................................................................24 8.2.2 Multiple encodings .............................................................................................................25

9 Video Client Application Development ..............................................................................................26 9.1 Symbian C++............................................................................................................................................26 9.2 Java™ Technology .................................................................................................................................26

10 Relevant Specifications ..........................................................................................................................28 10.1 3GPP Specifications...............................................................................................................................28 10.2 Other Specifications..............................................................................................................................28

11 Terms and Abbreviations ......................................................................................................................30 12 References .................................................................................................................................................32 13 Evaluate This Document ........................................................................................................................33


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Change History

June 16, 2003 Version 1.0 This document replaces “Video in Nokia phones”-document. Tools section, Nokia 6220 and Nokia 6600 added. Document structure is also changed.

July 12, 2004 Version 2.0 The Nokia 3220, Nokia 5140, Nokia 6220, Nokia 6230, Nokia 6820, Nokia 7200, and Nokia 7600 devices added. Document structure also changed: Series 40 devices added to the table, video client application development information added, and Platform approach included.

November 14, 2005 Version 3.0 Device-specific details removed, and published separately in www.forum.nokia.com/audiovideo. “Video and streaming content creation guide” document integrated into this document. Chapters on RealVideo 9/10, MPEG-4 AAC/AAC+/eAAC+ added. S60 3rd Edition added.


http://www.forum.nokia.com/audiovideo

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1 Introduction

This document will help developers create audio-visual content, services, and applications for video-capable Nokia devices. In practice, most of the newer Nokia products are video capable.

The document covers the basics of audio and video coding, including file formats. Different Nokia platforms and their capabilities are presented. Since actual product hardware and configuration might change those capabilities, device specifications are not covered in this document but can be found separately at www.forum.nokia.com/audiovideo.

Streaming is covered in its own separate chapter, including the basics of content creation, tools, and network technology. Video client development for both C++ and Java™ technology are not covered as such, but relevant links are presented. Also, relevant specifications and references are listed at the end of the document.

The term “video,” when used in the context of video streaming and video player, should be interpreted as the capability to render simultaneously both video and audio content.



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2 Video Player

The same user interface will be used for both video streaming and a 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 clip to be viewed is stored locally in the memory of the mobile terminal or memory card. The external session establishment of video streaming service is implemented using the Web browser or messaging applications (Short Message Service [SMS], Multimedia Messaging Service [MMS] viewers), which have the ability to launch external applications such as the player application. This is done by recognizing an rtsp:// URL or a downloaded definition file (.RAM file), which will launch the installed streaming player. In the player application, streaming links are typically launched from the player’s editable play list.

Downloading a file first and playing it afterwards is considered 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.

The creation of a video clip requires the following elements:

• One or more bit streams (for example, one video bit stream and, if present, an audio bit stream). A bit stream is the output of a video or an audio encoder. See Chapters 3, “Video Coding,” and 4, “Audio Coding,” for discussions of video and audio coding, respectively.

• One file format, which packages the audio-visual content into a file, synchronizes it, and allows access to it.

Video EncoderVideo Encoder

Video Audio

Audio EncoderAudio Encoder

CODEC=Coder+DECoder

Video Bitstream Audio BitstreamHeader

File Composer

Video BitstreamVideo Bitstream Audio BitstreamAudio Bitstream

FILE FORMAT

Examples of video codecs: H.263 baselineMPEG-4 video

Real Video 7/8/9Windows media video



Examples of speech/audio codecs: AMR

MPEG 2/4 AACRealAudio

Windows Media Audio



Windows Media Audio

Video EncoderVideo Encoder

Video Audio

Audio EncoderAudio Encoder

CODEC=Coder+DECoder

Video Bitstream Audio BitstreamHeader

File Composer

Video BitstreamVideo Bitstream Audio BitstreamAudio Bitstream

FILE FORMAT







Windows Media Audio



Windows Media Audio

Figure 1: Key elements for creating a video clip


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3 Video Coding

A video sequence consists of a series of still images. Video compression methods are based on reducing the redundant and perceptually irrelevant parts of video sequences. That redundancy can be categorized into spatial, temporal, and spectral redundancies. Spatial redundancy refers to the correlation between neighboring pixels. Temporal redundancy means that the same objects appearing in the previous image are likely to appear in the current image as well. Spectral redundancy addresses the correlation between the different color components of the same image. Compression can be achieved by generating motion-compensation data, which describes the motion between the current and the previous image. It can be said that the current image is predicted from the previous one.

Usually, however, efficient compression cannot be reached simply by reducing the redundancy of the sequence. Thus, video encoders must also discard some nonredundant 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 addition, the redundancy of the encoded bit stream is reduced by means of efficient lossless coding of compression parameters and coefficients. The main technique is the use of variable-length codes.

Video compression methods typically differentiate between images that can or cannot use temporal redundancy reduction. Compressed images that do not use temporal redundancy reduction methods are usually called INTRA or I-frames, whereas temporally predicted images are called INTER or P-frames. In the INTER frame case, the predicted (motion-compensated) image is rarely sufficiently precise, and therefore a spatially compressed prediction error image is also associated with each INTER frame.

In video coding, there is always a tradeoff between bit rate and quality. Some image sequences may be harder to compress than others due to rapid motion or complex texture, for example. In order to meet a constant bit-rate target, the video encoder controls the frame rate as well as the quality of images: The more difficult the image is to compress, the worse the image quality. If variable bit rate is allowed, the encoder can maintain a standard video quality.

3.1 H.263

ITU-T H.263 is an established codec used in various multimedia services, and it provides a wide “toolbox” of various encoding tools and coding complexities for different purposes. The tools to be used and the allowed maximum complexity for the particular mode are defined in so-called codec profiles and levels, respectively.

For most mobile multimedia services, the H.263 Profile 0, Level 10 (also known as “H.263 baseline”), has been defined as a mandatory codec. This is also the mainstream codec supported in Nokia video players.

H.263 uses the Discrete Cosine Transform (DCT) to reduce spatial redundancy. The transform converts a block of pixels to coefficients that represent the spatial frequency components of the block. Only the frequencies appearing in the block have high-amplitude coefficient values; other coefficients are close to zero. For example, a constantly colored block has only one spatial frequency and it is transformed to one nonzero DCT coefficient, whereas the other DCT coefficients remain zero. Consequently, the DCT coefficient block is easier to code with run-length codes than the original block of pixels. In order to gain compression, the transformed block is quantized, which means that the coefficients are rounded to certain quantization levels. The fewer possible quantization levels there are, the fewer bits it takes to represent a quantization level. An approximation of the original block of pixels can be restored from the coded DCT quantization levels by applying an inverse DCT. The fewer quantization levels used, the worse the quality of the reconstructed image. ITU-T H.263 allows 31 quantization step sizes that are controlled by the so-called quantization parameter.


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3.2 MPEG-4 Visual

This is an optional video codec in several recent multimedia standards and it is widely supported in more recent Nokia devices, in addition to H.263. Like H.263, MPEG-4 Visual (also called MPEG-4 Part 2) contains different profiles for different purposes. Nokia platforms support Simple Profile 0.

MPEG-4 Visual is a DCT-based compression standard, and the still texture part uses wavelet compression.

3.3 RealVideo 7 and RealVideo 8

RealVideo 7 and RealVideo 8 are two proprietary video coding formats developed by Real Networks. The RealPlayer installed onboard Nokia devices supports the decoding of video in RealVideo 7 and RealVideo 8 formats.

RealVideo 7 is similar to MPEG-4 and H.263 in that it makes use of I-frames and P-frames and is block transform-based. It also uses Bidirectional frames or B-frames that are computed based on interpolation between the previous and next I- and P-frames using motion vectors and spatial information. RealVideo 7 is more efficient than MPEG-4 or H.263 due to the use of B-frames and some advanced coding techniques created by RealNetworks.

RealVideo 8 is also similar to MPEG-4 and H.263 in that it makes use of I-frames and P-frames and is block transform-based. It also uses Bidirectional frames or B-frames. However, it is 30 to 40 percent better than RealVideo 7 due to major differences in the specific techniques used for transform coding, motion estimation, and filtering.

3.4 RealVideo 9 and RealVideo 10

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.

The RealPlayer installed onboard some of the Nokia devices supports the decoding of video in RealVideo 9 and RealVideo 10 formats.


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4 Audio Coding

Arbitrary sounds can be represented as a sum of waves having different frequencies and amplitudes. In other words, any sound is an amplitude waveform as a function of time. Sounds can be digitized when samples of the corresponding waveform are taken frequently enough. For arbitrary sounds and music, a 44.1 kHz sampling frequency is considered to provide high quality. For speech, an 8 kHz sampling frequency is adequate for most applications. Typically, 16 bits is enough to represent one sample.

Digitized audio can be compressed in various ways. A simple coding method is to use an adaptive step size to quantize audio samples. Such a technique is used in the IMA ADPCM audio coding standard that reserves 4 bits per sample. Consequently, if the sampling frequency is 8 kHz, IMA ADPCM-coded audio takes 32 Kbit/s. Another simple audio coding method is A-law PCM, which uses a logarithmic quantization step size and reserves 8 bits per sample.

More advanced audio coding methods take advantage of the human psychoacoustics model. Parts of the audio signal are barely audible and can be discarded or compressed. Typically, the advanced coding audio methods are categorized into generic audio coding and speech coding techniques. Generic audio coding algorithms are targeted for music and sound as well as human voices, whereas speech coding algorithms are aimed at speech only and perform relatively poorly when music is coded.

4.1 AMR-NB

One of the most advanced speech coding standards today is the Adaptive Multi-Rate (AMR) speech codec, which was developed by the European Telecommunications Standards Institute (ETSI). It includes eight speech coding modes, whose bit rates range from 4.75 to 12.2 Kbit/s. Some of the modes are the same as the earlier-defined voice telephony codec specified for other standards. For example, AMR at 12.2 Kbit/s is the same speech codec as the GSM Enhanced Full-Rate (EFR) codec. AMR is a mono type codec.

To provide the best listening experience, AMR encoding should be used for content that does not include complex, noisy, or critical music content. The limited audio bandwidth of 3.5 kHz means higher frequencies are not reproduced perfectly and are filtered with an anti-aliasing filter. Content proven to work satisfactorily with AMR includes news and sports coverage and light popular music.

4.2 AMR-WB

AMR-WB represents state-of-the-art technology in low bit rate wideband speech coding. Like AMR-NB, it is a multi-rate speech codec. AMR-WB technology uses nine bit rates between 6.6 and 23.85 Kbit/s at 16 kHz sampling rate. The speech processing is performed on 20 ms frames, so each AMR-WB encoded frame represents 320 speech samples. AMR-WB uses MIME type audio/amr-wb and file extension *.awb. AMR-WB payload format as well as MIME type is defined in RFC 3267[1].

AMR-WB was selected by the 3GPP in December 2000 and ITU-T in July 2001. The ITU-T AMR Wideband is now known as G.722.2. The 3GPP has several specifications available related to AMR-WB:

• 3GPP TS 26.190 [2]

• 3GPP TS 26.201 [3]

• 3GPP TS 26.174 [4]

• 3GPP TS 26.194 [5]


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4.3 RealAudio Voice, RealAudio 7, RealAudio 8, and RealAudio 10

RealPlayer in Nokia S60, Series 80, and Nokia 7710 devices supports RealAudio Voice, RealAudio 7, and RealAudio 8 audio codecs. RealAudio 7 is also known as RealAudio G2 codec.

RealAudio 7 is an Internet audio codec used for many legacy contents served by streaming servers. RealVoice is an ADPCM codec used for speech frequency ranges.

RealAudio 8 is a proprietary audio codec that supports various sampling and bit rates, starting from very low bit rates (3-4 Kbit/s). Nokia doesn’t recommend use of RealAudio 8 at bit rates covered with AMR-NB, but if necessary for bandwidth limitation reasons, the codec can be used. For information on the optimal use of bit rates and sampling rates, please consult RealNetworks’ Web guidelines.

RealAudio 10 is not a new codec, but a marketing name for RealNetworks’ latest collection of audio tools. For bit rates lower than 128 Kbps, RealAudio 10 uses RealAudio 8 codec, and for higher bit rates it employs MPEG-4 AAC codec (see Section 4.5).

4.4 MP3

MP3 is formally known as MPEG-1 Audio Layer 3, but is called MP3 based on its file name extension — .mp3. MP3 is a lossy compression format, employing a number of techniques to reduce the size of audio data. Discarding of information is based on the characteristics of human hearing, as explained earlier in this chapter.

The MP3 format is widely supported on recent Nokia devices, as well as other digital audio players, CD players, and PC software.

4.5 AAC

MPEG-4 Advanced Audio Coding (AAC) is a successor format of MP3 for audio coding at medium to high bit rates. It has a number of improvements over MP3, in coding efficiency and frequency handling. Roughly it can be said that 96 Kbps AAC encoded audio is perceived to be at least the same or better quality than 128 Kbps MP3.

4.6 AAC+ and eAAC+

AAC+ (also known as aacPlus) is standardized by MPEG under the name HE-AAC (High Efficiency AAC). It combines AAC and Spectral Band Replication (SBR). This combination is known as HE-AAC v1 (or aacPlus v1). A 48 kbps stream of AAC+ is considered to have a higher quality than 128 kbps MP3.

HE-AAC v2 adds support for Parametric Stereo (PS), further improving the codec’s performance at lower bit rates. This combination is also known as aacPlus and enhanced AAC+ (eAAC+).


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5 File Formats

Conceptually 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)

• MP4 file format (.mp4)

In accordance with the 3GPP specifications, Nokia supports the 3GPP file format (extension: .3gp) for the storage of video and associated audio (if present).

Note that the Nokia Video Player doesn’t commit to play back media content inside .mp4 files (MPEG-4 file format), although the file may contain media types supported by the player. If the .mp4 file declares 3GPP file format compatibility, the content will play out as originally intended by the content author, otherwise the player presentation may not reproduce original content.

Apple uses a .m4a file extension in its iTunes service, but the actual container is still MP4.


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6 Video Capabilities in Nokia Platforms

6.1 Series 40 Platform

Video-capable Nokia Series 40 products can record video clips using the integrated camera of the device. The video clip is saved to the internal memory of the device or to a memory card if available. The maximum file size for a video clip is set to 100 or 300 KB by default to be able to send it as an MMS message. In addition, some devices also offer extended video recording.

Video player features of Series 40 Platform-based devices differ greatly, so actual capabilities should always be checked from Forum Nokia Web site (http://www.forum.nokia.com/audiovideo).

6.2 S60 Platform

The S60 platform consists of several different versions, called Editions. Editions can be enhanced with Feature Packs, which add some features while keeping the platform offering consistent. Because of hardware differences and product differentiation, all devices based on the same Edition are not always identical with regard to audio and video capabilities. Actual device capabilities should always be checked from the Forum Nokia Web site (http://www.forum.nokia.com/audiovideo).

Note: S60 is the new brand name for the S60 platform, formerly know as the Series 60 Platform.

6.2.1 S60 1st Edition

S60 1st Edition features the Video Recorder and has two different players, the Nokia embedded Video Player and RealPlayer. Only RealPlayer is visible as a launchable application in the application grid.

6.2.1.1 Video Recorder

The Video Recorder can record video clips using the integrated camera. The video clip is saved either in the internal memory of the device or to a memory card. The clip is coded according to the H.263 Profile 0, Level 10 standard, with or without AMR-NB audio. Image size is set to 128 x 96 (Sub-QCIF) and the maximum frame rate is 10 frames per second. The maximum multimedia file size is set to 100 KB. RealPlayer can be used to play back the recorded video clip.

6.2.1.2 Nokia Video Player

The Nokia Video Player is not visible in the application grid, but it has been integrated to e-mail and the MMS client and is used to play back local content such as files in the memory card, e-mail, and MMS attachments. Maximum bit stream for video clips has been set to 64 Kbit/s. With H.263 codec, such a bit stream can be utilized to process 10 to 15 frames per second, depending on the content and encoding tools involved in content authoring. The optimal size for clips is 176 x 144 pixels. This player cannot be used to stream video or audio; it is meant only for local file playback.




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6.2.1.3 RealPlayer

Figure 2: RealPlayer in the Nokia 3650 device

• RealPlayer can be used to play local content as well as stream from remote streaming servers over General Packet Radio Service (GPRS) and CSD connections.

You can find Nokia products based on S60 1st Edition on the Forum Nokia Web site (http://www.forum.nokia.com/series60 | Devices).

6.2.2 S60 2nd Edition


Figure 3: Nokia 6600 Video Recorder

The Video Recorder can record video clips using the integrated camera. The video clip is saved either in the internal memory of the device or to a memory card. Clips are coded according to the H.263 Profile 0, Level 10 standard, or MPEG-4 Visual in some devices, with or without the AMR-NB audio track. Image size can be selected between 128 x 96 (Sub-QCIF), 176 x 144 (QCIF), or 352 x 288 (CIF) with a maximum 15 fps frame rate. RealPlayer can be used to play back the recorded video clip.


http://www.forum.nokia.com/series60

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6.2.2.2 RealPlayer

RealPlayer has been integrated to e-mail and the MMS client and is used to play back local content such as files in the memory card, e-mail, and MMS attachments. It can also be used to stream video content from remote streaming servers over GPRS, Enhanced GPRS (EGPRS), and CSD connections. Maximum bit stream for video clips has been set to 128 Kbit/s. With H.263 codec, such a bit stream can be utilized to process 10 to 15 frames per second, depending on the content and encoding tools involved in content authoring. The optimal size for clips is 176 x 144 pixels. Note that some devices may include hardware accelerated codecs, thus allowing better resolution and bit rates. Check actual device details at the Forum Nokia Web site (http://www.forum.nokia.com/audiovideo).

You can find Nokia products based on S60 2nd Edition on the Forum Nokia Web site (http://www.forum.nokia.com/series60 | Devices).

6.2.3 S60 3rd Edition


The Video Recorder can record video clips using the integrated camera. The video clip is saved either in the internal memory of the device or to a memory card. Clips are coded according to the H.263 Profile 0, Level 10 standard, or MPEG-4 Visual in some devices, with or without AAC audio track. Image size can be selected between 128 x 96 (Sub-QCIF), 176 x 144 (QCIF), or 352 x 288 (CIF), with a maximum 15 fps frame rate. RealPlayer can be used to play back the recorded video clip.

6.2.3.2 RealPlayer

RealPlayer has been integrated to e-mail and the MMS client and is used to play back local content such as files in the memory card, e-mail, and MMS attachments. It can also be used to stream video content from remote streaming servers over GPRS, EGPRS, Wideband CDMA (WCDMA), and CSD connections. With H.263 codec, such a bit stream can be utilized to process 10 to 15 frames per second, depending on the content and encoding tools involved in content authoring. The optimal size for clips is 176 x 144 pixels. Note that some devices may include hardware accelerated codecs, thus allowing better resolution and bit rates. Check actual device details on the Forum Nokia Web site (http://www.forum.nokia.com/audiovideo).

You can find Nokia products based on S60 3rd Edition on the Forum Nokia Web site at http://www.forum.nokia.com/series60 | Devices.

6.3 Series 80 2nd Edition

6.3.1 Video Recorder

The Video Recorder can record video clips using the integrated camera. The video clip is saved either in the internal memory of the device or to a memory card. Clips are coded according to the H.263 Profile 0, Level 10 standard, with or without AMR-NB audio depending on the device settings. Image size can be selected between 128 x 96 (Sub-QCIF) and 176 x 144 (QCIF) with a maximum 10 fps frame rate. RealPlayer can be used to play back the recorded video clip.

6.3.2 RealPlayer

RealPlayer has been integrated to e-mail and the MMS client and is used to play back local content such as files in the memory card, e-mail, and MMS attachments. It can also be used to stream video content from remote streaming servers over GPRS, EGPRS, and CSD connections. Maximum bit stream for video clips has been set to 128 Kbit/s. With H.263 codec, such a bit stream can be utilized to






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process 10 to 15 frames per second, depending on the content and encoding tools involved in content authoring. The optimal size for clips is 176 x 144 pixels. Check full device details on the Forum Nokia Web site (http://www.forum.nokia.com/audiovideo).

You can find a list of Nokia Series 80 products on the Forum Nokia Web site (http://www.forum.nokia.com/series80 | Devices).

6.4 Nokia 7710 Device

6.4.1 Video Recorder

The Video Recorder can record video clips using the integrated camera. The video clip is saved either in the internal memory of the device or to a memory card. Clips are coded according to the H.263 Profile 0, Level 10 standard, with or without AMR-NB audio depending on the device settings. Image size can be selected between 128 x 96 (Sub-QCIF) and 176 x 144 (QCIF) with a maximum 10 fps frame rate. The maximum multimedia file size is set to 95 KB. RealPlayer can be used to play back the recorded video clip.

6.4.2 RealPlayer

RealPlayer has been integrated to e-mail and the MMS client and it is used to play back local content such as files in the memory card, e-mail, and MMS attachments. It can also be used to stream video content from remote streaming servers over GPRS, EGPRS, and CSD connections. Maximum bit stream for video clips has been set to 128 Kbit/s. With H.263 codec, such a bit stream can be utilized to process 10 to 15 frames per second, depending on the content and encoding tools involved in content authoring. The optimal size for clips is 176 x 144 pixels. Check full device details on the Forum Nokia Web site (http://www.forum.nokia.com/audiovideo)

You can find more information about the Nokia 7710 device on the Forum Nokia Web site (http://forum.nokia.com/7710).





http://forum.nokia.com/7710

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7 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.

Available transfer bandwidth for streaming sessions will vary based on the access technology used and the configuration of the operator network. 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.

Figure 4: Streaming in mobile network

7.1 Streaming Video Creation – Basic Steps

The following procedure outlines the basic steps in streaming video creation:

1. Select one of any of the commonly used video editing tools, e.g., QuickTime, Adobe, etc., to create the video content.

2. Export your content to the compressed format (RealMedia or 3GPP formats) and perform the actual crunching compression.

3. Here the 3GPP file may be "hinted" in preparation for the streaming session.

4. The server extracts the media content from the file and sends it to the network, according to the appropriate payload formats.

Video editing Compression and conversion to 3GP or MP4

Hinting tool, if needed

Streaming server

Depending on the implementations, some of the steps described above can be merged. A server may be capable of doing media transport protocol layer packetization on the fly, that is, it may be able to understand a nonhinted file and simply stream it. Encoding and hinting can also be merged in the same element. This is the case, for example, in the Helix Mobile Producer (for 3GPP media) and the


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Apple QuickTime Pro tool (version 6.3 and above) with 3GPP support. Since there’s no common hinting language for streaming server files yet, all hinting tools today address one specific server.

7.1.1 3GPP-compatible content authoring tools

Video Conversion

Input Output Basic Editing (Cut and Paste)

Hint Track Generation

Server

RealNetworks RealProducer .AVI, MPEG, etc.

*.rm No No, not needed for Real Streaming

Yes, for Real Media

RealNetworks and Envivio

Helix Mobile Producer

.AVI, MOV, MPEG, etc.

*.3gp No Yes, for 3GPP-serving Real servers

Yes, Helix Universal Server Mobile (3GPP-serving Real servers)

Nokia Nokia Multimedia Converter 2.0

.AVI,

.MOV, MPEG, etc.

*.3gp No No Noncommercial test server. Packetization on the fly – omits any hint tracks

Apple QuickTime Pro

.AVI,

.MOV,

.MPEG, etc.

*.3gp Yes Yes, for Apple QuickTime Streaming Server

Yes, QuickTime Streaming Server

PacketVideo pvAuthor .AVI .MOV .MPEG .etc

*.3gp No No No

7.1.2 Players for PC environment

Player Name

Free Version

Commercial Version

3GPP Support

Web Link

RealNetworks RealPlayer Yes, basic version

Yes, RealPlayer Plus

Yes http://www.real.com/


http://www.real.com/

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Apple QuickTime

Yes QuickTime Pro (allows exporting to 3GP)

Yes http://www.apple.com/quicktime

PacketVideo PV player No Yes Yes http://www.packetvideo.com/

Nokia Nokia Multimedia Player

Yes No Yes http://www.nokia.com/pcsuite

Note: Nokia does not guarantee the correctness and completeness of the information provided above about third-party software. This list is meant as an aid to developers who wish to probe further, and does not imply any endorsement by Nokia, nor any guarantee about the availability, performance, compliance with 3GPP specifications, and conditions of use of this software.

The reader is encouraged to retrieve updated information directly from the relevant companies.

7.2 Network and Bit-Rate Options for Streaming

Table 1 includes identified network service configuration options for streaming, differentiated by the network technology over which the service is intended to be used.

Table 1: Network and bit-rate options for streaming

Configuration Number

Network Configuration Available Bandwidth, kbit/s

Suggested Bit Rate for Streamable Content, kbit/s

1** HSCSD 2 TS DL 28.8 20

2** HSCSD 3 TS DL 43.2 35

3 GPRS 2 TS DL (CS 2) 26.8 20

4 GPRS 3 TS DL (CS 2) 40.2 28

5 GPRS 4 TS DL (CS 2) 53.6 38

6 EGPRS 2 TS (MCS 6) 59.2 42

7 EGPRS 3 TS (MCS 6) 88.8 63

8 EGPRS 4 TS (MCS 6) 118.4 84.2

9 WCDMA GBR=MBR=64 64 47


http://www.apple.com/quicktime

http://www.packetvideo.com/

http://www.nokia.com/pcsuite

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10 WCDMA GBR=MBR=128 128 92

11 CDMA20001xRTT 144 40

12 CDMA20001xEV-DO

2400 64 – 100

13 CDMA2000 1xEV-DV

3100 64 - 100

** Connection method could be ISDN V.110, ISDN V.120, or normal modem type

Disclaimer: Note that other manufacturer’s devices may be providing time-slot combinations or WCDMA downlink bearers not listed in the table, and network operators may limit their service offering, QoS parameters such as maximum or guaranteed bit rate, or allocation of time slots per EGPRS subscriber. Thus, consultation with the operators is recommended. Real-time dataflow, for example, video/audio streaming, requires a more stable bit rate than best-effort data like browsing or e-mail. That’s why the suggested bit rate is slightly lower than the available bandwidth for the configuration. Note also that suggested bit rates in Table 1 are media bit rates (audio+video) and don’t include packetization headers.

7.3 Content Creation with 3GPP Codecs

This section lists the basic technical information on available coding parameters per each codec, and gives parameterization guidance on most important adjustable media parameters. The same media types are usually available for local playback on the device and/or via streaming services from a remote server, thus developers should note that some parameterization applies only for streaming. Note that optional media types may not be supported depending on the client device capabilities.

7.3.1 Audio

7.3.1.1 Adaptive Multi-Rate Narrowband Speech Codec (AMR-NB)

• Mandatory speech codec in 3G PSS

• Mainly used for speech encoding at a very low bit rate

• Sampling frequency: 8,000 Hz, mono

• One AMR frame = 20 ms = 160 samples

• Can be used for both Constant Bit Rate (CBR) and Variable Bit Rate (VBR) encoding/decoding

• Main CBR encoder bit-rate switches (kbit/s): 4.75 – 5.15 – 5.90 – 6.70 – 7.40 – 7.95 – 10.2 – 12.2

• VBR can be achieved by dynamically changing the bit-rate switch. Switching can be done on a frame-by-frame basis

• Possible relevant encoder switches:

o DTX (ON/OFF): When ON, uses silence indicators (SID) for silence frames, that is, consumes fewer bits

7.3.1.2 Adaptive Multi-Rate Wideband Speech Codec (AMR-WB)

• Mainly used for high-quality speech/low-quality audio encoding at low bit rate

• Sampling frequency: 16,000 Hz, mono


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• One AMR-WB frame = 20 ms = 320 samples

• Can be used for both CBR and VBR encoding/decoding

• Main CBR encoder bit-rate switches (kbit/s): 6.60 – 8.85 – 12.65 – 14.25 – 15.85 – 18.25 – 19.85 – 23.05 – 23.85


• Possible relevant encoder switches:

o DTX (ON/OFF): When ON, uses SID for silence frames, i.e., consumes fewer bits

7.3.1.3 MPEG-4 Advanced Audio Codec (AAC)

• Optional audio codec in 3G PSS

• Mainly used for high-quality audio encoding at reasonable bit rates

• Sampling frequency: Up to 48,000 Hz, mono/stereo

• Support for AAC-LC (Low Complexity Mode); may also support AAC-LTP (Long Term Prediction)

• One AAC frame = 1,024 samples

• Can be used for both CBR and VBR encoding/decoding

• Reasonable encoder bit-rate switches (kbit/s): 24 – 48 – 56 – 96


7.3.2 Video

7.3.2.1 H.263

• Mandatory video codec in 3G PSS

• Supports H.263 Profile 0 Level 10; may also support Profile 3 Level 10

• Frame size: QCIF (176 x 144) or Sub-QCIF (128 x 96)

• Frame rate: Max. 15 fps

• Bit rate: Max. 64 kbit/s*

• Content can be encoded using constant frame rate or variable frame rate, not exceeding the selected frame rate

• Content can be encoded using CBR or VBR, not exceeding the selected bit rate

• Reasonable CBR encoder bit-rate switches (kbit/s): 15 – 20 – 25 – 30 – 35 – 40 – 50 – 60 (the actual bit rate takes into account the presence of other medium and the bearer size)

* Bit rate can be exceeded in local playback beyond the conformance level point, up to ~128 kbit/s, while frame rate is saturated in 15 fps. Performance may degrade if player settings are set to prefer sharp image to fast frame rate or associated audio content will cause player to consume more computational power than available at the device hardware.

7.3.2.2 MPEG-4 Visual

• Optional video codec in 3G PSS

• Support Visual Simple Profile Level 0

• Frame size: Max. QCIF (176 x 144). Suggested QCIF or Sub-QCIF


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• Frame rate: Max. 15 fps

• Bit rate: Max. 64 kbit/s*

• Content can be encoded using constant frame rate or variable frame rate, not exceeding the selected frame rate

• Content can be encoded using CBR or VBR, not exceeding the selected bit rate

• Reasonable CBR encoder bit rate switches (kbit/s): 15 – 20 – 25 – 30 – 35 – 40 – 50 – 60 (the actual bit rate takes into account the presence of other medium and the bearer size)

* Bit rate can be exceeded in local playback beyond the conformance level point, up to ~128 kbit/s, while frame rate is saturated in 15 fps. Performance may degrade if player settings are set to prefer sharp image to fast frame rate or associated audio content will cause player to consume more computational power than available at the device hardware.

7.4 Suggested Video Encoder Configurations

Table 2: Information applies to both H.263 and MPEG-4 Visual.

Video Bit Rate (only video, kbit/s)

Frame Size (pixels) Suggested Intra Refresh Period Range (seconds)*

Suggested Frame Rates (constant fps)

Sub-QCIF (128 x 96) 5 – 10 5 to 7.5 15

QCIF (176 x 144) 5 – 10 2.5 to 3

Sub-QCIF (128 x 96) 5 – 10 7.5 to 10 20

QCIF (176 x 144) 5 – 10 3 to 5

Sub-QCIF (128 x 96) 5 – 10 10 to 15 25

QCIF (176 x 144) 5 – 10 5 to 7.5

Sub-QCIF (128 x 96) 5 - 10 10 to 15 30

QCIF (176 x 144) 5 - 10 7.5 to 10

Sub-QCIF (128 x 96) 5 - 10 10 to 15 35

QCIF (176 x 144) 5 - 10 7.5 to 10

Sub-QCIF (128 x 96) 5 - 10 10 to 15 40

QCIF (176 x 144) 5 - 10 10 to 15

Sub-QCIF (128 x 96) 5 - 10 15 50

QCIF (176 x 144) 5 - 10 15


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Sub-QCIF (128 x 96) 5 - 10 15 60

QCIF (176 x 144) 5 - 10 15

* The Intra frames help resynchronization at rebufferings during streaming, as well as qualitative improvement if packet losses occur. The Intra period may be decreased/increased to gain from quality. The suggested value for content served on-demand is 10 seconds.

• Streaming use case: Selected video bit rate = suggested total bit rate (network) – selected audio bit rate

• A selection of two-pass encoder could increase the visual quality with the same bit-rate budget

• Usage if variable fps could increase image quality, but could also introduce time-wise nonconstant frame updates on the display screen

• Intra refresh period can be changed to tune the visual quality. For 3G PSS streaming, Intra frames are generally anchor points for stream synchronization for a server

o A maximum Intra period of 10 seconds is suggested for on-demand and live streaming configurations

o For local video clips sent, for example, via MMS, forced periodic Intra frames are unnecessary, given that the used encoder process always provides the Intra frame after a scene change event in the source sequence


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8 Tools for Video Content Creation

Forum Nokia offers tools for creating video content aimed at mobile devices. Nokia Multimedia Converter 2.0 has the ability to convert the most common video/audio formats, such as AVI, MOV, MP3, and WAV, to 3GP file format. This tool also includes a console version, which enables developers to integrate the conversion to their system and convert the content on the fly. The tool is available at the Forum Nokia Web site, http://www.forum.nokia.com/tools.

8.1 RealMedia Content Creation with RealProducer and Helix Mobile Producer Authoring Tools

This section presents parameterization guidance for generation of mobile optimized content with RealMedia content types via the dedicated tools available from RealNetworks. In general, official content authoring guidelines are also available directly from RealNetworks at http://www.realnetworks.com/resources/howto/mobile/index.html.

8.1.1 Video encoding

• Use RealVideo 8, RealVideo 9, or RealVideo 10 encoding. For the best possible compatibility, use RealVideo 8

• Use two-pass encoding

• Enable VBR

• Use VBR startup latency of 10 seconds

• Use key-frame difference of 10,000 milliseconds

• Enable loss protection

• Suggested motion-related parameter: “Normal Motion Video”

• Frame size (suggested): QCIF (176 x 144) or Sub-QCIF (128 x 96)

• Maximum frame rate suggested: 15 fps (10 fps is the safest from RealPlayer Mobile performance point of view)

• For local playback use case, the maximum bit rate suggested is 80 kbit/s

• For streaming use case, see Table 2 in Section 7.4, which is also applicable to RealVideo

8.1.2 Audio encoding

• Use RealAudio 8 or RealAudio Voice (for speech)

• Use frequency response from 8 to 16 kHz for speech and from 20 to 44 kHz for music

• Streaming use case: Selected audio bit rate = selected total bit rate (network) – selected video bit rate

8.2 Tips and Tricks

There are many small details and bits of information that will make the end-user experience of mobile video more appealing. Below are several very basic authoring guidelines for selecting and editing content.

8.2.1 Selectivity for authored sequences

Authors should avoid source video sequences with:


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http://www.realnetworks.com/resources/howto/mobile/index.html

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o Blank or black first frame (resulting from a video edit)

o High scene-change frequency (one per 1- 2 seconds or fractions of a second)

o Fast horizontal/vertical or diagonal panning

o Fast zooming

• Encoding at 20 – 50 kbit/s and 3 –5 fps achievable via streaming over GPRS cannot reproduce TV-like end-user experience, irrespective of technology used.

• A badly chosen video sequence can ruin the result of an otherwise optimal content creation process.

• Avoid re-encoding from an already encoded content. Always use the source audio and video sequences.

8.2.2 Multiple encodings

It may be advisable to generate multiple bit-rate versions of the content at the same time, once it is aimed for streaming and for several terminal types that can utilize various radio technologies (GPRS, EGPRS, WCDMA, CDMA in the U.S. and Korea, etc.). Table 1 in Section 7.2 gives a good estimate of the suitable total session encoding rates, including the packetization overheads.

As long as the 3GPP service is unable to signal the alternative bit-rate sessions for the mobile client (Rel-4, Rel-5 versions of the PSS service), the session offering towards the mobile client must be based on the client’s indicated capabilities. Nokia streaming-enabled terminals will provide the necessary profiling and capability information via the CC/PP- and UAProf-based mechanism defined in the 3GPP technical specification 26.234.

The aforementioned Rel-4 and Rel-5 limitation also applies to file management — lack of a generally defined server file format gives server manufacturers freedom to select their preferred solution for content management on and preparation for the specific streaming server. For content authors, the guideline is to generate a 3GP file with or without hint track, and include only the specific media track on the file. Tool and server manufacturers may have their own guidance on the file preparation requirements in order to ensure that the files are streamable from the manufacturer’s server platform.


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9 Video Client Application Development

9.1 Symbian C++

There are already several sources of information about video client application development. The following list presents documentation and examples related to the subject.

Documentation:

• Symbian OS: Creating Video Applications In C++ http://www.forum.nokia.com/documents| C++ Documents

• Introduction To Symbian OS v7.0s Multimedia Framework: http://www.symbian.com/technology/symbos-v7s-det.html#t6

• C++ MMF API references (included also in SDK help):

• MMF Base classes: http://www.symbian.com/developer/techlib/v70sdocs/doc_source/reference/cpp/MMFBaseClasses/index.html#MMFBaseClasses%2eindex

• MMF Client: http://www.symbian.com/developer/techlib/v70sdocs/doc_source/reference/cpp/MMFClient/index.html#MMFClient%2etoc

• MMF Common: http://www.symbian.com/developer/techlib/v70sdocs/doc_source/reference/cpp/MMFCommon/index.html#MMFCommon%2etoc

• MMF Controller: http://www.symbian.com/developer/techlib/v70sdocs/doc_source/reference/cpp/MMFController/index.html#MMFController%2eindex).

• Using Multimedia Framework – Client API: http://www.symbian.com/developer/techlib/v70sdocs/doc_source/DevGuides/cpp/MultiMedia/MMFClientApi/index.html#MMFClientApiCover%2eindex

• How To Write Multimedia Framework Plug-Ins: http://www.symbian.com/developer/techlib/v70sdocs/doc_source/DevGuides/cpp/MultiMedia/MMFGuide/index.html#MMFGuide%2eMMFGuide. Included also in SDK help.

Examples:

• Series 60 Developer Platform 2.0: Video Example v1.0 http://www.forum.nokia.com/symbian | Code and Examples

• Series 60 Developer Platform 2nd Edition Feature Pack 1: Video Recorder/Player Example http://www.forum.nokia.com/symbian | Code and Examples

9.2 Java™ Technology

In Java technology, access to the device’s camera is implemented through the Mobile Media API (JSR-135), which provides the support to play back and record video and audio.

Documents:

• Mobile Media API (JSR-135) Specification: http://jcp.org/aboutJava/communityprocess/final/jsr135/

• Working With The Mobile Media API (JSR-135) – Part I: http://www.symbian.com/developer/techlib/papers/Working_with_Mobile_Media_API.pdf


http://www.forum.nokia.com/documents

http://www.symbian.com/technology/symbos-v7s-det.html#t6

http://www.symbian.com/developer/techlib/v70sdocs/doc_source/reference/cpp/MMFBaseClasses/index.html#MMFBaseClasses%2eindex

http://www.symbian.com/developer/techlib/v70sdocs/doc_source/reference/cpp/MMFBaseClasses/index.html#MMFBaseClasses%2eindex

http://www.symbian.com/developer/techlib/v70sdocs/doc_source/reference/cpp/MMFClient/index.html#MMFClient%2etoc

http://www.symbian.com/developer/techlib/v70sdocs/doc_source/reference/cpp/MMFClient/index.html#MMFClient%2etoc

http://www.symbian.com/developer/techlib/v70sdocs/doc_source/reference/cpp/MMFCommon/index.html#MMFCommon%2etoc

http://www.symbian.com/developer/techlib/v70sdocs/doc_source/reference/cpp/MMFCommon/index.html#MMFCommon%2etoc

http://www.symbian.com/developer/techlib/v70sdocs/doc_source/reference/cpp/MMFController/index.html#MMFController%2eindex

http://www.symbian.com/developer/techlib/v70sdocs/doc_source/reference/cpp/MMFController/index.html#MMFController%2eindex

http://www.symbian.com/developer/techlib/v70sdocs/doc_source/DevGuides/cpp/MultiMedia/MMFClientApi/index.html#MMFClientApiCover%2eindex

http://www.symbian.com/developer/techlib/v70sdocs/doc_source/DevGuides/cpp/MultiMedia/MMFClientApi/index.html#MMFClientApiCover%2eindex

http://www.symbian.com/developer/techlib/v70sdocs/doc_source/DevGuides/cpp/MultiMedia/MMFGuide/index.html#MMFGuide%2eMMFGuide

http://www.symbian.com/developer/techlib/v70sdocs/doc_source/DevGuides/cpp/MultiMedia/MMFGuide/index.html#MMFGuide%2eMMFGuide

http://www.forum.nokia.com/symbian

http://www.forum.nokia.com/symbian

http://jcp.org/aboutJava/communityprocess/final/jsr135/

http://www.symbian.com/developer/techlib/papers/Working_with_Mobile_Media_API.pdf

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• Working With The Mobile Media API (JSR-135) – Part II: http://www.symbian.com/developer/techlib/papers/midptools/MobileMediapart2_v1.1.pdf

• Mobile Media API Implementation In Nokia Developer Platforms: www.forum.nokia.com/java | Documents

• Brief Introduction To The Mobile Media API: www.forum.nokia.com/java | Code and Examples


http://www.symbian.com/developer/techlib/papers/midptools/MobileMediapart2_v1.1.pdf

http://www.forum.nokia.com/java

http://www.forum.nokia.com/java

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10 Relevant Specifications

This chapter addresses the main 3GPP specifications related to mobile video and streaming and provides a brief synopsis of each one. Additional study of the basic standards set by other standardization bodies will provide more in-depth information. These specifications are, with some exceptions, available via the Internet, and are widely referenced in the 3GPP service specification.

10.1 3GPP Specifications

3GPP, the standardization body for third-generation mobile networks, has published several specifications related to mobile video and streaming:

Specification Description

TS 26.233: Transparent End-to-End Packet-Switched Streaming Services (PSS); General Description

A general description of a transparent packet-switched streaming service in 3G networks.

TS 26.234: Transparent End-to-End Packet-Switched Streaming Services (PSS); Protocols and Codecs

Specifies the protocols and codecs for the streaming service, standardized and deployed within the 3GPP compliant systems.

10.2 Other Specifications

Specification Description

IETF STD 0006: User Datagram Protocol

RFC 3550 - RTP: A Transport Protocol for Real-Time Applications

RFC 3551 –RTP: Profile for Audio and Video Conferences with Minimal Control

These documents specify the means for sending/transporting real-time or streaming data using UDP and streaming control with RTSP and SDP over TCP.

RFC 2429: RTP Payload Format for H.263 Video

RFC 3016: RTP Payload Format for MPEG-4 Audio/Visual Streams

RFC 3267: RTP Payload Format for AMR and AMR-WB Audio Codecs

These documents specify the real-time transport (RTP) payload formats to be used for the multimedia coded bit streams during streaming or at the storage phase.

IETF STD 007: TCP Protocol Specifies an application-level protocol for control over the delivery of prestored or real-time data. It enables VCR-like control capabilities for the user. RFC 2326: Real-Time Streaming Protocol

(RTSP)

RFC 2327: Session Description Protocol Specifies a protocol that enables the description of


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(SDP) the multimedia session with the help of a well-defined and formatted structure. This protocol is mainly utilized by the RTSP protocol.

ITU-T Recommendation H.263 Video

ISO/IEC 14496-2:2001: Coding of Audio/Visual Objects; Part 3: Audio (MPEG-4 Audio, a.k.a., AAC)

ISO/IEC 14496-2:2001: Coding of Audio/Visual Objects; Part 2: Visual (MPEG-4 Visual)

Documents specify the syntax of the encoded audio and video media bit streams.


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11 Terms and Abbreviations

Term or abbreviation Meaning

3GPP MIME subtype for 3GPP file format; also Third Generation Partnership Project (gen.)

3GP or 3gp File name extension for 3GPP file format

ADPCM Adaptive Pulse Code Modulation

AMR-NB Adaptive Multi-Rate Narrow Band speech codec

AMR-WB Adaptive Multi-Rate Wideband speech codec

API Application Programming Interface

AVI Microsoft Audio-Video Interleaved file format

CD-ROM Read-Only Compact Disc

CSD Circuit Switched Data

DCT Discrete Cosine Transform

GPRS General Packet Radio System

GSM Global System for Mobile Communication

HSCSD GSM High-Speed Circuit Switched Data

HTML Hypertext Markup Language

Hz Hertz, 1/sec

IMA Interactive Multimedia Association

ITU-T International Telecommunication Union, Telecommunication Standardization Sector

Kbit/s kilobits per second

MMS Multimedia Messaging Service

MOV or mov File name extension for Apple QuickTime file format

MPEG ISO/IEC Moving Pictures Experts Group

MPG or mpg File name extension for MPEG-1 file format

MP3 MPEG-1 Audio Layer 3 audio coding

MP4 MIME subtype for MPEG-4 file format

mp4 File name extension for MPEG-4 file format

NIM Nokia Interleaved Multimedia file format

PC Personal Computer

PCM Pulse Code Modulation

QCIF Quarter Common Intermediate Format

RAM or ram File extension for RealNetworks’ simple URI descriptor files

RGB Red-Green-Blue color space

RM or rm File extension for RealMedia file format


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Term or abbreviation Meaning

Sub-QCIF Sub-Quarter Common Interchange Format

WAV Microsoft waveform audio file format

YUV Color space, Y is the luminance or grayscale component; U and V are chrominance or color difference components


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12 References

[1] RFC 3267 – Real-Time Transport Protocol (RTP) Payload Format And File Storage Format For The Adaptive Multi-Rate (AMR) And Adaptive Multi-Rate Wideband (AMR-WB) Audio Codecs, June 2002

[2] 3GPP TS 26.190 – AMR Wideband Speech Codec (release 5), December 2001, Version 5.1.0

[3] 3GPP TS 26.201 – AMR Wideband Speech Codec; Frame Structure, March 2001, Version 5.0.0

[4] 3GPP TS 26.174 – Adaptive Multi-Rate (AMR) Wideband Speech Codec Test Sequences, December 2002, Version 5.4.0

[5] 3GPP TS 26.194 – AMR Wideband Speech Codec; Voice Activity Detector (VAD), March 2001, Version 5.0.0


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13 Evaluate This Document

Please spare a moment to help us improve documentation quality and recognize the resources you find most valuable, by rating this resource.


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