Mobile Blog: Video, Media, Augmented Reality, Rich Media, IVVR

photo credit: Georg Wittberger

Als Fortsetzung zu meinem Artikel vom April 2009 Videotelefonie in Deutschland hier die aktuelle Situation:

Vergleich Kosten von Videotelefonie (Stand: Februar 2010)

o2 Germany

Die Videotelefonie kostet in allen Tarifen, z.B. o2 o, leider weiterhin, ins O2 Netz € 0,69 und in andere deutsche Mobilfunknetze € 0,99. Nach Auskunft der o2 Kundenbetreuung sind keine Preissenkungen mehr zu erwarten. Ich muss als Videotelefonie-Kenner offen sagen: Zumindest bei o2 hat Videotelefonie keine Zukunft und wird daher weder vergünstigt noch durch interessante Services wie IVVR (Interactive Voice & Video Response) gepushed.

T-Mobile Deutschland

T-Mobile führt in seiner Tarifübersicht Videotelefonie nicht mehr auf. Aber aus den über 30-seitigen(!) Tarifdetails geht hervor, dass die Videotelefonie zu anderen T-Mobile Anschlüssen € 0,29 und in andere Netze 0,69 € pro Minute kostet. Im Vergleich zu € 0,59 bzw. € 1,20 gegenüber dem April 2009 ist dies eine deutliche Vergünstigung. Diese sollte T-Mobile bewerben!

E-Plus BASE

Videotelefonie ist nicht möglich. Siehe Fussnoten.

Vodafone Deutschland

In den SuperFlat Tarifen sind Videogespräche wie normale Sprachanrufe durch die Flatrates abgedeckt. Somit ist Videotelefonie für Vodafone SuperFlat Nutzer kostenlos!

Bitten beachten: Die günstigeren Tarife sind u.U. nur nach Vertragsverlängerung oder -umstellung nutzbar. Keine Gewähr.

Video call set-up times are generally between 1 to 5 seconds (1-second call set-up when using MONA specified in H.324 Annex K.) independently of the IVVR (Interactive Voice & Video Response) application one is going to use, which is sometimes faster than the initialisation process of complex J2ME (Java 2 Micro Edition) applications. This makes quick on-the-go lookup or entry of information pleasant. However, what happens when the caller needs to interrupt a gaming session or the call is interrupted because of missing network coverage or exceeded battery life? Games should enable users to start and stop with breaks in between, since the time they have to spend may be brief. Mobile games are used especially to pass time for just a couple of minutes or even seconds when waiting for the bus, riding the subway, or to relieve boredom during TV commercials. Therefore, all mobile applications need to apply ways to interrupt a session and quickly resume to the last state as the user desires. This requirement also applies to IVVR applications. As application and user data of IVVR programs can be completely stored on the server-side, there are no limitations to auto-save program states or record the user’s actions. With the caller’s unique phone number as an identifier, it is easy to develop resumable applications.

photo credit: phauly

In desktop video conferencing, the video conferencing application is normally bundled to an Instant Messaging software that includes text chat capabilities. Users can appoint or prearrange a video conference using textual chat. In contrast, the current evolution of video telephony in UMTS (Universal Mobile Telecommunications System) networks based on the circuit-switched 3G-324M service does not seamlessly combine video conferencing with other communication channels. The notion of video telephony in the mobile environment is nearer to standard voice calling than in the stationary world. Therefore, it is more likely that somebody will place a video call without prior announcement. This leads to privacy and inconvenience concerns. The callee might not want to be seen during a conversation for a variety reasons: A video call “turns you ugly” (Harlow) because the build-in cameras are usually not placed just above the user’s line of sight but in the suboptimal position below the nose. Further, the video quality is meagre, and lightning conditions are poor. People might feel that exposing their face over a video call invades their privacy and, most times, callees do not want callers to see how he or she looks. Furthermore, the use of video telephony can depend on social factors. Societies in South East Asian countries—for example, Malaysia—are considered non-confrontational. This can be seen when people make decisions on which channel they use for communication. The author’s experiences in South East Asia revealed that most people prefer non-confrontational communication such as SMS (Short Message Service), instant messaging or e-mail, even in the business environment or with good friends. Voice calling is avoided as much as possible for a first or unexpected contact. It is obvious that P2P (Peer-to-peer) video calling is considered even more intrusive—and therefore unlikely to succeed in these societies.

According to an informal research of Sachendra Yadav (Yadav), opinion leaders and technology experts feel that video calling does not add much to a conversation compared to voice calling. In comparison to desktop video conferencing, which is mostly free nowadays, the cost-benefit analysis leads to resistance for using mobile video telephony.

For many reasons, 3G video telephony as a person-to-person conversational service is not as successful as projected. The existing technical foundation for video calling can be used to deliver IVVR (Interactive Voice & Video Response) services. A wide range of IVVR applications is imaginable, and some service providers and network operators already deploy them. Furthermore, special IVVR applications such as P2P Video Avatar can even compensate the drawbacks of classic P2P video telephony, making P2P-alike video telephony successful after all.

photo credit: Iain Farrell

Even with a great deal of marketing, early attempts to convert users to the video telephony technology flopped (Jones and Marsden). In contrast, desktop video conferencing is incredibly popular for private person-to-person conversations and widely used for video conferencing in business environments such as telepresence for computer-supported cooperative work (CSCW).

In desktop video conferencing scenarios, typically a stationary computer is used. Camera and microphone are fixed and usually maintain the same distance from the person participating during the conversation. Moreover, lighting conditions are generally better than “on-the-go”, as a desktop is easier to illuminate correctly than a scene in the mobile environment. When performing mobile video telephony, lighting conditions change over time when the caller moves or the environment changes; moreover, the camera is usually not fixed. During mobile video telephony, the caller is likely to hold the handset in front of his face by extending his arm, making the video wiggly. In combination with the meagre bandwidth and low-resolution video, this can considerably degrade the video quality shown on the callee’s side. These considerations about the video quality problems in the mobile environment also play a major role in IVVR (Interactive Voice & Video Response) applications that take advantage of the instant video streaming capabilities that 3G-324M video telephony offers. Bad video quality negatively influences camera-based games, gesture recognition, or P2P (Peer-to-peer) services that intentionally change the video for dynamic video overlays such as for the P2P Avatar, because motion analysis algorithms perform better with a sharp and clear video signal.

photo credit: Steven Fernandez

Media compression, error concealment measures, and the characteristics of wireless networks have side effects on the quality of 3G video telephony and IVVR (Interactive Voice & Video Response) applications.

3G-324M requires only the use of speech codecs. In contrast to audio codecs, speech codecs are designed for speech transmission within a narrow frequency range, making them inappropriate for transmission of music or a range of artificial sounds. This fact needs to be considered when designing IVVR applications—especially games, as most games utilize music and sound effects to create an immersive atmosphere.

H.263 and MPEG-4 Part II baseline were designed for images of natural scenes with predominately low-frequency components, meaning that the colour values of spatial and temporally adjacent pixels vary smoothly except in regions with sharp edges. In addition, human eyes can tolerate more distortion of high-frequency components than of the low-frequency components (Kwon and Driessen). In reference to the explanation of Kwon and Driessen, video codecs used for 3G-324M video telephony are great for natural scenes and talking-head scenarios. Depending on the type of IVVR application, these characteristics work against a good user experience.

Typical desktop or web applications have a monochromatic user-interface with boxes, buttons, and fonts that are clearly readable. Based on user interaction, the user interface can change its appearance frequently, perhaps only for some parts of the user interface or perhaps the whole screen. It is obvious that codecs used for 3G-324M video telephony are unsuitable for this kind of video transmission. Compressing such user interfaces with H.263 creates blurred fonts and tattered buttons and lines, leading to a user interfaces too distorted for a good user experience. The comparable high round-trip delays can make interaction tedious, with interfaces that require a high rate of user interaction and screen changes.

Depending on the type of game, the compression characteristics of video codecs used in 3G-324M can be advantageous. Contemporary 3D games such as first-person shooters or simulation games try to model the game environment as realistic as possible, creating natural-looking scenes and making them appropriate for compression using video codecs defined for 3G-324M.

However, more problematic are the delay requirements for mobile games that are essential for a good gameplay experience. 3GPP (3rd Generation Partnership Project) defines a delay variation of below 75ms for real-time games  and considers first-person shooters the most demanding ones with respect to delay requirements (3GPP). Other types of games, such as turn-based strategy games or visual novels, may tolerate a higher end-to-end delay and may require lower data rates.