Information Technology Reference
In-Depth Information
for quantifying purposes. The objective of the thesis is to research
the relationship of the spatiotemporal dynamics of the content and
network status to the deduced perceptual quality of a H.263-based
encoded video. Once this relationship has been established, it is
shown how it can be further exploited toward proposing a technique
for video quality prediction at a pre-encoding state.
3.2 Research on Circuit-Switched Mobile Video
3G-324M [15,16] is an umbrella standard that enables real-time multime-
dia services over CS wireless networks. It includes protocol elements for
multiplexing and demultiplexing of speech, video, user, and control data
(H.223) [7-11] in a single 64 Kb/s circuit, call control (H.245). video (H.263 [13]
and MPEG-4) and audio codecs [19] (AMR-NB [20-23] and G.723.1 [12]). A
block diagram of 3G-324M and the relevant 3GPP specifications is presented in
Figure 3.1. Note that the 3GPP [17] call setup requirements are spread in several
documents. The 3G-324M is derived from H.324 [14], which is a standard made
by ITU-T for low bit rate multimedia communication, while H.245 and H.223
are two main parts under H.324 and have given specific descriptions about the
procedures of message transformation and data transmission multiplexing.
H.324 and its annex C are referred to as H.324M for mobile terminals.
3.2.1 Summarization of the H.324
H.324 describes terminals for low bit rate multimedia communication, utiliz-
ing V.34 modems operating over the General Switched Telephone Network
(GSTN). H.324 terminals may carry real-time voice, data and video, or any
combination, including video telephony.
Videocap
Audiorec
Videoplay
Audioplay
Video
encoder
Audio
encoder
Video
decoder
Audio
decoder
3G-324M Protocol Stack
3G Network Interface
Figure 3.1
3G324M General structure.
