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1. Introduction
Video streaming service is widely used according to the development of
wired and wireless network environment and video coding
technology. The streaming video service in the fluctuant and
heterogeneous network environments is required by ubiquitous
video consumption. To satisfy these requirements in the
streaming video service, we can use the SVC (MPEG-4 Scalable
Video Coding) bitstream whose syntax enables a scalable data
extraction. Further, it is necessary to extract a bitstream in
real-time by changing scalabilities.
In our research, we propose the model of real-time bitstream
extractor. And we also suggest the extraction methods of the
bitstream with changing scalability in real-time.
2. Real time Scalable Bitstream Extraction
For QoS guaranteed video streaming in the fluctuated network, one needs to
change bitstream scalability in real-time. In this project, we
propose a real-time bitstream extractor. To have the real-time
bitstream extractor, the following three points could be
considered. One is that bitstream information for the extraction
is analyzed and stored before actual extraction process. Second,
the extractor should have appropriate structure to be able to
process in real-time according to varying input parameters.
Third, the extractor should have a reasonable processing unit to
extract the bitstream in real-time by changing scalability.
Figure 1 shows the proposed structure (a) and algorithm (b) of
the bitstream extractor. |
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Fig. 1. (a) Extractor Structure
(b) Extractor Algorithm |
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As shown in figure 1, the proposed extractor consists of
two parts: Bitstream Analyzer, Bitstream Extractor. Input
parameters of the proposed extractor have four values:
resolution, frame rate, required bitrate, and CGS_Flag. Input
parameters decide a scalability measure for the extracted
bitstream. The processing unit which works in real-time is a GOP
unit, which is minimum data unit to support the scalability of
SVC bitstream. The bitstream analyzer analyzes and keeps the
bitstream information needed for the extraction. The process of
extraction is performed in the bitstream extraction part. |
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Fig.
2. Extraction point decision module. |
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The proposed extraction algorithm in this project is
composed of 3 steps. First step is to decide a proper extraction
point by using input parameters and bitstream information. The
extraction point decision module decides the decision of
extraction point and outputs 3 parameters: Ext_Spatial_Layer,
Ext_Temporal_Level, Ext_FGS_Layer. The Ext_Spatial_Layer has the
value of dependency id of the input resolution. The
Ext_Temporal_Level has the temporal level of the input frame
rate. The Ext_FGS _Layer is decided by the required bitrate. In
second step, input source bitstream is divided into GOP unit in
the bitstream separation module and the segmented bitstream is
sent to the extraction module. In third step, extraction module
extracts the segmented bitstream by using the output parameter
of the extraction point decision module(figure 2). Three steps
are repeated until the end of input bitstream.
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Fig.
3. Temporal(Frame rate) Change |
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Fig.
4. Quality(SNR) Change |
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| 3. Experiments
The information of test SVC bitstream for the experiment is shown
below(Table1, 2 and 3). |
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Table 1.Test
Bitstream Information |
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Table
2.Bitstream Information |
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Table
3.Input Parameter |
| Follows figures are Implemented GUIs. |
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Fig.
5.Server GUI |
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Fig.
6.Client GUI |
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Below figure is Result of this Experiment.
This result is something for validating the proposed methods.
Test result give the evidence for good working of proposed extractor
with proposed extraction method. As a result, we identify the
validation of the proposed methods in this project. |
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Fig. 7.
Result |
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배태면, 김덕연, 노용만, 강정원,
김재곤,”실시간 스케일러빌러티 변환 SVC 비트스트림에 대한 연구”, 방송공학회 추계학술대회 |
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배태면, 김영석, 노용만, 최해철, 김재곤,
"QoS 기반 스트리밍 서비스를 위한 실시간 SVC 비트스트림 추출기에 대한 연구", 전자공학회 추계학술대회.
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Tae Meon Bae, Duck Yeon
Kim, Yong Man Ro, Hae Chul Choi, Jae Gon Kim ,"Real-time
Scalable Bitstream Extraction in Video Streaming Service" WIAMIS
2006 (submitted) |
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Dong San Jun, Jung Won
Kang , Hae Chul Choi, Jae Gon Kim,Tae Meon Bae, Yong Man Ro, “Dynamic
spatial layer switching support at the point of IDR picture”
JVT-R060, 75th MPEG JVT meeting |
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View The Demo
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