• The Journal of the Acoustical Society of Korea
• /
• v.22 no.7
• /
• pp.612-621
• /
• 2003

As the use of MP3 audio compression increased, the demand for the insertion of additive data about copyright or information on music contents has been groved and the related research has been progressed actively. When an additive data is inserted into MP3 bitstream, it should not to happen any distortion of music quality or the change of file size, due to the modification of MP3 bitstream structure. In our study, to make these conditions satisfied, we inserted some additive data to bitstream by modifying some bits of linbits among the quantized integer coefficients having big values. At this time, we consider the characteristics of linbits and their distributions. As a result of subjective sound quality test through MOS test, we confirmed that the quality of MOS 4.6 can be achieved at the data insertion rate of 60 bytes/sec. Using the proposed method, it is possible to effectively insert an additive data such as copyright information or information about media itself, so that various applications like audio database management can be realized.

• Journal of Broadcast Engineering
• /
• v.16 no.5
• /
• pp.693-704
• /
• 2011

As mobile devices become multi-functional, and converge into a single platform, there is a strong need for a codec that is able to provide consistent quality for speech and music contents. MPEG-D USAC standardization activities started at the 82nd MPEG meeting with a CfP and approved Study on DIS at the 96th MPEG meeting. MPEG-D USAC is converged technology of AMR-WB+ and HE-AAC V2. Specifically, USAC utilizes three core codecs (AAC, ACELP, and TCX) for low frequency regions, SBR for high frequency regions, the MPEG Surround for stereo information, and window transition technology for smoothing transition between various core coder. USAC can provide consistent sound quality for both speech and music contents and can be applied to various applications such as multi-media download to mobile devices, digital radio, mobile TV and audio books.

• The Journal of the Korea Contents Association
• /
• v.12 no.5
• /
• pp.1-9
• /
• 2012

The popularity of digital music and smart phones led to develope noise-robust real-time audio fingerprinting system in various ways. In particular, The Multiple Hashing(MLH) of fingerprint algorithms is robust to noise and has an elaborate structure. In this paper, we propose a filter engine based on MLH to achieve better performance. In this approach, we compose a energy-intensive filter to improve the accuracy of Q/R from music database and a statistic filter to remove continuity and redundancy. The energy-intensive filter uses the Discrite Cosine Transform(DCT)'s feature gathering energy to low-order bits and the statistic filters use the correlation between searched fingerprint's information. Experimental results show that the superiority of proposed algorithm consists of the energy and statistical filtering in noise environment. It is found that the proposed filter engine achieves more robust to noise than Philips Robust Hash(PRH), and a more compact way than MLH.

• Convergence Security Journal
• /
• v.8 no.4
• /
• pp.41-49
• /
• 2008

VoIP is a service that changes the analogue audio signal into a digital signal and then transfers the audio information to the users after configuring it as a packet; and it has an advantage of lower price than the existing voice call service and better extensibility. However, VoIP service has a system structure that, compared to the existing PSTN (Public Switched Telephone Network), has poor call quality and is vulnerable in the security aspect. To make up these problems, TLS service was introduced to enhance the security. In practical system, however, since QoS problem occurs, it is necessary to develop the VoIP security system that can satisfy QoS at the same time in the security aspect. In this paper, a user authentication VoIP system that can provide a service according to the security and the user through providing a differential service according to the approach of the users by adding AA server at the step of configuring the existing VoIP session is suggested. It was found that the proposed system of this study provides a quicker QoS than the TLS-added system at a similar level of security. Also, it is able to provide a variety of additional services by the different users.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.45 no.3
• /
• pp.44-53
• /
• 2008

In this paper, we present the design of delta-sigma modulation-based class-D amplifier for driving headphones in portable audio applications. The presented class-D amplifier generates PWM(pulse width modulation) signals using a single-bit fourth-order high-performance delta-sigma modulator. To achieve a high SNR(signal-to-noise ratio) and ensure system stability, the locations of the modulator loop filter poles and zeros are optimized and thoroughly simulated. The test chip is fabricated using a standard $0.18{\mu}m$ CMOS process. The active area of the chip is $1.6mm^2$. It operates for the signal bandwidth from 20Hz to 20kHz. The measured THD+N(total harmonic distortion plus noise) at the $32{\Omega}$ load terminal is less than 0.03% from a 3V power supply.

• Broadcasting and Media Magazine
• /
• v.11 no.4
• /
• pp.118-131
• /
• 2006

With rapid development in ultra fast communication and digital multimedia, the realistic broadcasting technology, that can stimulate five human senses beyond the conventional audio-visual service is emerging as a new generation broadcasting technology. In this paper, we introduce a haptic broadcasting system and related core system and component techniques by which we can 'touch and feel' objects in an audio-visual scene. The system is composed of haptic media acquisition and creation, contents authoring, in the haptic broadcasting, the haptic media can be 3-D geometry, dynamic properties, haptic surface properties, movement, tactile information to enable active touch and manipulation and passive movement following and tactile effects. In the proposed system, active haptic exploration and manipulation of a 3-D mesh, active haptic exploration of depth video, passive kinesthetic interaction, and passive tactile interaction can be provided as potential haptic interaction scenarios and a home shopping, a movie with tactile effects, and conducting education scenarios are produced to show the feasibility of the proposed system.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.8 no.3
• /
• pp.622-629
• /
• 2004

Recently, as digital broadcasting and internet are spreaded out of the world, we can easily use informations with less restrictions of time and space. According to the current trends, concerns for the ways of representing multimedia data has been rapidly increased, and users demand the services with integrated document that takes not only simple text and image but also time varying audio-visual data. Therefore, in 1998, W3C presented an international standard, SMIL in order to solve multimedia object representation and synchronization problems. By using SMIL, various multimedia elements can be integrated as a multimedia document with proper view in a space and time. Using this SMIL document, we can create new internet radio broadcasting service that delivers not only audio data but also various text, image and video. In this paper, we describe on a SMIL document editor for the common users to be able to represent time varying multimedia data with special layout and synchronization of time and space.

• The Journal of the Acoustical Society of Korea
• /
• v.28 no.7
• /
• pp.589-598
• /
• 2009

As mobile devices become multi-functional, and converge into a single platform, there is a strong need for a codec that is able to provide consistent quality for speech and music content MPEG-D USAC standardization activities started at the 82nd MPEG meeting with a CfP and approved WD3 at the 88th MPEG meeting. MPEG-D USAC is converged technology of AMR-WB+ and HE-AAC V2. Specifically, USAC utilizes three core codecs (AAC ACELP and TCX) for low frequency regions, SBR for high frequency regions and the MPEG Surround tool for stereo information. USAC can provide consistent sound quality for both speech and music content and can be applied to various applications such as multi-media download to mobile device Digital radio Mobile TV and audio books.

• Journal of the Institute of Electronics Engineers of Korea TE
• /
• v.39 no.4
• /
• pp.355-355
• /
• 2002

In this paper, we designed a FPU(floating point unit) that it is very important and requires of high density when digital audio is designed. Almost audio system must support the multi-channel and required for high quality. A floating point arithmetic function in MPEG-2 AAC that implemented by hardware is able to realtime decoding when DSP realization. The reason is that MPEG-2 AAC is compatible to the Audio field of MPEG-4 and afterwards. We designed a FPU by hardware to increase the speed of a floating point unit with much calculation part in the MPEG-2 AAC Decoder. A FPU is composed of a multiplier and an adder. A multiplier used the Radix-4 Booth algorithm and an adder adopted 1's complement method for speed up. A form of a floating point unit has 8bit of exponent part and 24bit of mantissa. It's compatible with the IEEE single precision format and adopted a pipeline architecture to increase the speed of a processor. All of sub blocks are based on ISO/IEC 13818-7 standard. The algorithm is tested by C language and the design does by use of VHDL(VHSIC Hardware Description Language). The maximum operation speed is 23.2MHz and the stable operation speed is 19MHz.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2008.10a
• /
• pp.524-527
• /
• 2008

Recently, digital and the Internet are widespread out of the world, and multimedia processing technology and the development of information and communication technology in education using the Internet as the demand is rapidly increasing. Also, we tan easily use informations with less restrictions of time and space. however, several kinds of audio, media to integrate multimedia data, such as the proliferation of demands for representation. Therefore, in 1998, W3C presented an international standard, SMIL in order to solve multimedia object representation and synchronization problems. By using SMIL, various multimedia elements can be integrated as a multimedia document with proper view in a spate and time. Using this SMIL document, we can create new internet radio broadcasting service that delivers not noly audio data but also various text, image and video. In this paper, with the system, teachers can easily create multimedia courseware and living broadcast their torture on network, students can receive audio-video information of the teacher, screen displays of the teachers computer. Moreover students can communicate with teacher simultaneously by text editor windows. Students can also order courseware after class.