• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.469-472
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• 2001

MPEC Audio Layer-III(MP3)알고리듬은 복호화기에 비해 부호화기가 월등히 많은 연산량을 가지고 있는 비대칭 구조를 가지고 있다. MP3 부호화기의 대부분의 연산량은 복잡한 초월함수 연산이 포함되는 심리음향모델과 반복 루프 과정을 수행하는 비선형 양자화와 비트 할당과정 이 차지한다. 본 논문에서는 MP3 부호화기의 실시간 구현을 위한 알고리듬 레벨의 최적화를 수행하였다. MP3 부호화기의 연산량을 줄이기 위해 심리음향모델을 간략화하고 반복 루프의 회수를 최소화할 수 있는 방법을 제안하였다. 프레임당 한 그래뉼의 심리음향모델 정보를 계산하여 한 프레임 내에서의 심리음향모델 정보를 추정함으로써 연산량을 45% 이상 감소시켰다. 또한 외부 반복 루프의 반복 회수를 줄이기 위하여 외부 반복 루프의 반복에 따른 스케일 팩터(Scale Factor) 및 양자화 스탭의 증가 패턴을 관찰하고 최적화된 스캐일 팩터 증가 방법을 제안하였다. 제안된 고속화 방법은 주관적 음질 평가를 통해 성능을 검증하였다.

• The KIPS Transactions:PartD
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• v.9D no.2
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• pp.323-328
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• 2002

In recent years, e-Commerce is very active on the Internet, especially the World Wide Web alone: with the popularization of Internet using high-speed networks. Especially, Circulation of Multimedia Contents like MP3 data if widely being focused as one of the popular researches. However, the existing models of AOD (Audio On Demand) System lack substantial illegal copy protection or copyright protection. In this paper, we propose an AOD System that guarantees substantial illegal copy protection and copyright protection based on the PKI (Public Key Infrastructure). As transmitting MP3 data using the user's public key, the proposed .method prevents the attack of dropper during transmitting data. Also, it guarantees the right of users and distributors by prohibiting illegal users from using MP3 data.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.772-775
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• 2005

This paper describes a study on the digital watermarking algorithm which is used to confirm the copyright protection of digital audio data. The digital audio watermarking algorithm based on psychoacoustic model is used for the inaudibility of the watermark data. The psychoacoustic model which is a key algorithm in MP3 audio compression is analyzed by MATLAB simulation, and is applied to digital audio watermark insertion.

• The Journal of the Acoustical Society of Korea
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• v.32 no.4
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• pp.346-353
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• 2013

This paper deals with the implementation of a high-quality audio system for karaoke. For improving the key/tempo changes performance, we separated the audio into many musical instrument channels. By separating musical instrument channels, high-quality key/tempo changes can be achieved and we confirmed this using the cross-correlation distribution and the MOS evaluation. The improved audio system was implemented using the TMS320C6747 DSP with fixed/floating-point operations. The implemented audio system can perform the multi-channel WMA decoding, the MP3 encoding/decoding, the wav playing, the EQ, and the key/tempo changes in real time. The WMA channels used for processing the separated instrument channels. The audio system includs the MP3 encoding/decoding function for playing and recording and the wav channel for the effect sound.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.190-193
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• 2013

Before Smartphone releases, playing music form previous cellphone is very limited, so we need mp3 player instead. However, when Smartphone releases, a function of playing multimedia became one of the important things in Samrtphone including all functions of mp3 player. Even though it is easier to use since you can play music and multimedia in one device, it still has problem issues on the sound quality. This thesis will discuss about functions of EQ from Smartphone music players. After that, we will to achieve high fidelity sound through balance adjustment of Right Mark Audio Analyzer program.

• International Journal of Computer Science & Network Security
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• v.22 no.7
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• pp.427-442
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• 2022

MP3 is one of the most widely used file formats for encoding and representing audio data. One of the reasons for this popularity is their significant ability to reduce audio file sizes in comparison to other encoding techniques. Additionally, other reasons also include ease of implementation, its availability and good technical support. Steganography is the art of shielding the communication between two parties from the eyes of attackers. In steganography, a secret message in the form of a copyright mark, concealed communication, or serial number can be embedded in an innocuous file (e.g., computer code, video film, or audio recording), making it impossible for the wrong party to access the hidden message during the exchange of data. This paper describes a new steganography algorithm for encoding secret messages in MP3 audio files using an improved least significant bit (LSB) technique with high embedding capacity. Test results obtained shows that the efficiency of this technique is higher compared to other LSB techniques.

• Journal of Broadcast Engineering
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• v.13 no.5
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• pp.744-751
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• 2008

In this paper, we investigate methods to enhance the perceptual quality of MP3-coded audios. Based on the high frequency reconstruction method by Liu, in the proposed method, we determine adaptively the starting point of high frequency reconstruction. We also present an improved linear estimation method. For high frequency component generation, we compare two methods. One is a replication of low-frequency components and the other is an insertion of additive white Gaussian noise signals. Through subjective tests, we shall show that the proposed method can improve the perceptual quality of MP3-coded audio.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.59-68
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• 2013

iPod Touch provided so various application software beyond the early music playback function, and enhanced its UI to the level of UX. Because of these, it was evaluated as innovative. In addition, even though various images were provided through the Internet, some people still classify MP3P as audio device in its product category. As for how audio device became video or image device and which factor contributed to such happening, there may be various factors, such as social, cultural, and technical change, other than fundamental change of medium itself. This study is regarding medium characteristics of MP3Player. In other words, this study classified genealogical changes, which can be categorized into 4 points. This study also analyzed the property of each point according to this classification. The result of analysis showed that there is a relation with technological as well as social context in such genealogical change in MP3player. Even though there are various elements in the change of a device, it can be suggested that the factors of genealogical change in MP3player are influenced by a totality of social needs and contexts and technical changes.

• MALSORI
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• no.61
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• pp.75-86
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• 2007

In this paper, we propose a scalable audio coder, which has a variable bandwidth from the narrowband speech bandwidth to the audio bandwidth and also has a bit-rate from 8 to 320 kbits/s, in order to cope with the quality of service(QoS) according to the network load. First of all, the proposed scalable coder splits bandwidth of the input audio into narrowband up to around 4 kHz and above. Next, the narrowband signals are compressed by a speech coding method compatible to an existing standard speech coder such as G.729, and the other signals whose bandwidth is above the narrowband are compressed on the basis of a psychoacoustic model. It is shown from the objective quality tests using the signal-to-noise ratio(SNR) and the perceptual evaluation of audio quality(PEAQ) that the proposed scalable audio coder provides a comparable quality to the MPEG-1 Layer III (MP3) audio coder.

• The Journal of the Acoustical Society of Korea
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• v.32 no.1
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• pp.64-70
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• 2013

In this paper, we suggest a new audio watermarking method for audio contents copyrights that can efficiently provide protection from MP3 compression attacks. Watermarks were inserted at the coefficients repeatedly from low frequencies to high frequencies after DCT transform in commonly used Cox's spread spectrum method. Because the methods using arbitrary coefficients are not effective, we use the new weight functions that make small losses for the watermark coefficients during attacks, using psychological acoustics. In the results of various sound clips, the suggested method had overall better outcomes than the Cox's method by preserving watermarks and reducing distortions of the original sounds.