Perancangan dan Analisis Kinerja Steganography pada MPEG SAOC Menggunakan Improved Spread Spectrum

Object-based audio technology is important for audio reproduction because of providing the users with an ability to change the audio composition. As a result, MPEG Spatial Audio Object Coding (SAOC) as an international standard for encoding object-based audio has been widely used in many applications. However, the object-based audio transmission scheme is different than conventional audio transmission technology, so the use of steganography in MPEG SAOC needs to be further studied. In this work, a steganography technique has been developed based on Improved Spread Spectrum (ISS). There are two embedding configurations used in this study: embedding on MPEG SAOC audio objects and embedding on MPEG SAOC downmix signals. The performance of these two embedding configurations was analyzed by measuring ISS embedding capacity. As a comparison to the ISS method on channel-based audio, the ISS is also applied to Advanced Audio Coding (AAC). Based on the experiments, the embedding capacity of both proposed configurations varies depending on the bandwidth of audio signals. However, the downmix signal has a capacity of 20% higher than the audio objects. Moreover, the ISS embedding capacity on the MPEG SAOC downmix signal is similar to the embedding capacity on the AAC.

Autocorrelation Modulation-Based Audio Blind Watermarking Robust Against High Efficiency Advanced Audio Coding

High Efficiency Advanced Audio Coding (HE-AAC) is a lossy compression method for digital audio data which supplies high-quality audio at a very low bit rate. In this paper, the audio blind watermarking algorithm, on the basis of autocorrelation modulation, is introduced to maximize the robustness against low-bit rate HE-AAC. The watermark is embedded by modulating the normalized correlation of the original signal as well as its delayed version. The signal-to-noise ratio of before and after HE-AAC compression decides the strength of the embedding watermark. The watermarking embedding strength is guaranteed by the feedback process. The effectiveness of the proposed method is proven using the Perceptual Evaluation of Audio Quality algorithm and bit error rate of recovered watermarks under HE-AAC compression on mono, stereo and 5.1 channel audio. Experimental results show that the proposed method provides good performance in terms of imperceptibility, robustness and data payload compared with some recent state-of-the-art watermarking methods under an MPEG-2 Audio Layer III (MP3) compression attack.

Investigation of Lossless Audio Compression using IEEE 1857.2 Advanced Audio Coding

<p>Audio compression is a method of reducing the space demand and aid transmission of the source file which then can be categorized by lossy and lossless compression. Lossless audio compression was considered to be a luxury previously due to the limited storage space. However, as storage technology progresses, lossless audio files can be seen as the only plausible choice for those seeking the ultimate audio quality experience. There are a lot of commonly used lossless codecs are FLAC, Wavpack, ALAC, Monkey Audio, True Audio, etc. The IEEE Standard for Advanced Audio Coding (IEEE 1857.2) is a new standard approved by IEEE in 2013 that covers both lossy and lossless audio compression tools. A lot of research has been done on this standard, but this paper will focus more on whether the IEEE 1857.2 lossless audio codec to be a viable alternative to other existing codecs in its current state. Therefore, the objective of this paper is to investigate the codec’s operation as initial measurements performed by researchers show that the lossless compression performance of the IEEE compressor is better than any traditional encoders, while the encoding speed is slower which can be further optimized.</p>