Hi-Fi
Hi-Fi paper presents a sufficiently low bit
rate Hi-Fi audio coding technique with low computation
designed for transmitting real-time high-quality audio signal over wireless
channel. This technique applies wavelet packet transform to decompose audio
signal into subbands to eliminate redundant data using spectral and temporal
masking properties. The encoded audio data is framed with some critical field
is protected by channel coding to improve noise immunity when frames are
transmitted wirelessly.
Experimental results show that transparent CD-audio
quality can be achieved at 80kbps encoding bit rate. Moreover, the proposed
technique still offers near CD-audio quality when frames are transmitted over
AWGN channel with BER below 10-5. These encouraging results clearly exhibit the
superior features of our technique compared to others such as Ogg/Vorbis and
MP3, which are ubiquitously employed nowadays.
Current hi-fi audio CODECs employ entropy
coding such as run-length and Huffman code, where important parameters required
to decode are assumed to be error−free. Otherwise, the frame will be discarded
making it susceptible to noisy wireless channel. As a result, we identify such
parameters and protect them using channel coding that can correct up to 29 bits
(one of every seven bits). Perceptual coding technique is used reduce the bit
rate based on “human hearing masking” property. In general, perceptual codec
consists of five modules which are filer bank, psychoacoustic analyzer, bit
allocation, quantizing and encoding, and framing.
You can download full Hi-Fi seminar abstract from here.
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