Sanjeev Mehrotra, Wei-ge Chen, and Kishore Kotteri
Audio coding at low bitrates suffers from artifacts due to spectrum
Typical audio codecs code multi-channel sources using transforms across
the channels to remove redundancy such as middle (mid)
- side (M/S) coding.
At low bitrates, the spectrum of the coded channels is truncated and
the spectrum of the channels with lower energy, such as
the side channel, is truncated severely, sometimes entirely.
This results in a muffled sound due to truncation of all coded
channels beyond a certain frequency.
It also results in a loss of spatial image even at low frequencies
due to severe truncation of the side channel.
Previously we have developed a low bitrate coding method to combat
the loss of higher frequencies caused by spectrum truncation.
In this paper, we present a novel low bitrate audio coding scheme to
mitigate the loss of spatial image.
Listening tests show that the combination of the two low bitrate coding
methods results in a audio codec that can get good quality even
at bitrates as low as 32kbps for stereo content with low decoder
In Proc. Int'l Conf. Acoustics, Speech, and Signal Processing
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