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Topic: Could possibly SBC codec benefit from dither? (Read 2263 times) previous topic - next topic
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Could possibly SBC codec benefit from dither?

From what I've yet understood from specification and source code, SBC just culls subband samples to their calculated depth. Would it be possible to reduce error of subband sample bitdepth reduction using dither, and perhaps even noise-shaping?

I.e. just plainly adding appropriate amount of TPDF dither to each subband sample if it's without noise shaping. If it's with noise shaping, then have a stack of last 80 or 160 (Didn't yet figure out exact amount) to perform windowing and decoding back into standard in-order samples, adding them to corresponding input samples and noise-shaping the error, then converting new-formed samples again into subband samples and culling them according to already calculated bit allocation.

Would it work or the transforms would convert the harmless dither noise into something like frequency modulation?

Could possibly SBC codec benefit from dither?

Reply #1
If enough resolution is used throughout the calculations then the only time that you need to add dither is when the resolution is reduced to its final bitdepth to pass to the DAC.

Could possibly SBC codec benefit from dither?

Reply #2
If enough resolution is used throughout the calculations then the only time that you need to add dither is when the resolution is reduced to its final bitdepth to pass to the DAC.


As far as I understand, SBC essentially reduces bit depth of integer subband samples, which are derived by matrixing PCM samples, so it's not like, for example, mp3, which has floating point coefficients, at all. Therefore, as bit depth is reduced, it seems to be beneficial to preserve information in culled bits by dithering the samples.

Could possibly SBC codec benefit from dither?

Reply #3
I see, so you are talking about encoding rather than decoding.

 
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