Analysis of subband quantization noise level and shapes: a function of wideband audio codec tandemming
Bibliographic record
Abstract
Newly developed codecs for wideband audio signals rely on subband coding and psychoacoustic modeling to achieve significant reduction in the bit rate of a digital audio signal. An investigation into the shape and level of quantization noise introduced into a coded audio signal is performed. Psychoacoustic principles reveal that quantization noise is masked, i.e. made inaudible, if its spectral shape fails below that of the original signal by a 13 dB threshold. Simulation results show that there is a strong correlation of quantization noise and original signal shapes at low bit allocations. Quantization noise levels which increase result in a degradation of the quality of a codec. A criterion for the evaluation of a codec is its performance when tandemmed. Simulation results reveal that there can be up to an 18 dB increase in average subband noise energy for eight tandems. Surprisingly, subbands more vulnerable to an increase in quantization noise tend to exhibit a high signal to mask ratio, as determined by the psychoacoustic model.>
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.008 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".