On the Use of Band-Passed Excitation Codebooks for CELP Coding of Speech
Bibliographic record
Abstract
This paper explores the benefits of using multiple band-passed codebooks to replace the single full-band excitation codebook of classical code-excited linear prediction for coding high quality speech in the range of 8-16 kb/s. In the classical method, the residual signal in the LPC frame is divided temporally into subframes and each subframe is coded using a single full-band excitation code book. In this study, we divide the residual signal in the LPC frame into its band-passed components and match each component with an entry from a band-passed code book. Our results indicate objective and subjective advantages for using three codebooks, each with the gain and shape components. In particular, the codebooks required for the frequencies above 1 kHz are very small. Also, by subsampling, the large low frequency (0-1 kHz) codebook can be searched very rapidly resulting in a significant complexity advantage.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".