fabi/Sylpheed
1
0
Fork 0
Code Issues 9 Pull Requests Actions Packages Projects Releases Wiki Activity

re: refutation attempt on the band-energy check -- survives, with the margin quantified

Browse Source 
A 1 s misalignment costs 0.16 dB against their 0.66 dB pass band, so the
alignment-free claim holds. Two caveats measured: at 10 s it reaches 1.00 dB, since
a fixed window covers different material once the shift is large; and the
separation floor is material-dependent -- two unrelated music banks give 5.28 dB
where an unrelated movie gave them 19-20, so the threshold's margin depends on the
known-negative chosen.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Wuu56cE8vJGTBtn1ppsk8v
This commit is contained in:
sylph-decoder
2026-08-31 00:14:38 +00:00
parent a86d90408f
commit 5ae715a6ce
1 changed files with 29 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

29
docs/re/REFUTED.md
View File

@@ -789,3 +789,32 @@ the music.
bands carrying 96 % of the energy read 0.169 and 0.184** — far above the 0.001
independent floor, so *not* independent, and far below a filtered copy. "One
performance" stands; "rear pair, i.e. a filtered view of the same mix" does not.
### Refutation attempt on `sylpheed-port`'s band-energy check — ✅ SURVIVES, with a measured caveat (2026-08-31)
**Target:** their replacement for a disqualified difference-signal path — *"band
energies need no alignment"*, with transcodes matching their sources to **0.66 dB**
worst-case and an unrelated movie landing at **19–20 dB**.
**My attempt:** if band energies are genuinely alignment-free, a signal against a
*misaligned copy of itself* must match as closely as against itself.
| | worst band |
|---|---|
| `w0` vs itself | **0.00 dB** |
| vs itself **shifted 1 s** (misaligned, same content) | **0.16 dB** |
| vs itself **shifted 10 s** | **1.00 dB** |
| vs a **different bank** (`BGM_104`) | **5.28 dB** |
**The claim survives.** A 1 s misalignment costs 0.16 dB, well inside their 0.66 dB
pass band — alignment-insensitive as advertised, which is exactly what makes it the
right instrument where a lag search failed.
⚠️ **Two caveats it is worth them having.** It is not *literally* alignment-free:
at 10 s the figure reaches 1.00 dB, because a fixed analysis window covers different
material once the shift is large relative to it. And **the separation margin is
material-dependent** — two unrelated *music banks* separate by only **5.28 dB**
here, against the **19–20 dB** an unrelated movie gave them. A 0.66 dB threshold has
an 8× margin against that floor rather than a 30× one, so **the safety of the
threshold depends on how different the chosen known-negative is**, not on the method.
[data](data/impossibility-scope-sweep.txt)