fix README formatting

README.md

@@ -65,7 +65,7 @@ energy. Everything above this point is silence or noise.
 **The Nyquist ceiling:** Digital audio is made of snapshots (samples). For CD
 quality (44100 snapshots per second), there is a hard limit: you cannot store
 a frequency higher than half the snapshot rate = **22050 Hz**. This is called
-the *Nyquist frequency*. It is a physical ceiling — higher frequencies simply
+the *Nyquist frequency*. It is a physical ceiling - higher frequencies simply
 cannot exist.
 
 **How lossy encoding changes it:** MP3 and other lossy codecs deliberately cut
@@ -84,7 +84,7 @@ off high frequencies to save space. The cutoff gets lower as the bitrate drops:
 close to the theoretical maximum. This is what we expect from a 320 kbps
 encode. If this same file showed 54% (~12000 Hz), it would mean the treble
 was chopped off by an aggressive low-bitrate encoder, and someone just
-re-encoded it at 320 kbps — the cutoff is permanent and cannot be restored.
+re-encoded it at 320 kbps - the cutoff is permanent and cannot be restored.
 That would be an **UPSCALED** file.
 
 ---
@@ -96,9 +96,9 @@ tcd measures this as the frequency gap between the −20 dB point (still loud)
 and the −60 dB cutoff (essentially silent). A narrow gap = a sharp drop.
 
 **The analogy:** Imagine the frequency graph as a mountain ridge. A lossless
-recording rolls off like a natural hillside — gradual, smooth, taking
+recording rolls off like a natural hillside - gradual, smooth, taking
 thousands of Hz to go from loud to silent. A lossy encoder's lowpass filter
-creates a cliff — a near-vertical drop from audible signal to nothing.
+creates a cliff - a near-vertical drop from audible signal to nothing.
 
 **What the number means:** Steepness is the width (in Hz) of that drop zone.
 The smaller the number, the sharper the cliff:
@@ -111,11 +111,11 @@ The smaller the number, the sharper the cliff:
 | >5000 Hz  | Gentle slope       | Natural acoustic roll-off (lossless) |
 
 To understand steepness, imagine a guitar string being plucked. The sound
-naturally fades across many frequencies — the harmonics near the top end of
+naturally fades across many frequencies - the harmonics near the top end of
 your hearing get quieter and quieter over a broad range. This is a gentle
 slope. Now imagine someone put a pair of scissors on the frequency spectrum
-and cut everything above a certain note. That sharp edge — the difference
+and cut everything above a certain note. That sharp edge - the difference
-between "still audible" and "completely gone" in just a few hundred Hz — is
+between "still audible" and "completely gone" in just a few hundred Hz - is
 what lossy compression does. The steepness number tells you how sharp that
 scissor cut was.
 
@@ -126,7 +126,7 @@ scissor cut was.
 **What it measures:** How "bumpy" or "irregular" the spectrum looks just
 before the cutoff point.
 
-**The analogy:** Lossy encoding introduces quantization noise — tiny
+**The analogy:** Lossy encoding introduces quantization noise - tiny
 rounding errors that are unevenly distributed across frequencies. In the
 frequency graph, this looks like a jagged, bumpy line instead of a smooth
 one. Think of it like a dirt road vs a paved highway: lossless audio is
@@ -161,10 +161,10 @@ is severe.
 
 | Band ratio | What it means |
 |------------|---------------|
-| >0.85      | Healthy high end — likely native lossless |
+| >0.85      | Healthy high end - likely native lossless |
-| 0.70–0.85  | Mild roll-off — could be lossy or natural |
+| 0.70–0.85  | Mild roll-off - could be lossy or natural |
-| 0.50–0.70  | Significant high-end loss — likely lossy |
+| 0.50–0.70  | Significant high-end loss - likely lossy |
-| <0.50      | Severe high-end loss — almost certainly lossy or transcoded |
+| <0.50      | Severe high-end loss - almost certainly lossy or transcoded |
 
 ---
 
@@ -173,8 +173,8 @@ is severe.
 **What it measures:** The average noise level in the highest quarter of the
 frequency range (roughly 16500–22050 Hz).
 
-**The analogy:** Imagine listening in a quiet room — the background hiss is
+**The analogy:** Imagine listening in a quiet room - the background hiss is
-very low. Now imagine that same room with a fan running — the background
+very low. Now imagine that same room with a fan running - the background
 noise rises. A lossy encoder introduces quantization noise that raises the
 "background hiss" in the high frequencies.
 
@@ -183,10 +183,10 @@ quieter (better). Less negative = noisier (worse):
 
 | Noise floor | What it means |
 |-------------|---------------|
-| −90 to −110 dB | Very clean — native lossless |
+| −90 to −110 dB | Very clean - native lossless |
-| −70 to −90 dB | Moderate — could be lossy or quiet lossless |
+| −70 to −90 dB | Moderate - could be lossy or quiet lossless |
-| −50 to −70 dB | Noisy — likely lossy |
+| −50 to −70 dB | Noisy - likely lossy |
-| >−50 dB      | Very noisy — almost certainly lossy or transcoded |
+| >−50 dB      | Very noisy - almost certainly lossy or transcoded |
 
 ---
 
@@ -215,7 +215,7 @@ the file is **UPSCALED**. For example, a file claiming 320 kbps (expecting
 ≥90%) but showing a cutoff of 70% (≈15400 Hz) would be flagged as upscaled
 from ~96 kbps.
 
-Otherwise it is **NATIVE** — a genuine single encode at this bitrate.
+Otherwise it is **NATIVE** - a genuine single encode at this bitrate.
 
 ### Scenario 2: The input file is lossless (FLAC, WAV, ALAC, etc.)
 
@@ -224,7 +224,7 @@ decoding a lossy file and re-encoding to lossless?
 
 tcd uses a **two-layer** check:
 
-**Layer 1 — Cutoff + Steepness (primary):**
+**Layer 1 - Cutoff + Steepness (primary):**
 
 | Cutoff range | Max steepness allowed | If exceeded → |
 |-------------|----------------------|---------------|
@@ -236,10 +236,10 @@ tcd uses a **two-layer** check:
 
 This works because lossy cutoffs are always sharp (low steepness). A lossless
 recording that happens to have a low cutoff (e.g., a muddy recording with
-little treble) would still have a *gradual* roll-off (high steepness) — you
+little treble) would still have a *gradual* roll-off (high steepness) - you
 need both a low cutoff **and** a sharp drop to convict.
 
-**Layer 2 — Roughness + Band ratio (secondary):**
+**Layer 2 - Roughness + Band ratio (secondary):**
 
 If Layer 1 did not trigger but the cutoff is above 80%, tcd checks roughness
 and band ratio. This catches transcodes where the cutoff happens to be high
@@ -260,9 +260,9 @@ If neither layer triggers, the file is **GENUINE** (native lossless).
 
 | Verdict | Input codec | What it means |
 |---------|------------|---------------|
-| **NATIVE** | lossy | Encoded once at the stated bitrate — genuine |
+| **NATIVE** | lossy | Encoded once at the stated bitrate - genuine |
 | **UPSCALED** | lossy | Originally encoded at a lower bitrate, then re-encoded higher |
-| **GENUINE** | lossless | Appears to be native lossless — no evidence of lossy origin |
+| **GENUINE** | lossless | Appears to be native lossless - no evidence of lossy origin |
 | **TRANSCODE** | lossless | Originated from a lossy source, decoded to lossless |
 | **SILENT** | any | No detectable audio content |
 
@@ -282,7 +282,7 @@ Auto-remove mode (`-a`)
 
 When `-a` is passed, any file that is not classified as NATIVE or GENUINE is
 automatically deleted after analysis. This is useful for batch cleanup of
-corrupt or transcoded libraries. Careful — this will eat data.
+corrupt or transcoded libraries. Careful - this will eat data.
 
 ---
 
@@ -292,7 +292,7 @@ Why the method is (somewhat!) scientifically reliable
 ### 1. Lossy encoding leaves a permanent spectral fingerprint
 
 Every lossy audio codec discards information. The most obvious form is a
-**lowpass filter** — once applied, the frequencies above the cutoff are gone
+**lowpass filter** - once applied, the frequencies above the cutoff are gone
 forever. Decoding back to PCM and re-encoding to lossless cannot restore them.
 This means a "lossless" FLAC file made from an MP3 will contain the MP3's
 permanent spectral cutoff.