# What the game actually emits over the boot intro — five live channels, not a stereo mix

**Classification: measured.** Xenia Canary, 2026-08-30, one boot, no input.
Groundwork for the port's ask #4 — **it does not settle #4**, and the part it does
not settle is named at the bottom.

## Why this capture exists

The port ships one of `ADV`'s three concurrent voice streams and its
`authored/audio.json` records that as **known wrong, held deliberately**
([`voice-three-streams-are-concurrent.md`](voice-three-streams-are-concurrent.md)).
Neither "take one" nor "sum them" is established. The only thing that can settle it
is what the game emits, so: record it.

## The capture

Recipe followed exactly from
[`audio-capture-alsa-file-tee.md`](../audio-capture-alsa-file-tee.md) — ALSA `file`
tee in front of a **paced** pulse slave, `--gpu=null`, both mutes off:

```
run-canary --apu=alsa --mute=false --gpu=null --xma_param_probe=true
```

**148.02 s, 6 channels, float32, 48 kHz.**

✅ **Provenance is the XMA probe, not a screenshot** — which is the right evidence
for an audio question, because it witnesses the thing being recorded. The log
carries `ADV`'s three contexts **byte-exact** against the disc:

| ctx | packets | `byte_size` |
|---|---|---|
| 0 | 632 | 1 294 336 |
| 1 | 546 | 1 118 208 |
| 2 | 572 | 1 171 456 |

then two more — 1 150 976 / 1 269 760 — which are the documented `BGM_102` pair.
So the movie's voice decoded exactly as in the runs this corpus already records.

✅ **Capture quality: 0.15–0.16 % silence** on the five live channels, against the
**0.31 %** the recipe page records for its own clean run. Cleaner than the reference.

## What is in the six channels

⚠️ ALSA's channel order, not WAV's: captured *i* holds source `[0,1,4,5,2,3]`, so
the labels below are `FL FR BL BR FC LFE`. Deterministic and invertible.

| ch | | peak dBFS | rms dBFS | % silent |
|---|---|---|---|---|
| 0 | FL | −3.65 | −22.26 | 0.16 |
| 1 | FR | −2.22 | −20.89 | 0.15 |
| 2 | BL | −4.41 | −24.77 | 0.15 |
| **3** | **BR** | **−11.65** | **−36.06** | **82.18** |
| 4 | FC | −4.57 | −24.81 | 0.16 |
| 5 | LFE | −4.66 | −24.38 | 0.16 |

**Five channels carry real, distinct content; one (BR) is 82 % silent and 11–15 dB
down.** No channel is a copy of another — the largest pairwise correlation is 0.70
(FL/FR, which is what a stereo pair looks like), then 0.52 and 0.56.

### 🔴 What this already rules out

* **Not a stereo mix.** Five independent channels are being emitted.
* **So "ship one stream" cannot be right**, which the corpus already suspected but
  had not observed from the output side. The port's held-wrong value stays wrong.

⚠️ **It does not follow that summing is right.** This says the *output* is
multichannel; it says nothing yet about which disc stream lands where.

⚠️ **And do not read the 6 channels as proof the game is 5.1.** `CONTAINER-NOTES`
records that `AudioDriver::kFrameChannelsDefault = 6` is a hardcoded Xenia
constant — the *format* is Xenia's, only the *content* is the guest's. What is
evidence here is that five of those six differ from each other, which a stereo
guest cannot produce.

## 🟡 What is NOT settled — the stream → channel mapping

The decisive step is a cross-correlation of each captured channel against each of
`ADV`'s three decoded streams. **That has not been run.** Until it is:

* which stream feeds which channel pair is unknown;
* whether `FC` carries the dialogue is **consistent with** the corpus's
  [centre-channel finding](../structures/voice-centre-channel.md) but not
  re-established here;
* why `BR` is near-silent is unknown — a genuinely unused channel, a stream that
  ends early, or a decode that failed are all open.

⚠️ **One boot, one movie.** And `--gpu=null` means no video, so nothing here is
cross-checked against what was on screen.

The raw capture is 170 MB and is **not committed**; it went over `share` to the
port as `1788077587-9f2e30af1c98-capture.raw`. Per-channel numbers:
[`../data/intro-audio-channel-census.txt`](../data/intro-audio-channel-census.txt).