Run audio analysis and Whisper concurrently

doctate-common/src/lib.rs

@@ -13,6 +13,6 @@ pub use constants::{
     UPLOAD_PATH,
 };
 pub use oneliners::{ONELINER_FILENAME, ONELINERS_PATH, OnelinerEntry, OnelinersResponse};
-pub use recordings::{RECORDING_META_SUFFIX, RecordingMeta, Transcript, TranscriptState};
+pub use recordings::{Loudness, RECORDING_META_SUFFIX, RecordingMeta, Transcript, TranscriptState};
 pub use timestamp::{filename_stem_to_recorded_at, now_rfc3339, recorded_at_to_filename_stem};
 pub use url::join_url;

server/src/transcribe/worker.rs

@@ -3,7 +3,7 @@ use std::sync::Arc;
 use std::time::Duration;
 
 use doctate_common::oneliners::OnelinerState;
-use doctate_common::{RecordingMeta, Transcript, TranscriptState};
+use doctate_common::{Loudness, RecordingMeta, Transcript, TranscriptState};
 use time::OffsetDateTime;
 use time::format_description::well_known::Rfc3339;
 use tracing::{error, info, warn};
@@ -12,6 +12,7 @@ use super::{TranscribeReceiver, ffmpeg, ollama, whisper};
 use crate::config::{Config, WhisperUserSettings};
 use crate::events::{self, CaseEventKind, EventSender};
 use crate::gazetteer::Gazetteer;
+use crate::loudness;
 use crate::oneliner_locks::OnelinerLocks;
 use crate::paths;
 use crate::settings::Settings;
@@ -69,34 +70,33 @@ pub async fn run(
             }
         };
 
-        // Probe the container duration on the remuxed copy (its `moov`
-        // atom sits at the start, so ffprobe returns without seeking
-        // to EOF). We carry the value in memory and persist it
-        // together with the transcript at the end of the pipeline.
-        // Non-fatal: a probe failure leaves `duration_seconds = None`
-        // and the recordings scan falls back to a read-only ffprobe
-        // for the UI render.
-        let duration_seconds = match ffmpeg::probe_duration_seconds(remuxed.path()).await {
-            Ok(s) => Some(s),
-            Err(e) => {
-                warn!(
-                    audio = %audio_path.display(),
-                    error = %e,
-                    "ffprobe duration failed — meta will record null duration"
-                );
-                None
-            }
-        };
-
-        let text = match whisper::transcribe(
+        // Run audio analysis (duration + volumedetect) and Whisper
+        // concurrently against the remuxed tempfile. The volumedetect
+        // pass is decode-bound on a CPU core (~100-500 ms for typical
+        // dictation lengths); Whisper dominates the wallclock with a
+        // GPU/network round-trip in seconds, so the analysis cost
+        // disappears behind the join.
+        //
+        // `tokio::join!` (not `try_join!`) intentionally awaits both
+        // futures even on error: a failed analysis must not throw
+        // away a successful transcript, and a failed transcript must
+        // drop any analysis values — without a meta sidecar the
+        // page-load heal re-enqueues, and that retry must run the
+        // analysis fresh.
+        let (analysis_result, whisper_result) = tokio::join!(
+            ffmpeg::analyze_audio(remuxed.path()),
+            whisper::transcribe(
                 &client,
                 &settings.whisper.url,
                 remuxed.path(),
                 timeout,
                 &user_whisper,
-        )
-        .await
-        {
+            ),
+        );
+
+        // Whisper is the gating outcome: without a transcript we don't
+        // write any meta, regardless of whether the analysis succeeded.
+        let text = match whisper_result {
             Ok(t) => t,
             Err(e) => {
                 error!(audio = %audio_path.display(), error = %e, "whisper call failed");
@@ -118,6 +118,39 @@ pub async fn run(
             }
         };
 
+        // Translate the analysis outcome into the two `RecordingMeta`
+        // fields. Silent files (volumedetect → -inf dB) keep a valid
+        // duration but skip loudness — `serde_json` refuses non-finite
+        // floats, and persisting `+Inf` gain would loop the worker
+        // forever (write fails → no sidecar → idempotency gate stays
+        // open → retry hits the same trap).
+        let (duration_seconds, loudness) = match analysis_result {
+            Ok(a) if a.mean_db.is_finite() && a.max_db.is_finite() => {
+                let gain_db = loudness::compute_gain_db(a.mean_db, a.max_db);
+                (
+                    Some(a.duration_seconds),
+                    Some(Loudness {
+                        mean_db: a.mean_db,
+                        max_db: a.max_db,
+                        gain_db,
+                    }),
+                )
+            }
+            Ok(a) => {
+                // Silent (or zero-sample) audio: duration is still
+                // valid, but there is no level to amplify against.
+                (Some(a.duration_seconds), None)
+            }
+            Err(e) => {
+                warn!(
+                    audio = %audio_path.display(),
+                    error = %e,
+                    "audio analysis failed — meta will record null duration and loudness"
+                );
+                (None, None)
+            }
+        };
+
         // Normalize terminology against the curated vocab before
         // persisting. Downstream consumers (oneliner, analyze) read
         // the canonical path.
@@ -137,7 +170,7 @@ pub async fn run(
         let meta = RecordingMeta {
             transcript,
             duration_seconds,
-            loudness: None,
+            loudness,
         };
         if let Err(e) = paths::write_recording_meta_atomic(&audio_path, &meta).await {
             error!(meta = %meta_path.display(), error = %e, "writing recording meta failed");
@@ -148,6 +181,7 @@ pub async fn run(
             audio = %audio_path.display(),
             bytes = bytes_logged,
             duration = ?duration_seconds,
+            gain_db = ?meta.loudness.as_ref().map(|l| l.gain_db),
             "Recording meta written"
         );