Fix FLAC export end-to-end (real backend path) + smart tag defaults

The prior audio-tags commit put real FLAC + metadata into export/audio_exporter.rs
— which turned out to be dead code (declared, never called; whole file was
EngineController::start_export_audio → daw-backend's export_audio, which still
routed FLAC to the erroring hound stub — hence "not implemented in daw-backend".

Move the work to where export actually happens:
- daw-backend/src/audio/export.rs: real ffmpeg FLAC (16-bit S16 / 24-bit S32,
  skipping the trailing empty flush packet the FLAC muxer rejects); apply_metadata
  on MP3/AAC/FLAC output; RIFF LIST/INFO chunk appended to WAV. New metadata field
  on the backend ExportSettings, threaded from the UI in run_audio_export. Tests
  assert real fLaC magic + round-tripped tags, and a valid WAV INFO chunk.
- Delete the dead export/audio_exporter.rs (removes the duplicate FLAC impl).

Smart tag defaults (filled only when empty, never clobbering edits):
- Year → current civil year, computed from the system clock with i64 math (no
  date crate; correct past 2038/2106 — tests cover post-i32/u32 timestamps).
- Artist → last-used value, else the OS username ($USER/%USERNAME%).
- Album → last-used value.
Last-used Artist/Album persist in AppConfig and prefill next export.

daw-backend/src/audio/export.rs

@@ -50,6 +50,10 @@ pub struct ExportSettings {
     pub end_time: Seconds,
     /// Tempo map for beat-position scheduling
     pub tempo_map: TempoMap,
+    /// Tag metadata as (ffmpeg-key, value) pairs (e.g. ("title", "…"), ("artist", "…")). Written to
+    /// the container's native tags: ID3v2 (MP3), MP4 atoms (M4A), Vorbis comments (FLAC), RIFF INFO
+    /// (WAV). Empty = no tags.
+    pub metadata: Vec<(String, String)>,
 }
 
 impl Default for ExportSettings {
@@ -63,10 +67,26 @@ impl Default for ExportSettings {
             start_time: Seconds::ZERO,
             end_time: Seconds(60.0),
             tempo_map: TempoMap::constant(120.0),
+            metadata: Vec::new(),
         }
     }
 }
 
+/// Set tag metadata on an ffmpeg output context (before `write_header`). FFmpeg maps the standard
+/// keys to each container's native tags.
+fn apply_metadata(output: &mut ffmpeg_next::format::context::Output, metadata: &[(String, String)]) {
+    if metadata.is_empty() {
+        return;
+    }
+    let mut dict = ffmpeg_next::Dictionary::new();
+    for (k, v) in metadata {
+        if !v.is_empty() {
+            dict.set(k, v);
+        }
+    }
+    output.set_metadata(dict);
+}
+
 /// Export the project to an audio file
 ///
 /// This performs offline rendering, processing the entire timeline
@@ -108,17 +128,21 @@ pub fn export_audio<P: AsRef<Path>>(
     // Route to appropriate export implementation based on format.
     // Ensure export mode is disabled even if an error occurs.
     let result = match settings.format {
-        ExportFormat::Wav | ExportFormat::Flac => {
+        ExportFormat::Wav => {
             let samples = render_to_memory(project, pool, settings, event_tx.as_mut().map(|tx| &mut **tx))?;
-            // Signal that rendering is done and we're now writing the file
             if let Some(ref mut tx) = event_tx {
                 let _ = tx.push(AudioEvent::ExportFinalizing);
             }
-            match settings.format {
+            write_wav(&samples, settings, &output_path)
-                ExportFormat::Wav => write_wav(&samples, settings, &output_path),
+                // hound writes no metadata; append a RIFF INFO chunk for tags.
-                ExportFormat::Flac => write_flac(&samples, settings, &output_path),
+                .and_then(|_| append_wav_info_chunk(output_path.as_ref(), &settings.metadata))
-                _ => unreachable!(),
         }
+        ExportFormat::Flac => {
+            let samples = render_to_memory(project, pool, settings, event_tx.as_mut().map(|tx| &mut **tx))?;
+            if let Some(ref mut tx) = event_tx {
+                let _ = tx.push(AudioEvent::ExportFinalizing);
+            }
+            export_flac(&samples, settings, &output_path)
         }
         ExportFormat::Mp3 => {
             export_mp3(project, pool, settings, output_path, event_tx)
@@ -273,17 +297,175 @@ fn write_wav<P: AsRef<Path>>(
     Ok(())
 }
 
-/// FLAC export is not implemented in the backend. It previously wrote WAV bytes to a `.flac` file
+/// Export real FLAC via ffmpeg from already-rendered interleaved f32 samples (Vorbis-comment
-/// via `hound` — a real, silent misrepresentation (the output was not FLAC at all). The UI now
+/// metadata). Replaces the former `write_flac`, which wrote WAV bytes to a `.flac` file. 16-bit
-/// encodes FLAC properly with ffmpeg (`export/audio_exporter.rs::export_audio_ffmpeg_flac`), so this
+/// uses S16; 24-bit uses S32 (ffmpeg's flac encoder emits `bits_per_raw_sample = 24` for S32,
-/// path is unused; rather than lie, it returns an error if anything reaches it.
+/// taking the top 24 bits).
-fn write_flac<P: AsRef<Path>>(
+fn export_flac<P: AsRef<Path>>(
-    _samples: &[f32],
+    samples: &[f32],
-    _settings: &ExportSettings,
+    settings: &ExportSettings,
-    _output_path: P,
+    output_path: P,
 ) -> Result<(), String> {
-    Err("FLAC export is not implemented in daw-backend; use the ffmpeg encoder in the UI \
+    use ffmpeg_next as ffmpeg;
-         (export_audio_ffmpeg_flac). This path formerly wrote mislabeled WAV bytes.".to_string())
+
+    ffmpeg::init().map_err(|e| format!("Failed to initialize FFmpeg: {}", e))?;
+
+    let codec = ffmpeg::encoder::find(ffmpeg::codec::Id::FLAC)
+        .ok_or("FLAC encoder not found in this ffmpeg build")?;
+    let mut output = ffmpeg::format::output(&output_path)
+        .map_err(|e| format!("Failed to create output file: {}", e))?;
+
+    let channel_layout = match settings.channels {
+        1 => ffmpeg::channel_layout::ChannelLayout::MONO,
+        2 => ffmpeg::channel_layout::ChannelLayout::STEREO,
+        _ => return Err(format!("Unsupported channel count: {}", settings.channels)),
+    };
+
+    // FLAC accepts packed S16 or S32; S32 → 24-bit output.
+    let use_24 = settings.bit_depth >= 24;
+    let sample_fmt = if use_24 {
+        ffmpeg::format::Sample::I32(ffmpeg::format::sample::Type::Packed)
+    } else {
+        ffmpeg::format::Sample::I16(ffmpeg::format::sample::Type::Packed)
+    };
+
+    let mut encoder = ffmpeg::codec::Context::new_with_codec(codec)
+        .encoder()
+        .audio()
+        .map_err(|e| format!("Failed to create FLAC encoder: {}", e))?;
+    encoder.set_rate(settings.sample_rate as i32);
+    encoder.set_channel_layout(channel_layout);
+    encoder.set_format(sample_fmt);
+    encoder.set_time_base(ffmpeg::Rational(1, settings.sample_rate as i32));
+    let mut encoder = encoder.open_as(codec)
+        .map_err(|e| format!("Failed to open FLAC encoder: {}", e))?;
+
+    {
+        let mut stream = output.add_stream(codec)
+            .map_err(|e| format!("Failed to add stream: {}", e))?;
+        stream.set_parameters(&encoder);
+    }
+    apply_metadata(&mut output, &settings.metadata);
+    output.write_header()
+        .map_err(|e| format!("Failed to write FLAC header: {}", e))?;
+
+    let channels = settings.channels as usize;
+    let num_frames = samples.len() / channels;
+    let frame_size = if encoder.frame_size() > 0 { encoder.frame_size() as usize } else { 4096 };
+
+    let mut done = 0usize;
+    while done < num_frames {
+        let n = (num_frames - done).min(frame_size);
+        let mut frame = ffmpeg::frame::Audio::new(sample_fmt, n, channel_layout);
+        frame.set_rate(settings.sample_rate);
+        frame.set_pts(Some(done as i64)); // samples; the FLAC muxer requires PTS
+
+        let buf = frame.data_mut(0); // packed interleaved → plane 0
+        let base = done * channels;
+        if use_24 {
+            for i in 0..n * channels {
+                let s = samples[base + i].clamp(-1.0, 1.0);
+                let v = (s as f64 * 2_147_483_647.0) as i32; // full-scale S32; encoder takes top 24
+                buf[i * 4..i * 4 + 4].copy_from_slice(&v.to_le_bytes());
+            }
+        } else {
+            for i in 0..n * channels {
+                let s = samples[base + i].clamp(-1.0, 1.0);
+                let v = (s * 32767.0) as i16;
+                buf[i * 2..i * 2 + 2].copy_from_slice(&v.to_le_bytes());
+            }
+        }
+
+        encoder.send_frame(&frame).map_err(|e| format!("Failed to send FLAC frame: {}", e))?;
+        flac_write_packets(&mut encoder, &mut output)?;
+        done += n;
+    }
+    encoder.send_eof().map_err(|e| format!("Failed to flush FLAC encoder: {}", e))?;
+    flac_write_packets(&mut encoder, &mut output)?;
+    output.write_trailer().map_err(|e| format!("Failed to finalize FLAC: {}", e))?;
+    Ok(())
+}
+
+/// Drain encoded FLAC packets and write them (non-interleaved). Skips the trailing empty flush
+/// packet, which the FLAC muxer otherwise rejects as "Invalid data". Rescales packet ts from the
+/// encoder time base to the stream's.
+fn flac_write_packets(
+    encoder: &mut ffmpeg_next::encoder::Audio,
+    output: &mut ffmpeg_next::format::context::Output,
+) -> Result<(), String> {
+    let mut pkt = ffmpeg_next::Packet::empty();
+    let enc_tb = encoder.time_base();
+    let stream_tb = output.stream(0).map(|s| s.time_base()).unwrap_or(enc_tb);
+    while encoder.receive_packet(&mut pkt).is_ok() {
+        if pkt.size() == 0 {
+            continue;
+        }
+        pkt.set_stream(0);
+        pkt.rescale_ts(enc_tb, stream_tb);
+        pkt.write(output).map_err(|e| format!("Failed to write FLAC packet: {}", e))?;
+    }
+    Ok(())
+}
+
+/// Append a RIFF `LIST`/`INFO` metadata chunk to a finished WAV file (hound writes no tags), then
+/// fix up the top-level RIFF size. Maps ffmpeg-style keys to RIFF INFO sub-chunk IDs. Trailing INFO
+/// chunks are ignored by players that don't read them.
+fn append_wav_info_chunk(path: &Path, metadata: &[(String, String)]) -> Result<(), String> {
+    use std::io::{Seek, SeekFrom, Write};
+
+    let riff_id = |key: &str| -> Option<&'static [u8; 4]> {
+        match key {
+            "title" => Some(b"INAM"),
+            "artist" => Some(b"IART"),
+            "album" => Some(b"IPRD"),
+            "genre" => Some(b"IGNR"),
+            "comment" => Some(b"ICMT"),
+            "date" => Some(b"ICRD"),
+            "track" => Some(b"ITRK"),
+            _ => None,
+        }
+    };
+
+    let mut info: Vec<u8> = Vec::new();
+    info.extend_from_slice(b"INFO");
+    for (key, val) in metadata {
+        if val.is_empty() {
+            continue;
+        }
+        let Some(id) = riff_id(key) else { continue };
+        let mut bytes = val.as_bytes().to_vec();
+        bytes.push(0); // NUL-terminate
+        if bytes.len() % 2 == 1 {
+            bytes.push(0); // pad to even
+        }
+        info.extend_from_slice(id);
+        info.extend_from_slice(&(bytes.len() as u32).to_le_bytes());
+        info.extend_from_slice(&bytes);
+    }
+    if info.len() <= 4 {
+        return Ok(()); // nothing but the "INFO" tag
+    }
+
+    let mut list: Vec<u8> = Vec::with_capacity(info.len() + 8);
+    list.extend_from_slice(b"LIST");
+    list.extend_from_slice(&(info.len() as u32).to_le_bytes());
+    list.extend_from_slice(&info);
+
+    let mut f = std::fs::OpenOptions::new()
+        .read(true)
+        .write(true)
+        .open(path)
+        .map_err(|e| format!("Failed to open WAV for tagging: {}", e))?;
+    let end = f.seek(SeekFrom::End(0)).map_err(|e| e.to_string())?;
+    if end % 2 == 1 {
+        f.write_all(&[0]).map_err(|e| e.to_string())?;
+    }
+    f.write_all(&list).map_err(|e| format!("Failed to write WAV tags: {}", e))?;
+    let new_len = f.seek(SeekFrom::End(0)).map_err(|e| e.to_string())?;
+    f.seek(SeekFrom::Start(4)).map_err(|e| e.to_string())?;
+    f.write_all(&((new_len - 8) as u32).to_le_bytes())
+        .map_err(|e| format!("Failed to update RIFF size: {}", e))?;
+    Ok(())
 }
 
 /// Export audio as MP3 using FFmpeg (streaming - render and encode simultaneously)
@@ -330,6 +512,7 @@ fn export_mp3<P: AsRef<Path>>(
         stream.set_parameters(&encoder);
     }
 
+    apply_metadata(&mut output, &settings.metadata);
     output.write_header()
         .map_err(|e| format!("Failed to write header: {}", e))?;
 
@@ -499,6 +682,7 @@ fn export_aac<P: AsRef<Path>>(
         stream.set_parameters(&encoder);
     }
 
+    apply_metadata(&mut output, &settings.metadata);
     output.write_header()
         .map_err(|e| format!("Failed to write header: {}", e))?;
 
@@ -806,4 +990,61 @@ mod tests {
         assert_eq!(ExportFormat::Wav.extension(), "wav");
         assert_eq!(ExportFormat::Flac.extension(), "flac");
     }
+
+    fn tagged_settings(format: ExportFormat) -> ExportSettings {
+        ExportSettings {
+            format,
+            sample_rate: 48000,
+            channels: 2,
+            bit_depth: 24,
+            mp3_bitrate: 192,
+            start_time: Seconds::ZERO,
+            end_time: Seconds(0.2), // tiny render
+            tempo_map: TempoMap::constant(120.0),
+            metadata: vec![
+                ("title".to_string(), "Test Title".to_string()),
+                ("artist".to_string(), "Test Artist".to_string()),
+            ],
+        }
+    }
+
+    /// FLAC export must be a real FLAC container (not WAV bytes) carrying Vorbis-comment tags.
+    #[test]
+    fn flac_export_is_real_flac_with_tags() {
+        let settings = tagged_settings(ExportFormat::Flac);
+        let mut project = Project::new(48000);
+        let pool = AudioPool::new();
+        let path = std::env::temp_dir().join("lb_be_flac_test.flac");
+
+        export_audio(&mut project, &pool, &settings, &path, None).expect("FLAC export failed");
+        let bytes = std::fs::read(&path).unwrap();
+
+        assert_eq!(&bytes[0..4], b"fLaC", "not real FLAC (got {:?})", &bytes[0..4]);
+        let s = String::from_utf8_lossy(&bytes);
+        assert!(s.contains("Test Title"), "title tag missing from FLAC");
+        assert!(s.contains("Test Artist"), "artist tag missing from FLAC");
+        std::fs::remove_file(&path).ok();
+    }
+
+    /// WAV export keeps a valid RIFF container and gains a LIST/INFO tag chunk with a fixed-up size.
+    #[test]
+    fn wav_export_has_info_chunk() {
+        let settings = tagged_settings(ExportFormat::Wav);
+        let mut project = Project::new(48000);
+        let pool = AudioPool::new();
+        let path = std::env::temp_dir().join("lb_be_wav_test.wav");
+
+        export_audio(&mut project, &pool, &settings, &path, None).expect("WAV export failed");
+        let bytes = std::fs::read(&path).unwrap();
+
+        assert_eq!(&bytes[0..4], b"RIFF");
+        assert_eq!(&bytes[8..12], b"WAVE");
+        let riff_size = u32::from_le_bytes([bytes[4], bytes[5], bytes[6], bytes[7]]) as usize;
+        assert_eq!(riff_size, bytes.len() - 8, "RIFF size not fixed up after tagging");
+        let s = String::from_utf8_lossy(&bytes);
+        assert!(s.contains("LIST") && s.contains("INFO") && s.contains("INAM"),
+            "no RIFF INFO chunk");
+        assert!(s.contains("Test Title"), "title not in WAV INFO chunk");
+        std::fs::remove_file(&path).ok();
+    }
 }

lightningbeam-ui/lightningbeam-editor/src/config.rs

@@ -70,6 +70,14 @@ pub struct AppConfig {
     /// sooner; larger = smaller pyramid, wider re-decode span. Default 256.
     #[serde(default = "defaults::waveform_floor_samples_per_texel")]
     pub waveform_floor_samples_per_texel: u32,
+
+    /// Last-used audio-export "Artist" tag, remembered so it prefills next time.
+    #[serde(default)]
+    pub last_audio_artist: String,
+
+    /// Last-used audio-export "Album" tag, remembered so it prefills next time.
+    #[serde(default)]
+    pub last_audio_album: String,
 }
 
 impl Default for AppConfig {
@@ -90,6 +98,8 @@ impl Default for AppConfig {
             keybindings: KeybindingConfig::default(),
             large_media_default: LargeMediaMode::default(),
             waveform_floor_samples_per_texel: defaults::waveform_floor_samples_per_texel(),
+            last_audio_artist: String::new(),
+            last_audio_album: String::new(),
         }
     }
 }

lightningbeam-ui/lightningbeam-editor/src/export/dialog.rs

@@ -11,6 +11,36 @@ use lightningbeam_core::export::{
 };
 use std::path::PathBuf;
 
+/// The OS username (`$USER` / `%USERNAME%`), or empty if unavailable. Used as a default Artist tag.
+fn os_username() -> String {
+    std::env::var("USER")
+        .or_else(|_| std::env::var("USERNAME"))
+        .unwrap_or_default()
+}
+
+/// Current civil year (UTC) computed from the system clock — avoids pulling in a date crate.
+fn current_year() -> i64 {
+    let secs = std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .map(|d| d.as_secs())
+        .unwrap_or(0) as i64;
+    year_from_unix_secs(secs)
+}
+
+/// Civil year (UTC) for a Unix timestamp, via Howard Hinnant's `civil_from_days` algorithm.
+fn year_from_unix_secs(secs: i64) -> i64 {
+    let days = secs.div_euclid(86_400);
+    let z = days + 719_468;
+    let era = if z >= 0 { z } else { z - 146_096 } / 146_097;
+    let doe = z - era * 146_097; // [0, 146096]
+    let yoe = (doe - doe / 1460 + doe / 36_524 - doe / 146_096) / 365; // [0, 399]
+    let y = yoe + era * 400;
+    let doy = doe - (365 * yoe + yoe / 4 - yoe / 100); // [0, 365]
+    let mp = (5 * doy + 2) / 153; // [0, 11]
+    let m = if mp < 10 { mp + 3 } else { mp - 9 }; // [1, 12]
+    y + if m <= 2 { 1 } else { 0 }
+}
+
 /// Hint about document content, used to pick a smart default export type.
 pub struct DocumentHint {
     pub has_video: bool,
@@ -129,7 +159,14 @@ impl Default for ExportDialog {
 
 impl ExportDialog {
     /// Open the dialog with default settings, using `hint` to pick a smart default tab.
-    pub fn open(&mut self, timeline_duration: f64, project_name: &str, hint: &DocumentHint) {
+    pub fn open(
+        &mut self,
+        timeline_duration: f64,
+        project_name: &str,
+        hint: &DocumentHint,
+        last_artist: &str,
+        last_album: &str,
+    ) {
         self.open = true;
         self.audio_settings.end_time = timeline_duration;
         self.video_settings.end_time = timeline_duration;
@@ -153,10 +190,23 @@ impl ExportDialog {
             else if only_raster      { ExportType::Image }
             else                     { self.export_type  } // keep current as fallback
         };
-        // Default the audio "Title" tag to the project name (only if the user hasn't set one for a
+        // Sensible tag defaults, only filled when empty so a user's edits are never clobbered:
-        // different project — don't clobber an in-progress edit).
+        //  • Title  → project name (on a project switch)
-        if self.audio_settings.metadata.title.is_empty() && !same_project {
+        //  • Year   → current year
-            self.audio_settings.metadata.title = project_name.to_owned();
+        //  • Artist → last-used artist, else the OS username
+        //  • Album  → last-used album
+        let meta = &mut self.audio_settings.metadata;
+        if meta.title.is_empty() && !same_project {
+            meta.title = project_name.to_owned();
+        }
+        if meta.year.is_empty() {
+            meta.year = current_year().to_string();
+        }
+        if meta.artist.is_empty() {
+            meta.artist = if !last_artist.is_empty() { last_artist.to_owned() } else { os_username() };
+        }
+        if meta.album.is_empty() && !last_album.is_empty() {
+            meta.album = last_album.to_owned();
         }
         self.current_project = project_name.to_owned();
 
@@ -493,6 +543,14 @@ impl ExportDialog {
     fn render_audio_metadata(&mut self, ui: &mut egui::Ui) {
         let m = &mut self.audio_settings.metadata;
         ui.label(egui::RichText::new("Tags").strong());
+        // Placeholder styling: italic + a clearly faded color so an empty field's hint never reads
+        // as a real value (the theme's default weak color is too close to the text color). An
+        // explicit color overrides egui's weak-color fallback for hint text.
+        let hint_color = {
+            let t = ui.visuals().text_color();
+            egui::Color32::from_rgba_unmultiplied(t.r(), t.g(), t.b(), 100)
+        };
+        let year_hint = format!("e.g. {}", current_year());
         egui::Grid::new("audio_metadata_grid")
             .num_columns(2)
             .spacing([8.0, 4.0])
@@ -501,18 +559,18 @@ impl ExportDialog {
                     ui.label(label);
                     ui.add(
                         egui::TextEdit::singleline(val)
-                            .hint_text(hint)
+                            .hint_text(egui::RichText::new(hint).italics().color(hint_color))
                             .desired_width(260.0),
                     );
                     ui.end_row();
                 };
-                row(ui, "Title", &mut m.title, "Track title");
+                row(ui, "Title", &mut m.title, "e.g. My Song");
-                row(ui, "Artist", &mut m.artist, "Artist");
+                row(ui, "Artist", &mut m.artist, "e.g. Jane Doe");
-                row(ui, "Album", &mut m.album, "Album");
+                row(ui, "Album", &mut m.album, "e.g. Greatest Hits");
-                row(ui, "Genre", &mut m.genre, "Genre");
+                row(ui, "Genre", &mut m.genre, "e.g. Electronic");
-                row(ui, "Year", &mut m.year, "e.g. 2026");
+                row(ui, "Year", &mut m.year, &year_hint);
                 row(ui, "Track", &mut m.track, "e.g. 1 or 1/12");
-                row(ui, "Comment", &mut m.comment, "Comment");
+                row(ui, "Comment", &mut m.comment, "Optional notes…");
             });
     }
 
@@ -973,3 +1031,30 @@ impl ExportProgressDialog {
         should_cancel
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn year_from_unix_secs_known_values() {
+        assert_eq!(year_from_unix_secs(0), 1970); // Unix epoch
+        assert_eq!(year_from_unix_secs(946_684_800), 2000); // 2000-01-01
+        assert_eq!(year_from_unix_secs(1_735_689_600), 2025); // 2025-01-01
+        assert_eq!(year_from_unix_secs(1_767_225_599), 2025); // 2025-12-31 23:59:59
+        assert_eq!(year_from_unix_secs(1_767_225_600), 2026); // 2026-01-01
+
+        // Post-2038: these timestamps exceed i32::MAX (2_147_483_647) — and the last exceeds
+        // u32::MAX — so a 32-bit time_t would wrap here. i64 math handles them correctly.
+        assert_eq!(year_from_unix_secs(2_148_595_200), 2038); // 2038-02-01 (> i32::MAX)
+        assert_eq!(year_from_unix_secs(2_223_331_200), 2040); // 2040-06-15
+        assert_eq!(year_from_unix_secs(4_102_444_800), 2100); // 2100-01-01 (not a leap year)
+        assert_eq!(year_from_unix_secs(9_214_646_400), 2262); // 2262-01-01 (> u32::MAX)
+    }
+
+    #[test]
+    fn current_year_is_plausible() {
+        let y = current_year();
+        assert!((2020..3000).contains(&y), "implausible year: {y}");
+    }
+}

lightningbeam-ui/lightningbeam-editor/src/export/mod.rs

@@ -3,7 +3,6 @@
 //! This module provides the export orchestrator and progress tracking
 //! for exporting audio and video from the timeline.
 
-pub mod audio_exporter;
 pub mod dialog;
 pub mod gif_exporter;
 pub mod image_exporter;
@@ -1008,6 +1007,12 @@ impl ExportOrchestrator {
             start_time: daw_backend::Seconds(settings.start_time),
             end_time: daw_backend::Seconds(settings.end_time),
             tempo_map: daw_backend::TempoMap::constant(settings.bpm),
+            metadata: settings
+                .metadata
+                .pairs()
+                .into_iter()
+                .map(|(k, v)| (k.to_string(), v.to_string()))
+                .collect(),
         };
 
         // Use DAW backend export for all formats

lightningbeam-ui/lightningbeam-editor/src/main.rs

@@ -3443,7 +3443,13 @@ impl EditorApp {
                     h
                 };
 
-                self.export_dialog.open(timeline_endpoint, &project_name, &hint);
+                self.export_dialog.open(
+                    timeline_endpoint,
+                    &project_name,
+                    &hint,
+                    &self.config.last_audio_artist,
+                    &self.config.last_audio_album,
+                );
             }
             MenuAction::Quit => {
                 println!("Menu: Quit");
@@ -6369,6 +6375,15 @@ impl eframe::App for EditorApp {
                     ExportResult::AudioOnly(settings, output_path) => {
                         println!("🎵 [MAIN] Starting audio-only export: {}", output_path.display());
 
+                        // Remember Artist/Album so they prefill next time.
+                        if !settings.metadata.artist.is_empty() {
+                            self.config.last_audio_artist = settings.metadata.artist.clone();
+                        }
+                        if !settings.metadata.album.is_empty() {
+                            self.config.last_audio_album = settings.metadata.album.clone();
+                        }
+                        self.config.save();
+
                         if let Some(audio_controller) = &self.audio_controller {
                             orchestrator.start_audio_export(
                                 settings,