From 9ea1eea3ea91f6fe194df616e2a79faf2707add5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=C3=A1=C5=A1=20Ml=C3=A1dek?= <t@mldk.cz>
Date: Mon, 19 Sep 2022 22:27:20 +0200
Subject: [PATCH] feat: if `audiowaveform` is present, generate & cache peaks
 on backend

requires https://github.com/bbc/audiowaveform/ to be installed and on $PATH
---
 src/previews/audio.rs                         | 91 ++++++++++++-------
 .../display/blobs/AudioViewer.svelte          | 12 ++-
 2 files changed, 70 insertions(+), 33 deletions(-)

diff --git a/src/previews/audio.rs b/src/previews/audio.rs
index 29b99f7..150f283 100644
--- a/src/previews/audio.rs
+++ b/src/previews/audio.rs
@@ -14,41 +14,68 @@ const COLOR: &str = "#dc322f"; // solarized red
 
 impl<'a> Previewable for AudioPath<'a> {
     fn get_thumbnail(&self, options: HashMap<String, String>) -> Result<Option<Vec<u8>>> {
-        let outfile = tempfile::Builder::new().suffix(".webp").tempfile()?;
+        match options.get("type").map(|x| x.as_str()) {
+            Some("json") => {
+                let outfile = tempfile::Builder::new().suffix(".json").tempfile()?;
 
-        let color = options
-            .get("color")
-            .map(String::to_owned)
-            .unwrap_or_else(|| COLOR.into());
-        let dimensions = options
-            .get("dimensions")
-            .map(String::to_owned)
-            .unwrap_or_else(|| "860x256".into());
+                // -i long_clip.mp3 -o long_clip.json --pixels-per-second 20 --bits 8
+                let audiowaveform_cmd = Command::new("audiowaveform")
+                    .args(["-i", &self.0.to_string_lossy()])
+                    .args(["-o", &*outfile.path().to_string_lossy()])
+                    .args(["--pixels-per-second", "20"])
+                    .args(["--bits", "8"])
+                    .output()?;
 
-        let thumbnail_cmd = Command::new("ffmpeg")
-            .args(["-i", &self.0.to_string_lossy()])
-            .args([
-                "-filter_complex",
-                &format!(
-                    "[0:a]aformat=channel_layouts=mono, compand=gain=-2,
-                     showwavespic=s={dimensions}:colors={color},
-                     drawbox=x=(iw-w)/2:y=(ih-h)/2:w=iw:h=1:color={color}"
-                ),
-            ])
-            .args(["-vframes", "1"])
-            .arg(&*outfile.path().to_string_lossy())
-            .arg("-y")
-            .output()?;
+                if !audiowaveform_cmd.status.success() {
+                    return Err(anyhow!(
+                        "Failed to retrieve file duration: {:?}",
+                        String::from_utf8_lossy(&audiowaveform_cmd.stderr)
+                    ));
+                }
 
-        if !thumbnail_cmd.status.success() {
-            return Err(anyhow!(
-                "Failed to render thumbnail: {:?}",
-                String::from_utf8_lossy(&thumbnail_cmd.stderr)
-            ));
+                let mut buffer = Vec::new();
+                outfile.as_file().read_to_end(&mut buffer)?;
+                Ok(Some(buffer))
+            }
+            Some("image") | None => {
+                let outfile = tempfile::Builder::new().suffix(".webp").tempfile()?;
+
+                let color = options
+                    .get("color")
+                    .map(String::to_owned)
+                    .unwrap_or_else(|| COLOR.into());
+                let dimensions = options
+                    .get("dimensions")
+                    .map(String::to_owned)
+                    .unwrap_or_else(|| "860x256".into());
+
+                let thumbnail_cmd = Command::new("ffmpeg")
+                    .args(["-i", &self.0.to_string_lossy()])
+                    .args([
+                        "-filter_complex",
+                        &format!(
+                            "[0:a]aformat=channel_layouts=mono, compand=gain=-2,
+                             showwavespic=s={dimensions}:colors={color},
+                             drawbox=x=(iw-w)/2:y=(ih-h)/2:w=iw:h=1:color={color}"
+                        ),
+                    ])
+                    .args(["-vframes", "1"])
+                    .arg(&*outfile.path().to_string_lossy())
+                    .arg("-y")
+                    .output()?;
+
+                if !thumbnail_cmd.status.success() {
+                    return Err(anyhow!(
+                        "Failed to render thumbnail: {:?}",
+                        String::from_utf8_lossy(&thumbnail_cmd.stderr)
+                    ));
+                }
+
+                let mut buffer = Vec::new();
+                outfile.as_file().read_to_end(&mut buffer)?;
+                Ok(Some(buffer))
+            }
+            Some(_) => Err(anyhow!("type has to be one of: image, json")),
         }
-
-        let mut buffer = Vec::new();
-        outfile.as_file().read_to_end(&mut buffer)?;
-        Ok(Some(buffer))
     }
 }
diff --git a/webui/src/components/display/blobs/AudioViewer.svelte b/webui/src/components/display/blobs/AudioViewer.svelte
index 3bf6720..ce38f48 100644
--- a/webui/src/components/display/blobs/AudioViewer.svelte
+++ b/webui/src/components/display/blobs/AudioViewer.svelte
@@ -147,6 +147,7 @@
       responsive: true,
       backend: "MediaElement",
       mediaControls: true,
+      normalize: true,
       xhr: { cache: "force-cache" },
       plugins: [
         TimelinePlugin.default.create({
@@ -202,7 +203,16 @@
       setTimeout(() => wavesurfer.setCurrentTime(region.start));
     });
 
-    wavesurfer.load(`${API_URL}/raw/${address}`);
+    try {
+      const peaksReq = await fetch(`${API_URL}/thumb/${address}?type=json`);
+      const peaks = await peaksReq.json();
+      wavesurfer.load(`${API_URL}/raw/${address}`, peaks.data);
+    } catch (e) {
+      console.warn(
+        `Failed to load peaks from server (${e}), falling back to client-side render...`
+      );
+      wavesurfer.load(`${API_URL}/raw/${address}`);
+    }
   });
 </script>