[Bug]: Invalid mpris position report

[zoriya]

Preflight Checklist

• I use the latest version of YouTube Music (Application).
• I have searched the issue tracker for a bug report that matches the one I want to file, without success.
• I understand that th-ch/youtube-music has NO affiliation with Google or YouTube

YouTube Music (Application) Version

3.3.12

Checklists

• I use the portable version of the YouTube Music Application.
• I can reproduce this issue in the official version of (WEB) YTM.

What operating system are you using?

Other Linux

Operating System Version

Linux fuhen 6.6.36 #1-NixOS SMP PREEMPT_DYNAMIC Thu Jun 27 11:49:15 UTC 2024 x86_64 GNU/Linux

What CPU architecture are you using?

x64

Last Known Working YouTube Music (Application) version

/shrug

Reproduction steps

1. Enable the MPRIS plugin
2. Start playing a song, wait a few seconds
3. Run playerctl position and see something like 0.0025
4. Seek somewhere on the song (say 1:00`
5. Run playerctl position and see the position you seeked to (so 60.567 for example)
6. Wait a few seconds
7. Run playerctl position and see the same value (or close to) as before (so 60.4567 instead of 65.12 for example)

Expected Behavior

Mpris's position should be reported correctly, even when not seeking manually

Actual Behavior

See reproduction steps.

Enabled plugins

[YTMusic] Plugin "shortcuts::menu" loaded
[YTMusic] Plugin "lyrics-genius::menu" loaded
[YTMusic] Plugin "downloader::menu" loaded
[YTMusic] Plugin "album-color-theme::menu" loaded
[YTMusic] Plugin "shortcuts::menu" loaded
[YTMusic] Plugin "lyrics-genius::menu" loaded
[YTMusic] Plugin "downloader::menu" loaded
[YTMusic] Plugin "album-color-theme::menu" loaded

Additional Information

No response

[bqcrabtree]

I'm seeing this issue still in v3.4.1

[h-banii]

I've been having this issue for a while, here's more information about it:

• last known working version: v3.3.6
• I'm almost sure the first bad commit is eaf9d31
• workaround: reload page through the menu view > reload

I could not bisect it properly because there were some broken commits for me, but reverting eaf9d31 seems to fix it.

Here's a demonstration video of the issue (and the workaround):

mpris_position.mp4

(In the video you can see the position does not update when playing the song, it stays at around the same timestamp)

---

Edit: I figured it out

The issue happens because this callback isn't called (reloading the page triggers this event, which runs the callback and fixes the issue)

youtube-music/src/plugins/shortcuts/mpris.ts

Lines 121 to 130 in 32a572b

	ipcMain.on('ytmd:player-api-loaded', () => {
	win.webContents.send('ytmd:setup-seeked-listener', 'mpris');
	win.webContents.send('ytmd:setup-time-changed-listener', 'mpris');
	win.webContents.send('ytmd:setup-repeat-changed-listener', 'mpris');
	win.webContents.send('ytmd:setup-volume-changed-listener', 'mpris');
	win.webContents.send('ytmd:setup-fullscreen-changed-listener', 'mpris');
	win.webContents.send('ytmd:setup-autoplay-changed-listener', 'mpris');
	requestFullscreenInformation();
	requestQueueInformation();
	});

That event used to be sent AFTER registerMPRIS(), so the callback runs. However, after commit eaf9d31 that event is sent BEFORE registerMPRIS(), i.e. before the listener is created.

youtube-music/src/plugins/shortcuts/main.ts

Lines 51 to 53 in eaf9d31

	ipcMain.once('ytmd:video-src-changed', (_) => {
	registerMPRIS(window);
	});

---

Anyway, here's a possible solution (I'm not opening a PR, because the bad commit was already reverted 7599cc6 )

diff --git a/src/plugins/shortcuts/main.ts b/src/plugins/shortcuts/main.ts
index 84c29899..59f40d13 100644
--- a/src/plugins/shortcuts/main.ts
+++ b/src/plugins/shortcuts/main.ts
@@ -48,9 +48,10 @@ export const onMainLoad = async ({
   _registerLocalShortcut(window, 'CommandOrControl+L', search);
 
   if (is.linux()) {
-    ipcMain.once('ytmd:video-src-changed', (_) => {
-      registerMPRIS(window);
-    });
+    const channels = ['ytmd:player-api-loaded','ytmd:video-src-changed']
+      .map((channel) => new Promise((resolve) => ipcMain.once(channel, resolve)));
+
+    Promise.all(channels).then(() => registerMPRIS(window));
   }
 
   const { global, local } = config;
diff --git a/src/plugins/shortcuts/mpris.ts b/src/plugins/shortcuts/mpris.ts
index cdfc9d4b..59b269b4 100644
--- a/src/plugins/shortcuts/mpris.ts
+++ b/src/plugins/shortcuts/mpris.ts
@@ -118,7 +118,7 @@ function registerMPRIS(win: BrowserWindow) {
       player.setPosition(player.getPosition() + offset);
     };
 
-    ipcMain.on('ytmd:player-api-loaded', () => {
+    const onApiLoaded = () => {
       win.webContents.send('ytmd:setup-seeked-listener', 'mpris');
       win.webContents.send('ytmd:setup-time-changed-listener', 'mpris');
       win.webContents.send('ytmd:setup-repeat-changed-listener', 'mpris');
@@ -127,7 +127,10 @@ function registerMPRIS(win: BrowserWindow) {
       win.webContents.send('ytmd:setup-autoplay-changed-listener', 'mpris');
       requestFullscreenInformation();
       requestQueueInformation();
-    });
+    };
+
+    onApiLoaded();
+    ipcMain.on('ytmd:player-api-loaded', onApiLoaded);
 
     ipcMain.on('ytmd:seeked', (_, t: number) => {
       player.setPosition(secToMicro(t));