Retro Music Player app and playlists

Until now I've used the Google Play Music app. One reason was that I could store songs I regularly hear locally on my device and didn't need to stream them over and over again via the mobile data connection.

As Google Play Music is being discontinued and I have transferred my collection to its successor - the Youtube Music App - only to find that I have to pay 9,99 € a month for the privilege to have the music I already bought played back locally without streaming.

I've managed - with some difficulty - to download my collection and my playlists from Google Music and I'm now trying to find an app which can play my music (most do) and can import my playlists (here lies the problem).

The Retro Music Player app is an open-source music player for Android which claims to be able to import and export playlists. But this is only partially true.

The export works perfectly as it is implemented in the app. The import is (currently) performed by the operating system and its implementation ranges from "works perfectly" to "doesn't work at all" as many bug reports on GitHub can attest to.

Until RMP decides to implement the playlist import in the app itself the functionality of this feature is left to chance.

Wake Me Up After You Go-Go

I took me days but I got Wake-on-LAN working on my new B450 Tomahawk Max. I need this functionality to power-on the machine from another always-on-computer on the network so that I can access it while I am on the road.

The reason that WoL was not working was presumably not the BIOS (which I did update to the current version (E7C02AMS.360)), it was neither the router nor the network cable – as mentioned elsewhere – and my BIOS settings were correct as well. 

It turns out that contrary to my other computers it is not enough to simply turn on the settings in the BIOS as shown below.  The operating system must inform the motherboard Ethernet subsystem “which kind of WoL” it should use – otherwise that setting, which is not accessible from the BIOS, stays disabled, nothing will happen and it looks as if WoL were not working at all.

The most common WoL option is the so called Magic Packet which can be sent by utilities like etherwake (on Linux) or Wake-on-LAN (on Android), but apparently there are other options as well.

Windows user can specify the option to use in the Control Center, but I’m not running Window, I’m using Ubuntu Linux 20.04 LTS… What to do?  The answer is ethtool.

Let’s start with the BIOS settings:

Settings\Advanced\Integrated Peripherals
   Onboard LAN Controller: Enabled  ... (which is the default)

Settings\Advanced\Power Management Setup
   ErP Ready: Disabled   ... (which is the default)

Settings\Advanced\Wake Up Event Setup
  Resume By PCI-E Device: Enabled

With Linux running, determine the device identifier of your onboard Ethernet “card” using the ifconfig command:

    ifconfig

If ifconfig is not installed run:

    sudo apt install net-tools

Furthermore you need ethtool:

    sudo apt install ethtool

The name of my ethernet device is: enp34s0
Change the following commands accordingly.

Enter:

    sudo ethtool enp34s0

Look for the line “Wake-on:”. If the value in this line is “d” then the WoL function is (d)isabled. To make it react to the WoL Magic Packet is has to be set to “g”.

    sudo ethtool -s enp34s0 wol g

Check the setting again with:

    sudo ethtool enp34s0

Shut-down the computer and try to wake it with a WoL tool as mentioned above.

This command needs to be executed after each boot. The simplest way to achieve this is to append or create the file /etc/rc.local:

#!/bin/bash
ethtool -s enp34s0 wol g
exit 0

Don’t forget to make it executable:

    sudo chmod 744 /etc/rc.local


A more elaborate way can be found here. Note: Check the path of ethtool with “which ethtool” and correct the script accordingly.

Wake-up happy….

Links

• https://www.thomas-krenn.com/en/wiki/Wake_On_LAN_under_Linux

P.S.: Here is the German version of the BIOS options:

Settings\Erweitert\Integrierte Peripheriegeräte
   Onboard LAN Controller: Aktiviert     (default)

Settings\Erweitert\Energieverwaltungs Konfiguration
  ErP Ready: Deaktiviert    (default)

Settings\Erweitert\Einrichtung der Reaktiverungsereignisse
  Fortsetzung durch PCI-E-Gerät: Aktiviert

How to set the active camera ... when Blender renders in the background

Background rendering, i.e. rendering without the UI and based on command line parameters alone, is usually the domain of render farms.

But there are situations where this functionality is useful for normal users as well: scripts.

In my case the blend file contains a complex architectural model and various cameras (which you can conveniently set-up and switch between with the “Stored Views” add-on).

Some of those cameras are (virtual) panoramic cameras.  Their output will be fed into a generator script to calculate multi-res images for use with the web panorama viewer pannellum (https://pannellum.org) to create a virtual tour.

Wouldn’t it be nice to have a script producing the rendered pictures for all those cameras; it might even call the pannellum generator script afterwards to calculate the multi-res images needed for the virtual tour...

When Blender is started in background mode, various parameters can be set from the command line - among others the frame and scene to be rendered, the render engine and the output path.

Missing however are some settings I would like for my workflow: the active camera and the dimension percentage (Output Properties > Dimensions > Resolution > %). Those values are stored in the blend file and used in the render process.

If you want rendered images from multiple cameras you usually open the blend file, switch the camera, save the blend file and re-render…

As for the other setting: I sometimes forget to switch the resolution from my usual 50% to 100% before starting to render. While rendering without the UI you don’t notice this right away.  Something that sets this value to 100% would be nice.

The solution

Blender’s command line option --python-expr lets you enter a short Python snippet which gives you access to all settings in your scene.

To switch the active camera in the current screen use

import bpy
bpy.context.scene.camera = bpy.context.scene.objects.get('XXXXXX')

where XXXXXX is the name of the camera.

The command for setting the resolution percentage value is

bpy.context.scene.render.resolution_percentage = 100

You can test these commands in Blender’s Python console.

Note: It does matter where you put the --python-expr command on the command line. If used at the end of the command it will be ineffective because it changes the parameter after the render process.

My typical Blender background render command looks like this:

blender -b myblend.blend --python-expr "import bpy; bpy.context.scene.camera = bpy.context.scene.objects.get('Camera XXXX'); bpy.context.scene.render.resolution_percentage = 100" -o /tmp/pic_#### -F PNG -x 1 -f 1 -E CYCLES

• -b: background render of myblend.blend.
• --python-expr: use camera ‘Camera XXXX’ and render at 100%
• -o: store under /tmp/pic_####
• -F: store as PNG
• -x: add the PNG extension
• -f: render frame 1
• -E: use cycles render engine

You might use this technique to change other values on the fly without them being saved back to disk.