No transcode for lossless audio

[Andrewfd]

Hi

I have a Apple Lossless music library (ripped from CDs) on a Mac Mini. I have installed Universal Media Server 9.8.1 and want to use it to serve bit perfect lossless files to my client, an Android device connected to a DAC headphone amp.

I have two questions

How to I turn off all the transcoding in UMS?

Why does every album have a subfolder called Transcode?

What is the difference between the audio files in the album folder and the files in the Transcode sub folder?

Thanks

Andrew

[Nadahar]

1) You shouldn't turn off all transcoding. That's a quite common misunderstanding, although I don't know where people are getting the idea. UMS doesn't "transcode for fun". Its only supposed to transcode when the renderer can't handle the media file in question. The alternative to transcoding is thus no playback, not "better quality". As long as the renderer can handle the media, UMS won't transcode unless there's a bug or the renderer configuration is wrong. Instead, you should read (you'll find plenty on this forum) on how to verify/modify your renderer configuration file so that it correctly reflects everything your renderer can handle.

2) The transcode subfolder can be turned off in the configuration. Inside, you'll find all the "possible" (they aren't always really possible, some won't work) transcoding variations for the file in question, including a "no transcoding" option. In short, when you play a file outside the transcode folder, UMS will try to determine (based on the renderer configuration and the media analysis) whether or not to transcode, and if so - how to transcode. In the "transcode" folder, you can make the selection manually instead. It is useful for testing what works on a given renderer (playing the "no transcode" version will for example tell you that the renderer supports the media natively), or for the rare case where automatic selection can't be configured to make the right choice. That mostly applies to video, where you have a combination of audio and subtitles tracks to choose from and you can use this folder to select a different combination of these than what is configured.

[Andrewfd]

That's really useful knowledge. Thanks.

In my case, the renderer is in two parts. It will be an Android device but running an app called USB Audio Player. Android devices often limit or resample audio in their firmware, but UAP bypasses that an allows the audio file to pass to a connected DAC unaltered. In my case most of the audio will be CD quality lossless 44/16.

Will UMS see the android device and assume it's limitations without realising that UAP can accept any and all qualities of stream (as can the USB DAC it will feed, except for MQA audio)?

[Nadahar]

UMS doesn't know the device's limitations, which is why a dedicated renderer configuration file is needed. If one doesn't already exist for your setup (seems unlikely), you'll have to create your own/tweak an existing. Creating/modifying a renderer configuration file isn't well documented in any one place, but there are bits and pieces of information spread "all over the place". You can find all the information you need on this forum if you have some persistence, but it will take some searching and reading.

I would start with e.g the BubbleUPnP/MXPlayer configuration and then modify it until it fits. You will also have to modify the "search strings" that's used by UMS to match a renderer and the configuration file. Since you're only handling audio, things gets a lot simpler - video is so much more complicated to get right. You can turn off video and images in the renderer configuration, so that you're left with an "audio only renderer". Once that's done, you only need to tweak which formats/containers and codecs are supported and you should be good to go.