piCorePlayer6.1.0-Xenomai-44.1-48KHz雙機入門簡易安裝教學

[seeteeyou]

所以小弟會先測試OTG模式，把RPi4當成音效卡看看。
或許Noël之後還會有Update...

或許 RPi4 能夠帶領我們向終點邁進多一步：

ian's fifo 通通無法徹底消除前端數位播放差異，只能打折，還是哭哭......

事緣是醬子的，索價 299 鎂的 Euphony OS 近來增添了另一種 RAM 的緩衝模式，好處是把現有 queue 中包含的所有檔案拷貝入 RAM 之後就能夠暫時把網路卡關掉，然後每次相隔五分鐘才檢查一下 queue 的內容有沒有任何改變，最後的結果就是消除／大大降低網路帶來的干擾：

https://audiophilestyle.com/forums/t...hread/page/64/

when queue is filled from NAS and fully buffered to RAM and when playback starts - network can be disconnected

Hi, yes talked to Zeljko last night. Basically before you could only buffer & play 2 songs if you pulled out the cable. Now you can buffer & play as many as you like then pull cable out.

Add album, buffer, then in expert menu press play. See below, it automatically shuts down network completely. It also auto populates how long for (album time length).

But nothing like the change that disconnecting the network has made. Tonight I sat through a Jeffrey Foucault album on buffer and network disconnected in Expert. I really enjoyed it, but it wasn't until I listened to a track again with network connected and wondered what had happened. I had to do the Expert disconnect again for that track and sure enough, a real change to detail, air and tone. What's that all about?

The difference is very obvious; the Matrix in the chain was a good change, this is again something I don't want to miss. Despite the inability to skip, add or stop play, so far it is worth it.

既然暫時關掉網路卡是可行的話，那麼 USB Host 和 USB OTG 大概也問題不大吧？假如能夠把一定數目的檔案拷貝入 8GB RAM 的 RPi4 是否可以暫時關掉 Roon Core 那邊的 USB 輸出呢？

因此小弟就去看看一些關於 UAC2 gadget 的 patches，當中 Ruslan Bilovol 兄就提及 ALSA 的 loopback driver：

https://patchwork.kernel.org/project...bmitter=121671

貌似虛擬音效卡：

https://www.alsa-project.org/wiki/Matrix:Module-aloop
https://www.systutorials.com/docs/linux/man/1-alsaloop/
https://sysplay.in/blog/linux/2019/0...pback-devices/

還有 JACK 和 PulseAudio：

https://github.com/actions/virtual-e...ts/issues/1114
https://stackoverflow.com/questions/...cord-it-to-fil

當然最重要的就是如何利用 RPi4 的 RAM 來建立緩衝，該不是用 alsa-utils 的 arecord 寫入 RAM disk 那麼簡單吧？