ArchQ 數位訊源入門 -> 究極

[seeteeyou]

我比較有興趣的是 MPD上的SlimProto plugin，小弟的功力不夠，目前看來沒什麼機會。

This is an ALSA plugin required by SlimStreamer
https://github.com/gimesketvirtadieni/slimplexor

SlimStreamer is an audio streaming software for Linux with multi-room functionality. SlimStreamer captures audio playback from ALSA and broadcasts it to connected Squeezebox devices (real or ‘virtual’ like squeezelite).
https://github.com/gimesketvirtadieni/slimstreamer

已經好幾年沒有任何更新了，大概就是被放棄的說，且看有沒有甚麼可取之處吧：

https://www.diyaudio.com/community/t.../#post-5285442

I use SlimProto (SlimProto TCP protocol - SqueezeboxWiki), the same protocol used by Logitech Media Server (Logitech Media Server - SqueezeboxWiki). In other words, SlimStreamer mimics Logitech Media Server. This protocol came a long way; companies like Slim Devices and Logitech put a lot of expertise into it: SlimProto is the next version of SLIMP3, it supports lots of codecs, it allows using various sample rates, synchronisation, DSD over PCM (have not tested), … However the main reason I have chosen using it – players can be Pi Model A or Zero with decent DAC running a single SW player (squeezelite). The rest of the music functionality is done on server (regular player, MPD, Mopidy, Spotify, ShairPlay, …).

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https://forums.slimdevices.com/forum...ox-com-servers

After a more than ten year journey, as of February 2024, we will discontinue our UESmartRadio.com and MySqueezebox.com servers. We would like to thank you for your loyalty and support throughout this time.

短期內也不會有重大的變動，畢竟 LMS 實屬開源的軟件，但是前景還是比較堪憂。

另外 Apple Music 提供的無損 ALAC 檔案已經被「大補帖」化：

https://github.com/WorldObservationLog

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實際上 Apple Music 和 TIDAL 的 Dolby Atmos 格式還有這種好處：

https://www.audioholics.com/news/son...ew-format-wars

Both formats solve problems associated with the so-called "Loudness Wars" by being mastered at significantly lower volume than most stereo tracks. According to Mastering Engineer Ian Shepherd, Atmos specifies mastering at an integrated loudness of -18 LUFS. From lurking audio pro communities I've learned that's as much as 10dB lower than the many of today's stereo masters. You'll have to turn-up the volume, but for your effort you may hear more dynamic range and subtle detail missing in so much of today's two-channel recordings.

https://web.archive.org/web/20230922...-why-with-fix/

The low volume level requires listeners to turn up their system in order to hear the same average loudness, but this results in improved sound quality and clarity when compared with traditional stereo mixes.

https://www.travsonic.com/why-dolby-atmos-is-quieter/

The lower volume level may require listeners to turn up their system to achieve the same average loudness as previous stereo releases. However, this adjustment improves sound quality and clarity compared to traditional stereo mixes.

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當然最重要的事情就是如何利用兩聲道的系統欣賞 Atmos 格式：

https://audiophilestyle.com/forums/t...omment-1265920

The traditional two channel and the Atmos two channel cometimes can me very similar, but other times can be very different. It all depends on the mix. With the two channel Atmos, you still have the rendering process to place all the channels and objects. This is NOT as simple as a fold down or downmix, there is a lot of math involved and grouping of objects for the best quality or smallest file size etc... It's a totally different world from something like a 5.1/7.1 downmix to 2.0.

[SOFTWARE] How to play Dolby AC4 IMS/DD+JOC files on Windows/macOS
https://bugmenot.com/view/sharemania.us
https://sharemania.us/threads/softwa...-macos.201269/

How To Decode and Play Dolby TrueHD Atmos on Windows and macOS
https://audiophilestyle.com/ca/immer...d-macos-r1092/

Lossless TrueHD Atmos Just Got Much Easier
https://audiophilestyle.com/ca/immer...-easier-r1170/

Music Media Helper (Tools for Multichannel Audio & Music Videos)
https://www.quadraphonicquad.com/for...-videos.22693/

下載那個 DRP 之後就可以動工了，channel_layout 是 2.0：

https://gist.github.com/Plazik/e9502...1ea7879aaa3d5d

等同 MMH 的這個選項：

https://audiophilestyle.com/forums/t...omment-1262840

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TIDAL 的 Dolby Atmos：

https://github.com/ebb-earl-co/tidal...-file#features

[sam0402]

音樂資訊的挖掘、傳遞和維持

在小弟的系統到了滿意的境界後，會常常發出囋嘆，原來這張專輯竟有這種聲音出來。
最近對這張專輯(ZZT 050901)感到訝異，怎麼2004年的CD，竟有如此多的資訊量！小弟在教會的會堂裡，也因此注意到資訊量的問題。
cover.jpg

在教堂裡有足夠大的空間，管風琴會產生許多反射音。在許多管子(樂器)同時發聲下，除了直接音外，會感受到反射音是由前方以填滿空間的方式湧過來。
但能全面錄下這些反射音的專輯似乎不多，小弟意外的收了這套管風琴的專輯(應該是我根本不知道有買它)。

小弟想談的是，資訊量的問題。小弟回想在系統不斷進化的歷程上，是那些因素才能把大量的音樂資訊播放出來？或者是說，真正的把現場的音樂資訊給播出來。
第一是錄音：要有完整資訊的錄音。這不是廢話嗎？不過小弟發現有完整資訊量的錄音可能少之又少，因為很多資訊在錄音、後製、傳遞過程中被吃掉了！這在後面會提到。
第二資訊的挖掘：要有ArchQ等級的播放器，配合性能夠強的電腦，才能把好錄音的資訊完整的送出。沒到位的軟硬體，播出的內容就是會少資訊。反之，錄音時的軟硬體也會面臨相同的問題。
第三資訊的傳遞：電腦播出的資訊要用對的傳遞方式才能以最少損失的方式送進後端。如香堡寶級的同軸數位線，USB 4 線的大頻寬(這也是小弟堅持用的原因)配合 Type-C HUB。而錄音時一樣會遇到。
第四資訊的維持：這就有點意思了，可能不好解釋，但用過就知道：香堡寶電源線。它是不會掉資訊的電源線，也就是小弟第一次用它時的描述：水把沙子填滿了。但應該是反過來講，用不好的線材，水被倒掉了，剩下沙子。另一個能維持資訊的是DC(AC)接地線，它能維持資訊不被干擾，聲音就不會暈開散掉。同樣的，若錄音時沒用上香堡寶等級的電源線，想必也是會掉資訊。

最後還有一張CD是資訊量錄好錄滿的，就是教授推的Hortus 226。