soundbox, branch alsa-loop

WIP: doc: Explain ALSA loop device use case

2024-01-24T19:29:09Z

doc: Rework user guide for streaming

2024-01-21T08:19:43Z

The default streaming guide is now far away from the original taken from the FFmpeg streaming guide. Since the command can handle a lot of inputs its also not useful to send sine waves to soundbox devices.

doc: Add user guide for device discovery

2024-01-20T20:55:22Z

doc: Add OpenRC service configuration

2024-01-20T20:25:20Z

This makes sure the audio-receiving software `ffplay` runs all the time.

doc: Split configuration section into subsections

2024-01-20T14:12:42Z

doc: Add lldpd configuration

2024-01-20T11:05:15Z

This makes a soundbox device discoverable via the Link Layer Discovery Protocol (LLDP). That way a client application can lookup the available soundbox devices inside the network to display playback options.

doc: Always use MP3 as audio codec

2024-01-14T19:50:59Z

While transcoding to a lossy formate like MP3 is not recommended [1] forquality reasons it has the advantage that alway UPD / Matroska / MP3 is used for soundbox. That way the stream can be stopped and started at any time without re-launching ffplay on the soundbox device. This could make the SSH connection to the soundbox not longer needed. [1]: https://trac.ffmpeg.org/wiki/Encode/HighQualityAudio#WhenshouldItranscodeaudio

doc: Simplify streaming commands

2024-01-14T19:48:43Z

doc: Switch from RTP to Matroska and UDP

2024-01-14T19:27:05Z

The Matroska format has to advantage that a stream can be stopped and the restarted at any time without executing new commands on the soundbox device. Since Matroska and RTP have similar / redundant features [1] the transport protocol is switched to plain UDP. [1]: https://en.wikipedia.org/wiki/Comparison_of_video_container_formats#cite_note-22

Add versioned documentation file in artifacts dir

2024-01-14T14:59:55Z

The full soundbox-- prefix was only used for the artifact tar archive name so far. This has the advantage that the file names inside that archive are shorter like 'documentation.pdf'. But sometimes it is useful to pass only the documentation around as a PDF file because it is easier for people to open it compared to a tar file. For this purpose a second artifact installation for the documentation PDF is added including the soundbox-- prefix.

doc: Fix duplicated period

2024-01-14T14:46:35Z

doc: Switch to multicast for streaming

2024-01-14T13:14:45Z

This allows to stream to multiple devices at the same time. Nevertheless it still works for a point to point stream.

doc: Explain how to enable default RPi audio

2024-01-14T13:10:35Z

The soundbox software should be portable to other Raspberry Pis without the HiFiBerry DAC too.

doc: Unify replacable parts of streaming command

2024-01-14T11:22:51Z

doc: Use native audio codec for streaming

2024-01-14T11:04:06Z

The music streaming documentation used to enforce re-encoding via ffmpeg to save bandwidth. This led to pretty poor audio quality. This is not the purpose of soundbox. It is assumed that the user wants the highest possible audio quality as default.

doc: Add Alpine Linux config guide

2024-01-14T10:44:18Z

Configuring the Alpine Linux operating system correctly for soundbox is not trivial. Since it is very important it has to be documented in detail.

doc: Switch to tar-based installation

2024-01-14T10:44:12Z

The tar-based installation is more difficult to explain but has the advantage that the partition size is maximized from the beginning. This is way easier than resizing the partition after the installation.

doc: Add Alpine Linux installation instructions

2024-01-12T21:02:02Z

This is currently the recommended OS installation for soundbox.

mech: Rework front panel

2024-01-10T20:07:42Z

The positions of the connectors had to be adapted to the new PCB case dimensions. Furthermore the micro USB port which is built in to supply the device with power is now the only visible micro USB port from the outside. The other one is unused and could lead to confusion. User might plug in the power cable into the wrong port. Hiding this misleading USB port is an elegant way to avoid this problem. Developers can still open the device to make use of that port if required.

mech: Adapt thickness and spacing

2024-01-09T19:14:31Z

The front panel has to be very close and thin so that USB and HDMI cables can still be connected when only the ports are cut out of the panel.

mech: pcb_case: Add spacers

2024-01-09T18:59:04Z

Since a proper norm-based distance bolt was not found printing spacers is the easiest way to make the case producable independent of part availability.

mech: pcb_case: Align connector_z and bolt length

2024-01-09T18:44:42Z

This makes sure that the bolts inside the connectors align with them. Thus the bolts do not stick inside the case which might lead to PCB collisions.

mech: pcb_case: Fix height calculation

2024-01-09T18:26:25Z

The height should take into account that the shell is two instead of one times the thickness high. This is relevant for the vertical spacing.

doc: Change paragraph distance

2024-01-06T19:50:43Z

There used to be no extra space between paragraphs which in combination with no indentation was not useful.

doc: Fix missing `-re` flag for ffmpeg streaming

2024-01-05T21:03:23Z

This flag makes sure the file is streamed in native frame rate and not e.g. way faster. This is the expected behaviour.

doc: Switch from UDP port 1234 to UDP port 5316

2024-01-05T19:58:34Z

This port should be used in the future as soundbox standard port.

doc: Add example for FFMpeg MP3 streaming

2024-01-05T11:03:13Z

This allows more testing than only streaming sine waves.

doc: Add section 'Playing audio'

2024-01-05T10:48:23Z

This documents a basic FFmpeg streaming example so that soundbox devices can be tested.

doc: Write section 'Versioning'

2024-01-05T09:52:04Z

This section is important to communicate how to interpret version numbers in the context of this device repository.

doc: Build twice with LaTeX

2024-01-05T09:07:04Z

This is required to build the table of contents and similar parts of the document correctly.