Difference between revisions of "LiveTranStack"
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[[Category:Ongoing_Projects]] | [[Category:Ongoing_Projects]] | ||
== Description == | == Description == | ||
| − | * Hardware / Software solution to enable live interpretation of | + | * Hardware / Software solution to enable live interpretation of events, anywhere there's IP and power (we could use power banks as USB UPSs) |
| + | |||
| + | ''Could be simplified as a simple IP intercom / duplex HW-SW stack'' | ||
== Goal == | == Goal == | ||
| Line 23: | Line 25: | ||
== HW details == | == HW details == | ||
| − | We need a mute momentary switch. Also a buzzer (to diagnose start-up / majors problems) | + | We need a mute momentary switch. Also a buzzer (to diagnose start-up / majors problems). |
All of what follows will be implemented twice par device (or plus). | All of what follows will be implemented twice par device (or plus). | ||
| − | USB port for the audio devices, and a way to be sure which is which. | + | |
| − | Two (digital?) pots (mic and headphone gains) | + | * USB port for the audio devices, and a way to be sure which is which. |
| − | A enable/disable switch (with built-in led if cheap enough?) | + | * Two (digital?) pots (mic and headphone gains) |
| − | One LED to indicate if a mic is open (if not inside switch). | + | * A enable/disable switch (with built-in led if cheap enough?) |
| + | * One LED to indicate if a mic is open (if not inside switch). | ||
We map the digipots to alsa volume controls. | We map the digipots to alsa volume controls. | ||
| Line 39: | Line 42: | ||
'''Setup:''' | '''Setup:''' | ||
| + | |||
Parameters such as audio source (upstream) IP:port, also downstream IP:port and codec parameters are stored somewhere (sd) | Parameters such as audio source (upstream) IP:port, also downstream IP:port and codec parameters are stored somewhere (sd) | ||
| − | Also the language code of the stream (can we mux this somehow, or is it upstream's responsiblity) | + | |
| + | Also the language code of the stream (can we mux this somehow ([https://www.xiph.org/ogg/doc/framing.html Maybe as a stream serial number]), or is it upstream's responsiblity) | ||
| + | |||
Optionally drive a 2line led display and have enough buttons to set ip:ports and number of devices? | Optionally drive a 2line led display and have enough buttons to set ip:ports and number of devices? | ||
'''On boot:''' | '''On boot:''' | ||
| + | |||
Enumerate USB devices. If one is absent, keep beeping its led. If both are absent, buzz till reset. | Enumerate USB devices. If one is absent, keep beeping its led. If both are absent, buzz till reset. | ||
| + | |||
If an upstream is set, attempt connection. If no connection, buzz / blink in another pattern. | If an upstream is set, attempt connection. If no connection, buzz / blink in another pattern. | ||
| + | |||
Software mix both sources and feed the output into an OGG Opus encoder. Stream this (UDP broadcast? or set ip:port) | Software mix both sources and feed the output into an OGG Opus encoder. Stream this (UDP broadcast? or set ip:port) | ||
| + | |||
(Optionally mix upstream with lower level) | (Optionally mix upstream with lower level) | ||
| + | |||
'''While true:''' | '''While true:''' | ||
| + | |||
while mute button is pressed: | while mute button is pressed: | ||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| + | Cut USB inputs. Don't change upstream level. | ||
| + | |||
| + | * If no input is enabled, Upstream level = 1; | ||
| + | * If at least one input is enabled, Upstream < 1; | ||
| + | |||
| + | |||
| + | * On upstream failure: attempt reco (maybe double beep and blink) | ||
| + | * On downstream failure: same (maybe triple beep and blink) | ||
| Line 69: | Line 84: | ||
* Figure out how to control audio volumes via GPIO | * Figure out how to control audio volumes via GPIO | ||
* Test the darn thing in a real setting | * Test the darn thing in a real setting | ||
| + | * Compare headsets for ambient noise resistance and comfort vs price / availability | ||
* Monitor power use, derive estimation of battery-operation capacity | * Monitor power use, derive estimation of battery-operation capacity | ||
== Participants == | == Participants == | ||
* [[User:Fzn]] (Leader) | * [[User:Fzn]] (Leader) | ||
Revision as of 08:29, 26 January 2017
Contents
Description
- Hardware / Software solution to enable live interpretation of events, anywhere there's IP and power (we could use power banks as USB UPSs)
Could be simplified as a simple IP intercom / duplex HW-SW stack
Goal
- At least two mic/headphones
- Cheap
- OSS / OSHW
- Qualitatively good
Obstacles
- Network, software mixing and codec latency
- Mics getting ambient noise
Components
- Raspberry pi or other GNU/Linux embedded system with USB, ethernet and GPIO
- pots, switches and LEDs
- USB mic-headphones
- OGG Opus
- Power source
- [2 line lcd?]
HW details
We need a mute momentary switch. Also a buzzer (to diagnose start-up / majors problems).
All of what follows will be implemented twice par device (or plus).
- USB port for the audio devices, and a way to be sure which is which.
- Two (digital?) pots (mic and headphone gains)
- A enable/disable switch (with built-in led if cheap enough?)
- One LED to indicate if a mic is open (if not inside switch).
We map the digipots to alsa volume controls.
SW details
Then, let's assume a GNU/Linux distro
Setup:
Parameters such as audio source (upstream) IP:port, also downstream IP:port and codec parameters are stored somewhere (sd)
Also the language code of the stream (can we mux this somehow (Maybe as a stream serial number), or is it upstream's responsiblity)
Optionally drive a 2line led display and have enough buttons to set ip:ports and number of devices?
On boot:
Enumerate USB devices. If one is absent, keep beeping its led. If both are absent, buzz till reset.
If an upstream is set, attempt connection. If no connection, buzz / blink in another pattern.
Software mix both sources and feed the output into an OGG Opus encoder. Stream this (UDP broadcast? or set ip:port)
(Optionally mix upstream with lower level)
While true:
while mute button is pressed:
Cut USB inputs. Don't change upstream level.
- If no input is enabled, Upstream level = 1;
- If at least one input is enabled, Upstream < 1;
- On upstream failure: attempt reco (maybe double beep and blink)
- On downstream failure: same (maybe triple beep and blink)
Roadmap
- Test streaming a mono Opus to a raspi, look at usage, figure out a couple quality / latency settings.
- Test encoding a mono Opus from a raspi, same.
- Test doing the same with software mixing enabled (broadcasting a mix of the input stream and some local audio)
- Test doing the same using an USB audio device as playback and capture at the same time.
- Double it.
- Figure out how to GPIO efficiently at the same time (implement buzzer and visual alerts)
- Figure out how to control audio volumes via GPIO
- Test the darn thing in a real setting
- Compare headsets for ambient noise resistance and comfort vs price / availability
- Monitor power use, derive estimation of battery-operation capacity
Participants
- User:Fzn (Leader)
