Q : Is is possible to use AVB over a standard network adapter (without HW support)
A : No, not for high fidelity Audio automotive or pro equipment.
Although it is possible to apply the same algorithms with as reference a timer for SW timestamp, but that might induce one or more orders of magnitude of precision loss, that results in a different concepts of buffer dimensioning and so on.
Q : ptp target precision (~ 5 ns)
5 ns ? 5 us ? 48 KHz => ~ 20 us 1, 2 samples ? => 50 us
produce a sample (3 ms), touch the screen (interrupt) => loop 2ms, 2 ms buffer (100 samples)
streaming musing (1 s) (Automotive Infotainment - can involve network)
Lip sync not problematic because none of the audio/video is real time, you can delay both stream with the same amount => sync 20~40 ms.
cold start latency : is a different KPI than the sync delta of video audio => (~ 500 ms).
Phase manipulation in case of audio zones
problem starts if the different zones are played from different network devices
Network stability, reduction of jitter
=> SRP Stream reservation protocol AVB over RTP IP without HW
Renesas example on references, usage of OpenAvenu
Avenu as open source but more reliable implementation than other existing ones
Q : Steps to be taken for starting the SW
Q : clock recovery algorithm, might recover smoother by catching up
Brainstorming
Use cases
1) external Amplifier, controlled by Android only (cross ECU interface used by headunit only) 2) interact of an Android Audio ECU with the rest of the audio system other ECUs (e.g. remote control - e.g. non Android system) 3) interact with the Audio System from a server
Relations to existing work in other SIG
CVII : Common Vehicle Interface Initiative VSS : Vehicle Signal specification VSC : Vehicle Service Catalogue (list of interfaces)
Audio and VSS, data interfaces,...
common model for data (call functions with params, services, interfaces, franca,...)
-no dealing with streaming data, rather simply connection points urls exchange -can we define similar things to audio e.g. currently played track, volume,... ? -requests to add media in VSS
-standardized interface for audio/media streaming, renewed interest by Hyundai - complex question, OEM => standardize / Netflix => App custom standard
- if possible to add info in VSS - different scope from cross ECU interfaces
-prevent fragmentation by collecting a survey about state of the art - MPRIS dbus standard
1) Bluetooth : the AVRCP allows to control
2) Project Mode : / Audroid Auto - has virtual key input generator (volume up/down,...)
3) the same infrastructure from Project mode : can be used to inject the same as if it was a projected mode
4) Automotive : specific vehicle HAL service vehicle bus and converts in Android key codes Android input system
Q: if volume key up/down limited to current volume ? A: in automotive concept of volume groups which has the focus Q: If the same interface include the audio settings A: no intended in that interface A: done through the audio effects HAL which is manufacturer specific _______________________________________________________ mention as info : MQTT Pub/Sub mechanism
Remote topic split in two : - play pause,... - effects, calibration,... _______________________________________________________
Q: What to develop next in the project
- Organization of the Android build => scripting the build ongoing, testing,...
Q: interest in AVB networked devices ? - control / routing - available AVB in automotive / professional audio - https://github.com/Avnu/OpenAvnu - Android (no many echos about AOSP/AVB) - NXP/Renesas/ : board has AVB support - Hikey 960 does not support AVB - HW mandatory, not only low cost but automotive HW - Android 11 support for Dragonboard
Q: Any close to Android transport protocol or if it's part of the applications A: usually part of the applications A: approach interfacing Android system from outside like any Android app would do