Xilinx ALSA SDI Audio driver
Table of contents
Introduction
The Xilinx® LogiCORE™ IP UHD SDI Audio Core is a soft Xilinx IP core for use with the Xilinx Vivado® Design Suite. This IP can be configured in Embed/Extract mode to provide embed PCM audio with SDI Video or extract PCM audio from SDI AV stream.
Typical system using SDI Rx and SDI Tx:
Following design depicts the typical SDI embed/extract IP interfaces for audio recording and playback.
Audio Formatter is set in AES_TO_PCM for SDI Audio in extract mode and PCM_TO_AES in embed mode.
The SDI audio Rx/Tx driver is based on the ALSA framework(refer ASoC sound card). This driver registers one of the 'component' expected by the ALSA framework. This SDI audio driver along with Audio Formatter and Sound Card drivers will create a SDI audio pipeline. Driver cannot be used as standalone. The driver is present at https://github.com/Xilinx/linux-xlnx/blob/master/sound/soc/xilinx/xlnx_sdi_audio.c
IP/Driver Features
| IP Features | 2021.1 |
|---|---|
Supports up to 32 channels of audio. | Supports up to 8 channels |
20/24-bit audio at multiple sample rates (32 KHz, 44.1 KHz and 48 KHz) | Yes |
| Synchronous and asynchronous audio support | Yes |
| Supports 192-bit AES3 channel status extraction | Yes |
| Reports the presence and status of audio groups on the incoming SDI stream | Yes |
| AXI4-Stream interface to carry audio samples in AES3 format | Yes |
| AXI4-Lite and port based interface for configuration of the core | Yes |
Known Issues & Limitations
- Only 8 channels supported.
- Not tested for 20 bit depth.
- AES3 data is given as debug information.
Kernel Configurations
Below kernel config options should be enabled.
CONFIG_SND_SOC=y CONFIG_SND_SOC_XILINX_SDI=y
Device Tree Bindings
The dts node should be defined with correct hardware configuration. How to define the node is documented in, xlnx,v-uhdsdi-audio.txt
Test Procedure
The driver has been tested using following tools.
- ALSA Utilities.
- Gstreamer Utilities.
Procedure to test SDI audio with ALSA Utilities
Recording a file: arecord tool is used to record the audio file.
Following is the recording audio file with 24bit bit depth, 48khz sampling frequency and 2 channel audio properties.
arecord -Dhw:0,1 -fS24_LE -r 48000 -c 2 -d 30 -t raw file.raw
Playing a file: aplay tool is used to play the audio file.
Following is the playing audio file with 24bit bit depth, 48khz sampling frequency and 2 channel audio properties.
aplay -D hw:0,0 -fS24_LE -r 48000 -c 2 -d 30 -t raw file.raw
Procedure to test SDI audio with Gstreamer Utilities
Recording a file: gst-launch is used to record the audio file.
Following is the recording audio file with 24bit bit depth, 48khz sampling frequency and 2 channel audio properties. gst-launch is using alsa src plugin to enable recording with SPDIF driver.
gst-launch-1.0 alsasrc device=hw:1,1 ! queue ! audio/x-raw,format=S24_32LE,rate=48000,channels=2 ! filesink location=48000.raw
Playing a file: gst-launch is used to play the audio file.
Following is the playing audio file with 24bit bit depth, 48khz sampling frequency and 2 channel audio properties. gst-launch is using alsa sink plugin to enable playback with SPDIF driver.
gst-launch-1.0 filesrc location=48000.raw ! audio/x-raw,format=S24_32LE,rate=48000,channels=2 ! alsasink device=hw:0,0
Boards Supported
Driver has been tested on the following boards
- ZCU106 Rev 1.0
Change log
2024.1
- Summary
- No changes
2021.2 & 2022.1 & 2022.2
- Summary
- No changes
2021.1
- Summary:
- 8 Channel audio support added
2020.1
- Summary
- No changes
2019.2
- Summary
- No changes
2019.1
- Summary:
- Used Common Clock Framework(CCF) API to configure clocks.
- Added support for audio enablement in 4K video mode (upto 2 channels).
- Commits:
2018.3:
- Summary
- Initial version released
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