Application Note MUSIC NEST UDP streaming example OP-AN-021. Description. Brief introduction

Transcription

1 Application Note MUSIC NEST UDP streaming example OP-AN-021 Device: openpicus FLYPORT and Music Nest IDE version: 2.2 External Libs: VLSICodec OpenPicus Free IDE Connections: stereo 3.5mm standard jack Description This app shows an example of how to play audio from a UDP streaming source. VLC (VideoLan Client is used as music encoder and network streamer. The app uses MUSIC Nest expansion board, compatible with Flyport Wi-Fi and Flyport Ethernet modules. Author: serra82@gmail.com Brief introduction MUSIC NEST can be used with both FLYPORT Wi-Fi or FLYPORT Ethernet modules. It integrates a multiple audio decoder (MP3, WMA, Ogg Vorbis, etc...), and a micro SD socket for FAT file system storage (both FAT16/32 can be used). This application note uses the MUSIC NEST expansion board hardware to provide the following services: UDP Socket (FLYPORT is the UDP Server) VS1053 with SPI interface to decode compressed music data micro SD card slot is NOT USED, since music data comes from the network FLYPORT Module acts as UDP Server, any Client can connect to its socket and stream audio content to its output. Pay attention that only one client at time can access to UDP Server. User can customize UDP port value (default is 4000), and turn up / down volume using cgi requests via Flyport web server. 1

2 Firmware build: User can take advance of provided templates that are just configured to set the right size of UDP Socket buffer. If a application note project template is used, the reading of this chapter can be skipped until the Music NEST libs. Instead, if user decide to create a custom firmware starting by a default IDE template, due to the need of a large buffer to receive music data on the fly, the TCP/IP wizard should be used with attention to configure the right Sockets sizes. Following is a detailed description of the TCP/IP wizard setup: 1) default services and default network configuration are enough to provide the UDP Streaming for Music NEST demo 2) TCP Socket configuration (this configuration is to prepare to TCP streaming buffers, not used in this demo): - GENERIC_TCP_CLIENT TX: 125 RX: GENERIC_TCP_SERVER TX: 200 RX: HTTP_SERVER count:2 TX 1000 RX: DEFAULT TX:100 RX:100 - FTP_COMMAND count:0 - FTP_DATA count:0 2

3 3) UDP sockets configuration as: - Socket n.1 Buffer size: Other Sockets not enabled 4) leave default setting for hardware configuration (UART port: 1 Buffer size: 256) and finish wizard Music Nest libs Insert as external lib in the project VlsiCodec.c/.h (see.zip file relative to this application note) First of all in FlyportTask() inizialize the VLSI codec: VlsiHWInit(); VlsiInitNewMode(); Now you can start to send mp3 file to nest Music in multiples of 32 byte with VlsiWriteDataN(AudioBufferPoint, 32); or change volume level with: right = 100; left = 100; VlsiSetVolume( right, left); To test the Hardware communication, a sine tone test function is provided: VlsiSineTest(126); If you can listen a tone from the phone/line output jack, the communication is ok. 3

4 Firmware example: UDP music streaming from VLC The simplest way to try the Music Nest demo firmware is to receive music data from a PC or MAC that uses VLC as UDP streaming Client. Flyport module is the UDP Server, so inside the code it can be seen the command to open an UDP socket: UDPSocketServer = UDPServerOpen(StreamPort); Inside a while loop Flyport receives mp3 data and sends it to VLSI Codec via SPI Bus: while( ((CurrentPacketSize >= 32) && (AudioBuffSize >= CacheSize)) ((CurrentPacketSize == 0) && (AudioBuffSize > 0)) ) if (AudioBuffSize >= 32) wri = 32; else wri = AudioBuffSize; UDPRead(UDPSocketServer, AudioBuffUDP, wri); do wri2 = VlsiWriteDataN(AudioBuffUDP, wri); //audio pointer if ( wri == wri2 ) CurrentPacketSize -= wri2; AudioBuffSize -= wri2; else #if (DEBUG > 1) UARTWrite(1, "Busy\n\r"); #endif vtaskdelay(1); while((wri2 == 0) && (AudioBuffSize > 0)); AudioBuffSize = CurrentPacketSize; In addiction to audio streaming, also volume can be controlled at run-time. To change volume settings just open a browser and write the following CGI request: to turn up volume to turn down volume 4

5 Setup a testing environment To test the application note, it is needed to download and install VLC (VideoLAN Client) on a PC (it is available for both Windows and Linux) or on a MAC. Please, download the software from the site Once correctly installed, and before open VLC, please make sure both PC (or MAC) and Flyport are connected to the same network. To correctly start to stream music data to UDP Server Socket of Flyport module, open VLC and follow the following steps: Select a music file with Ctrl+S or using the Media Stream... menu: Add the desired file and press Stream button: 5

6 Skip all the windows using the next button until it is shown the following window: The string provides to VLC all the compression and connection parameters to VLC, like IP_FLYPORT and PORT that user should customize at his needs. :sout=#transcodevcodec=none,acodec=mp3,ab=128,channels=2,samplerate=44100: stdaccess=udp,mux=raw,dst=ip_flyport:port Now Click on Stream button and enjoy your favorite music through Music Nest stereo output! 6