djiplayer.py

from lib import USBDev
from lib import FIFOWriter
import time
import os
# import tkinter as tk
import subprocess
import shlex

StartPlayer = True
StatusInterval = 0.5


headset = USBDev.USBDev()
headset.StartDevCheckThread()

output = FIFOWriter.FIFOWriter()
output.Open()
# print("Writing to FIFO at " + output.FIFO)

# A bit of cheese.  Raspberry Pi OS:
PlayCmd = "/usr/bin/ffplay -fs -i " + output.FIFO + " -analyzeduration 1 -probesize 32 -sync ext"
WrapPlayCmd = ["/usr/bin/lxterminal", "-e", PlayCmd]
PlayerProc = None

# State globals:
BytesWritten = 0
LastStatus = 0
StatusData = dict()
StatusData['Msg'] = "Starting Up"

###############################################################################

def PrintStatus(update):
    """Update the program status"""
    global LastStatus
    now = time.time()
    if (now - LastStatus) < StatusInterval:
        return
    print(update['Msg'] + "               ", end='\r')
    LastStatus = now

###############################################################################

def StartPlayer():
    global PlayCmd, WrapPlayCmd, PlayerProc

    if PlayerProc:
        # PlayerProc.terminate()
        PlayerProc.kill()
        subprocess.run(["/usr/bin/killall", "ffplay"])

    # PlayerProc = subprocess.Popen(WrapPlayCmd)
    PlayerProc = subprocess.Popen(shlex.split(PlayCmd),
        stdout=subprocess.DEVNULL,
        stderr=subprocess.DEVNULL,
        stdin=subprocess.DEVNULL
        )

###############################################################################

while True:
    PrintStatus(StatusData)
    if not PlayerProc:
        StartPlayer()
    
    if headset.DevicePresent == False:
        # print("Waiting on headset...")
        StatusData['Msg'] = "Waiting on headset..."
        # If we are waiting on a headset and data has been written, everything needs to be reset:
        if BytesWritten:
            BytesWritten = 0
            output.Reset()
            StartPlayer()    # Really a restart, since we're unlinking the FIFO

        # No sense being speedy on the loop when we are waiting on a human
        time.sleep(.5)
        continue

    packet = headset.RecvData()
    if packet == None:
        # print("RecvData() returned None: {}".format(headset.LastError.strerror))
        StatusData['Msg'] = "Device State: " + headset.DeviceStatus
        continue

    out = output.Write(packet)

    if out:
        BytesWritten += out
        StatusData['Total'] = BytesWritten
    else:
        # print("Pausing output, no readers...")
        StatusData['Msg'] = "Output buffer full, pausing output..."
        time.sleep(.5)
        continue

    # print("In write loop, error: " + str(output.LastError) + ", total bytes written: " + str(BytesWritten))
    StatusData['Msg'] = "Device State: " + headset.DeviceStatus
    # time.sleep(.5)
    # exit()