Add time-limit argument

[mattia-lecci]

• I have checked that a similar feature request does not already exist.

Related but not solving my issue:

• stop recording option is not available in scrcpy #1032
• What is the best way to interrupt recording (programmable) in Windows? #818
• stop recording option is not available in scrcpy #1032

Is your feature request related to a problem? Please describe.
I am trying to automate the acquisition of videos from an android phone which can last for hours.
I know how long the recording should be, so something like adb screenrecord --time-limit would be great (see here)

Describe the solution you'd like
Something similar to adb screenrecord --time-limit=S <file> would be great (see here), where S is the amount of time in seconds of the desired recording duration.

Describe alternatives you've considered
My automation system is only working on windows, unfortunately.
I tried interrupting the scrcpy process after a fixed amount of time in multiple ways but it is either not stopping or produces a corrupted video file.

Tests:

• start /B scrcpy -Nr test.mp4 && timeout /t 5 /nobreak >nul && taskkill /im scrcpy.exe /f: corrupted file
• Python script

import subprocess, signal, time

proc = subprocess.Popen(["scrcpy", "-Nr", "test.mp4"],
                        creationflags=subprocess.CREATE_NEW_PROCESS_GROUP)
print("sleeping")
time.sleep(5)
print("terminating")
proc.terminate() # also tried proc.send_signal(signal.CTRL_C_EVENT) and proc.send_signal(signal.CTRL_BREAK_EVENT)

• Results: corrupted file with terminate() and CTRL_BREAK_EVENT, process not terminating with CTR_C_EVENT. In any case, no useful output file
• While running scrcpy, send adb shell pkill <adb process pid> (see What is the best way to interrupt recording (programmable) in Windows? #818 (comment)). Nothing happens.

[rom1v]

As a workaround, did you test #818 (comment)?

[rom1v]

Ah yes, it's your last test. Weird, it should work.

[rom1v]

Just to be sure, if you run scrcpy -Nr file.mp4 manually and press Ctrl+c in the terminal, is the recorded file corrupted?

[mattia-lecci]

Yes, pressing pressing Ctrl+c from windows terminal does work as expected. Sorry for not mentioning that!

[nnnpa31]

You can refer to this:
https://stackoverflow.com/questions/7085604/sending-c-to-python-subprocess-objects-on-windows

In python's subprocess, when sending CTRL+C command for stdin of a specific process ID, it will wait for the process to finish before sending it. Therefore, you should change the pid to 0 and send CTRL_C_EVENT to the parent process in order to achieve the purpose of interrupting the process.
which mean:

os.kill(0, signal.CTRL_C_EVENT)
#       ^Here

[mattia-lecci]

Thank you @nnnpa31 !
I had to slightly modify the code suggested in this answer.

The following setup is working for me.

# demo.py
# this script is launched by wrapper.py

import signal, sys, time, subprocess

def signal_handler(signal, frame):
  print('Ctrl+C received in demo.py')
  time.sleep(1)
  sys.exit(0)

signal.signal(signal.SIGINT, signal_handler)

print('demo.py started')
proc = subprocess.Popen(["scrcpy", "-Nr", "test.mp4"]) # simple scrcpy command

# wrapper.py

import subprocess, time, signal, sys, os

def signal_handler(signal, frame):
  print('Ctrl+C received in wrapper.py')
  time.sleep(1)

signal.signal(signal.SIGINT, signal_handler)
print("wrapper.py started")
subprocess.Popen("python demo.py")
time.sleep(5) # Run for 5 seconds
os.kill(0, signal.CTRL_C_EVENT)

Launching this with python wrapper.py record a 5s video as expected.

This is a nice workaround and it works well enough for me, so I'll close the issue.
Having it natively into scrcpy, though, would be even better!

[nnnpa31]

Having it natively into scrcpy, though, would be even better!

I agree.

[rom1v]

See #4052