python 中的 gstreamer 管道未正确保存.mp4 视频

Question

I have a script in Python where I record the stream from four cameras to mp4 through gstreamer. I define a signal so that the capture terminates if Ctrl-C is pressed, and it works fine. In the gstreamer pipeline itself, I have a property added at the source numbuffers = 600 because I want the capture to stop after 600 frames anyway if I don't press Ctrl-C before then.

My problem is this, if I interrupt through the keyboard all four mp4 videos are saved correctly, but if I let it finish by itself after the 600 frames the second to fourth videos are fine while the first video will have "no playable stream", even if having the same size as the other videos.

I don't understand why only the first video is not saved or closed correctly, any hints? This is my code:

import gi
import signal
import threading
import logging
from time import time, sleep
gi.require_version('Gst', '1.0')
from gi.repository import Gst, GObject

logging.basicConfig(level=logging.INFO)

def on_message(bus: Gst.Bus, message: Gst.Message, loop: GObject.MainLoop):
    mtype = message.type
    """
        Gstreamer Message Types and how to parse
    """
    if mtype == Gst.MessageType.EOS:
        logging.info("End-of-stream\n")
        loop.quit()

    elif mtype == Gst.MessageType.ERROR:
        err, debug = message.parse_error()
        logging.info("Warning: %s: %s\n" % (err, debug))
        loop.quit()

    elif mtype == Gst.MessageType.WARNING:
        err, debug = message.parse_warning()
        logging.info("Error: %s: %s\n" % (err, debug))

    return True


def signal_handler(signal, frame):
    for i in range(0,n_cams):
        pipelines[i].send_event(Gst.Event.new_eos())

signal.signal(signal.SIGINT, signal_handler)

# Initialize
GObject.threads_init()
Gst.init(None)

n_cams = 4
buses = []
pipelines = []

for i in range(0,n_cams):
    logging.info("Starting camera " + str(i))

    command = ("nvarguscamerasrc sensor-id={} num-buffers=600 ! "
            "video/x-raw(memory:NVMM), width=(int)1920, height=(int)1080, format=(string)NV12, framerate=(fraction)30/1 ! "
            "queue max-size-buffers=4 leaky=2 ! "
            "nvv4l2h265enc control-rate=1 bitrate=8000000 ! video/x-h265, stream-format=(string)byte-stream ! "
            "h265parse ! qtmux ! filesink location=test_{}.mp4").format(i)

    logging.info("Parse launch " + command)
    pipelines.append(Gst.parse_launch(command))


loop = GObject.MainLoop()

for i in range(0,n_cams):
    buses.append(pipelines[i].get_bus())
    buses[i].add_signal_watch()
    buses[i].connect("message", on_message, loop)

logging.info("Starting pipelines")

for i in range(0,n_cams):
    pipelines[i].set_state(Gst.State.PLAYING)

loop.run()

# stop
for i in range(0,n_cams):
    pipelines[i].send_event(Gst.Event.new_eos())
    pipelines[i].set_state(Gst.State.NULL)

Answer 1

I think you are getting lucky in the ctrl-c case in the first place. In the ctrl-case when you send an EOS, you should wait for the EOS to reach the bus before setting the pipeline sate to NULL.

Similar problem with your actual described problem. You have 4 pipelines but only one main loop. You quit the loop after the first pipeline reaches EOS. Instead you should wait until all pipelines have reached EOS.

Ps I think the send_event after # stop does not actually do anything.