Python FFmpeg 查询 rtsp 太慢

Question

目前，我正在尝试使用python和FFmpeg来查询原始格式为h264的rtsp数据。

直播视频信息为，fps:29；分辨率：1280*720.

我希望我可以查询相同格式的数据"h264"并放入python队列中以备将来使用。

这是我的代码：

class CCTVReader(threading.Thread):
def __init__(self, queue, URL, fps=29):
    super().__init__()
    self.queue = queue
    self.command = ["ffmpeg",  "-y",
                    "-hwaccel",  "nvdec",
                    "-c:v",  "h264_cuvid",
                    "-vsync", "0",
                    "-max_delay", "500000",
                    "-reorder_queue_size", "10000",
                    "-i",  "rtsp://xxx.xxx.xxx.xxx:xxx/Streaming/Channels/101?transportmode=multicast",
                    "-pix_fmt", "yuv420p",
                    "-preset", "slow",
                    "-an", "-sn",
                    "-vf", "fps=29",
                    "-"]
def run(self):
    pipe = sp.Popen(self.command, stdout = sp.PIPE, bufsize=1024**3, shell=True)
    timer = time.time()
    counter = 0
    while True:
        self.queue.put(pipe.stdout.read(int(1280*720*6//4)))

但是，在我运行这个程序大约 10 秒后，我的控制台显示警告消息：

[rtsp @ 0000020be0fbb9c0] max delay reached. need to consume packet
[rtsp @ 0000020be0fbb9c0] RTP: missed 127 packets

看来我的命令输入不正确。

你能给我一些关于如何处理这个问题的建议吗？

非常感谢

Answer 1

假设你想在不修改数据的情况下抓取视频流，你需要为 FFmpeg 设置不同的参数集：

设置"-c:v", "h264"作为输入参数（在"-i"之前），用于通知FFmpeg输入是h264视频流。
将 "-c:v", "copy" 设置为输出参数（在 "-i" 之后），因此 FFmpeg 将输入视频流复制到输出 PIPE，无需修改（无需解码和编码）。
设置"-f", "h264"作为输出参数，用于将PIPE输出格式设置为h264。

这是一个工作代码示例（请阅读评论）：

import ffmpeg
import numpy as np
import subprocess as sp
import threading
import queue

class CCTVReader(threading.Thread):
    def __init__(self, q, in_stream):
        super().__init__()
        self.q = q
        self.command = ["ffmpeg",
                        "-c:v", "h264",     # Tell ffmpeg that input stream codec is h264
                        "-i", in_stream,    # Read stream from file vid.264
                        "-c:v", "copy",     # Tell ffmpeg to copy the video stream as is (without decding and encoding)
                        "-an", "-sn",       # No audio an no subtites
                        "-f", "h264",       # Define pipe format to be h264
                        "-"]                # Output is a pipe

    def run(self):
        pipe = sp.Popen(self.command, stdout=sp.PIPE, bufsize=1024**3)  # Don't use shell=True (you don't need to execute the command through the shell).

        # while True:
        for i in range(100):  # Read up to 100KBytes for testing
            data = pipe.stdout.read(1024)  # Read data from pip in chunks of 1024 bytes
            self.q.put(data)

            # Break loop if less than 1024 bytes read (not going to work with CCTV, but works with input file)
            if len(data) < 1024:
                break

        try:
            pipe.wait(timeout=1)  # Wait for subprocess to finish (with timeout of 1 second).
        except sp.TimeoutExpired:
            pipe.kill()           # Kill subprocess in case of a timeout (there should be a timeout because input stream still lives).


# Build synthetic video, for testing begins:
################################################
# width, height = 1280, 720
# in_stream = "vid.264"
# sp.Popen("ffmpeg -y -f lavfi -i testsrc=size=1280x720:duration=5:rate=1 -c:v libx264 -crf 23 -pix_fmt yuv420p " + in_stream).wait()
################################################

#in_stream = "rtsp://xxx.xxx.xxx.xxx:xxx/Streaming/Channels/101?transportmode=multicast",

#Use public RTSP Streaming for testing
in_stream = "rtsp://wowzaec2demo.streamlock.net/vod/mp4:BigBuckBunny_115k.mov"

q = queue.Queue()

cctv_reader = CCTVReader(q, in_stream)
cctv_reader.start()
cctv_reader.join()

if q.empty():
    print("There is a problem (queue is empty)!!!")
else:
    # Write data from queue to file vid_from_queue.264 (for testingg)
    with open("vid_from_queue.264", "wb") as queue_save_file:
        while not q.empty():
            queue_save_file.write(q.get())

我使用 public RTSP Streaming 并使用生成的合成视频文件测试了代码（注释了用于测试文件的代码）。

代码将输出存储到 vid_from_queue.264。
.264 文件可以播放 - 文件格式是基本的 h264 视频流。

这是抓取的视频流的最后一帧：

Python FFmpeg 查询 rtsp 太慢

Python FFmpeg query rtsp too slow

python

ffmpeg

rtsp