rtsp – RTSP 推流

[English]

rtsp 模块通过 RTSP 协议发送 H.264 NAL 单元，使 VLC、ffplay 等客户端能通过网络观看摄像头画面。需与 h264 – H.264 编码 配合使用。该模块可用于 ESP32-P4 构建。

采集、编码与推流

import network, sensor, h264, rtsp, time
from machine import Pin

WIDTH, HEIGHT, FPS = 320, 240, 30

lan = network.LAN(
    mdc=Pin(31),
    mdio=Pin(52),
    reset=Pin(51),
    phy_addr=1,
    phy_type=network.PHY_IP101,
)
lan.active(True)

for _ in range(100):
    if lan.isconnected():
        break
    time.sleep_ms(100)
if not lan.isconnected():
    raise OSError("Ethernet connection failed")

sensor.reset()
sensor.set_pixformat(sensor.RGB565)
sensor.set_framesize(sensor.QVGA)
sensor.skip_frames(time=1000)

enc = h264.H264Encoder(WIDTH, HEIGHT, fps=FPS, bitrate=3_000_000)
server = rtsp.RTSPServer(WIDTH, HEIGHT, fps=FPS, listen_port=8554)

print("rtsp://%s:8554/" % lan.ifconfig()[0])
try:
    while True:
        server.send(enc.encode(sensor.snapshot()))
finally:
    server.stop()
    enc.close()

上述以太网引脚映射适用于带 IP101 RMII PHY 的 ESP32-P4X-Function-EV-Board，其他产品开发板应使用对应的网络配置。RTSPServer 公布的宽度、高度和帧率必须与编码器配置一致。

客户端与队列行为

可使用 ffplay rtsp://<board-ip>:8554/ 或其他支持 RTSP 的播放器打开输出地址。send() 会将一帧编码数据加入队列，并且不会等待客户端；没有客户端连接或客户端处理过慢时，帧可能被丢弃，从而避免阻塞采集循环。如果高分辨率或高码率编码帧超过默认限制，可增大 max_frame_len。

停止服务

释放网络或编码器资源前必须调用 server.stop()。使用 try/finally 可以确保脚本被中断或抛出异常时仍会完成资源清理。

参见

编解码与推流 完整介绍了采集、编码与推流的整个流程。

可运行示例：example/01-Camera/02-RTSP/stream_rtsp.py。

Classes

class rtsp.RTSPServer(width, height, *, fps=..., listen_port=..., max_frame_len=...)

Minimal RTSP server that streams H.264 video over the network. Create it once Wi-Fi is up, then push encoded NAL units from an h264.H264Encoder with send(). Clients connect to rtsp://<board-ip>:<listen_port>/. Only video (no audio) is served.

Start the RTSP server and advertise the given stream format.

参数:

  • width – advertised video width in pixels.

  • height – advertised video height in pixels.

  • fps – advertised frame rate, used for SDP and pacing.

  • listen_port – TCP port the RTSP service binds to.

  • max_frame_len – max accepted encoded frame size in bytes; 0 uses width*height as a safe ceiling.

send(nal)

Queue one encoded H.264 frame (Annex-B NAL units) for delivery. Frames are sent in order; if the client is slow or absent the frame is dropped rather than blocking the caller. Frames larger than max_frame_len are ignored.

参数:

nal – encoded frame bytes from h264.H264Encoder.encode().

stop()

Stop the server, join its task, and free queued frames.