Jetson Xavier上OpenCV VideoWriter保存的视频无法打开求助

针对你遇到的视频保存后无法打开的问题，核心原因大概率是帧尺寸不匹配或CPU编码兼容性问题，结合Jetson平台的硬件特性，以下是具体解决方法：

一、先排查基础问题：帧尺寸匹配 #

直接使用/dev/video0时，摄像头实际输出的帧尺寸可能和你手动设置的640x480不符，导致视频文件头信息错误，无法被播放器识别。

修改代码，先获取摄像头实际输出的分辨率，再初始化视频写入器：

import numpy as np
import cv2

source = "/dev/video0"
cap = cv2.VideoCapture(source)

# 获取摄像头实际输出的帧尺寸
width = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
height = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
print(f"摄像头实际帧尺寸: {width}x{height}")

# 用实际尺寸初始化VideoWriter
fourcc = cv2.VideoWriter_fourcc(*'XVID')
out = cv2.VideoWriter('./output.avi', fourcc, 30.0, (width, height))

count = 0
while(cap.isOpened()):
    ret, frame = cap.read()
    if ret==True:
        out.write(frame)
        print(count)
        try:
            cv2.imshow('frame',frame)
        except:
            pass    
        if cv2.waitKey(1) & 0xFF == ord('q') or count >100:
            break
        count +=1
    else:
        break

cap.release()
out.release()
cv2.destroyAllWindows()

二、推荐方案：使用GStreamer硬件加速读写视频 #

Jetson平台对GStreamer硬件加速支持完善，用硬件编码替代CPU编码，既能提升效率，也能避免兼容性问题。

完整代码（读写均用GStreamer硬件加速） #

import numpy as np
import cv2

# GStreamer硬件加速读取管道（匹配你的摄像头格式）
gstr_in = "v4l2src device=/dev/video0 ! video/x-raw,format=YUY2,width=640,height=480,framerate=30/1 ! nvvidconv ! video/x-raw(memory:NVMM) ! nvvidconv ! video/x-raw, format=BGRx ! videoconvert ! video/x-raw, format=BGR ! appsink drop=1 "
cap = cv2.VideoCapture(gstr_in, cv2.CAP_GSTREAMER)

if not cap.isOpened():
    print("无法打开摄像头")
    exit()

width = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
height = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
print(f"帧尺寸: {width}x{height}")

# GStreamer硬件编码写MP4（JetPack 4.6+用nvv4l2h264enc，旧版本用omxh264enc）
gstr_out = f"appsrc ! video/x-raw,format=BGR,width={width},height={height},framerate=30/1 ! videoconvert ! video/x-raw,format=NV12 ! nvv4l2h264enc bitrate=5000000 ! h264parse ! mp4mux ! filesink location=output.mp4 sync=false"
out = cv2.VideoWriter(gstr_out, cv2.CAP_GSTREAMER, 0, 30.0, (width, height))

if not out.isOpened():
    print("无法初始化视频写入器")
    cap.release()
    exit()

count = 0
while cap.isOpened():
    ret, frame = cap.read()
    if not ret:
        break
    
    out.write(frame)
    print(count)
    
    try:
        cv2.imshow('frame', frame)
    except:
        pass
    
    if cv2.waitKey(1) & 0xFF == ord('q') or count > 100:
        break
    count += 1

# 必须先释放写入器，确保文件头正确写入
out.release()
cap.release()
cv2.destroyAllWindows()

关键注意事项 #

1. GStreamer插件完整性：确保Jetson已安装必要的GStreamer插件，缺失则执行：

   sudo apt-get install gstreamer1.0-plugins-good gstreamer1.0-plugins-bad gstreamer1.0-plugins-ugly
   

2. 正确释放资源：必须先调用out.release()再释放摄像头，否则视频文件无法完成收尾，导致播放器无法识别。
3. 编码格式选择：优先用MP4格式搭配H.264编码，兼容性远优于AVI格式。

内容的提问来源于stack exchange，提问作者M.Akyuzlu