将opencv帧写入HLS段文件时出错

Question

我正在通过 opencv 处理 hls 视频片段。我的目的是创建另一个带有已处理帧的段文件。经过一些研究，我发现它可以使用 gstreamer 管道来实现。我按照示例进行了操作，但它对我不起作用

代码示例

   vs = cv2.VideoCapture(video)
   fourcc = cv2.VideoWriter_fourcc(*"MJPG")
   writer = cv2.VideoWriter("appsrc num-buffers=100 ! x264enc ! queue ! mpegtsmux name=mux ! filesink location="+outpath, fourcc, 30, (W, H), True)
   while True:
       frame = vs.read()
       frame = frame[1]
       frame = imutils.resize(frame, width=500)
       rgb = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
       writer.write(frame)

错误

OpenCV: FFMPEG: tag 0x47504a4d/'MJPG' is not supported with codec id 7 and format 'mpegts / MPEG-TS (MPEG-2 Transport Stream)'
[ERROR:0] global /private/var/folders/nz/vv4_9tw56nv9k3tkvyszvwg80000gn/T/pip-req-build-gi6lxw0x/opencv/modules/videoio/src/cap.cpp (563) open VIDEOIO(CV_IMAGES): raised OpenCV exception:

OpenCV(4.4.0) /private/var/folders/nz/vv4_9tw56nv9k3tkvyszvwg80000gn/T/pip-req-build-gi6lxw0x/opencv/modules/videoio/src/cap_images.cpp:267: error: (-215:Assertion failed) number < max_number in function 'icvExtractPattern'

我尝试了不同可能的编解码器组合（'MJPG'、'MPV4'、'MPEG' 等），但到目前为止还没有运气:(。非常感谢任何帮助/建议。谢谢！

Answer 1

对于x264enc，您需要定义fourcc：

• 如果你安装了x264

  fourcc = cv2.VideoWriter_fourcc(*'x264')
  
  

  或

  fourcc = cv2.VideoWriter_fourcc(*'mp4v')
  

就我而言，mp4v 有效

import cv2

vs = cv2.VideoCapture("video.mp4")

fourcc = cv2.VideoWriter_fourcc(*'mp4v')

W = int(vs.get(cv2.CAP_PROP_FRAME_WIDTH))
H = int(vs.get(cv2.CAP_PROP_FRAME_HEIGHT))

writer = cv2.VideoWriter("result.mp4", fourcc, 30.0, (W, H), True)

while True:
    ret, frame = vs.read()
    if ret:
        writer.write(frame)
    else:
        break

vs.release()
writer.release()