Question

我想为从前端上传并发回的视频用户生成缩略图（例如，提取帧为1s）。 user_upload = request.files['file'] 这样做的正确方法是什么？是否可以在不将文件保存到本地并先读取的情况下提取帧？

subprocess.call(['ffmpeg', '-i', user_upload, '-ss',
                     '00:00:00.000', '-vframes', '1', output_dir])

或

     vidcap = cv2.VideoCapture(user_upload)
     success, image = vidcap.read()
     count = 0
     while success and count < 1:
         cv2.imwrite("frame%d.jpg" % count, image)     # save frame as JPEG file
         success, image = vidcap.read()
         print('Read a new frame: ', success)
         count += 1

FFmpeg和cv2都需要读入Path，而不是FileStorage。

  File "/Users/glwang/bikan/yc2020/eb-flask/siyu/utils.py", line 8, in capture_thumnail
    '00:00:00.000', '-vframes', '1', output_dir])
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/subprocess.py", line 267, in call
    with Popen(*popenargs, **kwargs) as p:
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/subprocess.py", line 709, in __init__
    restore_signals, start_new_session)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/subprocess.py", line 1275, in _execute_child
    restore_signals, start_new_session, preexec_fn)
TypeError: expected str, bytes or os.PathLike object, not FileStorage

此外，当我尝试首先在本地保存文件并使用FFmpeg提取框架时， user_upload.save('path/to/somewhere') 它显示

File "/siyu/utils.py", line 7, in capture_thumnail
    video_input.save(video_input.filename)
  File "/Users/lib/python3.6/site-packages/werkzeug/datastructures.py", line 3070, in save
    copyfileobj(self.stream, dst, buffer_size)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/shutil.py", line 79, in copyfileobj
    buf = fsrc.read(length)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/tempfile.py", line 738, in read
    return self._file.read(*args)
ValueError: read of closed file

生成从前端烧瓶发送的视频的缩略图

0 个答案: