python - "float"读取帧时对象无法解释为整数

Question

我正在尝试使用 imageio API 读取帧。我有一个 reader 作为使用 imageio.get_reader(video_path,"ffmpeg") 收到的对象。我有以下帧阅读器功能

def read_frames(reader, frame_q, use_webcam):
    if use_webcam:
        time.sleep(15)
        frame_cnt = 0
        while True:
            #if frame_cnt % 5 == 0:    
            #    ret, frame = reader.read()
            #    cur_img = frame[:,:,::-1]
            #    frame_q.put(cur_img)
            #else:
            #    ret, frame = reader.read()
            ret, frame = reader.read()
            cur_img = frame[:,:,::-1] # bgr to rgb from opencv reader
            frame_q.put(cur_img)
            if frame_q.qsize() > 100:
                time.sleep(1)
            else:
                time.sleep(DELAY/1000.)

            #print(cur_img.shape)

    else:
        #for cur_img in reader: # this is imageio reader, it uses rgb
        nframes = reader.get_length() **#getting error here**
        # if nframes == float('inf') or nframes ==float('-inf'):
        #     return float("nan")
        # return int(nframes)  

        for ii in range(nframes):
            while frame_q.qsize() > 500: # so that we dont use huge amounts of memory
                time.sleep(1)
            cur_img = reader.get_next_data()
            frame_q.put(cur_img)
            #shape = cur_img.shape
            #noisy_img = np.uint8(cur_img.astype(np.float) + np.random.randn(*shape) * 20)
            #frame_q.put(noisy_img)
            if ii % 100 == 0:
                print("%i / %i frames in queue" % (ii, nframes))
        print("All %i frames in queue" % (nframes))

回溯:

    Traceback (most recent call last):
  File "/home/prashantb/anaconda3/envs/demo/lib/python3.6/multiprocessing/process.py", line 258, in _bootstrap
    self.run()
  File "/home/prashantb/anaconda3/envs/demo/lib/python3.6/multiprocessing/process.py", line 93, in run
    self._target(*self._args, **self._kwargs)
  File "multiprocess_detect_actions.py", line 67, in read_frames
    for ii in range(nframes):
TypeError: 'float' object cannot be interpreted as an integer

我尝试使用代码中注释的float('inf')，但在这种情况下它没有用。我还尝试将浮点值转换为整数，但它显示相同的错误。我将不胜感激您对此的建议。谢谢。

Answer 1

在 imageio 2.5.0 版本的发行说明中，他们提到了对 ffmpeg 插件引入的一些更改:

“ffmpeg 插件的读取器现在始终将 inf 报告为帧数。使用 reader.count_frames() 获取实际数量，或根据元数据中的 fps 和持续时间估计它。”

https://imageio.readthedocs.io/en/stable/releasenotes.html#version-2-5-0-06-02-2019

这应该可以解决你的问题。