Response to the use of ffmpegcv in the code about deep-license-plate-recognition HOT 2 CLOSED

Try the lastest version of ffmpegcv by pip install git+https://github.com/chenxinfeng4/ffmpegcv.git. It supports more precise video-duration and average-fps.

In [1]: import ffmpegcv

# MKV file. Duration should be 283.682
In [2]: ffmpegcv.video_info.get_info_precise('2024-01-18_09-57-41_cam4.mkv')
Out[2]: VideoInfo(width=2560, height=1440, fps=25.007, count=7094, codec='hevc', duration=283.682)

In [3]: ffmpegcv.video_info.get_info('2024-01-18_09-57-41_cam4.mkv')
Out[3]: VideoInfo(width=2560, height=1440, fps=25.0, count=7094, codec='hevc', duration=283.76)


# identical file in MP4 format. Duration should be 283.682
In [4]: ffmpegcv.video_info.get_info('2024-01-18_09-57-41_cam4.mp4')
Out[4]: VideoInfo(width=2560, height=1440, fps=25.0, count=7094, codec='hevc', duration=283.682)

In [5]: ffmpegcv.video_info.get_info_precise('2024-01-18_09-57-41_cam4.mp4')
Out[5]: VideoInfo(width=2560, height=1440, fps=25.007, count=7094, codec='hevc', duration=283.682)

The ffmpegcv get_info_precise will get the precise duration by calculating the time stamp of the first and last frame WITHOUT DECODING THE STREAM.

cmd = ('ffprobe -v error -select_streams v:0 -show_entries frame=pts_time '
           f' -of default=noprint_wrappers=1:nokey=1 -read_intervals 0%+#1,99999% "{video}"')

Since the get_info_precise would take a bit more time than get_info, so the ffmpeg.VideoCapture will use get_info for general cases. Even though, the get_info_precise is much more effient than looping in opencv.

from deep-license-plate-recognition.

Hello @chenxinfeng4

1. We had resolved the gray scale bug by doing an ffmpegcv upgrade
2. For FPS we are calculating it manually by counting frames for 500ms using fps_cap.get(cv2.CAP_PROP_POS_MSEC) it works okay for RTSP too. Which i don't think reading last frame with fprobe will work

Thanks for your comments.

from deep-license-plate-recognition.