RuntimeError: No ffmpeg exe could be found.

When using imageio to read youtube videos in python as shown below:

import cv2
import imageio
from pytube import YouTube
import numpy as np


def car_detection(url, frame_gap, initial_path, name):
    cars_classifier = cv2.CascadeClassifier(
        'cars.xml')
    yt = YouTube(url)
    stream = yt.streams.filter(file_extension='mp4').first()
    stream.download(output_path=initial_path, filename=name)
    path = initial_path
    path += '/'
    path += name
    path += '.mp4'

    reader = imageio.get_reader(path)
    frame_number_counter = 0
    traffic_density_values = []
    for frame in reader:
        frame_number_counter = frame_number_counter + 1
        if frame is not None:
            if frame_number_counter == 1 or frame_number_counter % frame_gap == 0:
                blur = cv2.blur(np.float32(frame), (3, 3))
                gray = cv2.cvtColor(blur, cv2.COLOR_BGR2GRAY)
                gray = np.array(gray, dtype='uint8')
                cars = cars_classifier.detectMultiScale(gray)
                count = 0
                for (x, y, w, h) in cars:
                    count = count + 1
                traffic_density_values.append(count)
                key = cv2.waitKey(1)
                if key == 27:
                    break
        else:
            break
    print(traffic_density_values)
    return traffic_density_values

I receive the following error in my android studio logcat:

2021-01-23 01:13:34.022 22417-22570/Brian.Okoth.trafficapp E/AndroidRuntime: FATAL EXCEPTION: Thread-2
    Process: Brian.Okoth.trafficapp, PID: 22417
    com.chaquo.python.PyException: RuntimeError: No ffmpeg exe could be found. Install ffmpeg on your system, or set the IMAGEIO_FFMPEG_EXE environment variable.
        at <python>.imageio_ffmpeg._utils.get_ffmpeg_exe(_utils.py:49)
        at <python>.imageio_ffmpeg._io._get_exe(_io.py:19)
        at <python>.imageio_ffmpeg._io.read_frames(_io.py:140)
        at <python>.imageio.plugins.ffmpeg._initialize(ffmpeg.py:468)
        at <python>.imageio.plugins.ffmpeg._open(ffmpeg.py:323)
        at <python>.imageio.core.format.__init__(format.py:221)
        at <python>.imageio.core.format.get_reader(format.py:170)
        at <python>.imageio.core.functions.get_reader(functions.py:186)
        at <python>.car_detection_and_counter_python_script.car_detection(car_detection_and_counter_python_script.py:18)
        at <python>.chaquopy_java.call(chaquopy_java.pyx:380)
        at <python>.chaquopy_java.Java_com_chaquo_python_PyObject_callAttrThrowsNative(chaquopy_java.pyx:352)
        at com.chaquo.python.PyObject.callAttrThrowsNative(Native Method)
        at com.chaquo.python.PyObject.callAttrThrows(PyObject.java:232)
        at com.chaquo.python.PyObject.callAttr(PyObject.java:221)
        at com.example.trafficapp.car_detection_thread.run(car_detection_thread.java:46)

However, the python code works just fine on my pc. The error only occurs when i try to run the script with chaquopy. How can i install ffmpeg on my system, or set the IMAGEIO_FFMPEG_EXE environment variable? Below are the installed packages in build.gradle:

pip {
                install "sklearn"
                install "pandas"
                install "opencv-python"
                install "pytube==10.4.1"
                install "imageio"
                install "imageio-ffmpeg"
                install "numpy"
                install "ffmpeg"
                install "ffmpeg-python"

            }

[Brokoth]

@ashnaeldho Using chaquopy, send the path of the video on your phone to the python code.

 if (!Python.isStarted())
     Python.start(new AndroidPlatform(c));
 Python python = Python.getInstance();
 PyObject pyObj = python.getModule("python_script");
 PyObject returnedData = pyObj.callAttr(path);

You can use this method to get the root path:

String path = YourActivity.this.getFilesDir().toString()

Concatenate the remainder of the video’s path at the end of the path variable. Then you can refer to the python code above to see how you would handle the parameters you passed.

[ashnaeldho]

Hi,

I’m new to android studio. I want to develop an android app which can do motion detection. The motion detection algorithm is in python. So, my question is, if I want to use mobile-ffmpeg to convert video to frames and then do motion detection (planning to use some of the python codes above for getting frames), how can i pass the video to this python code? The video loading portion is done on Java.

I know chaquopy can be used for the communication between java and python, but I don’t know how to pass video to the python code above.

If someone knows the answer, can you please help me.