How can I pipe openCV images to ffmpeg (running ffmpeg as a subprocess)? (I am using spyder/anaconda)
I am reading frames from a video file and do some processing on eac
I'm Kind of late, But my powerful VidGear Python Library automates the process of pipelining OpenCV frames into FFmpeg on any platform with its WriteGear API's Compression Mode. OP, You can implement your answer as follows:
# import libraries
from vidgear.gears import WriteGear
import cv2
output_params = {"-s":"2048x2048", "-r":30} #define FFmpeg tweak parameters for writer
stream = cv2.VideoCapture(0) #Open live webcam video stream on first index(i.e. 0) device
writer = WriteGear(output_filename = 'Output.mp4', compression_mode = True, logging = True, **output_params) #Define writer with output filename 'Output.mp4'
# infinite loop
while True:
(grabbed, frame) = stream.read()
# read frames
# check if frame empty
if not is grabbed:
#if True break the infinite loop
break
# {do something with frame here}
gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
# write a modified frame to writer
writer.write(gray)
# Show output window
cv2.imshow("Output Frame", frame)
key = cv2.waitKey(1) & 0xFF
# check for 'q' key-press
if key == ord("q"):
#if 'q' key-pressed break out
break
cv2.destroyAllWindows()
# close output window
stream.release()
# safely close video stream
writer.close()
# safely close writer
Source: https://abhitronix.github.io/vidgear/gears/writegear/compression/usage/#using-compression-mode-with-opencv
You can check out VidGear Docs for more advanced applications and features.
Hope that helps!
I had similar problem once. I opened an issue on Github, turns out it may be a platform issue.
Related to your question, you can as well pipe OpenCV images to FFMPEG. Here's a sample code:
# This script copies the video frame by frame
import cv2
import subprocess as sp
input_file = 'input_file_name.mp4'
output_file = 'output_file_name.mp4'
cap = cv2.VideoCapture(input_file)
ret, frame = cap.read()
height, width, ch = frame.shape
ffmpeg = 'FFMPEG'
dimension = '{}x{}'.format(width, height)
f_format = 'bgr24' # remember OpenCV uses bgr format
fps = str(cap.get(cv2.CAP_PROP_FPS))
command = [ffmpeg,
'-y',
'-f', 'rawvideo',
'-vcodec','rawvideo',
'-s', dimension,
'-pix_fmt', 'bgr24',
'-r', fps,
'-i', '-',
'-an',
'-vcodec', 'mpeg4',
'-b:v', '5000k',
output_file ]
proc = sp.Popen(command, stdin=sp.PIPE, stderr=sp.PIPE)
while True:
ret, frame = cap.read()
if not ret:
break
proc.stdin.write(frame.tostring())
cap.release()
proc.stdin.close()
proc.stderr.close()
proc.wait()