无法使用 OpenCV 和 Python 写入和保存视频文件

Question

I'm trying to process frames from a video stream, and it as a new video.

This is what I'm doing:

fourcc = cv2.VideoWriter_fourcc(*'XVID')
out = cv2.VideoWriter('Videos/output.mp4',fourcc, fps, (1080,1080))

I keep getting:

OpenCV: FFMPEG: tag 0x44495658/'XVID' is not supported with codec id 13 and format 'mp4 / MP4 (MPEG-4 Part 14)'
OpenCV: FFMPEG: fallback to use tag 0x00000020/' ???'

I think I'm using the wrong fourcc value... Which one should I use? I've been trying a lot of them.

I'm using Ubuntu 16.04, Python 2.7.11 and OpenCV 3.1.0

Answer 1

Define the codec and create VideoWriter object like this

fourcc = cv2.VideoWriter_fourcc(*'MPEG')
out = cv2.VideoWriter('output.avi',fourcc, 20.0, (640,480))

Answer 2

For Windows users

I am using OpenCV 2 with Python 3.6, on Windows 10.

The 'XVID' codec, along with producing a .avi file, seems to be the most generic solution (if not the only one that works).

fourcc = cv.VideoWriter_fourcc(*'XVID')
out = cv.VideoWriter('test.avi', fourcc, 60, (320, 240))

In addition, only BGR can be directly written with such a VideoWriter declaration. Don't try to write gray frames: the output would be empty.

Answer 3

The problem that you are having is that you are trying to export the frames in XVID format but the name of your output file is ending with .mp4 . You should change the export format to MP4V or the name of your output file to .avi .

fourcc = cv2.VideoWriter_fourcc(*'MP4V')
out = cv2.VideoWriter('Videos/output.mp4',fourcc, fps, (1080,1080))

alternative

fourcc = cv2.VideoWriter_fourcc(*'XVID')
out = cv2.VideoWriter('Videos/output.avi',fourcc, fps, (1080,1080))

here you can find more information about the video codecs

Answer 4

The size of the frame(width,height) you are giving, should match the size of the frame you want to save. so
fw = int(cap.get(3)) fh = int(cap.get(4)) print("w,h",fw,fh) out = cv2.VideoWriter('fb1.avi',cv2.VideoWriter_fourcc('X','V','I','D'), fps, (fw,fh))

Answer 5

If you want to save video by opencv in mp4 format, let

Follow this link :

you should replace:

fourcc = cv2.VideoWriter_fourcc(*'XVID')

by:

fourcc = cv2.VideoWriter_fourcc(*'FMP4')

I tried and succeeded.

Answer 6

I had the same problem. With me, it turned out that I had switched the height and width of the video, so the frame dimensions did not match the video specifications and as a result nothing was written. Make sure they match exactly.

Also, OpenCV seems to give that same warning if the file extension does not match the codec used. Specifically, it wants .avi for the XVID codec.

Answer 7

If you are using linux try this

fourcc = 0x00000021
out = cv2.VideoWriter('Videos/output.mp4',fourcc, fps, (1080,1080))

Answer 8

我想保存为 .mp4，结果证明使用*"mp4v"是正确的代码，至少在 Linux 上是这样。

Answer 9

Install K-Lite Mega Codec Pack: https://filehippo.com/download_klite_mega_codec/
This error occurs because some codecs are not available by default in Windows media player. So by installing this software, the video works fine with same code.

Answer 10

I tried using different cv2.VideoWriter_fourcc types, i found in the answers. My system responded with :

OpenCV: FFMPEG: tag 0x34504d46/'FMP4' is not supported with codec id 12 and format 'mp4 / MP4 (MPEG-4 Part 14)' OpenCV: FFMPEG: fallback to use tag 0x7634706d/'mp4v'

so i used what FFMPEG suggested in the error messgae. I set fourcc = 0x7634706d and it worked. Thanks guys :)

Answer 11

On a mac

writer = cv2.VideoWriter('mysupervideo.mp4', cv2.VideoWriter.fourcc(*'mp4v'), 20, (width, height))

Works better