# Cannot write video files in most codecs

**URL:** <https://forum.opencv.org/t/cannot-write-video-files-in-most-codecs/7631>\
**Category:** Python\
**Tags:** ffmpeg, videoio\
**Created:** [February 17, 2022, 3:13pm UTC](https://forum.opencv.org/t/cannot-write-video-files-in-most-codecs/7631 "2022-02-17T15:13:06Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![zurycutler](https://avatars.discourse-cdn.com/v4/letter/z/b3f665/32.png) [@zurycutler](https://forum.opencv.org/u/zurycutler)\
**Post date:** [February 17, 2022, 3:13pm UTC](https://forum.opencv.org/t/cannot-write-video-files-in-most-codecs/7631/1 "2022-02-17T15:13:06Z")

</div>

I am attempting to write a video file using opencv in the ProRes 4444 codec. I have tried other codecs, such as XVID, and the code works perfectly, however no ProRes codec of any kind, nor DNxHD seem to be working.

Relavent code:  
#Above code specifies clipName, which increments for each clip created in the loop below  
subClip = cv2.VideoWriter(clipName, cv2.VideoWriter\_fourcc(\*‘apch’), 24, size)  
#Adds frames to subClip  
f = 0  
#clipRange contains new frames every time this code is run  
while f \< len(clipRange):  
subClip.write(clipRange[f])  
f += 1  
print(“Clip Created”)  
subClip.release()

I get the following error message:  
[prores @ 0x7fb8e4986600] Specified pixel format yuv420p is invalid or not supported [ERROR:0] global /private/var/folders/24/8k48jl6d249\_n\_qfxwsl6xvm0000gn/T/pip-req-build-xxsyexfp/opencv/modules/videoio/src/cap\_ffmpeg\_impl.hpp (2774) open Could not open codec prores, error: Unspecified error [ERROR:0] global /private/var/folders/24/8k48jl6d249\_n\_qfxwsl6xvm0000gn/T/pip-req-build-xxsyexfp/opencv/modules/videoio/src/cap\_ffmpeg\_impl.hpp (2791) open VIDEOIO/FFMPEG: Failed to initialize VideoWriter

I believe that opencv is looking for ffmpeg’s files in a location where they are not currently located. The directory it writes here “/private/var/folders/24” does not exist, nor can I find cap\_ffmpeg\_impl.hpp anywhere on my machine.

When I run cv.getBuildInformation(), I can see that FFMPEG is working:  
Video I/O:  
FFMPEG: YES  
- avcodec: YES (58.134.100)  
- avformat: YES (58.76.100)  
- avutil: YES (56.70.100)  
- swscale: YES (5.9.100)  
- avresample: YES (4.0.0)

Settings:

- OpenCV 4.5.3
- MacOS 11.5.2 on Intel (not apple silicon)
- Python 3.8.8
- ffmpeg 4.2.2  
built with clang version 4.0.1 (tags/RELEASE\_401/final)  
configuration: --prefix=/Users/zury.cutler/opt/anaconda3 --cc=x86\_64-apple-darwin13.4.0-clang --disable-doc --enable-avresample --enable-gmp --enable-hardcoded-tables --enable-libfreetype --enable-libvpx --enable-pthreads --enable-libopus --enable-postproc --enable-pic --enable-pthreads --enable-shared --enable-static --enable-version3 --enable-zlib --enable-libmp3lame --disable-nonfree --enable-gpl --enable-gnutls --disable-openssl --enable-libopenh264 --enable-libx264  
libavutil 56. 31.100 / 56. 31.100  
libavcodec 58. 54.100 / 58. 54.100  
libavformat 58. 29.100 / 58. 29.100  
libavdevice 58. 8.100 / 58. 8.100  
libavfilter 7. 57.100 / 7. 57.100  
libavresample 4. 0. 0 / 4. 0. 0  
libswscale 5. 5.100 / 5. 5.100  
libswresample 3. 5.100 / 3. 5.100  
libpostproc 55. 5.100 / 55. 5.100