Why not load the frame from videoObj?

videoObjref = VideoReader('Barrier.avi');
videoObj = VideoReader('output4.avi'); %video encoding using ffmpeg (h.264)
numFramesref = videoObjref.NumberOfFrames;
numFrames = videoObj.NumberOfFrames;

numFramesref=400

numFrames=400

vot=read(videoObj,inf);
figure()
imshow(vot)

this code is ok

vot=read(videoObjref,inf);
figure()
imshow(vot)

This code gives an error:

Error using VideoReader/read (line 86)
The frame index requested is beyond the end of the file.

Why not load the frame from videoObj?

The code used in ffmpeg: ffmpeg -i Barrier.avi -c:v libx264 -b:v 2M output4.avi