Can't get video's number of frames before processing?

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Liran
Liran am 28 Jul. 2014
Kommentiert: Walter Roberson am 21 Apr. 2016
I used videoReader--> read but i get "[]" in the number of frames field. i have tried using vision.VideoFileReader but it gives a less informative header ( without that kind of information)
I need the frame number BEFORE processing , not after. I am uploading the video so you could try yourselves

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Dinesh Iyer
Dinesh Iyer am 29 Jul. 2014
Hi Lirian,
The vision.VideoFileReader system object allows reading only one frame at a time and does not allow random access.
I tried to open this file using Windows Media Player but was unable to do so. I believe I need some additional codecs as you mentioned.
Can you try to force VideoReader to read the last frame as below
if true
vidObj = VideoReader('swipeCut.mp4');
read(vidObj, Inf);
vidObj.NumberOfFrames
end
This should display the last frame read. However, this operation might take time depending upon the size of the video.
I am curious however as to why you need the total number of frames?
Hope this helps.
Dinesh
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PRUDHVI RAJU
PRUDHVI RAJU am 21 Apr. 2016
Bearbeitet: Walter Roberson am 21 Apr. 2016
%
% Read Video
video = VideoReader('fp.avi');
%video = VideoReader('sv.mp4');
%no.of frames
nframes=video.NumberOfFrames;
Walter Roberson
Walter Roberson am 21 Apr. 2016
"Note: NumberOfFrames will be removed in a future release."

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Weitere Antworten (1)

Dima Lisin
Dima Lisin am 28 Jul. 2014
Thre maybe something wrong with the header of your video file. Can you try VideoReader on a different file?
  1 Kommentar
Liran
Liran am 28 Jul. 2014
Bearbeitet: Liran am 28 Jul. 2014
i have used VideoReader on other videos and it was fine of course , but i really need to do it on this video (i attached it).
The video was recorded via "Rec." app on a Samsung Note 3 with android 4.4 (Kitkat) and this app records these videos the same way.
i don't know if it helps you figure out the problem but before i downloaded new codecs i couldn't even read the file at all.

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