Warning: No video frames were written to this file. The file may be invalid.

Hi Everyone, I have a problem syncing a video to a graph, I used the following code but I get the error:

Warning: No video frames were written to this file. The file may be invalid.

Could anyone let me know?

%need to implement:
%way to choose frame 2 
%way to rotate input 1
%way to limit value of a (calculate?)
%
VID = VideoReader('movie1.mp4')
writerObj = VideoWriter('output_video','MPEG-4');
% default: 'MPEG-4'. For other options see 'doc Videowriter'
% MPEG-4 files require frame dimensions that are divisible by two. 
% If the input frame width for an MPEG-4 file is not an even number,
% VideoWriter pads the frame with a column of black pixels along the right side.
writerObj.FrameRate = 24;
%specify the FPS of the output video
open(writerObj);
skipcolumns=0
skiprows=0;
%DATA = csvread('datafile.csv',skiprows,skipcolumns);
XX=x;
YY=t;
prompt = 'Initial frame #?';
bgn = input(prompt)
prompt = 'How many frames? (press enter to process whole video)';
nframes = input(prompt)
prompt = 'Skip first n frames';
skip = input(prompt)
prompt = 'Data Aqc. Rate (Hz)?';
daqrate = input(prompt)
%Do we want the image to be rotated?
prompt = 'rotate? (0=0?,1=90? CCW, 2=180?,3=270? CCW)';
rotate = input(prompt)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%parameters that control how each frame looks like:%
a=0.3;
%choose between 0 and 1, see figure below:
margin=0.05;
edge=0.05;
%    plotting a wide image might look like this:
%    ____________________________________________   
%   |                                            |       ^
%   |                                            |       |
%   |                                            |       | 
%   |                                            |       |
%   |                                            |       |
%   |                                            |       |
%   |                                            |       |
%   |                      1                     |       |
%   |<------------------------------------------>|       |  1
%   |____________________________________________|       |
%   |                ? edge                      |       |
%   |________________V_____   ___________________|       |
%   |                      | |                   |       |
%   |                      |m|                   |       |
%   |        IMAGE         |a|      PLOT         |       |
%   |<-------------------->|r|<----------------->|       |
%   |          a           |g|    1-a-margin     |       |
%   |                      |i|                   |       |
%   |                      |n|                   |       |
%   |______________________|_|___________________|       |
%   |                ?edge                       |       |
%   |________________V___________________________|       V
%
%
%   plotting a tall image might look like this:
%    ____________________________________________  
%   |                                            |       ^
%   |                      1                     |       | 
%   |<------------------------------------------>|       |
%   |                                            |       |
%   |____________________________________________|       |
%   |                   edge  ?                  |       |
%   |_______________   _______V__________________|       |           
%   |               | |                          |       |
%   |               | |                          |       |  1
%   |               |m|                          |       |
%   |               |a|                          |       |
%   |               |r|                          |       |
%   |               |g|                          |       |
%   |    IMAGE      |i|          PLOT            |       |
%   |<------------->|n|<------------------------>|       |
%   |      a        | |       1-a-margin         |       |
%   |               | |                          |       | 
%   |               | |                          |       |
%   |_______________|_|__________________________|       |
%   |                  edge ?                    |       |
%   |_______________________V____________________|       V
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
fps=VID.FrameRate;
totalframes=VID.NumberOfFrames;
rate=daqrate/fps;
Xdata_1=[];
Ydata_1=[];
Xdata_2=[];
Ydata_2=[];
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
frameA=read(VID,bgn+skip+1); 
frameB = imrotate(frameA,rotate*90);
imshow(frameB);
title('press and hold shift to get a square')
rect = getrect(gcf)
x=[rect(1) rect(1)+rect(3)];
y=[rect(2) rect(2)+rect(4)];
ratio =(y(2)-y(1))/(x(2)-x(1))
close all;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%to figure out the maximum number of frames we can read in
total=size(nframes)
total=total(1);
j = bgn+skip+1;
datasize=size(XX);
datasize=datasize(1);
while((j<totalframes) && (round((j-bgn)*rate)<datasize))
    j=j+1   
end    
maxframes=j-(bgn+skip+1)-1
if(total==0)
    %pick the maximum frame#
    nframes=maxframes;
else(total>0)
    %pick the user frame number if it doesn't exceed max frame#
    nframes=min(nframes,maxframes);    
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%to get the resolution of your monitor minus menu elements
t=figure(1)
set(t,'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);
j=bgn+skip+1;
frame=read(VID,j); 
f=getframe(t);
d=size(f.cdata)
Yres=d(1)
Xres=d(2)
square=min(Xres,Yres)
close all;
pause(0.5);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%to get the right xlim & ylim
for j = (bgn+skip+1) : bgn+skip+nframes+1
    j
    Xdata_1(end+1)=XX(round((j-bgn)*rate));
    Ydata_1(end+1)=YY(round((j-bgn)*rate));    
end
u=figure(1);
plot(Xdata_1,Ydata_1);
XLIM=get(gca,'xlim') 
YLIM=get(gca,'ylim')
close all;
pause(0.5);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
h=figure('position',[1 1 square square],'color','w');
pause(0.5);
for k = (bgn+skip+1) : bgn+skip+nframes+1
    tic
    AA=subplot(1,2,1);
    set(AA,'position',[0, margin,a,ratio*(a)]);
    %left,bottom,width,height relative to the bottom left corner
    frame=read(VID,k); 
    frame = imrotate(frame,rotate*90);
    imshow(frame(y(1):y(2),x(1):x(2),:));
    Xdata_2(end+1)=XX(round((k-bgn)*rate));
    Ydata_2(end+1)=YY(round((k-bgn)*rate));
    BB=subplot(1,2,2);
    set(BB,'position',[a+margin,margin, 1-a-1.5*margin,ratio*a]);
    
    %left,bottom,width,height relative to the bottom left corner
    hold on
    plot(Xdata_1,Ydata_1,'LineWidth',2,'LineStyle',':','Color','blue')
    plot(Xdata_2,Ydata_2,'LineWidth',2.5,'LineStyle','-','Color','red')
    ylim=YLIM;
    xlim=XLIM;
    ylabel('Ylabel','FontSize',12,'FontWeight','bold','Color','r')   
    xlabel('Xlabel','FontSize',12,'FontWeight','bold','Color','r')  
    title('Title')    
    hold off
%     pause(0.01);
    %to reduce flicker in movie - you may or may not need this
    f=getframe(h);
    
    border=round(edge*square);
    %to make sure axes are not clipped
    max(1,round(square*(1-margin-(ratio)*a))-border)
    min(square,round(square*(1.0-margin))+border)
    
    f.cdata=f.cdata(max(1,round(square*(1-margin-(ratio)*a))-border):...
        min(square,round(square*(1.0-margin))+border),:,:);
    %crop the frames
    %f contains the square frame, minus the menu
    %e.g. on a 1440*900 monitor f.cdata is a 801*801 Y,X vector w/ position 
    %relative to the top left corner
    
    writeVideo(writerObj,f);
    toc    
end
%left,bottom,width,height
 
close(writerObj)
delete(VID)
delete(writerObj)
close all

[Walter Roberson]

TIme to use the debugger to step through your code.

VID = VideoReader('movie1.mp4')
[...]
totalframes=VID.NumberOfFrames;

Caution: mp4 files are often written with variable frame rate, and when variable frame rate has been used, NumberOfFrames is often inaccurate, as it is estimated from the frame rate and the duration.

[Sujan Ponnappa]

I tried convert the video to .avi and then ran the code again, but i'm getting the same error.

[Jan]

Please post a copy of the complete error message.

Do you have write access to the current folder? Did you follow Walter's suggestion to use the debugger?

[Sujan Ponnappa]

I don't get an error .

Warning: No video frames were written to this file. The file may be invalid. 

I get the warning and nothing happens after this. I checked the whether there is write access and it is there.

I'll try to run the debugger now.

I have a video and the data to obtain the plot. I want to have the video and the plot in the same frame so I can see both .

[Sujan Ponnappa]

Warning: No video frames were written to this file. The file may be invalid. 
> In VideoWriter/close (line 282)
  In videoedit (line 199) 

Warning from VideoWriter>VideoWriter.close (line 282)
                    warning(message('MATLAB:audiovideo:VideoWriter:noFramesWritten'));