How to reshape on 4D matrix after using fread in RGB RAW file?

The following code loads the mp4 file correctly and saves it in a 3D matrix.

r = 1;
fileName = testDummyMP4;

readerobj = VideoReader(fileName, 'tag', 'myreader1');
F = get(readerobj, 'numberOfFrames');

tampon = single(read(readerobj,1));
tampon = imresize(tampon(:,:,1),r);
I = zeros(size(tampon,1),size(tampon,2),F,'uint8');

for k = 1:F
    disp(['Open: ' num2str(round(100*k/F)) '%'])
    vidFrames = single(read(readerobj,k));
    I(:,:,k) = imresize(vidFrames(:,:,2),r);
end;

imagesc((I(:,:,1)));

      

        
        
        
      

    

This is the result

I am trying to reverse engineer this code so that it gets the same result but for an 8bit rbg .raw file. Following the answers to this question, I tried the following:

You can download the 'M1302000245_1436389857.982603.raw'

rbg file here Or Google Drive version here

Ix = 256;
Iy = 256;
SF = 30; % Sample frequency
RecordingTime = 30; 
Iz = SF*RecordingTime
testDummy = 'M1302000245_1436389857.982603.raw'

fin = fopen(testDummy, 'r');
I = fread(fin, Ix*Iy*3*Iz, 'uint8');
fclose(fin);
I = reshape(I, [Ix Iy 3 Iz]); % The rbg should be 256x256x3x900

% I've tried each of the following manipulations before calling imagesc to no avail
% I = flipdim(imrotate(I, -90),2);
% I=impixel(I)
% I=I'

imagesc((I(:,:,1))); % view first slice

      

        
        
        
      

    

This gives:

What am I doing wrong?

Additional info: Recordings are taken using raspberry pi cameras with the following python code.

class BrainCamera:
    def __init__(self):
        self.video_format = "rgb"
        #self.video_quality = 5

        # Set up the settings of the camera so that
        # Exposure and gains are constant.
        self.camera = picamera.PiCamera()
        self.camera.resolution = (256,256)
        self.camera.framerate = 30
        sleep(2.0)
        self.camera.shutter_speed = self.camera.exposure_speed
        self.camera.exposure_mode = 'off'
        g = self.camera.awb_gains
        self.camera.awb_mode = 'off'
        self.camera.awb_gains = g
        self.camera.shutter_speed = 30000
        self.camera.awb_gains = (1,1)

    def start_recording(self, video_name_path):
        self.camera.start_recording(video_name_path, format=self.video_format)
        self.camera.start_preview()

    def stop_recording(self):
        self.camera.stop_recording()
        self.camera.stop_preview()

    # Destructor
    def __del__(self):
        print ("Closed Camera")
        self.camera.close()