Write video data to file
Write Image to Motion JPEG 2000 File
Write an RGB image to a Motion JPEG 2000 file with lossless compression.
Create an array containing data from the sample still image,
A = imread('peppers.png');
VideoWriter object for a new video file. Use the
'Archival' profile to specify a Motion JPEG 2000 file with lossless compression.
v = VideoWriter('myFile','Archival');
Verify the type of video compression for the new file.
ans = 'Motion JPEG 2000'
Open the video file for writing. Then, write the image data in
A to the file.
Close the video file.
Write Indexed Image to AVI File
Read image and colormap data from the sample indexed image file,
[X,map] = imread('corn.tif');
VideoWriter object for a new indexed AVI file.
v = VideoWriter('myIndexed.avi','Indexed AVI');
Assign the colormap data to the
Colormap property of
v.Colormap = map;
Open the file for writing. After you open the file, you cannot change the properties of
Write the image data in
X to the video file. Then, close the file.
Convert MPEG-4 to AVI File
Convert the example file,
to an uncompressed AVI file.
Create objects to read and write the video, and open the AVI file for writing.
reader = VideoReader('xylophone.mp4'); writer = VideoWriter('transcoded_xylophone.avi', ... 'Uncompressed AVI'); writer.FrameRate = reader.FrameRate; open(writer);
Read and write each frame.
while hasFrame(reader) img = readFrame(reader); writeVideo(writer,img); end close(writer);
Create AVI File from Animation
Write a sequence of frames to a compressed AVI file by generating a sequence of frames, creating a video object for the file to write to, and then writing the frames to the video file.
Setup the axes and figure properties to generate frames for the video.
Z = peaks; surf(Z); axis tight manual set(gca,'nextplot','replacechildren');
Create a video writer object for the output video file and open the object for writing.
v = VideoWriter('peaks.avi'); open(v);
Generate a set of frames, get the frame from the figure, and then write each frame to the file.
for k = 1:20 surf(sin(2*pi*k/20)*Z,Z) frame = getframe(gcf); writeVideo(v,frame); end close(v);
v — Input
VideoWriter object. Use
VideoWriter to create the
img — Values representing grayscale or RGB color images
2-D array | 3-D array | 4-D array
Values representing grayscale or RGB color images, specified as a 2-D, 3-D, or 4-D array:
For a single grayscale, monochrome, or indexed image,
imgmust be two dimensional: height-by-width
For a single truecolor (RGB) image,
imgis three dimensional: height-by-width-by-3.
For a sequence of grayscale images,
imgis four dimensional:. height-by-width-by-1-by-frames. The height and width must be consistent for all frames within a file.
For a sequence of RGB images,
imgis four dimensional: height-by-width-by-3-by-frames. The height and width must be consistent for all frames within a file.
When creating AVI or MPEG-4 files:
imgis an array of
uint8values representing one or more grayscale or RGB color images, which
writeVideowrites as one or more RGB video frames.
Data of type
doublemust be in the range
[0,1], except when writing indexed AVI files.
When creating Motion JPEG 2000 files:
imgis an array of
int16values representing one or more monochrome or RGB color images.
frame — Frame data
1-by-1 structure array | 1-by-
F array of structures
Frame data, specified as a 1-by-1 structure array representing
a single frame, or a 1-by-
F array of structures
representing multiple frames. Each frame contains two fields:
frame array is typically returned by the
colormap is not empty, then each element
cdata should be a 2-D (height-by-width) array.
The height and width must be consistent for all frames within a file.
colormap can contain a maximum of 256 entries.
Each element of
colormap must be in the range
When you create a
VideoWriter object. the
and the size of
cdata determine how
|Size of each element of ||Behavior of |
|2-D (height-by-width)||Use frame as provided.|
|2-D (height-by-width)||Use frame as provided. |
All other profiles
|2-D (height-by-width)||Construct RGB image frames using the |
|3-D (height-by-width-by-3)||Ignore the |