writeVideo
Write video data to file
Description
Examples
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, peppers.png
.
A = imread("peppers.png");
Create a 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.
v.VideoCompressionMethod
ans = 'Motion JPEG 2000'
Open the VideoWriter
object for writing and write the image data in A
to the file.
open(v) writeVideo(v,A)
Close the VideoWriter
object.
close(v)
Write Indexed Image to AVI File
Read image and colormap data from the sample indexed image file, corn.tif
.
[X,map] = imread("corn.tif");
Create a VideoWriter
object for a new indexed AVI file.
v = VideoWriter("myIndexed.avi","Indexed AVI");
Assign the colormap data to the Colormap
property of v
.
v.Colormap = map;
Open the VideoWriter
object for writing. After you open v
, you cannot change its properties.
open(v)
Write the image data in X
to the video file.
writeVideo(v,X)
Close the VideoWriter
object.
close(v)
Convert MPEG-4 to AVI File
Create objects to read and write a sample video, and open the AVI file for writing.
reader = VideoReader("xylophone_video.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
Clear the VideoReader
object and close the VideoWriter
object.
clear reader
close(writer)
Create AVI File from Animation
Set up the axes and figure properties to generate frames for the video.
Z = peaks; surf(Z); axis tight manual
set(gca,"NextPlot","replacechildren")
Create a VideoWriter
object for the output video file and open the object for writing.
v = VideoWriter("peaks.avi");
open(v)
Generate a set of frames, get each 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 the VideoWriter
object.
close(v)
Input Arguments
v
— Input VideoWriter
object
VideoWriter
object
Input VideoWriter
object. Use VideoWriter
to create the
object.
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,
img
must be two dimensional: height-by-widthFor a single truecolor (RGB) image,
img
is three dimensional: height-by-width-by-3.For a sequence of grayscale images,
img
is 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,
img
is 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:
img
is an array ofsingle
,double
, oruint8
values representing one or more grayscale or RGB color images, whichwriteVideo
writes as one or more RGB video frames.Data of type
single
ordouble
must be in the range[0,1]
, except when writing indexed AVI files.
When creating Motion JPEG 2000 files:
img
is an array ofuint8
,int8
,uint16
, orint16
values representing one or more monochrome or RGB color images.
Data Types: single
| double
| int8
| int16
| uint8
| uint16
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: cdata
and colormap
.
The frame
array is typically returned by the getframe
function.
If colormap
is not empty, then each element
of 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 [0,1]
.
When you create a VideoWriter
object, the profile
input
and the size of cdata
determine how
writeVideo
uses frame
.
profile of VideoWriter object | Size of each element of cdata | Behavior of writeVideo |
---|---|---|
| 2-D (height-by-width) | Use frame as provided. |
'Grayscale AVI' | 2-D (height-by-width) | Use frame as provided. colormap should be
empty. |
All other profiles | 2-D (height-by-width) | Construct RGB image frames using the colormap field |
3-D (height-by-width-by-3) | Ignore the colormap field. Construct RGB
image frames using the cdata field |
Data Types: struct
Version History
Introduced in R2010b
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