Frames to video conversion

 aviObject = avifile('Myvid1.avi')
 for ctr = 441:500
 iFrame = clock; 
 fname = ['IMG' num2str(ctr),'.PNG']; 
 I = imread(fname);                  
 F = im2frame(I);                    
 aviObject = addframe(aviObject,I);  
 elapsed = etime(clock, iFrame);
 pause(5 - elapsed); 
 end
 aviObject = close(aviObject);

This is my code to create video from frames.. It shows error..

 ??? Error using ==> im2frame
 Indexed movie frame must have a non-empty colormap

Why..? My images are 600*800uint8 type..

Answer 1

[Walter Roberson]

[I, cmap] = imread(fname); 
F = im2frame(I, cmap);

[Lalit Patil]

still problem.. colormap is empty for image.

 cmap = []

This is the image

http://speedy.sh/wkGFf/IMG447.PNG

[Walter Roberson]

Before the loop:

cmap = gray(256);

Then in the loop,

I = imread(fname);
F = im2frame(I, cmap);

[SETTE Houda]

@Lalit Patil how did you reserve this problem please ?

Answer 2

[yanqi liu]

（1）demo1

use video to images

function Video2Images(videoFilePath)
clc;
if nargin < 1
    videoFilePath = 'traffic.avi';
end
nFrames = GetVideoImgList(videoFilePath);

function nFrames = GetVideoImgList(videoFilePath)
% 获取视频图像序列
% 输入参数：
%  vidioFilePath——视频路径信息
% 输出参数：
%  videoImgList——视频图像序列

xyloObj = VideoReader(videoFilePath);

nFrames = xyloObj.NumberOfFrames;
vidHeight = xyloObj.Height;
vidWidth = xyloObj.Width;

[pathstr, name, ext] = fileparts(videoFilePath);

video_imagesPath = fullfile(pwd, sprintf('%s_images', name));
if ~exist(video_imagesPath, 'dir')
    mkdir(video_imagesPath);
end
files = dir(fullfile(video_imagesPath, '*.jpg'));
if length(files) == nFrames
    return;
end
h = waitbar(0, '', 'Name', '获取视频图像序列...');
steps = nFrames;
for step = 1 : nFrames
    temp = read(xyloObj, step);
    temp_str = sprintf('%s\\%04d.jpg', video_imagesPath, step);
    imwrite(temp, temp_str);
    pause(0.01);
    waitbar(step/steps, h, sprintf('已处理：%d%%', round(step/nFrames*100)));
end
close(h)

(2) demo2

use images to video

function Images2Video(imgFilePath, filename_out)
if nargin < 2
    imgFilePath = fullfile(pwd, 'traffic_images');
    filename_out = fullfile(pwd, 'out.avi');
end
% 清理空间
clc;
% 起始帧
startnum = 1;
% 默认结束帧为jpg图像数目
endnum = size(ls(fullfile(imgFilePath, '*.jpg')), 1);
% 创建对象句柄
writerObj = VideoWriter(filename_out);
% 设置帧率
writerObj.FrameRate = 24;
% 开始打开
open(writerObj);
% 进度条
h = waitbar(0, '', 'Name', 'Write Video File...');
% 总帧数
steps = endnum - startnum;
for num = startnum : endnum
    % 当前序号的名称
    file = sprintf('%04d.jpg', num);
    % 当前序号的位置
    file = fullfile(imgFilePath, file);
    % 读取
    frame = imread(file);
    % 转化为帧对象
    frame = im2frame(frame);
    % 写出
    writeVideo(writerObj,frame);
    % 刷新
    pause(0.01);
    % 进度
    step = num - startnum;
    % 显示进度条
    waitbar(step/steps, h, sprintf('Process：%d%%', round(step/steps*100)));
end
% 关闭句柄
close(writerObj);
% 关闭进度条
close(h);