/
mp4_video.m
132 lines (124 loc) · 5.88 KB
/
mp4_video.m
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classdef mp4_video < VideoWriter
% Create mp4 video from figure window, like VideoWriter.
%
% Example for a moving circle:
% h = rectangle('Position', [0 0 1 1], 'Curvature', 1, 'FaceColor', 'k');
% axis equal; axis off; xlim([0 10]); ylim([0 10]); % set axis range
% vw = mp4_video('movingCircle.mp4', 4); % 4 frames per second
% for x = 0:9 % circle location range
% h.Position(1:2) = x; % move along diagonal
% vw.addFrame(); % add current frame to video buffer
% end
% vw.save(); % finish the video
%
% No special toolbox is needed for Windows and OSX. For Linux, ffmpeg is needed.
% In case ffmpeg is not available, the uncompressed avi file will be kept.
%
% This is based on VideoWriter, but restricts the output to the popular mp4
% video only. The major benefits include enabling Linux support for mp4 format,
% supporting Matlab throught ssh/putty connection, and supporting figure with UI
% controls. The rect feature allows all OS to capture part of the figure so to
% exclude UI control if needed.
% 20200323 Wrote it by Xiangrui.Li at gmail.com
properties
rect; % [left bottom width height] of video in figure. Default full window
end
methods
function obj = mp4_video(filename, frameRate, pos)
% Construct mp4_video object to write video.
% vw = mp4_video(filename, frameRate, rect);
% filename: result file name (required). .mp4 will be added if needed.
% frameRate: frames per second. Default 30.
% pos: Position in pixels to extract frame in figure, or a figure
% component, for example panel or axes, to capture.
% Default [] meeans full figure window.
profile = 'MPEG-4';
if ~ismember(profile, {VideoWriter.getProfiles.Name}) % likely Linux
profile = 'Uncompressed AVI'; % use ffmpeg to compress later
[err, ~] = system('ffmpeg -version');
if err
fprintf(['OS ffmpeg was not installed or not on path. '...
'An uncompressed avi video will be created.\n']);
end
end
if ~endsWith(filename, '.mp4'), filename = [filename '.mp4']; end
obj@VideoWriter(filename, profile); % superclass constructor
if nargin>2
if ~isnumeric(pos)
pos = round(getpixelposition(pos, 1));
pos(3:4) = floor(pos(3:4)/2) * 2;
end
obj.rect = pos;
end
if nargin>1 && ~isempty(frameRate), obj.FrameRate = frameRate; end
end
function addFrame(this, fh)
% Capture a frame from specified figure or gcf if omitted.
persistent use_getframe noui;
if isempty(use_getframe), use_getframe = true; noui = false; end
if nargin<2 || ~ishandle(fh), fh = gcf; end
if this.FrameCount < 1 % determine if use getframe and -noui
open(this);
try getframe(fh); catch, use_getframe = false; end
if ~use_getframe
try print(fh, '-RGBImage', '-r0'); catch, noui = true; end
end
end
if use_getframe % print() works for all, but getframe() is faster
if isempty(this.rect), A = getframe(fh); % faster without rect
else, A = getframe(fh, this.rect);
end
elseif noui % needed when display disabled
A = print(fh, '-RGBImage', '-r0', '-noui');
else % try with UI, only use '-noui' if needed
A = print(fh, '-RGBImage', '-r0');
end
this.writeVideo(A);
end
function save(this)
% Finish writing and close video file.
this.close();
if strcmpi(this.FileFormat, 'mp4'), return; end % suppose getframe works
sz = [this.Width this.Height];
if isempty(this.rect), this.rect = [0 0 sz-mod(sz,2)]; end
opts = '-y -pix_fmt yuv420p '; % overwrite, yuv420p for "dumb players"
if ~isequal(this.rect(3:4), sz)
r4 = this.rect([3 4 1 2]); r4(4) = sz(2)-r4(4)-r4(2);
opts = sprintf('%s-vf crop=%d:%d:%d:%d ', opts, r4);
end
nam = fullfile(this.Path, this.Filename);
[err, str] = system(['ffmpeg -i "' nam '" ' opts '"' nam(1:end-4) '"']);
if err, disp(str); else, delete(nam); end
end
function set.rect(this, rect)
if isempty(rect), return; end
rect = floor(rect);
if any(mod(rect(3:4),2))
error('Width and height must be even numbers');
end
this.rect = rect;
end
end
methods(Hidden)
% Override inherited methods, make them hidden
function lh = addlistener(varargin); lh=addlistener@VideoWriter(varargin{:}); end
function lh = listener(varargin); lh=listener@VideoWriter(varargin{:}); end
function p = findprop(varargin); p = findprop@VideoWriter(varargin{:}); end
function lh = findobj(varargin); lh = findobj@VideoWriter(varargin{:}); end
function TF = eq(varargin); TF = eq@VideoWriter(varargin{:}); end
function TF = ne(varargin); TF = ne@VideoWriter(varargin{:}); end
function TF = lt(varargin); TF = lt@VideoWriter(varargin{:}); end
function TF = le(varargin); TF = le@VideoWriter(varargin{:}); end
function TF = gt(varargin); TF = gt@VideoWriter(varargin{:}); end
function TF = ge(varargin); TF = ge@VideoWriter(varargin{:}); end
function lh = get(varargin); lh = get@VideoWriter(varargin{:}); end
function notify(varargin); notify@VideoWriter(varargin{:}); end
function delete(varargin); delete@VideoWriter(varargin{:}); end
function close(varargin); close@VideoWriter(varargin{:}); end
function open(varargin); open@VideoWriter(varargin{:}); end
function set(varargin); set@VideoWriter(varargin{:}); end
function saveobj(varargin); saveobj@VideoWriter(varargin{:}); end
function setdisp(varargin); setdisp@VideoWriter(varargin{:}); end
function writeVideo(varargin); writeVideo@VideoWriter(varargin{:}); end
end
end