Merge pull request felixge#64 from phated/master

add image size option to png encoder

README.md

@@ -119,6 +119,8 @@ server. Once you have done that, you should try feeding them into the
 Returns a new `Client` object. `options` include:
 
 * `ip`: The IP of the drone. Defaults to `'192.168.1.1'`.
+* `frameRate`: The frame rate of the PngEncoder. Defaults to `5`.
+* `imageSize`: The image size produced by PngEncoder. Defaults to `null`.
 
 #### client.createREPL()
 

lib/video/PngEncoder.js

@@ -19,6 +19,7 @@ function PngEncoder(options) {
   this.readable = true;
 
   this._spawn       = options.spawn || spawn;
+  this._imageSize   = options.imageSize || null;
   this._frameRate   = options.frameRate || 5;
   this._pngSplitter = options.pngSplitter || new PngSplitter();
   this._log         = options.log;
@@ -87,14 +88,17 @@ PngEncoder.prototype._initFfmpegAndPipes = function() {
 };
 
 PngEncoder.prototype._spawnFfmpeg = function() {
+  var ffmpegOptions = [];
+  ffmpegOptions.push('-i', '-'); // input flag
+  ffmpegOptions.push('-f', 'image2pipe'); // format flag
+  if(this._imageSize){
+    ffmpegOptions.push('-s', this._imageSize); // size flag
+  }
+  ffmpegOptions.push('-vcodec', 'png'); // codec flag
+  ffmpegOptions.push('-r', this._frameRate); // framerate flag
+  ffmpegOptions.push('-'); // output
   // @TODO allow people to configure the ffmpeg path
-  return this._spawn('ffmpeg', [
-    '-i' ,'-',
-    '-f', 'image2pipe',
-    '-vcodec', 'png',
-    '-r', this._frameRate,
-    '-',
-  ]);
+  return this._spawn('ffmpeg', ffmpegOptions);
 };
 
 PngEncoder.prototype.end = function() {