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README.md

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+jsmpeg
+==========
+
+#### An MPEG1 Video Decoder in JavaScript ####
+
+jsmpeg is a MPEG1 Decoder, written in JavaScript. It's "hand ported", i.e. not compiled with
+emscripten or similar. This will probably make it obsolete with the advent of asmjs.
+
+Some demos and more info: (phoboslab.org/log/2013/05/mpeg1-video-decoder-in-javascript)[http://www.phoboslab.org/log/2013/05/mpeg1-video-decoder-in-javascript]
+
+
+### Usage ###
+
+```javascript
+// Synopsis: var player = new jsmpeg(urlToFile, options);
+// The 'options' argument and all of its properties is optional. If no canvas element 
+// is given, jsmpeg will create its own, to be accessed at .canvas
+
+// Example:
+var canvas = document.getElementById('videoCanvas');
+var player = new jsmpeg('file.mpeg', {canvas: canvas, autoplay: true, loop: true});
+
+player.pause();
+player.play();
+player.stops();
+
+
+// An 'onload' callback can be specified in the 'options' argument
+var mpegLoaded = function( player ) {
+	console.log('Loaded', player);
+}
+var player = new jsmpeg('file.mpeg', {onload:mpegLoaded});
+
+// If you don't use 'autoplay' and don't explicitly call .play(), you can get individual
+// video frames (a canvas element) like so:
+var frame = null;
+while( (frame = player.nextFrame()) ) {
+	someOtherCanvasContext.drawImage(frame, 0, 0);
+}
+```
+
+### Limitations ###
+
+- Playback can only start when the file is fully loaded. I'm waiting for chunked XHR with ArrayBuffers to arrive in browsers.
+- MPEG files with B-Frames look weird - frames are not reordered. This should be relatively easy
+to fix, but most encoders seem to not use B-Frames at all by default.
+- The width of the MPEG video has to be a multiple of 2.
+- Only raw MPEG video streams are supported. The decoder hates Stream Packet Headers in between
+macroblocks.
+
+You can use (FFmpeg)[http://www.ffmpeg.org/] to encode videos in a suited format. This will crop
+the size to a multiple of 2, omit B-Frames and force a raw video stream:
+
+```
+ffmpeg -i in.mp4 -f mpeg1video -vf "crop=iw-mod(iw\,2):ih-mod(ih\,2)" -b 0 out.mpg
+```