Function GifRecorder

src/__tests__/MediaStreamRecorder.js:2066–2200

(mediaStream)

// GifRecorder.js

function GifRecorder(mediaStream) {
    if (typeof GIFEncoder === 'undefined') {
        throw 'Please link: https://cdn.webrtc-experiment.com/gif-recorder.js';
    }

    // void start(optional long timeSlice)
    // timestamp to fire "ondataavailable"
    this.start = function(timeSlice) {
        timeSlice = timeSlice || 1000;

        var imageWidth = this.videoWidth || 320;
        var imageHeight = this.videoHeight || 240;

        canvas.width = video.width = imageWidth;
        canvas.height = video.height = imageHeight;

        // external library to record as GIF images
        gifEncoder = new GIFEncoder();

        // void setRepeat(int iter)
        // Sets the number of times the set of GIF frames should be played.
        // Default is 1; 0 means play indefinitely.
        gifEncoder.setRepeat(0);

        // void setFrameRate(Number fps)
        // Sets frame rate in frames per second.
        // Equivalent to setDelay(1000/fps).
        // Using "setDelay" instead of "setFrameRate"
        gifEncoder.setDelay(this.frameRate || this.speed || 200);

        // void setQuality(int quality)
        // Sets quality of color quantization (conversion of images to the
        // maximum 256 colors allowed by the GIF specification).
        // Lower values (minimum = 1) produce better colors,
        // but slow processing significantly. 10 is the default,
        // and produces good color mapping at reasonable speeds.
        // Values greater than 20 do not yield significant improvements in speed.
        gifEncoder.setQuality(this.quality || 1);

        // Boolean start()
        // This writes the GIF Header and returns false if it fails.
        gifEncoder.start();

        startTime = Date.now();

        function drawVideoFrame(time) {
            if (isPaused) {
                setTimeout(drawVideoFrame, 500, time);
                return;
            }

            lastAnimationFrame = requestAnimationFrame(drawVideoFrame);

            if (typeof lastFrameTime === undefined) {
                lastFrameTime = time;
            }

            // ~10 fps