            source.connect(offlineContext.destination);
                                    source.start(0);

                                    offlineContext.startRendering().then(function(renderedBuffer) {
                                        audio = renderedBuffer.getChannelData(0);

                                        //printTextarea('js: audio recorded, size: ' + audio.length + ', old size: ' + (audio0 == null ? 0 : audio0.length));

                                        var audioAll = new F