playback for electron

2018-11-12 21:49:11 +01:00
parent 6b5ab72756
commit ecf506fd91
3 changed files with 192 additions and 2 deletions
@@ -0,0 +1,103 @@
+const { config, getRadio } = require('../handlers/config');
+const cp = require("child_process");
+const { log } = require("abr-log")("listen-electron");
+
+let transcoder, listenTimer;
+
+// play audio locally
+function play(radio, delay, playToken, onData) {
+	try {
+		log.info("play " + radio + " at delay " + delay);
+
+		const radioObj = getRadio(...radio.split("_"));
+		if (!radioObj) {
+			return "radio not found";
+		}
+
+		//let skipPcmBytes = Math.max(config.user.streamInitialBuffer - 0.5) * 44100 * 2 * 2; // 44100 Hz, stereo, 16 bit.
+
+		var initialBuffer = radioObj.liveStatus.audioCache.readLast(+delay+config.user.streamInitialBuffer,config.user.streamInitialBuffer);
+		//log.debug("listen: readCursor set to " + radioObj.liveStatus.audioCache.readCursor);
+
+		if (!initialBuffer) {
+			log.error("/listen/" + radio + "/" + delay + ": initialBuffer not available");
+			return "buffer not available";
+		}
+
+		stop(); // shut down previous trancoder
+
+		transcoder.stdout.on("data", function(data) {
+			onData(playToken, data);
+		});
+
+		log.info("listen: send initial buffer of " + initialBuffer.length + " bytes");
+
+		setImmediate(function() {
+			transcoder.stdin.write(initialBuffer);
+		});
+
+		var sendMore = function() {
+			/*if (listenRequestDate !== state.requestDate) {
+				log.warn("request canceled because another one has been initiated");
+				return stop();
+			}*/
+			var radioObj = getRadio(...radio.split("_"));
+			if (!radioObj) {
+				log.error("/listen/" + radio + "/" + delay + ": radio not available");
+				return stop();
+			}
+			var audioCache = radioObj.liveStatus.audioCache;
+			if (!audioCache) {
+				log.error("/listen/" + radio + "/" + delay + ": audioCache not available");
+				return stop();
+			}
+			//var prevReadCursor = audioCache.readCursor;
+			transcoder.stdin.write(audioCache.readAmountAfterCursor(config.user.streamGranularity));
+			//onData(audioCache.readAmountAfterCursor(config.user.streamGranularity));
+			//log.debug("listen: readCursor=" + audioCache.readCursor);
+		}
+
+		listenTimer = setInterval(sendMore, 1000*config.user.streamGranularity);
+
+	} catch(e) {
+		log.error("play error=" + e);
+		log.error(e.stack);
+	}
+	return null;
+}
+
+function newTranscoder() {
+	log.debug("new transcoder");
+	transcoder = cp.spawn('ffmpeg', [
+		'-i', 'pipe:0',
+		'-acodec', 'pcm_s16le',
+		'-ar', 44100,
+		'-ac', 2,
+		'-f', 'wav',
+		'-v', 'fatal',
+		'pipe:1'
+	], { stdio: ['pipe', 'pipe', process.stderr] });
+	/*log.debug("stdin hWM: " + transcoder.stdin._writableState.highWaterMark);
+	transcoder.stdin._writableState.highWaterMark = 1024;
+	log.debug("stdin hWM: " + transcoder.stdin._writableState.highWaterMark);
+	log.debug("stdout hWM: " + transcoder.stdout._readableState.highWaterMark);
+	transcoder.stdout._readableState.highWaterMark = 1024;
+	log.debug("stdout hWM: " + transcoder.stdout._readableState.highWaterMark);*/
+}
+
+newTranscoder();
+
+function stop() {
+	log.debug("stop");
+	if (listenTimer) {
+		clearInterval(listenTimer);
+		if (transcoder && transcoder.stdin) {
+			transcoder.stdin.end();
+			transcoder.kill();
+			newTranscoder();
+		}
+	}
+}
+
+exports.play = play;
+exports.stop = stop;
@@ -13,6 +13,18 @@
    <noscript>
      You need to enable JavaScript to run this app.
    </noscript>
+    <script type="text/javascript">
+      const isElectron = navigator.userAgent.toLowerCase().indexOf(' electron/') > -1;  // in a Electron environment (https://github.com/electron/electron/issues/2288)
+      const isCordovaApp = document.URL.indexOf('http://') === -1 && document.URL.indexOf('https://') === -1 && !isElectron;
+
+      if (isElectron) {
+        console.log("detected Electron environment");
+        //require("../../index.js"); // start main process for stream analysis
+        //require("adblockradio-buffer-server");
+        navigator.abrserver = require("electron").remote.require("../adblockradio-buffer");
+        navigator.abrlisten = require("electron").remote.require("../adblockradio-buffer/api/listen-electron");
+      }
+    </script>
    <div id="root" style="display: flex;"></div>
  </body>
 </html>
@@ -2,11 +2,85 @@
 /* global Media */
 /* global Android */

-var isCordovaApp = document.URL.indexOf('http://') === -1 && document.URL.indexOf('https://') === -1;
+const isElectron = navigator.userAgent.toLowerCase().indexOf(' electron/') > -1;
+const isCordovaApp = document.URL.indexOf('http://') === -1 && document.URL.indexOf('https://') === -1 && !isElectron;

 var audioElement, play, stop, setVolume;

-if (isCordovaApp) {
+if (isElectron) {
+	console.log("listen: detected Electron env");
+
+	let audioCtx, gainNode;
+	let source;
+	let startTime; //, startPlayback;
+
+	function newContext() {
+		console.log("new context");
+		audioCtx = new (window.AudioContext || window.webkitAudioContext)();
+		gainNode = audioCtx.createGain();
+		gainNode.gain.value = 0.5;
+		gainNode.connect(audioCtx.destination);
+	}
+
+	newContext();
+
+	play = function(url, callback) {
+		if (startTime) {
+			stop();
+			return setTimeout(function() {
+				play(url, callback);
+			}, 50);
+		}
+		startTime = +new Date();
+		let nextStartTime = null; //audioCtx.currentTime;
+		//audioElement = document.createElement('audio');
+		const spl = decodeURIComponent(url).split('?')[0].split("/"); // assuming following URL format: "listen/" + encodeURIComponent(radio) + "/" + (delay/1000)
+		navigator.abrlisten.play(spl[1], spl[2], startTime, function(receivedStartTime, PCMAudioChunk) {
+			if (receivedStartTime !== startTime) {
+				console.log('received obsolete PCM chunk');
+				return;
+			}
+			if (!nextStartTime) {
+				console.log('start playback');
+				nextStartTime = audioCtx.currentTime;
+			}
+			//if (!startPlayback) startPlayback = new Date();
+			const PCMAudioChunk2 = Int8Array.from(PCMAudioChunk); //);
+			const frames = PCMAudioChunk2.byteLength / 4;
+			//console.log(frames / 44100 + " s => cursor = " + nextStartTime + " buffer=" + (nextStartTime - ((+new Date() - startPlayback)/1000) + " s"));
+			const arrayBuffer = audioCtx.createBuffer(2, frames, 44100);
+
+			const nowBufferingL = arrayBuffer.getChannelData(0);
+			const nowBufferingR = arrayBuffer.getChannelData(1);
+			for (var i = 0; i < frames; i++) {
+				nowBufferingL[i] = (PCMAudioChunk2[4*i] + 256 * PCMAudioChunk2[4*i + 1]) / 32768;
+				nowBufferingR[i] = (PCMAudioChunk2[4*i + 2] + 256 * PCMAudioChunk2[4*i + 3]) / 32768;
+			}
+
+			source = audioCtx.createBufferSource();
+			source.buffer = arrayBuffer;
+			source.connect(gainNode);
+			source.start(nextStartTime);
+			nextStartTime += frames / 44100;
+		});
+	}
+
+	stop = function() {
+		console.log("playback stop");
+		navigator.abrlisten.stop();
+		//source.stop(audioCtx.currentTime);//disconnect(gainNode);
+		audioCtx.close();
+		startTime = null;
+		newContext();
+		//setVolume(0);
+	}
+
+	setVolume = function(vol) {
+		console.log("set volume = " + vol);
+		gainNode.gain.value = vol;
+	}
+
+} else if (isCordovaApp) {
 	play = function(url, callback) {
 		if (audioElement && audioElement.stop) audioElement.stop();
 		audioElement = new Media(url, function() {
@@ -17,6 +91,7 @@ if (isCordovaApp) {
 			console.log("stream status=" + status);
 		});
 		audioElement.play();
+		if (callback) setImmediate(callback);
 	}

 	stop = function() {