Camera: further streaming optimizations

Signed-off-by: Rick Waldron <waldron.rick@gmail.com>
tessel · Mar 23, 2016 · 2515876 · 2515876
1 parent 7bff719
commit 2515876
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Showing 2 changed files with 83 additions and 13 deletions.
diff --git a/lib/camera.js b/lib/camera.js
@@ -7,8 +7,8 @@ var Readable = require('stream').Readable;
 var priv = new Map();
 
 function scale(value, fromLow, fromHigh, toLow, toHigh) {
-  return (value - fromLow) * (toHigh - toLow) /
-    (fromHigh - fromLow) + toLow;
+  return ((value - fromLow) * (toHigh - toLow) /
+    (fromHigh - fromLow) + toLow) | 0;
 }
 
 function constrain(value, lower, upper) {
@@ -113,27 +113,41 @@ Camera.prototype.capture = function(options) {
     state.output = cameraDefaults.output;
   }
 
+  if (state.stream && state.quality > 0.9) {
+    state.quality = 0.9;
+  }
+
   var args = [
     // Overwrite: yes
     '-y',
     // Logging: fatal
     '-v', 'fatal',
-    '-r', '30',
+
+    // Input...
+    '-f', 'v4l2',
+    '-r', 4,
+    '-s', `${state.width}x${state.height}`,
     '-i', state.path,
+
+    // Output...
     '-s', `${state.width}x${state.height}`,
     '-q:v', scale(state.quality, 0, 1, 30, 1),
   ];
 
   if (state.stream) {
+    // args.splice(2, 0, '-f', 'v4l2');
+
     args.push(
-      // '-r', '30',
+      // '-r', 4,
       // '-i', '/dev/video0',
       // '-y',
       // '-s', '320x240',
       '-f', 'MJPEG',
       // '-f', 'h264',
       '-b:v', '64k',
-      '-r', '30',
+      // '-maxrate', '64k',
+      // '-movflags', '+faststart',
+      '-r', 4,
       'pipe:1'
     );
   } else {
@@ -155,13 +169,26 @@ Camera.prototype.capture = function(options) {
     }
   }
 
+
+  if (state.process && state.isStreaming) {
+    return this;
+  }
+
   state.process = cp.spawn('ffmpeg', args);
 
   if (state.stream) {
     state.isStreaming = true;
   }
 
   state.process.stdout.on('data', (data) => {
+    if (!data) {
+      return;
+    }
+
+    if (data && !data.length) {
+      return;
+    }
+
     if (state.isStreaming) {
       cs.push(data);
       this.emit('data', data);
@@ -175,6 +202,14 @@ Camera.prototype.capture = function(options) {
 
     state.isStreaming = false;
 
+    if (!buffer) {
+      return;
+    }
+
+    if (buffer && !buffer.length) {
+      return;
+    }
+
     if (error) {
       this.emit('error', error);
     } else {
@@ -208,6 +243,22 @@ Camera.prototype.stream = function() {
   });
 };
 
+Camera.prototype.stop = function() {
+  var state = priv.get(this);
+  if (!state.isStreaming) {
+    return this;
+  }
+  state.isStreaming = false;
+
+  if (state.process) {
+    state.process.kill('SIGTERM');
+    state.process = null;
+  }
+  this.emit('stop');
+  return this;
+};
+
+
 module.exports = Camera;
 
 if (global.IS_TEST_ENV) {

diff --git a/test/unit/camera.js b/test/unit/camera.js
@@ -93,8 +93,12 @@ exports['av.Camera'] = {
       '-y',
       '-v',
       'fatal',
+      '-f',
+      'v4l2',
       '-r',
-      '30',
+      4,
+      '-s',
+      '320x240',
       '-i',
       '/dev/video0',
       '-s',
@@ -127,8 +131,12 @@ exports['av.Camera'] = {
       '-y',
       '-v',
       'fatal',
+      '-f',
+      'v4l2',
       '-r',
-      '30',
+      4,
+      '-s',
+      '320x240',
       '-i',
       '/dev/video0',
       '-s',
@@ -160,8 +168,12 @@ exports['av.Camera'] = {
       '-y',
       '-v',
       'fatal',
+      '-f',
+      'v4l2',
       '-r',
-      '30',
+      4,
+      '-s',
+      '320x240',
       '-i',
       '/dev/video0',
       '-s',
@@ -193,8 +205,12 @@ exports['av.Camera'] = {
       '-y',
       '-v',
       'fatal',
+      '-f',
+      'v4l2',
       '-r',
-      '30',
+      4,
+      '-s',
+      '320x240',
       '-i',
       '/dev/video0',
       '-s',
@@ -253,27 +269,30 @@ exports['av.Camera'] = {
 
     test.equal(s instanceof CaptureStream, true);
     test.equal(s instanceof Readable, true);
-
     test.equal(this.spawn.callCount, 1);
     test.equal(this.spawn.lastCall.args[0], 'ffmpeg');
     test.deepEqual(this.spawn.lastCall.args[1], [
       '-y',
       '-v',
       'fatal',
+      '-f',
+      'v4l2',
       '-r',
-      '30',
+      4,
+      '-s',
+      '320x240',
       '-i',
       '/dev/video0',
       '-s',
       '320x240',
       '-q:v',
-      1,
+      3,
       '-f',
       'MJPEG',
       '-b:v',
       '64k',
       '-r',
-      '30',
+      4,
       'pipe:1',
     ]);