Ability to change the scaling algorithm and default is now bicubic instead of fast_bilinear. Related to #116

src/database-migration.js

@@ -20,7 +20,7 @@
 const path = require('path');
 var fs = require('fs');
 
-const TARGET_VERSION = 700;
+const TARGET_VERSION = 701;
 
 const STEPS = [
     // [v, v2, x] : if the current version is v, call x(db), and version becomes v2
@@ -33,6 +33,7 @@ const STEPS = [
     [    501,    600, () => extractFillersFromChannels() ],
     [    600,    601, (db) => addFPS(db) ],
     [    601,    700, (db) => migrateWatermark(db) ],
+    [    700,    701, (db) => addScalingAlgorithm(db) ],
 ]
 
 const { v4: uuidv4 } = require('uuid');
@@ -395,6 +396,7 @@ function ffmpeg() {
         normalizeResolution: true,
         normalizeAudio: true,
         maxFPS: 60,
+        scalingAlgorithm: "bicubic",
     }
 }
 
@@ -746,6 +748,14 @@ function migrateWatermark(db, channelDB) {
     console.log("Done migrating watermarks in channels.");
 }
 
+function addScalingAlgorithm(db) {
+    let ffmpegSettings = db['ffmpeg-settings'].find()[0];
+    let f = path.join(process.env.DATABASE, 'ffmpeg-settings.json');
+    ffmpegSettings.scalingAlgorithm = "bicubic";
+    fs.writeFileSync( f, JSON.stringify( [ffmpegSettings] ) );
+}
+
+
 module.exports = {
     initDB: initDB,
     defaultFFMPEG: ffmpeg,

src/ffmpeg.js

@@ -256,7 +256,7 @@ class FFMPEG extends events.EventEmitter {
 
             // Resolution fix: Add scale filter, current stream becomes [siz]
             let beforeSizeChange = currentVideo;
-            let algo = "fast_bilinear";
+            let algo =  this.opts.scalingAlgorithm;
             let resizeMsg = "";
             if (
                   (this.ensureResolution && ( streamStats.anamorphic || (iW != this.wantedW || iH != this.wantedH) ) )

web/directives/ffmpeg-settings.js

@@ -60,6 +60,13 @@ module.exports = function (dizquetv, resolutionOptions) {
                 {id: 60, description: "60 frames per second"},
                 {id: 120, description: "120 frames per second"},
             ];
+            scope.scalingOptions = [
+                {id: "bicubic", description: "bicubic (default)"},
+                {id: "fast_bilinear", description: "fast_bilinear"},
+                {id: "lanczos", description: "lanczos"},
+                {id: "spline", description: "spline"},
+            ];
+
         }
     }
 }

web/public/templates/ffmpeg-settings.html

@@ -91,10 +91,18 @@
             <br />
             <label>Video Buffer Size (k)</label>
             <input type="number" class="form-control form-control-sm" ng-model="settings.videoBufSize"/>
+            <br />
             <label>Max Frame Rate</label>
             <select class='form-control custom-select'  ng-model="settings.maxFPS" ria-describedby="fpsHelp"
             ng-options="o.id as o.description for o in fpsOptions" ></select>
             <small id='fpsHelp' class='form-text text-muted'>Will transcode videos that have FPS higher than this.</small>
+
+            <br />
+            <label>Scaling Algorithm</label>
+            <select class='form-control custom-select'  ng-model="settings.scalingAlgorithm" ria-describedby="scalingHelp"
+            ng-options="o.id as o.description for o in scalingOptions" ></select>
+            <small id='scalingHelp' class='form-text text-muted'>Scaling algorithm to use when the transcoder needs to change the video size.</small>
+
         </div>
 
         <div class="form-group">