feat(thumbnails): Allow download thumbnails (for offline usage) (shak…

…a-project#3280)

demo/common/assets.js

@@ -798,6 +798,7 @@ shakaAssets.testAssets = [
       .addFeature(shakaAssets.Feature.DASH)
       .addFeature(shakaAssets.Feature.ULTRA_HIGH_DEFINITION)
       .addFeature(shakaAssets.Feature.MP4)
+      .addFeature(shakaAssets.Feature.OFFLINE)
       .addFeature(shakaAssets.Feature.THUMBNAILS),
   new ShakaDemoAssetInfo(
       /* name= */ 'DASH-IF THUMBNAILS - Single adaptation set, 4 tiles at 10x1, each thumb 205x115',
@@ -807,6 +808,7 @@ shakaAssets.testAssets = [
       .addFeature(shakaAssets.Feature.DASH)
       .addFeature(shakaAssets.Feature.ULTRA_HIGH_DEFINITION)
       .addFeature(shakaAssets.Feature.MP4)
+      .addFeature(shakaAssets.Feature.OFFLINE)
       .addFeature(shakaAssets.Feature.THUMBNAILS),
   new ShakaDemoAssetInfo(
       /* name= */ 'DASH-IF THUMBNAILS - Single adaptation set, 1 tile at 10x20, each thumb 102x58',
@@ -816,6 +818,7 @@ shakaAssets.testAssets = [
       .addFeature(shakaAssets.Feature.DASH)
       .addFeature(shakaAssets.Feature.ULTRA_HIGH_DEFINITION)
       .addFeature(shakaAssets.Feature.MP4)
+      .addFeature(shakaAssets.Feature.OFFLINE)
       .addFeature(shakaAssets.Feature.THUMBNAILS),
   new ShakaDemoAssetInfo(
       /* name= */ 'DASH-IF THUMBNAILS - Two adaptation sets with different thumb resolutions',
@@ -825,6 +828,7 @@ shakaAssets.testAssets = [
       .addFeature(shakaAssets.Feature.DASH)
       .addFeature(shakaAssets.Feature.ULTRA_HIGH_DEFINITION)
       .addFeature(shakaAssets.Feature.MP4)
+      .addFeature(shakaAssets.Feature.OFFLINE)
       .addFeature(shakaAssets.Feature.THUMBNAILS),
   new ShakaDemoAssetInfo(
       /* name= */ 'DASH-IF THUMBNAILS - Live stream, Single adaptation set, 1x1 tiles (livesim)',

lib/offline/storage.js

@@ -549,6 +549,8 @@ shaka.offline.Storage = class {
     const variantIds = new Set();
     /** @type {!Set.<number>} */
     const textIds = new Set();
+    /** @type {!Set.<number>} */
+    const imageIds = new Set();
 
     // Collect the IDs of the chosen tracks.
     for (const track of chosenTracks) {
@@ -558,13 +560,18 @@ shaka.offline.Storage = class {
       if (track.type == 'text') {
         textIds.add(track.id);
       }
+      if (track.type == 'image') {
+        imageIds.add(track.id);
+      }
     }
 
     // Filter the manifest to keep only what the app chose.
     manifest.variants =
         manifest.variants.filter((variant) => variantIds.has(variant.id));
     manifest.textStreams =
         manifest.textStreams.filter((stream) => textIds.has(stream.id));
+    manifest.imageStreams =
+        manifest.imageStreams.filter((stream) => imageIds.has(stream.id));
 
     // Check the post-filtered manifest for characteristics that may indicate
     // issues with how the app selected tracks.
@@ -1063,6 +1070,9 @@ shaka.offline.Storage = class {
     for (const text of manifest.textStreams) {
       estimator.addText(text);
     }
+    for (const image of manifest.imageStreams) {
+      estimator.addImage(image);
+    }
 
     // TODO(joeyparrish): Break out stack-based state and method params into a
     // separate class to clean up.  See:
@@ -1487,6 +1497,10 @@ shaka.offline.Storage = class {
       set.add(text);
     }
 
+    for (const image of manifest.imageStreams) {
+      set.add(image);
+    }
+
     for (const variant of manifest.variants) {
       if (variant.audio) {
         set.add(variant.audio);

lib/offline/stream_bandwidth_estimator.js

@@ -93,6 +93,16 @@ shaka.offline.StreamBandwidthEstimator = class {
         shaka.offline.StreamBandwidthEstimator.DEFAULT_TEXT_BITRATE_;
   }
 
+  /**
+   * Create an estimate for the image stream.
+   *
+   * @param {shaka.extern.Stream} image
+   */
+  addImage(image) {
+    this.estimateByStreamId_[image.id] = image.bandwidth ||
+        shaka.offline.StreamBandwidthEstimator.DEFAULT_IMAGE_BITRATE_;
+  }
+
   /**
    * Get the estimate for a segment that is part of a stream that has already
    * added to the estimator.
@@ -171,3 +181,15 @@ shaka.offline.StreamBandwidthEstimator.DEFAULT_AUDIO_BITRATE_ = 393216;
  */
 shaka.offline.StreamBandwidthEstimator.DEFAULT_TEXT_BITRATE_ = 52;
 
+
+/**
+ * Since we don't normally get the bitrate for image, we still want to create
+ * some approximation so that it can influence progress.
+ *
+ * The size of the thumbnail usually is 2KB.
+ *
+ * @const {number}
+ * @private
+ */
+shaka.offline.StreamBandwidthEstimator.DEFAULT_IMAGE_BITRATE_ = 2048;
+

lib/util/player_configuration.js

@@ -381,11 +381,11 @@ shaka.util.PlayerConfiguration = class {
 
     // Since this default callback is used primarily by our own demo app and by
     // app developers who haven't thought about which tracks they want, we
-    // should select all text tracks, regardless of language.  This makes for a
-    // better demo for us, and does not rely on user preferences for the
+    // should select all image/text tracks, regardless of language.  This makes
+    // for a better demo for us, and does not rely on user preferences for the
     // unconfigured app.
     for (const track of tracks) {
-      if (track.type == ContentType.TEXT) {
+      if (track.type == ContentType.TEXT || track.type == ContentType.IMAGE) {
         selectedTracks.push(track);
       }
     }