From d43a6f18652bb009334b0da2942219ee13c6a514 Mon Sep 17 00:00:00 2001
From: Thibault Deckers <thibault.deckers@gmail.com>
Date: Mon, 8 Nov 2021 17:23:35 +0900
Subject: [PATCH] #115 changed video thumbnail strategy

---
 .../aves/decoder/VideoThumbnailGlideModule.kt | 16 +++++--------
 lib/widgets/common/thumbnail/image.dart       | 24 +++++++++++++++----
 2 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/android/app/src/main/kotlin/deckers/thibault/aves/decoder/VideoThumbnailGlideModule.kt b/android/app/src/main/kotlin/deckers/thibault/aves/decoder/VideoThumbnailGlideModule.kt
index d0f2138ff..6c548ef44 100644
--- a/android/app/src/main/kotlin/deckers/thibault/aves/decoder/VideoThumbnailGlideModule.kt
+++ b/android/app/src/main/kotlin/deckers/thibault/aves/decoder/VideoThumbnailGlideModule.kt
@@ -3,7 +3,6 @@ package deckers.thibault.aves.decoder
 import android.content.Context
 import android.media.MediaMetadataRetriever
 import android.net.Uri
-import android.os.Build
 import com.bumptech.glide.Glide
 import com.bumptech.glide.Priority
 import com.bumptech.glide.Registry
@@ -58,16 +57,13 @@ internal class VideoThumbnailFetcher(private val model: VideoThumbnail) : DataFe
                 try {
                     var bytes = retriever.embeddedPicture
                     if (bytes == null) {
-                        // try to match the thumbnails returned by the content resolver / Media Store
-                        // the following strategies are from empirical evidence from a few test devices:
-                        // - API 29: sync frame closest to the middle
-                        // - API 26/27: default representative frame at any time position
+                        // there is no consistent strategy across devices to match
+                        // the thumbnails returned by the content resolver / Media Store
+                        // so we derive one in an arbitrary way
                         var timeMillis: Long? = null
-                        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
-                            val durationMillis = retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION)?.toLongOrNull()
-                            if (durationMillis != null) {
-                                timeMillis = durationMillis / 2
-                            }
+                        val durationMillis = retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION)?.toLongOrNull()
+                        if (durationMillis != null) {
+                            timeMillis = if (durationMillis < 15000) 0 else 15000
                         }
                         val frame = if (timeMillis != null) {
                             retriever.getFrameAtTime(timeMillis * 1000)
diff --git a/lib/widgets/common/thumbnail/image.dart b/lib/widgets/common/thumbnail/image.dart
index 26af6f3d8..3edba69d8 100644
--- a/lib/widgets/common/thumbnail/image.dart
+++ b/lib/widgets/common/thumbnail/image.dart
@@ -94,18 +94,34 @@ class _ThumbnailImageState extends State<ThumbnailImage> {
 
     _lastException = null;
     _providers.clear();
+
+    final highQuality = entry.getThumbnail(extent: extent);
+    ThumbnailProvider? lowQuality;
+    if (widget.progressive && !entry.isSvg) {
+      if (entry.isVideo) {
+        // previously fetched thumbnail
+        final cached = entry.bestCachedThumbnail;
+        final lowQualityExtent = cached.key.extent;
+        if (lowQualityExtent > 0 && lowQualityExtent != extent) {
+          lowQuality = cached;
+        }
+      } else {
+        // default platform thumbnail
+        lowQuality = entry.getThumbnail();
+      }
+    }
     _providers.addAll([
-      if (widget.progressive && !entry.isSvg)
+      if (lowQuality != null)
         _ConditionalImageProvider(
           ScrollAwareImageProvider(
             context: _scrollAwareContext,
-            imageProvider: entry.getThumbnail(),
+            imageProvider: lowQuality,
           ),
         ),
       _ConditionalImageProvider(
         ScrollAwareImageProvider(
           context: _scrollAwareContext,
-          imageProvider: entry.getThumbnail(extent: extent),
+          imageProvider: highQuality,
         ),
         _needSizedProvider,
       ),
@@ -233,7 +249,7 @@ class _ThumbnailImageState extends State<ThumbnailImage> {
 
     if (animate && widget.heroTag != null) {
       final background = settings.imageBackground;
-      final backgroundColor = background.isColor? background.color : null;
+      final backgroundColor = background.isColor ? background.color : null;
       image = Hero(
         tag: widget.heroTag!,
         flightShuttleBuilder: (flight, animation, direction, fromHero, toHero) {