fixed page identification in multipage HEIC with non-unique track IDs

android/app/src/main/kotlin/deckers/thibault/aves/channel/calls/MetadataHandler.kt

@@ -593,10 +593,11 @@ class MetadataHandler(private val context: Context) : MethodCallHandler {
                             KEY_PAGE to i,
                             KEY_MIME_TYPE to trackMime,
                         )
+
+                        // do not use `MediaFormat.KEY_TRACK_ID` as it is actually not unique between tracks
+                        // e.g. there could be both a video track and an image track with KEY_TRACK_ID == 1
+
                         format.getSafeInt(MediaFormat.KEY_IS_DEFAULT) { page[KEY_IS_DEFAULT] = it != 0 }
-                        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
-                            format.getSafeInt(MediaFormat.KEY_TRACK_ID) { page[KEY_TRACK_ID] = it }
-                        }
                         format.getSafeInt(MediaFormat.KEY_WIDTH) { page[KEY_WIDTH] = it }
                         format.getSafeInt(MediaFormat.KEY_HEIGHT) { page[KEY_HEIGHT] = it }
                         if (isVideo(trackMime)) {
@@ -875,7 +876,6 @@ class MetadataHandler(private val context: Context) : MethodCallHandler {
         private const val KEY_HEIGHT = "height"
         private const val KEY_WIDTH = "width"
         private const val KEY_PAGE = "page"
-        private const val KEY_TRACK_ID = "trackId"
         private const val KEY_IS_DEFAULT = "isDefault"
         private const val KEY_DURATION = "durationMillis"
 

android/app/src/main/kotlin/deckers/thibault/aves/decoder/MultiTrackImageGlideModule.kt

@@ -27,7 +27,7 @@ class MultiTrackImageGlideModule : LibraryGlideModule() {
     }
 }
 
-class MultiTrackImage(val context: Context, val uri: Uri, val trackId: Int?)
+class MultiTrackImage(val context: Context, val uri: Uri, val trackIndex: Int?)
 
 internal class MultiTrackThumbnailLoader : ModelLoader<MultiTrackImage, Bitmap> {
     override fun buildLoadData(model: MultiTrackImage, width: Int, height: Int, options: Options): ModelLoader.LoadData<Bitmap> {
@@ -52,9 +52,9 @@ internal class MultiTrackImageFetcher(val model: MultiTrackImage, val width: Int
 
         val context = model.context
         val uri = model.uri
-        val trackId = model.trackId
+        val trackIndex = model.trackIndex
 
-        val bitmap = MultiTrackMedia.getImage(context, uri, trackId)
+        val bitmap = MultiTrackMedia.getImage(context, uri, trackIndex)
         if (bitmap == null) {
             callback.onLoadFailed(Exception("null bitmap"))
         } else {

android/app/src/main/kotlin/deckers/thibault/aves/metadata/MultiTrackMedia.kt

@@ -16,17 +16,17 @@ object MultiTrackMedia {
     private val LOG_TAG = LogUtils.createTag(MultiTrackMedia::class.java)
 
     @RequiresApi(Build.VERSION_CODES.P)
-    fun getImage(context: Context, uri: Uri, trackId: Int?): Bitmap? {
+    fun getImage(context: Context, uri: Uri, trackIndex: Int?): Bitmap? {
         val retriever = StorageUtils.openMetadataRetriever(context, uri) ?: return null
         try {
-            return if (trackId != null) {
+            return if (trackIndex != null) {
-                val imageIndex = trackIdToImageIndex(context, uri, trackId) ?: return null
+                val imageIndex = trackIndexToImageIndex(context, uri, trackIndex) ?: return null
                 retriever.getImageAtIndex(imageIndex)
             } else {
                 retriever.primaryImage
             }
         } catch (e: Exception) {
-            Log.w(LOG_TAG, "failed to extract image from uri=$uri trackId=$trackId", e)
+            Log.w(LOG_TAG, "failed to extract image from uri=$uri trackIndex=$trackIndex", e)
         } finally {
             // cannot rely on `MediaMetadataRetriever` being `AutoCloseable` on older APIs
             retriever.release()
@@ -34,7 +34,7 @@ object MultiTrackMedia {
         return null
     }
 
-    private fun trackIdToImageIndex(context: Context, uri: Uri, trackId: Int): Int? {
+    private fun trackIndexToImageIndex(context: Context, uri: Uri, trackIndex: Int): Int? {
         val extractor = MediaExtractor()
         try {
             extractor.setDataSource(context, uri, null)
@@ -42,7 +42,7 @@ object MultiTrackMedia {
             var imageIndex = 0
             for (i in 0 until trackCount) {
                 val trackFormat = extractor.getTrackFormat(i)
-                if (trackId == trackFormat.getInteger(MediaFormat.KEY_TRACK_ID)) {
+                if (trackIndex == i) {
                     return imageIndex
                 }
                 if (MimeTypes.isImage(trackFormat.getString(MediaFormat.KEY_MIME))) {
@@ -50,7 +50,7 @@ object MultiTrackMedia {
                 }
             }
         } catch (e: Exception) {
-            Log.w(LOG_TAG, "failed to get image index for uri=$uri, trackId=$trackId", e)
+            Log.w(LOG_TAG, "failed to get image index for uri=$uri, trackIndex=$trackIndex", e)
         } finally {
             extractor.release()
         }

android/build.gradle

@@ -1,6 +1,6 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 buildscript {
-    ext.kotlin_version = '1.4.30'
+    ext.kotlin_version = '1.4.31'
     repositories {
         google()
         mavenCentral()

lib/model/multipage.dart

@@ -71,7 +71,7 @@ class SinglePageInfo implements Comparable<SinglePageInfo> {
     final index = map['page'] as int;
     return SinglePageInfo(
       index: index,
-      pageId: map['trackId'] as int ?? index,
+      pageId: index,
       mimeType: map['mimeType'] as String,
       isDefault: map['isDefault'] as bool ?? false,
       width: map['width'] as int ?? 0,