Allow Media3 decoder fallback for Dolby Vision input

app/build.gradle.kts

@@ -40,6 +40,9 @@ android {
         compose = true
         buildConfig = true
     }
+    testOptions {
+        unitTests.isIncludeAndroidResources = true
+    }
     dependenciesInfo {
         includeInBundle = false
         includeInApk = false
@@ -76,4 +79,4 @@ dependencies {
     androidTestImplementation(libs.androidx.compose.ui.test.junit4)
     debugImplementation(libs.androidx.compose.ui.tooling)
     debugImplementation(libs.androidx.compose.ui.test.manifest)
-}
+}

app/src/main/java/compressedge/joshattic/us/viewmodel/CompressorViewModel.kt

@@ -1939,7 +1939,14 @@ class CompressorViewModel(application: Application) : AndroidViewModel(applicati
         val sourceHeight = sourceInfo?.height ?: state.originalHeight
         val sourceFps = if ((sourceInfo?.frameRate ?: 0f) > 0f) sourceInfo!!.frameRate else state.originalFps
 
-        if (!sourceMime.isNullOrBlank() && sourceWidth > 0 && sourceHeight > 0) {
+        // Dolby Vision may have an HEVC-compatible base layer even when the device
+        // advertises no video/dolby-vision decoder. Let Media3 inspect the actual
+        // profile and select a compatible decoder; an exact MIME check here would
+        // reject the file before DefaultDecoderFactory can try that fallback.
+        // Keep the original format intact so Media3 can validate compatibility.
+        if (!sourceMime.isNullOrBlank() && sourceWidth > 0 && sourceHeight > 0 &&
+            sourceMime != MimeTypes.VIDEO_DOLBY_VISION
+        ) {
             val decoderSupported = isCodecConfigurationSupported(
                 mimeType = sourceMime,
                 width = sourceWidth,

app/src/test/java/compressedge/joshattic/us/viewmodel/CompressorViewModelTest.kt

@@ -1,6 +1,10 @@
 package compressedge.joshattic.us.viewmodel
 
 import android.app.Application
+import android.content.Context
+import android.media.MediaCodecList
+import android.media.MediaExtractor
+import android.net.Uri
 import androidx.media3.common.MimeTypes
 import androidx.test.core.app.ApplicationProvider
 import compressedge.joshattic.us.model.CompressorUiState
@@ -10,6 +14,8 @@ import org.junit.Assert.*
 import org.junit.Before
 import org.junit.Test
 import org.junit.runner.RunWith
+import org.mockito.Mockito.mockConstruction
+import org.mockito.Mockito.`when`
 import org.robolectric.RobolectricTestRunner
 import org.robolectric.annotation.Config
 
@@ -110,6 +116,46 @@ class CompressorViewModelTest {
         assertEquals(QualityPreset.CUSTOM, viewModel.uiState.value.activePreset)
     }
 
+    @Test
+    fun dolbyVisionWithoutAdvertisedDecoderReachesOutputPlanning() {
+        val error = planWithNoAdvertisedCodecs(MimeTypes.VIDEO_DOLBY_VISION)
+        assertTrue(error.startsWith("This device can't encode"))
+    }
+
+    @Test
+    fun unsupportedHevcStillReportsDecoderFailure() {
+        val error = planWithNoAdvertisedCodecs(MimeTypes.VIDEO_H265)
+        assertEquals(
+            application.getString(
+                compressedge.joshattic.us.R.string.error_decoder_config_unsupported_details,
+                3840, 2160, 60f, "hevc"
+            ),
+            error
+        )
+    }
+
+    private fun planWithNoAdvertisedCodecs(sourceMime: String): String {
+        // Model the failing phone: no decoder advertises Dolby Vision. A source
+        // probe with no tracks falls back to the metadata already in UI state.
+        mockConstruction(MediaExtractor::class.java).use {
+            mockConstruction(MediaCodecList::class.java) { codecList, _ ->
+                `when`(codecList.codecInfos).thenReturn(emptyArray())
+            }.use {
+                val method = CompressorViewModel::class.java.getDeclaredMethod(
+                    "buildCompressionPlan", Context::class.java, CompressorUiState::class.java,
+                    Uri::class.java, Int::class.javaPrimitiveType, Int::class.javaPrimitiveType
+                ).apply { isAccessible = true }
+                val state = CompressorUiState(
+                    originalVideoMime = sourceMime, originalWidth = 3840,
+                    originalHeight = 2160, originalFps = 60f
+                )
+                val plan = method.invoke(viewModel, application, state, Uri.EMPTY, 2160, 0)
+                return plan.javaClass.getDeclaredMethod("getBlockingError")
+                    .apply { isAccessible = true }.invoke(plan) as String
+            }
+        }
+    }
+
     @Test
     fun testCompressedOutputFileName() {
         val state = CompressorUiState(