Allow Media3 decoder fallback for Dolby Vision input

app/build.gradle.kts

@@ -39,6 +39,9 @@ android {
     }
     // Built-in Kotlin derives the Kotlin jvmTarget from compileOptions, so the
     // deprecated kotlinOptions block is no longer needed.
+    testOptions {
+        unitTests.isIncludeAndroidResources = true
+    }
     buildFeatures {
         compose = true
         buildConfig = true

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

@@ -1636,7 +1636,14 @@ class CompressorViewModel(application: Application) : AndroidViewModel(applicati
         val sourceHeight = sourceInfo?.height ?: 0
         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/compress/joshattic/us/viewmodel/CompressorViewModelTest.kt

@@ -1,6 +1,7 @@
 package compress.joshattic.us.viewmodel
 
 import android.app.Application
+import android.media.MediaCodecList
 import androidx.media3.common.MimeTypes
 import androidx.test.core.app.ApplicationProvider
 import compress.joshattic.us.model.CompressorUiState
@@ -110,6 +111,53 @@ 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(
+                compress.joshattic.us.R.string.error_decoder_config_unsupported_details,
+                3840, 2160, 60f, "hevc"
+            ),
+            error
+        )
+    }
+
+    private fun planWithNoAdvertisedCodecs(sourceMime: String): String {
+        // With no advertised decoders, Dolby Vision should still reach output
+        // planning so Media3 can later validate the profile and try HEVC fallback.
+        assertTrue(MediaCodecList(MediaCodecList.ALL_CODECS).codecInfos.isEmpty())
+        val videoInfoClass = CompressorViewModel::class.java.declaredClasses
+            .single { it.simpleName == "VideoTrackInfo" }
+        val videoInfo = videoInfoClass.getDeclaredConstructor(
+            String::class.java, Int::class.javaPrimitiveType,
+            Int::class.javaPrimitiveType, Float::class.javaPrimitiveType
+        ).apply { isAccessible = true }.newInstance(sourceMime, 3840, 2160, 60f)
+        val probeClass = CompressorViewModel::class.java.declaredClasses
+            .single { it.simpleName == "TrackProbe" }
+        val probe = probeClass.getDeclaredConstructor(
+            videoInfoClass, String::class.java,
+            Int::class.javaPrimitiveType, Int::class.javaPrimitiveType
+        ).apply { isAccessible = true }.newInstance(videoInfo, null, 0, -1)
+        val method = CompressorViewModel::class.java.getDeclaredMethod(
+            "buildCompressionPlan", probeClass, CompressorUiState::class.java
+        ).apply { isAccessible = true }
+        val state = CompressorUiState(
+            originalVideoMime = sourceMime, originalWidth = 3840,
+            originalHeight = 2160, originalFps = 60f,
+            targetResolutionHeight = 2160, targetFps = 0
+        )
+        val plan = method.invoke(viewModel, probe, state)
+        return plan.javaClass.getDeclaredMethod("getBlockingError")
+            .apply { isAccessible = true }.invoke(plan) as String
+    }
+
     @Test
     fun testCompressedOutputFileName() {
         val state = CompressorUiState(