diff --git a/android/app/src/main/java/com/openipc/decoder/CodecInfo.java b/android/app/src/main/java/com/openipc/decoder/CodecInfo.java
new file mode 100644
index 00000000..c7e5e6f4
--- /dev/null
+++ b/android/app/src/main/java/com/openipc/decoder/CodecInfo.java
@@ -0,0 +1,88 @@
+/*
+ * Copyright (c) OpenIPC  https://openipc.org  Prosperity Public License 3.0.0
+ *
+ * CodecInfo.java — the device's video decoders and their abilities, for /stats.json (#88)
+ *
+ */
+
+package com.openipc.decoder;
+
+import android.media.MediaCodecInfo;
+import android.media.MediaCodecList;
+import android.os.Build;
+
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * What a shared key-frame decoder (#88) would rely on, per video decoder: the instance limit,
+ * adaptive playback (a new size mid-stream without a reconfigure) and the 1080p frame rate it
+ * declares. Built once; it does not change while the app runs.
+ */
+final class CodecInfo {
+    private static volatile List<Map<String, Object>> cached;
+
+    private CodecInfo() {}
+
+    /** The list, or null while it is still being built (Qodo on #137: never on the UI thread). */
+    static List<Map<String, Object>> videoDecodersIfReady() {
+        return cached;
+    }
+
+    /** Builds the list on a background thread, once. */
+    static void warmUp() {
+        if (cached != null) return;
+        Thread t = new Thread(CodecInfo::videoDecoders, "codec-info");
+        t.setDaemon(true);
+        t.start();
+    }
+
+    static synchronized List<Map<String, Object>> videoDecoders() {
+        List<Map<String, Object>> c = cached;
+        if (c != null) return c;
+        List<Map<String, Object>> out = new ArrayList<>();
+        MediaCodecInfo[] infos;
+        try {
+            infos = new MediaCodecList(MediaCodecList.ALL_CODECS).getCodecInfos();
+        } catch (RuntimeException e) {
+            return out; // not cached: the next request tries again
+        }
+        for (MediaCodecInfo ci : infos) {
+            // One broken entry must not hide the others (Qodo on #137)
+            try {
+                if (ci.isEncoder()) continue;
+                for (String type : ci.getSupportedTypes()) {
+                    if (!type.startsWith("video/")) continue;
+                    Map<String, Object> m = new LinkedHashMap<>();
+                    m.put("name", ci.getName());
+                    m.put("type", type);
+                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
+                        m.put("hardware", ci.isHardwareAccelerated());
+                    }
+                    try {
+                        MediaCodecInfo.CodecCapabilities caps = ci.getCapabilitiesForType(type);
+                        m.put("adaptive", caps.isFeatureSupported(
+                                MediaCodecInfo.CodecCapabilities.FEATURE_AdaptivePlayback));
+                        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+                            m.put("max_instances", caps.getMaxSupportedInstances());
+                        }
+                        MediaCodecInfo.VideoCapabilities v = caps.getVideoCapabilities();
+                        if (v != null && v.isSizeSupported(1920, 1080)) {
+                            m.put("fps_1080p", Math.round(
+                                    v.getSupportedFrameRatesFor(1920, 1080).getUpper()));
+                        }
+                    } catch (RuntimeException ignored) {
+                        // Capabilities of a broken entry: the name and type are still worth it
+                    }
+                    out.add(m);
+                }
+            } catch (RuntimeException ignored) {
+                // Skip this codec
+            }
+        }
+        cached = out;
+        return out;
+    }
+}
diff --git a/android/app/src/main/java/com/openipc/decoder/Decoder.java b/android/app/src/main/java/com/openipc/decoder/Decoder.java
index c97230d9..caa5836a 100755
--- a/android/app/src/main/java/com/openipc/decoder/Decoder.java
+++ b/android/app/src/main/java/com/openipc/decoder/Decoder.java
@@ -181,6 +181,8 @@ protected void onCreate(Bundle savedInstanceState) {
         mUserAgent = "User-Agent: OpenIPC-Decoder/" + mVersion + "\r\n";
         mDensity = getResources().getDisplayMetrics().density;
         credentials = CredentialStore.create();
+        // The decoder list for /stats.json, built off the UI thread (#88)
+        CodecInfo.warmUp();
 
         // --- Create managers ---
         videoDecoder = new MediaCodecManager(new MediaCodecManager.Listener() {
@@ -1331,6 +1333,9 @@ private Map<String, Object> debugDevice() {
         for (String ip : NetInfo.addresses()) urls.add("http://" + ip + ":" + DebugServer.PORT + "/");
         m.put("addresses", urls);
         m.put("server", DebugServer.get().state());
+        // The video decoders and what they can do: instances, adaptive playback (#88)
+        List<Map<String, Object>> decoders = CodecInfo.videoDecodersIfReady();
+        m.put("decoders", decoders != null ? decoders : "loading");
         return m;
     }