feat: per-slot Mirror in the camera settings (#226)

CHANGELOG.md

@@ -12,6 +12,12 @@ Versions after 2.17 are `MAJOR.MINOR.PATCH` (2.17 is followed by 2.17.1 or 2.18.
 `docs/testing.md`, "Versions and releases"); the headings below keep the numbers as they
 were released.
 
+## 2.18.0 — 2026-10-19
+
+- Mirror in the camera settings, next to Turn: flips the picture left to right in the single
+  view and the grid, for H.264, H.265 and MJPEG; a mirrored H.264/H.265 slot is drawn with
+  OpenGL ES (PR #246, closes #226).
+
 ## 2.17 — 2026-10-17
 
 - Turn in the camera settings (Auto, 0°, 90°, 180°, 270°), stored per slot; H.264/H.265 are

README.md

@@ -65,7 +65,7 @@ A beta channel is available on [Google Play](https://play.google.com/apps/intern
    ```
    rtsp://username:password@ip_address:554/stream=0
    ```
-   Under the URL you can choose the transport; Auto (UDP, falling back to TCP) is the default for a new slot. Below it, **Turn** turns the picture of a camera mounted sideways or upside down. Other URL types: [Transports](docs/transports.md).
+   Under the URL you can choose the transport; Auto (UDP, falling back to TCP) is the default for a new slot. Below it, **Turn** turns the picture of a camera mounted sideways or upside down, and **Mirror** flips it left to right. Other URL types: [Transports](docs/transports.md).
 4. Press **Save**. The app connects straight away and reconnects automatically if the stream drops.
 
 ## Controls

README.ru.md

@@ -65,7 +65,7 @@
    ```
    rtsp://username:password@ip_address:554/stream=0
    ```
-   Под адресом можно выбрать транспорт; у нового слота по умолчанию Auto (UDP с откатом на TCP). Ниже настройка **Turn** поворачивает картинку камеры, установленной боком или вверх ногами. Другие виды адресов — в [Transports](docs/transports.md) (на английском).
+   Под адресом можно выбрать транспорт; у нового слота по умолчанию Auto (UDP с откатом на TCP). Ниже настройка **Turn** поворачивает картинку камеры, установленной боком или вверх ногами, а **Mirror** отражает её слева направо. Другие виды адресов — в [Transports](docs/transports.md) (на английском).
 4. Нажмите **Save**. Приложение сразу подключится и само переподключится, если поток прервётся.
 
 ## Управление

README.zh-CN.md

@@ -65,7 +65,7 @@
    ```
    rtsp://username:password@ip_address:554/stream=0
    ```
-   地址下方可选择传输方式，新槽位默认为 Auto（优先 UDP，必要时回退到 TCP）。其下的 **Turn** 可旋转画面，适用于侧装或倒装的摄像机。其他地址格式见 [Transports](docs/transports.md)（英文）。
+   地址下方可选择传输方式，新槽位默认为 Auto（优先 UDP，必要时回退到 TCP）。其下的 **Turn** 可旋转画面，适用于侧装或倒装的摄像机；**Mirror** 可将画面左右镜像。其他地址格式见 [Transports](docs/transports.md)（英文）。
 4. 点击 **Save**。应用会立即连接；视频流中断时会自动重连。
 
 ## 操作说明

android/app/build.gradle

@@ -23,8 +23,8 @@ android {
         applicationId "com.openipc.decoder"
         minSdk 21
         targetSdk 36
-        versionCode 42
-        versionName "2.17"
+        versionCode 43
+        versionName "2.18.0"
 
         buildConfigField "String", "GIT_HASH", "\"${getGitHash()}\""
     }

android/app/src/main/java/com/openipc/decoder/Decoder.java

@@ -140,6 +140,8 @@ public class Decoder extends Activity
     private final Transport.Mode[] mTransports = new Transport.Mode[CAM_COUNT];
     /** Per slot (#201): degrees counter-clockwise, -1 for Auto (from the URL). */
     private final int[] mRotates = new int[CAM_COUNT];
+    /** Per slot (#226): the picture flipped left↔right. */
+    private final boolean[] mMirrors = new boolean[CAM_COUNT];
     private int mActive;
     private volatile String mHost;
     private String mVersion;
@@ -212,12 +214,9 @@ protected void onCreate(Bundle savedInstanceState) {
         // --- Create managers ---
         videoDecoder = new MediaCodecManager(new MediaCodecManager.Listener() {
             @Override public void onResolutionChanged(int w, int h) {
-                // The decoder turns the picture (#201, Android 6+ as in MediaCodecManager): a
-                // quarter turn swaps its sides
-                RtspClient c = rtspClient;
-                int r = c != null && Build.VERSION.SDK_INT >= Build.VERSION_CODES.M
-                        ? c.rotate() : 0;
-                if (r == 90 || r == 270) updateResolution(h, w);
+                // A quarter turn by the decoder (#201, Android 6+) or by the mirror's GL path
+                // (#226, any version) swaps the picture's sides
+                if (videoDecoder.swapsSides()) updateResolution(h, w);
                 else updateResolution(w, h);
             }
             @Override public void onDecoderStarted() { removeClearOverlay(); }
@@ -591,7 +590,7 @@ private void restartClean() {
 
     @Override
     public void onShowSettings() {
-        menuManager.showUrlEditor(mActive, mHosts, mTransports, mRotates);
+        menuManager.showUrlEditor(mActive, mHosts, mTransports, mRotates, mMirrors);
     }
 
     @Override
@@ -606,13 +605,17 @@ public void onShowSettings() {
     private void configureClient() {
         rtspClient.configure(mHost, mUserAgent, mTransports[mActive]);
         rtspClient.setSlotTurn(mRotates[mActive]);
+        rtspClient.setSlotMirror(mMirrors[mActive]);
     }
 
-    private void createDecoder() {
+    /** A decoder for the stream of video thread {@code gen}, with that stream's turn and mirror. */
+    private void createDecoder(int gen) {
         videoDecoder.setSurface(mVideoSurface);
         RtspClient c = rtspClient;
         videoDecoder.setRotation(c != null ? c.rotate() : 0);
-        videoDecoder.createDecoder(codecH265);
+        videoDecoder.setMirror(c != null && c.mirror());
+        // Restarted with new settings meanwhile: this decoder is dropped, the new thread makes one
+        videoDecoder.createDecoder(codecH265, () -> gen == listenerGen);
     }
 
     private void closeDecoder() { videoDecoder.closeDecoder(); }
@@ -652,6 +655,7 @@ private void loadSettings() {
             // Auto for a slot that has never stored one (#112)
             mTransports[i] = Transport.Mode.stored(pref.getString("transport_" + i, null));
             mRotates[i] = pref.getInt("rotate_" + i, -1);
+            mMirrors[i] = pref.getBoolean("mirror_" + i, false);
             // Plain URLs from older versions are re-saved encrypted right away
             if (credentials.needsMigration(stored)) {
                 if (migrate == null) migrate = pref.edit();
@@ -715,6 +719,7 @@ private void saveSettings() {
                     credentials.sealForSlot(mHosts[i], mUnreadable[i], DEFAULT_URL));
             edit.putString("transport_" + i, mTransports[i].name());
             edit.putInt("rotate_" + i, mRotates[i]);
+            edit.putBoolean("mirror_" + i, mMirrors[i]);
         }
         edit.apply();
 
@@ -1025,6 +1030,7 @@ private void createQuadCells() {
             quadCells[i] = new QuadCell(i, url, mode, quadViews[i], framePool, mUserAgent,
                     index -> runOnUiThread(() -> removeQuadOverlay(index)));
             quadCells[i].setSlotTurn(i < CAM_COUNT ? mRotates[i] : -1);
+            quadCells[i].setSlotMirror(i < CAM_COUNT && mMirrors[i]);
             quadCells[i].start();
         }
         quadAudio = getSharedPreferences("settings", MODE_PRIVATE).getInt("quad_audio", -1);
@@ -1629,6 +1635,10 @@ private Map<String, Object> debugState() {
             // Turned counter-clockwise, "size" is the turned one (#200, #201)
             int rotate = rtspClient != null ? rtspClient.rotate() : 0;
             if (rotate != 0) single.put("rotate", rotate);
+            if (rtspClient != null && rtspClient.mirror()) {
+                single.put("mirror", true);
+                if (videoDecoder.mirrorFailed()) single.put("mirror_failed", true);
+            }
             m.put("single", single);
         }
         QuadCell[] cells = quadCells;
@@ -1674,6 +1684,10 @@ private Map<String, Object> debugState() {
                     Map<String, Object> hb = cell.heartbeatStats();
                     if (hb != null) c.put("heartbeat", hb);
                     if (cell.rotate() != 0) c.put("rotate", cell.rotate());
+                    if (cell.mirror()) {
+                        c.put("mirror", true);
+                        if (cell.mirrorFailed()) c.put("mirror_failed", true);
+                    }
                 }
                 list.add(c);
             }
@@ -2291,7 +2305,7 @@ private boolean drawJpeg(Frame frame, int gen) {
         Surface s = mVideoSurface;
         RtspClient client = rtspClient;
         int rotate = client != null ? client.rotate() : 0;
-        int[] size = jpegRenderer.render(frame, s, rotate,
+        int[] size = jpegRenderer.render(frame, s, rotate, client != null && client.mirror(),
                 () -> gen == listenerGen && s == mVideoSurface);
         if (size != null) jpegShown(size[0], size[1]);
         return size != null;
@@ -2380,7 +2394,13 @@ && drawJpeg(buffer, gen)) {
                         framePool.recycle(buffer);
                     } else if (buffer != null) {
                         if (videoDecoder.decodeFrame(buffer, codecH265, 0)) {
-                            createDecoder();
+                            // Restarted meanwhile (new settings): the new thread makes the
+                            // decoder, with the new turn and mirror (#226)
+                            if (gen != listenerGen) {
+                                framePool.recycle(buffer);
+                                break;
+                            }
+                            createDecoder(gen);
                             // The frame that triggered creation (often the SPS) goes in too
                             videoDecoder.decodeFrame(buffer, codecH265, 0);
                         }