Disable default stdout/stderr for Xiaomi devices

Xiaomi device ROMs print internal errors using e.printStackTRace(),
flooding the console with irrelevant errors.

To get rid of them, on Xiaomi devices, trash the messages printed to the
console by direct calls to System.out and System.err.

Refs #994 <https://github.com/Genymobile/scrcpy/issues/994>
Refs #4213 <https://github.com/Genymobile/scrcpy/pull/4213>

README.md

@@ -25,12 +25,13 @@ It focuses on:
 [lowlatency]: https://github.com/Genymobile/scrcpy/pull/646
 
 Its features include:
- - [audio forwarding](doc/audio.md) (Android >= 11)
+ - [audio forwarding](doc/audio.md) (Android 11+)
  - [recording](doc/recording.md)
  - mirroring with [Android device screen off](doc/device.md#turn-screen-off)
  - [copy-paste](doc/control.md#copy-paste) in both directions
  - [configurable quality](doc/video.md)
- - Android device screen [as a webcam (V4L2)](doc/v4l2.md) (Linux-only)
+ - [camera mirroring](doc/camera.md) (Android 12+)
+ - [mirroring as a webcam (V4L2)](doc/v4l2.md) (Linux-only)
  - [physical keyboard/mouse simulation (HID)](doc/hid-otg.md)
  - [OTG mode](doc/hid-otg.md#otg)
  - and more…
@@ -77,6 +78,7 @@ documented in the following pages:
  - [Recording](doc/recording.md)
  - [Tunnels](doc/tunnels.md)
  - [HID/OTG](doc/hid-otg.md)
+ - [Camera](doc/camera.md)
  - [Video4Linux](doc/v4l2.md)
  - [Shortcuts](doc/shortcuts.md)
 

app/scrcpy.1

@@ -45,15 +45,15 @@ Set a list of comma-separated key:type=value options for the device audio encode
 
 The possible values for 'type' are 'int' (default), 'long', 'float' and 'string'.
 
-The list of possible codec options is available in the Android documentation
-.UR https://d.android.com/reference/android/media/MediaFormat
-.UE .
+The list of possible codec options is available in the Android documentation:
+
+<https://d.android.com/reference/android/media/MediaFormat>
 
 .TP
 .BI "\-\-audio\-encoder " name
 Use a specific MediaCodec audio encoder (depending on the codec provided by \fB\-\-audio\-codec\fR).
 
-The available encoders can be listed by \-\-list\-encoders.
+The available encoders can be listed by \fB\-\-list\-encoders\fR.
 
 .TP
 .BI "\-\-audio\-source " source
@@ -79,19 +79,19 @@ Default is 8M (8000000).
 .BI "\-\-camera\-ar " ar
 Select the camera size by its aspect ratio (+/- 10%).
 
-Possible values are "sensor" (use the camera sensor aspect ratio), "<num>:<den>" (e.g. "4:3") and "<value>" (e.g. "1.6").
+Possible values are "sensor" (use the camera sensor aspect ratio), "\fInum\fR:\fIden\fR" (e.g. "4:3") and "\fIvalue\fR" (e.g. "1.6").
 
 .TP
 .B \-\-camera\-high\-speed
 Enable high-speed camera capture mode.
 
-This mode is restricted to specific resolutions and frame rates, listed by --list-camera-sizes.
+This mode is restricted to specific resolutions and frame rates, listed by \fB\-\-list\-camera\-sizes\fR.
 
 .TP
 .BI "\-\-camera\-id " id
 Specify the device camera id to mirror.
 
-The available camera ids can be listed by \-\-list\-cameras.
+The available camera ids can be listed by \fB\-\-list\-cameras\fR.
 
 .TP
 .BI "\-\-camera\-facing " facing
@@ -131,7 +131,7 @@ Disable screensaver while scrcpy is running.
 .BI "\-\-display\-id " id
 Specify the device display id to mirror.
 
-The available display ids can be listed by \-\-list\-displays.
+The available display ids can be listed by \fB\-\-list\-displays\fR.
 
 Default is 0.
 
@@ -189,9 +189,11 @@ Inject computer clipboard text as a sequence of key events on Ctrl+v (like MOD+S
 
 This is a workaround for some devices not behaving as expected when setting the device clipboard programmatically.
 
+.TP
 .B \-\-list\-camera\-sizes
 List the valid camera capture sizes.
 
+.TP
 .B \-\-list\-cameras
 List cameras available on the device.
 
@@ -239,7 +241,7 @@ Disable device control (mirror the device in read\-only).
 
 .TP
 .B \-N, \-\-no\-playback
-Disable video and audio playback on the computer (equivalent to --no-video-playback --no-audio-playback).
+Disable video and audio playback on the computer (equivalent to \fB\-\-no\-video\-playback \-\-no\-audio\-playback\fR).
 
 .TP
 .B \-\-no\-audio
@@ -361,8 +363,7 @@ Request SDL to use the given render driver (this is just a hint).
 
 Supported names are currently "direct3d", "opengl", "opengles2", "opengles", "metal" and "software".
 
-.UR https://wiki.libsdl.org/SDL_HINT_RENDER_DRIVER
-.UE
+<https://wiki.libsdl.org/SDL_HINT_RENDER_DRIVER>
 
 .TP
 .B \-\-require\-audio
@@ -410,13 +411,13 @@ Set the maximum mirroring time, in seconds.
 
 .TP
 .BI "\-\-tunnel\-host " ip
-Set the IP address of the adb tunnel to reach the scrcpy server. This option automatically enables --force-adb-forward.
+Set the IP address of the adb tunnel to reach the scrcpy server. This option automatically enables \fB\-\-force\-adb\-forward\fR.
 
 Default is localhost.
 
 .TP
 .BI "\-\-tunnel\-port " port
-Set the TCP port of the adb tunnel to reach the scrcpy server. This option automatically enables --force-adb-forward.
+Set the TCP port of the adb tunnel to reach the scrcpy server. This option automatically enables \fB\-\-force\-adb\-forward\fR.
 
 Default is 0 (not forced): the local port used for establishing the tunnel will be used.
 
@@ -456,15 +457,15 @@ Set a list of comma-separated key:type=value options for the device video encode
 
 The possible values for 'type' are 'int' (default), 'long', 'float' and 'string'.
 
-The list of possible codec options is available in the Android documentation
-.UR https://d.android.com/reference/android/media/MediaFormat
-.UE .
+The list of possible codec options is available in the Android documentation:
+
+<https://d.android.com/reference/android/media/MediaFormat>
 
 .TP
 .BI "\-\-video\-encoder " name
 Use a specific MediaCodec video encoder (depending on the codec provided by \fB\-\-video\-codec\fR).
 
-The available encoders can be listed by \-\-list\-encoders.
+The available encoders can be listed by \fB\-\-list\-encoders\fR.
 
 .TP
 .BI "\-\-video\-source " source
@@ -634,7 +635,7 @@ Path to adb.
 
 .TP
 .B ANDROID_SERIAL
-Device serial to use if no selector (-s, -d, -e or --tcpip=<addr>) is specified.
+Device serial to use if no selector (\fB-s\fR, \fB-d\fR, \fB-e\fR or \fB\-\-tcpip=\fIaddr\fR) is specified.
 
 .TP
 .B SCRCPY_ICON_PATH
@@ -657,23 +658,14 @@ for the Debian Project (and may be used by others).
 
 
 .SH "REPORTING BUGS"
-Report bugs to
-.UR https://github.com/Genymobile/scrcpy/issues
-.UE .
+Report bugs to <https://github.com/Genymobile/scrcpy/issues>.
 
 .SH COPYRIGHT
-Copyright \(co 2018 Genymobile
-.UR https://www.genymobile.com
-Genymobile
-.UE
+Copyright \(co 2018 Genymobile <https://www.genymobile.com>
 
-Copyright \(co 2018\-2023
-.MT rom@rom1v.com
-Romain Vimont
-.ME
+Copyright \(co 2018\-2023 Romain Vimont <rom@rom1v.com>
 
 Licensed under the Apache License, Version 2.0.
 
 .SH WWW
-.UR https://github.com/Genymobile/scrcpy
-.UE
+<https://github.com/Genymobile/scrcpy>

app/src/cli.c

@@ -2296,7 +2296,7 @@ parse_args_with_getopt(struct scrcpy_cli_args *args, int argc, char *argv[],
         }
 
         if (opts->camera_size) {
-            if (opts->camera_ar) {
+            if (opts->max_size) {
                 LOGE("Could not specify both --camera-size and -m/--max-size");
                 return false;
             }

doc/camera.md

@@ -0,0 +1,150 @@
+# Camera
+
+Camera mirroring is supported for devices with Android 12 or higher.
+
+To capture the camera instead of the device screen:
+
+```
+scrcpy --video-source=camera
+```
+
+By default, it automatically switches [audio source](audio.md#source) to
+microphone (as if `--audio-source=mic` were also passed).
+
+```bash
+scrcpy --video-source=display  # default is --audio-source=output
+scrcpy --video-source=camera   # default is --audio-source=mic
+scrcpy --video-source=display --audio-source=mic    # force display AND microphone
+scrcpy --video-source=camera --audio-source=output  # force camera AND device audio output
+```
+
+
+## List
+
+To list the cameras available (with their declared valid sizes and frame rates):
+
+```
+scrcpy --list-cameras
+scrcpy --list-camera-sizes
+```
+
+_Note that the sizes and frame rates are declarative. They are not accurate on
+all devices: some of them are declared but not supported, while some others are
+not declared but supported._
+
+
+## Selection
+
+It is possible to pass an explicit camera id (as listed by `--list-cameras`):
+
+```
+scrcpy --video-source=camera --camera-id=0
+```
+
+Alternatively, the camera may be selected automatically:
+
+```bash
+scrcpy --video-source=camera                           # use the first camera
+scrcpy --video-source=camera --camera-facing=front     # use the first front camera
+scrcpy --video-source=camera --camera-facing=back      # use the first back camera
+scrcpy --video-source=camera --camera-facing=external  # use the first external camera
+```
+
+If `--camera-id` is specified, then `--camera-facing` is forbidden (the id
+already determines the camera):
+
+```bash
+scrcpy --video-source=camera --camera-id=0 --camera-facing=front  # error
+```
+
+
+### Size selection
+
+It is possible to pass an explicit camera size:
+
+```
+scrcpy --video-source=camera --camera-size=1920x1080
+```
+
+The given size may be listed among the declared valid sizes
+(`--list-camera-sizes`), but may also be anything else (some devices support
+arbitrary sizes):
+
+```
+scrcpy --video-source=camera --camera-size=1840x444
+```
+
+Alternatively, a declared valid size (among the ones listed by
+`list-camera-sizes`) may be selected automatically.
+
+Two constraints are supported:
+ - `-m`/`--max-size` (already used for display mirroring), for example `-m1920`;
+ - `--camera-ar` to specify an aspect ratio (`<num>:<den>`, `<value>` or
+   `sensor`).
+
+Some examples:
+
+```bash
+scrcpy --video-source=camera                          # use the greatest width and the greatest associated height
+scrcpy --video-source=camera -m1920                   # use the greatest width not above 1920 and the greatest associated height
+scrcpy --video-source=camera --camera-ar=4:3          # use the greatest size with an aspect ratio of 4:3 (+/- 10%)
+scrcpy --video-source=camera --camera-ar=1.6          # use the greatest size with an aspect ratio of 1.6 (+/- 10%)
+scrcpy --video-source=camera --camera-ar=sensor       # use the greatest size with the aspect ratio of the camera sensor (+/- 10%)
+scrcpy --video-source=camera -m1920 --camera-ar=16:9  # use the greatest width not above 1920 and the closest to 16:9 aspect ratio
+```
+
+If `--camera-size` is specified, then `-m`/`--max-size` and `--camera-ar` are
+forbidden (the size is determined by the value given explicitly):
+
+```bash
+scrcpy --video-source=camera --camera-size=1920x1080 -m3000  # error
+```
+
+
+## Frame rate
+
+By default, camera is captured at Android's default frame rate (30 fps).
+
+To configure a different frame rate:
+
+```
+scrcpy --video-source=camera --camera-fps=60
+```
+
+
+## High speed capture
+
+The Android camera API also supports a [high speed capture mode][high speed].
+
+This mode is restricted to specific resolutions and frame rates, listed by
+`--list-camera-sizes`.
+
+```
+scrcpy --video-source=camera --camera-size=1920x1080 --camera-fps=240
+```
+
+[high speed]: https://developer.android.com/reference/android/hardware/camera2/CameraConstrainedHighSpeedCaptureSession
+
+
+## Brace expansion tip
+
+All camera options start with `--camera-`, so if your shell supports it, you can
+benefit from [brace expansion] (for example, it is supported _bash_ and _zsh_):
+
+```bash
+scrcpy --video-source=camera --camera-{facing=back,ar=16:9,high-speed,fps=120}
+```
+
+This will be expanded as:
+
+```bash
+scrcpy --video-source=camera --camera-facing=back --camera-ar=16:9 --camera-high-speed --camera-fps=120
+```
+
+[brace expansion]: https://www.gnu.org/software/bash/manual/html_node/Brace-Expansion.html
+
+
+## Webcam
+
+Combined with the [V4L2](v4l2.md) feature on Linux, the Android device camera
+may be used as a webcam on the computer.

doc/video.md

@@ -1,5 +1,14 @@
 # Video
 
+## Source
+
+By default, scrcpy mirrors the device screen.
+
+It is possible to capture the device camera instead.
+
+See the dedicated [camera](camera.md) page.
+
+
 ## Size
 
 By default, scrcpy attempts to mirror at the Android device resolution.

server/src/main/java/com/genymobile/scrcpy/CameraCapture.java

@@ -227,7 +227,7 @@ public class CameraCapture extends SurfaceCapture {
         this.maxSize = maxSize;
         try {
             size = selectSize(cameraId, null, maxSize, aspectRatio, highSpeed);
-            return true;
+            return size != null;
         } catch (CameraAccessException e) {
             Ln.w("Could not select camera size", e);
             return false;

server/src/main/java/com/genymobile/scrcpy/CameraFacing.java

@@ -1,10 +1,12 @@
 package com.genymobile.scrcpy;
 
+import android.annotation.SuppressLint;
 import android.hardware.camera2.CameraCharacteristics;
 
 public enum CameraFacing {
     FRONT("front", CameraCharacteristics.LENS_FACING_FRONT),
     BACK("back", CameraCharacteristics.LENS_FACING_BACK),
+    @SuppressLint("InlinedApi") // introduced in API 23
     EXTERNAL("external", CameraCharacteristics.LENS_FACING_EXTERNAL);
 
     private final String name;

server/src/main/java/com/genymobile/scrcpy/Ln.java

@@ -8,6 +8,11 @@ import android.util.Log;
  */
 public final class Ln {
 
+    public interface ConsolePrinter {
+        void printOut(String message);
+        void printErr(String message, Throwable throwable);
+    }
+
     private static final String TAG = "scrcpy";
     private static final String PREFIX = "[server] ";
 
@@ -15,12 +20,17 @@ public final class Ln {
         VERBOSE, DEBUG, INFO, WARN, ERROR
     }
 
+    private static ConsolePrinter consolePrinter = new DefaultConsolePrinter();
     private static Level threshold = Level.INFO;
 
     private Ln() {
         // not instantiable
     }
 
+    public static void setConsolePrinter(ConsolePrinter consolePrinter) {
+        Ln.consolePrinter = consolePrinter;
+    }
+
     /**
      * Initialize the log level.
      * <p>
@@ -39,31 +49,28 @@ public final class Ln {
     public static void v(String message) {
         if (isEnabled(Level.VERBOSE)) {
             Log.v(TAG, message);
-            System.out.print(PREFIX + "VERBOSE: " + message + '\n');
+            consolePrinter.printOut(PREFIX + "VERBOSE: " + message + '\n');
         }
     }
 
     public static void d(String message) {
         if (isEnabled(Level.DEBUG)) {
             Log.d(TAG, message);
-            System.out.print(PREFIX + "DEBUG: " + message + '\n');
+            consolePrinter.printOut(PREFIX + "DEBUG: " + message + '\n');
         }
     }
 
     public static void i(String message) {
         if (isEnabled(Level.INFO)) {
             Log.i(TAG, message);
-            System.out.print(PREFIX + "INFO: " + message + '\n');
+            consolePrinter.printOut(PREFIX + "INFO: " + message + '\n');
         }
     }
 
     public static void w(String message, Throwable throwable) {
         if (isEnabled(Level.WARN)) {
             Log.w(TAG, message, throwable);
-            System.err.print(PREFIX + "WARN: " + message + '\n');
-            if (throwable != null) {
-                throwable.printStackTrace();
-            }
+            consolePrinter.printErr(PREFIX + "WARN: " + message + '\n', throwable);
         }
     }
 
@@ -74,14 +81,26 @@ public final class Ln {
     public static void e(String message, Throwable throwable) {
         if (isEnabled(Level.ERROR)) {
             Log.e(TAG, message, throwable);
-            System.err.print(PREFIX + "ERROR: " + message + "\n");
-            if (throwable != null) {
-                throwable.printStackTrace();
-            }
+            consolePrinter.printErr(PREFIX + "ERROR: " + message + '\n', throwable);
         }
     }
 
     public static void e(String message) {
         e(message, null);
     }
+
+    public static class DefaultConsolePrinter implements ConsolePrinter {
+        @Override
+        public void printOut(String message) {
+            System.out.print(message);
+        }
+
+        @Override
+        public void printErr(String message, Throwable throwable) {
+            System.err.print(message);
+            if (throwable != null) {
+                throwable.printStackTrace();
+            }
+        }
+    }
 }

server/src/main/java/com/genymobile/scrcpy/LogUtils.java

@@ -11,9 +11,7 @@ import android.hardware.camera2.params.StreamConfigurationMap;
 import android.media.MediaCodec;
 import android.util.Range;
 
-import java.util.Arrays;
 import java.util.List;
-import java.util.Set;
 import java.util.SortedSet;
 import java.util.TreeSet;
 

server/src/main/java/com/genymobile/scrcpy/ScreenCapture.java

@@ -48,8 +48,8 @@ public class ScreenCapture extends SurfaceCapture implements Device.RotationList
     }
 
     @Override
-    public boolean setMaxSize(int size) {
-        device.setMaxSize(size);
+    public boolean setMaxSize(int maxSize) {
+        device.setMaxSize(maxSize);
         return true;
     }
 

server/src/main/java/com/genymobile/scrcpy/Server.java

@@ -87,8 +87,6 @@ public final class Server {
     }
 
     private static void scrcpy(Options options) throws IOException, ConfigurationException {
-        Ln.i("Device: [" + Build.MANUFACTURER + "] " + Build.BRAND + " " + Build.MODEL + " (Android " + Build.VERSION.RELEASE + ")");
-
         if (Build.VERSION.SDK_INT < Build.VERSION_CODES.S && options.getVideoSource() == VideoSource.CAMERA) {
             Ln.e("Camera mirroring is not supported before Android 12");
             throw new ConfigurationException("Camera mirroring is not supported");
@@ -104,8 +102,8 @@ public final class Server {
         boolean video = options.getVideo();
         boolean audio = options.getAudio();
         boolean sendDummyByte = options.getSendDummyByte();
+        boolean camera = options.getVideoSource() == VideoSource.CAMERA;
 
-        boolean camera = true;
         Workarounds.apply(audio, camera);
 
         List<AsyncProcessor> asyncProcessors = new ArrayList<>();
@@ -208,6 +206,8 @@ public final class Server {
 
         Ln.initLogLevel(options.getLogLevel());
 
+        Ln.i("Device: [" + Build.MANUFACTURER + "] " + Build.BRAND + " " + Build.MODEL + " (Android " + Build.VERSION.RELEASE + ")");
+
         if (options.getList()) {
             if (options.getCleanup()) {
                 CleanUp.unlinkSelf();

server/src/main/java/com/genymobile/scrcpy/SurfaceCapture.java

@@ -56,9 +56,9 @@ public abstract class SurfaceCapture {
     /**
      * Set the maximum capture size (set by the encoder if it does not support the current size).
      *
-     * @param size Maximum size
+     * @param maxSize Maximum size
      */
-    public abstract boolean setMaxSize(int size);
+    public abstract boolean setMaxSize(int maxSize);
 
     /**
      * Indicate if the capture has been closed internally.

server/src/main/java/com/genymobile/scrcpy/VideoCodec.java

@@ -6,7 +6,7 @@ import android.media.MediaFormat;
 public enum VideoCodec implements Codec {
     H264(0x68_32_36_34, "h264", MediaFormat.MIMETYPE_VIDEO_AVC),
     H265(0x68_32_36_35, "h265", MediaFormat.MIMETYPE_VIDEO_HEVC),
-    @SuppressLint("InlinedApi") // introduced in API 21
+    @SuppressLint("InlinedApi") // introduced in API 29
     AV1(0x00_61_76_31, "av1", MediaFormat.MIMETYPE_VIDEO_AV1);
 
     private final int id; // 4-byte ASCII representation of the name

server/src/main/java/com/genymobile/scrcpy/Workarounds.java

@@ -14,6 +14,12 @@ import android.os.Build;
 import android.os.Looper;
 import android.os.Parcel;
 
+import java.io.FileDescriptor;
+import java.io.FileOutputStream;
+import java.io.OutputStream;
+import java.io.PrintStream;
+import java.io.PrintWriter;
+import java.io.StringWriter;
 import java.lang.ref.WeakReference;
 import java.lang.reflect.Constructor;
 import java.lang.reflect.Field;
@@ -55,6 +61,12 @@ public final class Workarounds {
             mustFillAppInfo = true;
             mustFillBaseContext = true;
             mustFillAppContext = true;
+        } else if (Build.MANUFACTURER.equalsIgnoreCase("xiaomi")) {
+            // Trash the messages printed to the console by direct calls to System.out and System.err.
+            // Xiaomi device ROMs may print internal errors using e.printStackTrace(), flooding the console with irrelevant errors.
+            ExclusiveConsolePrinter exclusiveConsolePrinter = new ExclusiveConsolePrinter();
+            exclusiveConsolePrinter.installNullSystemStreams();
+            Ln.setConsolePrinter(new ExclusiveConsolePrinter());
         }
 
         if (audio && Build.VERSION.SDK_INT == Build.VERSION_CODES.R) {
@@ -306,4 +318,48 @@ public final class Workarounds {
             throw new RuntimeException("Cannot create AudioRecord");
         }
     }
+
+    static class ExclusiveConsolePrinter implements Ln.ConsolePrinter {
+
+        static class NullOutputStream extends OutputStream {
+            @Override
+            public void write(byte[] b) {
+                // ignore
+            }
+
+            @Override
+            public void write(byte[] b, int off, int len) {
+                // ignore
+            }
+
+            @Override
+            public void write(int b) {
+                // ignore
+            }
+        }
+
+        private final PrintStream realOut = new PrintStream(new FileOutputStream(FileDescriptor.out));
+        private final PrintStream realErr = new PrintStream(new FileOutputStream(FileDescriptor.err));
+
+        void installNullSystemStreams() {
+            PrintStream nullStream = new PrintStream(new NullOutputStream());
+            System.setOut(nullStream);
+            System.setErr(nullStream);
+        }
+
+        @Override
+        public void printOut(String message) {
+            realOut.print(message);
+        }
+
+        @Override
+        public void printErr(String message, Throwable throwable) {
+            realErr.print(message);
+            if (throwable != null) {
+                StringWriter errors = new StringWriter();
+                throwable.printStackTrace(new PrintWriter(errors));
+                realErr.print(errors);
+            }
+        }
+    }
 }