Show a friendly hint for adb installation

Signed-off-by: Romain Vimont <rom@rom1v.com>

DEVELOP.md

@@ -189,7 +189,7 @@ The client uses 4 threads:
    recording,
  - the **controller** thread, sending _control messages_ to the server,
  - the **receiver** thread (managed by the controller), receiving _device
-   messages_ from the server.
+   messages_ from the client.
 
 In addition, another thread can be started if necessary to handle APK
 installation or file push requests (via drag&drop on the main window) or to
@@ -214,7 +214,7 @@ When a new decoded frame is available, the decoder _swaps_ the decoding and
 rendering frame (with proper synchronization). Thus, it immediatly starts
 to decode a new frame while the main thread renders the last one.
 
-If a [recorder] is present (i.e. `--record` is enabled), then it muxes the raw
+If a [recorder] is present (i.e. `--record` is enabled), then its muxes the raw
 H.264 packet to the output video file.
 
 [stream]: https://github.com/Genymobile/scrcpy/blob/ffe0417228fb78ab45b7ee4e202fc06fc8875bf3/app/src/stream.h

FAQ.md

@@ -3,102 +3,19 @@
 Here are the common reported problems and their status.
 
 
-## `adb` issues
+### On Windows, my device is not detected
 
-`scrcpy` execute `adb` commands to initialize the connection with the device. If
-`adb` fails, then scrcpy will not work.
+The most common is your device not being detected by `adb`, or is unauthorized.
+Check everything is ok by calling:
 
-In that case, it will print this error:
-
->     ERROR: "adb push" returned with value 1
-
-This is typically not a bug in _scrcpy_, but a problem in your environment.
-
-To find out the cause, execute:
-
-```bash
     adb devices
-```
 
-### `adb` not found
-
-You need `adb` accessible from your `PATH`.
-
-On Windows, the current directory is in your `PATH`, and `adb.exe` is included
-in the release, so it should work out-of-the-box.
-
-
-### Device unauthorized
-
-Check [stackoverflow][device-unauthorized].
-
-[device-unauthorized]: https://stackoverflow.com/questions/23081263/adb-android-device-unauthorized
-
-
-### Device not detected
-
-If your device is not detected, you may need some [drivers] (on Windows).
+Windows may need some [drivers] to detect your device.
 
 [drivers]: https://developer.android.com/studio/run/oem-usb.html
 
 
-### Several devices connected
-
-If several devices are connected, you will encounter this error:
-
->     adb: error: failed to get feature set: more than one device/emulator
-
-the identifier of the device you want to mirror must be provided:
-
-```bash
-scrcpy -s 01234567890abcdef
-```
-
-Note that if your device is connected over TCP/IP, you'll get this message:
-
->     adb: error: more than one device/emulator
->     ERROR: "adb reverse" returned with value 1
->     WARN: 'adb reverse' failed, fallback to 'adb forward'
-
-This is expected (due to a bug on old Android versions, see [#5]), but in that
-case, scrcpy fallbacks to a different method, which should work.
-
-[#5]: https://github.com/Genymobile/scrcpy/issues/5
-
-
-### Conflicts between adb versions
-
->     adb server version (41) doesn't match this client (39); killing...
-
-This error occurs when you use several `adb` versions simultaneously. You must
-find the program using a different `adb` version, and use the same `adb` version
-everywhere.
-
-You could overwrite the `adb` binary in the other program, or ask _scrcpy_ to
-use a specific `adb` binary, by setting the `ADB` environment variable:
-
-```bash
-set ADB=/path/to/your/adb
-scrcpy
-```
-
-
-### Device disconnected
-
-If _scrcpy_ stops itself with the warning "Device disconnected", then the
-`adb` connection has been closed.
-
-Try with another USB cable or plug it into another USB port. See [#281] and
-[#283].
-
-[#281]: https://github.com/Genymobile/scrcpy/issues/281
-[#283]: https://github.com/Genymobile/scrcpy/issues/283
-
-
-
-## Control issues
-
-### Mouse and keyboard do not work
+### I can only mirror, I cannot interact with the device
 
 On some devices, you may need to enable an option to allow [simulating input].
 In developer options, enable:
@@ -112,25 +29,18 @@ In developer options, enable:
 ### Mouse clicks at wrong location
 
 On MacOS, with HiDPI support and multiple screens, input location are wrongly
-scaled. See [#15].
+scaled. See [issue 15].
 
-[#15]: https://github.com/Genymobile/scrcpy/issues/15
+[issue 15]: https://github.com/Genymobile/scrcpy/issues/15
 
-Open _scrcpy_ directly on the monitor you use it.
+A workaround is to build with HiDPI support disabled:
 
+```bash
+meson x --buildtype release -Dhidpi_support=false
+```
 
-### Special characters do not work
+However, the video will be displayed at lower resolution.
 
-Injecting text input is [limited to ASCII characters][text-input]. A trick
-allows to also inject some [accented characters][accented-characters], but
-that's all. See [#37].
-
-[text-input]: https://github.com/Genymobile/scrcpy/issues?q=is%3Aopen+is%3Aissue+label%3Aunicode
-[accented-characters]: https://blog.rom1v.com/2018/03/introducing-scrcpy/#handle-accented-characters
-[#37]: https://github.com/Genymobile/scrcpy/issues/37
-
-
-## Client issues
 
 ### The quality is low on HiDPI display
 
@@ -141,11 +51,6 @@ On Windows, you may need to configure the [scaling behavior].
 
 [scaling behavior]: https://github.com/Genymobile/scrcpy/issues/40#issuecomment-424466723
 
-If your computer definition is far smaller than your screen, then you'll get
-poor quality. See [#40].
-
-[#40]: https://github.com/Genymobile/scrcpy/issues/40
-
 
 ### KWin compositor crashes
 
@@ -156,29 +61,19 @@ As a workaround, [disable "Block compositing"][kwin].
 [kwin]: https://github.com/Genymobile/scrcpy/issues/114#issuecomment-378778613
 
 
-## Crashes
-
-### Exception
+### I get an error "Could not open video stream"
 
 There may be many reasons. One common cause is that the hardware encoder of your
 device is not able to encode at the given definition:
 
-> ```
-> ERROR: Exception on thread Thread[main,5,main]
-> android.media.MediaCodec$CodecException: Error 0xfffffc0e
-> ...
-> Exit due to uncaughtException in main thread:
-> ERROR: Could not open video stream
-> INFO: Initial texture: 1080x2336
-> ```
-
-or
-
-> ```
-> ERROR: Exception on thread Thread[main,5,main]
-> java.lang.IllegalStateException
->         at android.media.MediaCodec.native_dequeueOutputBuffer(Native Method)
-> ```
+```
+ERROR: Exception on thread Thread[main,5,main]
+android.media.MediaCodec$CodecException: Error 0xfffffc0e
+...
+Exit due to uncaughtException in main thread:
+ERROR: Could not open video stream
+INFO: Initial texture: 1080x2336
+```
 
 Just try with a lower definition:
 

LICENSE

@@ -188,7 +188,7 @@
       identification within third-party archives.
 
    Copyright (C) 2018 Genymobile
-   Copyright (C) 2018-2020 Romain Vimont
+   Copyright (C) 2018-2019 Romain Vimont
 
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.

README.ko.md

@@ -475,7 +475,7 @@ _²화면이 꺼진 상태에서 우클릭 시 다시 켜지며, 그 외의 상
 ## 라이선스
 
     Copyright (C) 2018 Genymobile
-    Copyright (C) 2018-2020 Romain Vimont
+    Copyright (C) 2018-2019 Romain Vimont
 
     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.

README.md

@@ -37,11 +37,8 @@ control it using keyboard and mouse.
 
 ### Linux
 
-In Debian (_testing_ and _sid_ for now):
-
-```
-apt install scrcpy
-```
+On Linux, you typically need to [build the app manually][BUILD]. Don't worry,
+it's not that hard.
 
 A [Snap] package is available: [`scrcpy`][snap-link].
 
@@ -59,39 +56,20 @@ For Gentoo, an [Ebuild] is available: [`scrcpy/`][ebuild-link].
 [Ebuild]: https://wiki.gentoo.org/wiki/Ebuild
 [ebuild-link]: https://github.com/maggu2810/maggu2810-overlay/tree/master/app-mobilephone/scrcpy
 
-You could also [build the app manually][BUILD] (don't worry, it's not that
-hard).
-
-
 
 ### Windows
 
-For Windows, for simplicity, a prebuilt archive with all the dependencies
-(including `adb`) is available:
+For Windows, for simplicity, prebuilt archives with all the dependencies
+(including `adb`) are available:
 
+ - [`scrcpy-win32-v1.12.1.zip`][direct-win32]  
+   _(SHA-256: 0f4b3b063536b50a2df05dc42c760f9cc0093a9a26dbdf02d8232c74dab43480)_
  - [`scrcpy-win64-v1.12.1.zip`][direct-win64]  
    _(SHA-256: 57d34b6d16cfd9fe169bc37c4df58ebd256d05c1ea3febc63d9cb0a027ab47c9)_
 
+[direct-win32]: https://github.com/Genymobile/scrcpy/releases/download/v1.12.1/scrcpy-win32-v1.12.1.zip
 [direct-win64]: https://github.com/Genymobile/scrcpy/releases/download/v1.12.1/scrcpy-win64-v1.12.1.zip
 
-It is also available in [Chocolatey]:
-
-[Chocolatey]: https://chocolatey.org/
-
-```bash
-choco install scrcpy
-choco install adb    # if you don't have it yet
-```
-
-And in [Scoop]:
-
-```bash
-scoop install scrcpy
-scoop install adb    # if you don't have it yet
-```
-
-[Scoop]: https://scoop.sh
-
 You can also [build the app manually][BUILD].
 
 
@@ -159,12 +137,14 @@ scrcpy -b 2M  # short version
 
 #### Limit frame rate
 
-On devices with Android >= 10, the capture frame rate can be limited:
+The capture frame rate can be limited:
 
 ```bash
 scrcpy --max-fps 15
 ```
 
+This is officially supported since Android 10, but may work on earlier versions.
+
 #### Crop
 
 The device screen may be cropped to mirror only part of the screen.
@@ -236,13 +216,6 @@ scrcpy --serial 0123456789abcdef
 scrcpy -s 0123456789abcdef  # short version
 ```
 
-If the device is connected over TCP/IP:
-
-```bash
-scrcpy --serial 192.168.0.1:5555
-scrcpy -s 192.168.0.1:5555  # short version
-```
-
 You can start several instances of _scrcpy_ for several devices.
 
 #### SSH tunnel
@@ -518,7 +491,7 @@ Read the [developers page].
 ## Licence
 
     Copyright (C) 2018 Genymobile
-    Copyright (C) 2018-2020 Romain Vimont
+    Copyright (C) 2018-2019 Romain Vimont
 
     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.

app/meson.build

@@ -76,11 +76,9 @@ cc = meson.get_compiler('c')
 
 if host_machine.system() == 'windows'
     src += [ 'src/sys/win/command.c' ]
-    src += [ 'src/sys/win/net.c' ]
     dependencies += cc.find_library('ws2_32')
 else
     src += [ 'src/sys/unix/command.c' ]
-    src += [ 'src/sys/unix/net.c' ]
 endif
 
 conf = configuration_data()
@@ -98,9 +96,10 @@ conf.set_quoted('PREFIX', get_option('prefix'))
 # directory as the executable)
 conf.set('PORTABLE', get_option('portable'))
 
-# the default client TCP port for the "adb reverse" tunnel
+# the default client TCP port range for the "adb reverse" tunnel
 # overridden by option --port
-conf.set('DEFAULT_LOCAL_PORT', '27183')
+conf.set('DEFAULT_LOCAL_PORT_RANGE_FIRST', '27183')
+conf.set('DEFAULT_LOCAL_PORT_RANGE_LAST', '27199')
 
 # the default max video size for both dimensions, in pixels
 # overridden by option --max-size

app/scrcpy.1

@@ -43,7 +43,7 @@ Print this help.
 
 .TP
 .BI "\-\-max\-fps " value
-Limit the framerate of screen capture (only supported on devices with Android >= 10).
+Limit the framerate of screen capture (officially supported since Android 10, but may work on earlier versions).
 
 .TP
 .BI "\-m, \-\-max\-size " value
@@ -60,10 +60,10 @@ Disable device control (mirror the device in read\-only).
 Do not display device (only when screen recording is enabled).
 
 .TP
-.BI "\-p, \-\-port " port
-Set the TCP port the client listens on.
+.BI "\-p, \-\-port " port[:port]
+Set the TCP port (range) used by the client to listen.
 
-Default is 27183.
+Default is 27183:27199.
 
 .TP
 .B \-\-prefer\-text
@@ -261,7 +261,7 @@ Copyright \(co 2018 Genymobile
 Genymobile
 .UE
 
-Copyright \(co 2018\-2020
+Copyright \(co 2018\-2019
 .MT rom@rom1v.com
 Romain Vimont
 .ME

app/src/cli.c

@@ -42,8 +42,8 @@ scrcpy_print_usage(const char *arg0) {
         "        Print this help.\n"
         "\n"
         "    --max-fps value\n"
-        "        Limit the frame rate of screen capture (only supported on\n"
-        "        devices with Android >= 10).\n"
+        "        Limit the frame rate of screen capture (officially supported\n"
+        "        since Android 10, but may work on earlier versions).\n"
         "\n"
         "    -m, --max-size value\n"
         "        Limit both the width and height of the video to value. The\n"
@@ -58,9 +58,9 @@ scrcpy_print_usage(const char *arg0) {
         "        Do not display device (only when screen recording is\n"
         "        enabled).\n"
         "\n"
-        "    -p, --port port\n"
-        "        Set the TCP port the client listens on.\n"
-        "        Default is %d.\n"
+        "    -p, --port port[:port]\n"
+        "        Set the TCP port (range) used by the client to listen.\n"
+        "        Default is %d:%d.\n"
         "\n"
         "    --prefer-text\n"
         "        Inject alpha characters and space as text events instead of\n"
@@ -193,7 +193,7 @@ scrcpy_print_usage(const char *arg0) {
         arg0,
         DEFAULT_BIT_RATE,
         DEFAULT_MAX_SIZE, DEFAULT_MAX_SIZE ? "" : " (unlimited)",
-        DEFAULT_LOCAL_PORT);
+        DEFAULT_LOCAL_PORT_RANGE_FIRST, DEFAULT_LOCAL_PORT_RANGE_LAST);
 }
 
 static bool
@@ -221,6 +221,27 @@ parse_integer_arg(const char *s, long *out, bool accept_suffix, long min,
     return true;
 }
 
+static size_t
+parse_integers_arg(const char *s, size_t max_items, long *out, long min,
+                   long max, const char *name) {
+    size_t count = parse_integers(s, ':', max_items, out);
+    if (!count) {
+        LOGE("Could not parse %s: %s", name, s);
+        return 0;
+    }
+
+    for (size_t i = 0; i < count; ++i) {
+        long value = out[i];
+        if (value < min || value > max) {
+            LOGE("Could not parse %s: value (%ld) out-of-range (%ld; %ld)",
+                 name, value, min, max);
+            return 0;
+        }
+    }
+
+    return count;
+}
+
 static bool
 parse_bit_rate(const char *s, uint32_t *bit_rate) {
     long value;
@@ -286,14 +307,30 @@ parse_window_dimension(const char *s, uint16_t *dimension) {
 }
 
 static bool
-parse_port(const char *s, uint16_t *port) {
-    long value;
-    bool ok = parse_integer_arg(s, &value, false, 0, 0xFFFF, "port");
-    if (!ok) {
+parse_port_range(const char *s, struct port_range *port_range) {
+    long values[2];
+    size_t count = parse_integers_arg(s, 2, values, 0, 0xFFFF, "port");
+    if (!count) {
         return false;
     }
 
-    *port = (uint16_t) value;
+    uint16_t v0 = (uint16_t) values[0];
+    if (count == 1) {
+        port_range->first = v0;
+        port_range->last = v0;
+        return true;
+    }
+
+    assert(count == 2);
+    uint16_t v1 = (uint16_t) values[1];
+    if (v0 < v1) {
+        port_range->first = v0;
+        port_range->last = v1;
+    } else {
+        port_range->first = v1;
+        port_range->last = v0;
+    }
+
     return true;
 }
 
@@ -424,7 +461,7 @@ scrcpy_parse_args(struct scrcpy_cli_args *args, int argc, char *argv[]) {
                 opts->display = false;
                 break;
             case 'p':
-                if (!parse_port(optarg, &opts->port)) {
+                if (!parse_port_range(optarg, &opts->port_range)) {
                     return false;
                 }
                 break;

app/src/command.c

@@ -4,9 +4,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
 
 #include "config.h"
 #include "common.h"
@@ -58,6 +55,28 @@ argv_to_string(const char *const *argv, char *buf, size_t bufsize) {
     return idx;
 }
 
+static void
+show_adb_installation_msg() {
+    static const struct {
+        const char *binary;
+        const char *command;
+    } pkg_managers[] = {
+        {"apt", "apt install adb"},
+        {"apt-get", "apt-get install adb"},
+        {"brew", "brew install android-platform-tools"},
+        {"dnf", "dnf install android-tools"},
+    };
+    for (size_t i = 0; i < ARRAY_LEN(pkg_managers); ++i) {
+        if (cmd_search(pkg_managers[i].binary)) {
+            LOGI("You may install 'adb' by \"%s\"", pkg_managers[i].command);
+            return;
+        }
+    }
+
+    LOGI("You may download and install 'adb' from "
+         "https://developer.android.com/studio/releases/platform-tools");
+}
+
 static void
 show_adb_err_msg(enum process_result err, const char *const argv[]) {
     char buf[512];
@@ -71,6 +90,7 @@ show_adb_err_msg(enum process_result err, const char *const argv[]) {
             LOGE("Command not found: %s", buf);
             LOGE("(make 'adb' accessible from your PATH or define its full"
                  "path in the ADB environment variable)");
+            show_adb_installation_msg();
             break;
         case PROCESS_SUCCESS:
             // do nothing
@@ -205,14 +225,3 @@ process_check_success(process_t proc, const char *name) {
     }
     return true;
 }
-
-bool
-is_regular_file(const char *path) {
-    struct stat path_stat;
-    int r = stat(path, &path_stat);
-    if (r) {
-        perror("stat");
-        return false;
-    }
-    return S_ISREG(path_stat.st_mode);
-}

app/src/command.h

@@ -43,6 +43,9 @@ enum process_result {
     PROCESS_ERROR_MISSING_BINARY,
 };
 
+bool
+cmd_search(const char *file);
+
 enum process_result
 cmd_execute(const char *const argv[], process_t *process);
 

app/src/common.h

@@ -27,4 +27,9 @@ struct position {
     struct point point;
 };
 
+struct port_range {
+    uint16_t first;
+    uint16_t last;
+};
+
 #endif

app/src/scrcpy.c

@@ -280,7 +280,7 @@ scrcpy(const struct scrcpy_options *options) {
     bool record = !!options->record_filename;
     struct server_params params = {
         .crop = options->crop,
-        .local_port = options->port,
+        .port_range = options->port_range,
         .max_size = options->max_size,
         .bit_rate = options->bit_rate,
         .max_fps = options->max_fps,

app/src/scrcpy.h

@@ -5,6 +5,7 @@
 #include <stdint.h>
 
 #include "config.h"
+#include "common.h"
 #include "input_manager.h"
 #include "recorder.h"
 
@@ -15,7 +16,7 @@ struct scrcpy_options {
     const char *window_title;
     const char *push_target;
     enum recorder_format record_format;
-    uint16_t port;
+    struct port_range port_range;
     uint16_t max_size;
     uint32_t bit_rate;
     uint16_t max_fps;
@@ -41,7 +42,10 @@ struct scrcpy_options {
     .window_title = NULL, \
     .push_target = NULL, \
     .record_format = RECORDER_FORMAT_AUTO, \
-    .port = DEFAULT_LOCAL_PORT, \
+    .port_range = { \
+        .first = DEFAULT_LOCAL_PORT_RANGE_FIRST, \
+        .last = DEFAULT_LOCAL_PORT_RANGE_LAST, \
+    }, \
     .max_size = DEFAULT_MAX_SIZE, \
     .bit_rate = DEFAULT_BIT_RATE, \
     .max_fps = 0, \

app/src/server.c

@@ -6,11 +6,13 @@
 #include <libgen.h>
 #include <stdio.h>
 #include <SDL2/SDL_timer.h>
+#include <SDL2/SDL_platform.h>
 
 #include "config.h"
 #include "command.h"
 #include "util/log.h"
 #include "util/net.h"
+#include "util/str_util.h"
 
 #define SOCKET_NAME "scrcpy"
 #define SERVER_FILENAME "scrcpy-server"
@@ -18,20 +20,39 @@
 #define DEFAULT_SERVER_PATH PREFIX "/share/scrcpy/" SERVER_FILENAME
 #define DEVICE_SERVER_PATH "/data/local/tmp/scrcpy-server.jar"
 
-static const char *
+static char *
 get_server_path(void) {
+#ifdef __WINDOWS__
+    const wchar_t *server_path_env = _wgetenv(L"SCRCPY_SERVER_PATH");
+#else
     const char *server_path_env = getenv("SCRCPY_SERVER_PATH");
+#endif
     if (server_path_env) {
-        LOGD("Using SCRCPY_SERVER_PATH: %s", server_path_env);
         // if the envvar is set, use it
-        return server_path_env;
+#ifdef __WINDOWS__
+        char *server_path = utf8_from_wide_char(server_path_env);
+#else
+        char *server_path = SDL_strdup(server_path_env);
+#endif
+        if (!server_path) {
+            LOGE("Could not allocate memory");
+            return NULL;
+        }
+        LOGD("Using SCRCPY_SERVER_PATH: %s", server_path);
+        return server_path;
     }
 
 #ifndef PORTABLE
     LOGD("Using server: " DEFAULT_SERVER_PATH);
+    char *server_path = SDL_strdup(DEFAULT_SERVER_PATH);
+    if (!server_path) {
+        LOGE("Could not allocate memory");
+        return NULL;
+    }
     // the absolute path is hardcoded
-    return DEFAULT_SERVER_PATH;
+    return server_path;
 #else
+
     // use scrcpy-server in the same directory as the executable
     char *executable_path = get_executable_path();
     if (!executable_path) {
@@ -67,12 +88,17 @@ get_server_path(void) {
 
 static bool
 push_server(const char *serial) {
-    const char *server_path = get_server_path();
+    char *server_path = get_server_path();
+    if (!server_path) {
+        return false;
+    }
     if (!is_regular_file(server_path)) {
         LOGE("'%s' does not exist or is not a regular file\n", server_path);
+        SDL_free(server_path);
         return false;
     }
     process_t process = adb_push(serial, server_path, DEVICE_SERVER_PATH);
+    SDL_free(server_path);
     return process_check_success(process, "adb push");
 }
 
@@ -100,17 +126,6 @@ disable_tunnel_forward(const char *serial, uint16_t local_port) {
     return process_check_success(process, "adb forward --remove");
 }
 
-static bool
-enable_tunnel(struct server *server) {
-    if (enable_tunnel_reverse(server->serial, server->local_port)) {
-        return true;
-    }
-
-    LOGW("'adb reverse' failed, fallback to 'adb forward'");
-    server->tunnel_forward = true;
-    return enable_tunnel_forward(server->serial, server->local_port);
-}
-
 static bool
 disable_tunnel(struct server *server) {
     if (server->tunnel_forward) {
@@ -119,6 +134,100 @@ disable_tunnel(struct server *server) {
     return disable_tunnel_reverse(server->serial);
 }
 
+static socket_t
+listen_on_port(uint16_t port) {
+#define IPV4_LOCALHOST 0x7F000001
+    return net_listen(IPV4_LOCALHOST, port, 1);
+}
+
+static bool
+enable_tunnel_reverse_any_port(struct server *server,
+                               struct port_range port_range) {
+    uint16_t port = port_range.first;
+    for (;;) {
+        if (!enable_tunnel_reverse(server->serial, port)) {
+            // the command itself failed, it will fail on any port
+            return false;
+        }
+
+        // At the application level, the device part is "the server" because it
+        // serves video stream and control. However, at the network level, the
+        // client listens and the server connects to the client. That way, the
+        // client can listen before starting the server app, so there is no
+        // need to try to connect until the server socket is listening on the
+        // device.
+        server->server_socket = listen_on_port(port);
+        if (server->server_socket != INVALID_SOCKET) {
+            // success
+            server->local_port = port;
+            return true;
+        }
+
+        // failure, disable tunnel and try another port
+        if (!disable_tunnel_reverse(server->serial)) {
+            LOGW("Could not remove reverse tunnel on port %" PRIu16, port);
+        }
+
+        // check before incrementing to avoid overflow on port 65535
+        if (port < port_range.last) {
+            LOGW("Could not listen on port %" PRIu16", retrying on %" PRIu16,
+                 port, port + 1);
+            port++;
+            continue;
+        }
+
+        if (port_range.first == port_range.last) {
+            LOGE("Could not listen on port %" PRIu16, port_range.first);
+        } else {
+            LOGE("Could not listen on any port in range %" PRIu16 ":%" PRIu16,
+                 port_range.first, port_range.last);
+        }
+        return false;
+    }
+}
+
+static bool
+enable_tunnel_forward_any_port(struct server *server,
+                               struct port_range port_range) {
+    server->tunnel_forward = true;
+    uint16_t port = port_range.first;
+    for (;;) {
+        if (enable_tunnel_forward(server->serial, port)) {
+            // success
+            server->local_port = port;
+            return true;
+        }
+
+        if (port < port_range.last) {
+            LOGW("Could not forward port %" PRIu16", retrying on %" PRIu16,
+                 port, port + 1);
+            port++;
+            continue;
+        }
+
+        if (port_range.first == port_range.last) {
+            LOGE("Could not forward port %" PRIu16, port_range.first);
+        } else {
+            LOGE("Could not forward any port in range %" PRIu16 ":%" PRIu16,
+                 port_range.first, port_range.last);
+        }
+        return false;
+    }
+}
+
+static bool
+enable_tunnel_any_port(struct server *server, struct port_range port_range) {
+    if (enable_tunnel_reverse_any_port(server, port_range)) {
+        return true;
+    }
+
+    // if "adb reverse" does not work (e.g. over "adb connect"), it fallbacks to
+    // "adb forward", so the app socket is the client
+
+    LOGW("'adb reverse' failed, fallback to 'adb forward'");
+    return enable_tunnel_forward_any_port(server, port_range);
+}
+
 static process_t
 execute_server(struct server *server, const struct server_params *params) {
     char max_size_string[6];
@@ -161,13 +270,6 @@ execute_server(struct server *server, const struct server_params *params) {
     return adb_execute(server->serial, cmd, sizeof(cmd) / sizeof(cmd[0]));
 }
 
-#define IPV4_LOCALHOST 0x7F000001
-
-static socket_t
-listen_on_port(uint16_t port) {
-    return net_listen(IPV4_LOCALHOST, port, 1);
-}
-
 static socket_t
 connect_and_read_byte(uint16_t port) {
     socket_t socket = net_connect(IPV4_LOCALHOST, port);
@@ -221,7 +323,7 @@ server_init(struct server *server) {
 bool
 server_start(struct server *server, const char *serial,
              const struct server_params *params) {
-    server->local_port = params->local_port;
+    server->port_range = params->port_range;
 
     if (serial) {
         server->serial = SDL_strdup(serial);
@@ -235,30 +337,11 @@ server_start(struct server *server, const char *serial,
         return false;
     }
 
-    if (!enable_tunnel(server)) {
+    if (!enable_tunnel_any_port(server, params->port_range)) {
         SDL_free(server->serial);
         return false;
     }
 
-    // if "adb reverse" does not work (e.g. over "adb connect"), it fallbacks to
-    // "adb forward", so the app socket is the client
-    if (!server->tunnel_forward) {
-        // At the application level, the device part is "the server" because it
-        // serves video stream and control. However, at the network level, the
-        // client listens and the server connects to the client. That way, the
-        // client can listen before starting the server app, so there is no
-        // need to try to connect until the server socket is listening on the
-        // device.
-
-        server->server_socket = listen_on_port(params->local_port);
-        if (server->server_socket == INVALID_SOCKET) {
-            LOGE("Could not listen on port %" PRIu16, params->local_port);
-            disable_tunnel(server);
-            SDL_free(server->serial);
-            return false;
-        }
-    }
-
     // server will connect to our server socket
     server->process = execute_server(server, params);
 

app/src/server.h

@@ -6,6 +6,7 @@
 
 #include "config.h"
 #include "command.h"
+#include "common.h"
 #include "util/net.h"
 
 struct server {
@@ -14,7 +15,8 @@ struct server {
     socket_t server_socket; // only used if !tunnel_forward
     socket_t video_socket;
     socket_t control_socket;
-    uint16_t local_port;
+    struct port_range port_range;
+    uint16_t local_port; // selected from port_range
     bool tunnel_enabled;
     bool tunnel_forward; // use "adb forward" instead of "adb reverse"
 };
@@ -25,6 +27,10 @@ struct server {
     .server_socket = INVALID_SOCKET, \
     .video_socket = INVALID_SOCKET, \
     .control_socket = INVALID_SOCKET, \
+    .port_range = { \
+        .first = 0, \
+        .last = 0, \
+    }, \
     .local_port = 0, \
     .tunnel_enabled = false, \
     .tunnel_forward = false, \
@@ -32,7 +38,7 @@ struct server {
 
 struct server_params {
     const char *crop;
-    uint16_t local_port;
+    struct port_range port_range;
     uint16_t max_size;
     uint32_t bit_rate;
     uint16_t max_fps;

app/src/sys/unix/command.c

@@ -14,12 +14,50 @@
 #include <limits.h>
 #include <signal.h>
 #include <stdlib.h>
+#include <sys/stat.h>
 #include <sys/types.h>
+#include <sys/stat.h>
 #include <sys/wait.h>
 #include <unistd.h>
 
 #include "util/log.h"
 
+bool
+cmd_search(const char *file) {
+    char *path = getenv("PATH");
+    if (!path)
+        return false;
+    path = strdup(path);
+    if (!path)
+        return false;
+
+    bool ret = false;
+    size_t file_len = strlen(file);
+    char *saveptr;
+    for (char *dir = strtok_r(path, ":", &saveptr); dir;
+            dir = strtok_r(NULL, ":", &saveptr)) {
+        size_t dir_len = strlen(dir);
+        char *fullpath = malloc(dir_len + file_len + 2);
+        if (!fullpath)
+            continue;
+        memcpy(fullpath, dir, dir_len);
+        fullpath[dir_len] = '/';
+        memcpy(fullpath + dir_len + 1, file, file_len + 1);
+
+        struct stat sb;
+        bool fullpath_executable = stat(fullpath, &sb) == 0 &&
+            sb.st_mode & S_IXUSR;
+        free(fullpath);
+        if (fullpath_executable) {
+            ret = true;
+            break;
+        }
+    }
+
+    free(path);
+    return ret;
+}
+
 enum process_result
 cmd_execute(const char *const argv[], pid_t *pid) {
     int fd[2];
@@ -127,3 +165,14 @@ get_executable_path(void) {
     return NULL;
 #endif
 }
+
+bool
+is_regular_file(const char *path) {
+    struct stat path_stat;
+
+    if (stat(path, &path_stat)) {
+        perror("stat");
+        return false;
+    }
+    return S_ISREG(path_stat.st_mode);
+}

app/src/sys/unix/net.c

@@ -1,21 +0,0 @@
-#include "util/net.h"
-
-#include <unistd.h>
-
-#include "config.h"
-
-bool
-net_init(void) {
-    // do nothing
-    return true;
-}
-
-void
-net_cleanup(void) {
-    // do nothing
-}
-
-bool
-net_close(socket_t socket) {
-    return !close(socket);
-}

app/src/sys/win/command.c

@@ -1,9 +1,17 @@
 #include "command.h"
 
+#include <sys/stat.h>
+
 #include "config.h"
 #include "util/log.h"
 #include "util/str_util.h"
 
+bool
+cmd_search(const char *file) {
+    // :/
+    return false;
+}
+
 static int
 build_cmd(char *cmd, size_t len, const char *const argv[]) {
     // Windows command-line parsing is WTF:
@@ -90,3 +98,22 @@ get_executable_path(void) {
     buf[len] = '\0';
     return utf8_from_wide_char(buf);
 }
+
+bool
+is_regular_file(const char *path) {
+    wchar_t *wide_path = utf8_to_wide_char(path);
+    if (!wide_path) {
+        LOGC("Could not allocate wide char string");
+        return false;
+    }
+
+    struct _stat path_stat;
+    int r = _wstat(wide_path, &path_stat);
+    SDL_free(wide_path);
+
+    if (r) {
+        perror("stat");
+        return false;
+    }
+    return S_ISREG(path_stat.st_mode);
+}

app/src/sys/win/net.c

@@ -1,25 +0,0 @@
-#include "util/net.h"
-
-#include "config.h"
-#include "util/log.h"
-
-bool
-net_init(void) {
-    WSADATA wsa;
-    int res = WSAStartup(MAKEWORD(2, 2), &wsa) < 0;
-    if (res < 0) {
-        LOGC("WSAStartup failed with error %d", res);
-        return false;
-    }
-    return true;
-}
-
-void
-net_cleanup(void) {
-    WSACleanup();
-}
-
-bool
-net_close(socket_t socket) {
-    return !closesocket(socket);
-}

app/src/util/net.c

@@ -1,6 +1,7 @@
 #include "net.h"
 
 #include <stdio.h>
+#include <SDL2/SDL_platform.h>
 
 #include "config.h"
 #include "log.h"
@@ -115,3 +116,32 @@ bool
 net_shutdown(socket_t socket, int how) {
     return !shutdown(socket, how);
 }
+
+bool
+net_init(void) {
+#ifdef __WINDOWS__
+    WSADATA wsa;
+    int res = WSAStartup(MAKEWORD(2, 2), &wsa) < 0;
+    if (res < 0) {
+        LOGC("WSAStartup failed with error %d", res);
+        return false;
+    }
+#endif
+    return true;
+}
+
+void
+net_cleanup(void) {
+#ifdef __WINDOWS__
+    WSACleanup();
+#endif
+}
+
+bool
+net_close(socket_t socket) {
+#ifdef __WINDOWS__
+    return !closesocket(socket);
+#else
+    return !close(socket);
+#endif
+}

app/src/util/str_util.c

@@ -81,6 +81,35 @@ parse_integer(const char *s, long *out) {
     return true;
 }
 
+size_t
+parse_integers(const char *s, const char sep, size_t max_items, long *out) {
+    size_t count = 0;
+    char *endptr;
+    do {
+        errno = 0;
+        long value = strtol(s, &endptr, 0);
+        if (errno == ERANGE) {
+            return 0;
+        }
+
+        if (endptr == s || (*endptr != sep && *endptr != '\0')) {
+            return 0;
+        }
+
+        out[count++] = value;
+        if (*endptr == sep) {
+            if (count >= max_items) {
+                // max items already reached, could not accept a new item
+                return 0;
+            }
+            // parse the next token during the next iteration
+            s = endptr + 1;
+        }
+    } while (*endptr != '\0');
+
+    return count;
+}
+
 bool
 parse_integer_with_suffix(const char *s, long *out) {
     char *endptr;

app/src/util/str_util.h

@@ -31,6 +31,11 @@ strquote(const char *src);
 bool
 parse_integer(const char *s, long *out);
 
+// parse s as integers separated by sep (for example '1234:2000')
+// returns the number of integers on success, 0 on failure
+size_t
+parse_integers(const char *s, const char sep, size_t max_items, long *out);
+
 // parse s as an integer into value
 // like parse_integer(), but accept 'k'/'K' (x1000) and 'm'/'M' (x1000000) as
 // suffix

app/tests/test_cli.c

@@ -50,7 +50,7 @@ static void test_options(void) {
         "--max-size", "1024",
         // "--no-control" is not compatible with "--turn-screen-off"
         // "--no-display" is not compatible with "--fulscreen"
-        "--port", "1234",
+        "--port", "1234:1236",
         "--push-target", "/sdcard/Movies",
         "--record", "file",
         "--record-format", "mkv",
@@ -78,7 +78,8 @@ static void test_options(void) {
     assert(opts->fullscreen);
     assert(opts->max_fps == 30);
     assert(opts->max_size == 1024);
-    assert(opts->port == 1234);
+    assert(opts->port_range.first == 1234);
+    assert(opts->port_range.last == 1236);
     assert(!strcmp(opts->push_target, "/sdcard/Movies"));
     assert(!strcmp(opts->record_filename, "file"));
     assert(opts->record_format == RECORDER_FORMAT_MKV);

app/tests/test_strutil.c

@@ -187,6 +187,55 @@ static void test_parse_integer(void) {
     assert(!ok); // out-of-range
 }
 
+static void test_parse_integers(void) {
+    long values[5];
+
+    size_t count = parse_integers("1234", ':', 5, values);
+    assert(count == 1);
+    assert(values[0] == 1234);
+
+    count = parse_integers("1234:5678", ':', 5, values);
+    assert(count == 2);
+    assert(values[0] == 1234);
+    assert(values[1] == 5678);
+
+    count = parse_integers("1234:5678", ':', 2, values);
+    assert(count == 2);
+    assert(values[0] == 1234);
+    assert(values[1] == 5678);
+
+    count = parse_integers("1234:-5678", ':', 2, values);
+    assert(count == 2);
+    assert(values[0] == 1234);
+    assert(values[1] == -5678);
+
+    count = parse_integers("1:2:3:4:5", ':', 5, values);
+    assert(count == 5);
+    assert(values[0] == 1);
+    assert(values[1] == 2);
+    assert(values[2] == 3);
+    assert(values[3] == 4);
+    assert(values[4] == 5);
+
+    count = parse_integers("1234:5678", ':', 1, values);
+    assert(count == 0); // max_items == 1
+
+    count = parse_integers("1:2:3:4:5", ':', 3, values);
+    assert(count == 0); // max_items == 3
+
+    count = parse_integers(":1234", ':', 5, values);
+    assert(count == 0); // invalid
+
+    count = parse_integers("1234:", ':', 5, values);
+    assert(count == 0); // invalid
+
+    count = parse_integers("1234:", ':', 1, values);
+    assert(count == 0); // invalid, even when max_items == 1
+
+    count = parse_integers("1234::5678", ':', 5, values);
+    assert(count == 0); // invalid
+}
+
 static void test_parse_integer_with_suffix(void) {
     long value;
     bool ok = parse_integer_with_suffix("1234", &value);
@@ -249,6 +298,7 @@ int main(void) {
     test_strquote();
     test_utf8_truncate();
     test_parse_integer();
+    test_parse_integers();
     test_parse_integer_with_suffix();
     return 0;
 }

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

@@ -19,6 +19,7 @@ public class ScreenEncoder implements Device.RotationListener {
 
     private static final int DEFAULT_I_FRAME_INTERVAL = 10; // seconds
     private static final int REPEAT_FRAME_DELAY_US = 100_000; // repeat after 100ms
+    private static final String KEY_MAX_FPS_TO_ENCODER = "max-fps-to-encoder";
 
     private static final int NO_PTS = -1;
 
@@ -150,11 +151,10 @@ public class ScreenEncoder implements Device.RotationListener {
         // display the very first frame, and recover from bad quality when no new frames
         format.setLong(MediaFormat.KEY_REPEAT_PREVIOUS_FRAME_AFTER, REPEAT_FRAME_DELAY_US); // µs
         if (maxFps > 0) {
-            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
-                format.setFloat(MediaFormat.KEY_MAX_FPS_TO_ENCODER, maxFps);
-            } else {
-                Ln.w("Max FPS is only supported since Android 10, the option has been ignored");
-            }
+            // The key existed privately before Android 10:
+            // <https://android.googlesource.com/platform/frameworks/base/+/625f0aad9f7a259b6881006ad8710adce57d1384%5E%21/>
+            // <https://github.com/Genymobile/scrcpy/issues/488#issuecomment-567321437>
+            format.setFloat(KEY_MAX_FPS_TO_ENCODER, maxFps);
         }
         return format;
     }