AndroidVideoCapturer getSupportedFormats(): Change interface from JSON string to List/vector

This CL simplifies the VideoCapturer interface from 'String getSupportedFormatsAsJson() throws JSONException' to 'List<CaptureFormat> getSupportedFormats()'. The intermediate conversion to/from a JSON string is removed, and AndroidVideoCapturerJni converts the Java list to a C++ vector directly instead.

BUG=webrtc:5519
R=perkj@webrtc.org

Review URL: https://codereview.webrtc.org/1702603002 .

Cr-Commit-Position: refs/heads/master@{#11669}

webrtc/api/androidvideocapturer.cc

@@ -12,7 +12,6 @@
 
 #include "webrtc/api/java/jni/native_handle_impl.h"
 #include "webrtc/base/common.h"
-#include "webrtc/base/json.h"
 #include "webrtc/base/timeutils.h"
 #include "webrtc/media/engine/webrtcvideoframe.h"
 
@@ -119,29 +118,7 @@ AndroidVideoCapturer::AndroidVideoCapturer(
       frame_factory_(NULL),
       current_state_(cricket::CS_STOPPED) {
   thread_checker_.DetachFromThread();
-  std::string json_string = delegate_->GetSupportedFormats();
-  LOG(LS_INFO) << json_string;
-
-  Json::Value json_values;
-  Json::Reader reader(Json::Features::strictMode());
-  if (!reader.parse(json_string, json_values)) {
-    LOG(LS_ERROR) << "Failed to parse formats.";
-  }
-
-  std::vector<cricket::VideoFormat> formats;
-  for (Json::ArrayIndex i = 0; i < json_values.size(); ++i) {
-      const Json::Value& json_value = json_values[i];
-      RTC_CHECK(!json_value["width"].isNull() &&
-                !json_value["height"].isNull() &&
-                !json_value["framerate"].isNull());
-      cricket::VideoFormat format(
-          json_value["width"].asInt(),
-          json_value["height"].asInt(),
-          cricket::VideoFormat::FpsToInterval(json_value["framerate"].asInt()),
-          cricket::FOURCC_YV12);
-      formats.push_back(format);
-  }
-  SetSupportedFormats(formats);
+  SetSupportedFormats(delegate_->GetSupportedFormats());
 }
 
 AndroidVideoCapturer::~AndroidVideoCapturer() {

webrtc/api/androidvideocapturer.h

@@ -34,8 +34,7 @@ class AndroidVideoCapturerDelegate : public rtc::RefCountInterface {
   // The delegate may not call into AndroidVideoCapturer after this call.
   virtual void Stop() = 0;
 
-  // Must returns a JSON string "{{width=xxx, height=xxx, framerate = xxx}}"
-  virtual std::string GetSupportedFormats() = 0;
+  virtual std::vector<cricket::VideoFormat> GetSupportedFormats() = 0;
 };
 
 // Android implementation of cricket::VideoCapturer for use with WebRtc

webrtc/api/api.gyp

@@ -74,16 +74,6 @@
             4267,  # conversion from 'size_t' to 'int', possible loss of data.
             4389,  # signed/unsigned mismatch.
           ],
-          'conditions': [
-            ['build_json==1', {
-              'dependencies': [
-                '<(DEPTH)/third_party/jsoncpp/jsoncpp.gyp:jsoncpp',
-              ],
-              'export_dependent_settings': [
-                '<(DEPTH)/third_party/jsoncpp/jsoncpp.gyp:jsoncpp',
-              ],
-            }],
-          ],
         },
         {
           'target_name': 'libjingle_peerconnection_so',

webrtc/api/java/android/org/webrtc/CameraEnumerationAndroid.java

@@ -14,10 +14,6 @@ import static java.lang.Math.abs;
 import static java.lang.Math.ceil;
 import android.graphics.ImageFormat;
 
-import org.json.JSONArray;
-import org.json.JSONException;
-import org.json.JSONObject;
-
 import org.webrtc.Logging;
 
 import java.util.Collections;
@@ -42,7 +38,9 @@ public class CameraEnumerationAndroid {
   }
 
   public static synchronized List<CaptureFormat> getSupportedFormats(int cameraId) {
-    return enumerator.getSupportedFormats(cameraId);
+    final List<CaptureFormat> formats = enumerator.getSupportedFormats(cameraId);
+    Logging.d(TAG, "Supported formats for camera " + cameraId + ": " + formats);
+    return formats;
   }
 
   public static class CaptureFormat {
@@ -137,21 +135,6 @@ public class CameraEnumerationAndroid {
     return getNameOfDevice(android.hardware.Camera.CameraInfo.CAMERA_FACING_BACK);
   }
 
-  public static String getSupportedFormatsAsJson(int id) throws JSONException {
-    List<CaptureFormat> formats = getSupportedFormats(id);
-    JSONArray json_formats = new JSONArray();
-    for (CaptureFormat format : formats) {
-      JSONObject json_format = new JSONObject();
-      json_format.put("width", format.width);
-      json_format.put("height", format.height);
-      json_format.put("framerate", (format.maxFramerate + 999) / 1000);
-      json_formats.put(json_format);
-    }
-    Logging.d(TAG, "Supported formats for camera " + id + ": "
-        +  json_formats.toString(2));
-    return json_formats.toString();
-  }
-
   // Helper class for finding the closest supported format for the two functions below.
   private static abstract class ClosestComparator<T> implements Comparator<T> {
     // Difference between supported and requested parameter.

webrtc/api/java/android/org/webrtc/VideoCapturerAndroid.java

@@ -17,7 +17,6 @@ import android.os.SystemClock;
 import android.view.Surface;
 import android.view.WindowManager;
 
-import org.json.JSONException;
 import org.webrtc.CameraEnumerationAndroid.CaptureFormat;
 import org.webrtc.Logging;
 
@@ -284,6 +283,7 @@ public class VideoCapturerAndroid implements
     }
   }
 
+  @Override
   public List<CaptureFormat> getSupportedFormats() {
     return CameraEnumerationAndroid.getSupportedFormats(getCurrentCameraId());
   }
@@ -293,11 +293,6 @@ public class VideoCapturerAndroid implements
     return isCapturingToTexture;
   }
 
-  @Override
-  public String getSupportedFormatsAsJson() throws JSONException {
-    return CameraEnumerationAndroid.getSupportedFormatsAsJson(getCurrentCameraId());
-  }
-
   @Override
   public SurfaceTextureHelper getSurfaceTextureHelper() {
     return surfaceHelper;

webrtc/api/java/jni/androidvideocapturer_jni.cc

@@ -114,14 +114,40 @@ void AndroidVideoCapturerJni::AsyncCapturerInvoke(
   invoker_->AsyncInvoke<void>(rtc::Bind(method, capturer_, args...));
 }
 
-std::string AndroidVideoCapturerJni::GetSupportedFormats() {
-  jmethodID m =
-      GetMethodID(jni(), *j_video_capturer_class_,
-                  "getSupportedFormatsAsJson", "()Ljava/lang/String;");
-  jstring j_json_caps =
-      (jstring) jni()->CallObjectMethod(*j_video_capturer_, m);
-  CHECK_EXCEPTION(jni()) << "error during supportedFormatsAsJson";
-  return JavaToStdString(jni(), j_json_caps);
+std::vector<cricket::VideoFormat>
+AndroidVideoCapturerJni::GetSupportedFormats() {
+  JNIEnv* jni = AttachCurrentThreadIfNeeded();
+  jobject j_list_of_formats = jni->CallObjectMethod(
+      *j_video_capturer_,
+      GetMethodID(jni, *j_video_capturer_class_, "getSupportedFormats",
+                  "()Ljava/util/List;"));
+  CHECK_EXCEPTION(jni) << "error during getSupportedFormats";
+
+  // Extract Java List<CaptureFormat> to std::vector<cricket::VideoFormat>.
+  jclass j_list_class = jni->FindClass("java/util/List");
+  jclass j_format_class =
+      jni->FindClass("org/webrtc/CameraEnumerationAndroid$CaptureFormat");
+  const int size = jni->CallIntMethod(
+      j_list_of_formats, GetMethodID(jni, j_list_class, "size", "()I"));
+  jmethodID j_get =
+      GetMethodID(jni, j_list_class, "get", "(I)Ljava/lang/Object;");
+  jfieldID j_width_field = GetFieldID(jni, j_format_class, "width", "I");
+  jfieldID j_height_field = GetFieldID(jni, j_format_class, "height", "I");
+  jfieldID j_max_framerate_field =
+      GetFieldID(jni, j_format_class, "maxFramerate", "I");
+
+  std::vector<cricket::VideoFormat> formats;
+  formats.reserve(size);
+  for (int i = 0; i < size; ++i) {
+    jobject j_format = jni->CallObjectMethod(j_list_of_formats, j_get, i);
+    const int frame_interval = cricket::VideoFormat::FpsToInterval(
+        (GetIntField(jni, j_format, j_max_framerate_field) + 999) / 1000);
+    formats.emplace_back(GetIntField(jni, j_format, j_width_field),
+                         GetIntField(jni, j_format, j_height_field),
+                         frame_interval, cricket::FOURCC_NV21);
+  }
+  CHECK_EXCEPTION(jni) << "error while extracting formats";
+  return formats;
 }
 
 void AndroidVideoCapturerJni::OnCapturerStarted(bool success) {

webrtc/api/java/jni/androidvideocapturer_jni.h

@@ -40,7 +40,7 @@ class AndroidVideoCapturerJni : public webrtc::AndroidVideoCapturerDelegate {
              webrtc::AndroidVideoCapturer* capturer) override;
   void Stop() override;
 
-  std::string GetSupportedFormats() override;
+  std::vector<cricket::VideoFormat> GetSupportedFormats() override;
 
   // Called from VideoCapturer::NativeObserver on a Java thread.
   void OnCapturerStarted(bool success);

webrtc/api/java/src/org/webrtc/VideoCapturer.java

@@ -12,7 +12,7 @@ package org.webrtc;
 
 import android.content.Context;
 
-import org.json.JSONException;
+import java.util.List;
 
 // Base interface for all VideoCapturers to implement.
 // TODO(magjed): Simplify and improve this interface.
@@ -83,7 +83,7 @@ public interface VideoCapturer {
         int width, int height, int framerate);
   }
 
-  String getSupportedFormatsAsJson() throws JSONException;
+  List<CameraEnumerationAndroid.CaptureFormat> getSupportedFormats();
 
   SurfaceTextureHelper getSurfaceTextureHelper();