[Enhancement]Improve frame rendering

sdk/BUILD.gn

@@ -96,6 +96,7 @@ if (is_ios || is_mac) {
       "objc/base/RTCEncodedImage.h",
       "objc/base/RTCEncodedImage.m",
       "objc/base/RTCI420Buffer.h",
+      "objc/base/RTCNV12Buffer.h",
       "objc/base/RTCLogging.h",
       "objc/base/RTCLogging.mm",
       "objc/base/RTCMacros.h",
@@ -596,6 +597,16 @@ if (is_ios || is_mac) {
         "objc/components/video_frame_buffer/RTCCVPixelBuffer.h",
         "objc/components/video_frame_buffer/RTCCVPixelBuffer.mm",
       ]
+      # Stream-only: NV12 wrappers are built when the flag is enabled.
+      # Stream-only: enable gating macro for ObjC bridge policies.
+      # Stream-only: switch to NV12-enabled ObjC bridge implementation.
+      if (stream_enable_rendering_backend) {
+        sources += [
+          "objc/api/video_frame_buffer/RTCNativeNV12Buffer+Private.h",
+          "objc/api/video_frame_buffer/RTCNativeNV12Buffer.h",
+          "objc/api/video_frame_buffer/RTCNativeNV12Buffer.mm",
+        ]
+      }
       deps = [
         ":base_objc",
         "../rtc_base:logging",
@@ -642,6 +653,8 @@ if (is_ios || is_mac) {
         sources += [
           "objc/components/renderer/metal/RTCMTLVideoView.h",
           "objc/components/renderer/metal/RTCMTLVideoView.m",
+          "objc/components/renderer/metal/RTCVideoRenderingView.h",
+          "objc/components/renderer/metal/RTCVideoRenderingView.m",
         ]
       }
       if (is_mac) {
@@ -657,6 +670,42 @@ if (is_ios || is_mac) {
       ]
       configs += [ "..:common_objc" ]
       public_configs = [ ":common_config_objc" ]
+      # Stream-only: add shared Metal backend as a separate target.
+      if (stream_enable_rendering_backend) {
+        defines = [ "RTC_STREAM_RENDERING_BACKEND" ]
+        deps += [ ":stream_shared_metal_objc" ]
+      }
+    }
+
+    # Stream-only: iOS shared Metal implementation isolated here.
+    # XR (visionOS) is excluded until the shared backend is validated there.
+    if (stream_enable_rendering_backend && is_ios &&
+        !(target_environment == "xrsimulator" || target_environment == "xrdevice")) {
+      rtc_library("stream_shared_metal_objc") {
+        visibility = [ "*" ]
+        sources = [
+          "objc/components/renderer/metal/RTCSharedMetalRenderAdapter.h",
+          "objc/components/renderer/metal/RTCSharedMetalRenderAdapter.mm",
+          "objc/components/renderer/metal/RTCSharedMetalRenderingContext+Private.h",
+          "objc/components/renderer/metal/RTCSharedMetalRenderingContext.h",
+          "objc/components/renderer/metal/RTCSharedMetalRenderingContext.mm",
+          "objc/components/renderer/metal/RTCSharedMetalVideoView.h",
+          "objc/components/renderer/metal/RTCSharedMetalVideoView.mm",
+        ]
+        frameworks = [
+          "CoreVideo.framework",
+          "Metal.framework",
+          "QuartzCore.framework",
+          "UIKit.framework",
+        ]
+        deps = [
+          ":base_objc",
+          ":videoframebuffer_objc",
+          "../rtc_base:checks",
+        ]
+        configs += [ "..:common_objc" ]
+        public_configs = [ ":common_config_objc" ]
+      }
     }
 
     # TODO(bugs.webrtc.org/9627): Remove this target.
@@ -1036,6 +1085,9 @@ if (is_ios || is_mac) {
         "environment_construction",
       ]
       configs += [ "..:no_global_constructors" ]
+      if (stream_enable_rendering_backend) {
+        defines = [ "RTC_STREAM_RENDERING_BACKEND" ]
+      }
       sources = [
         "objc/api/peerconnection/RTCAudioDeviceModule.h",
         "objc/api/peerconnection/RTCAudioDeviceModule+Private.h",
@@ -1528,6 +1580,13 @@ if (is_ios || is_mac) {
           "objc/components/audio/RTCAudioCustomProcessingDelegate.h",
           "objc/components/audio/RTCAudioProcessingConfig.h",
         ]
+        # Stream-only: export NV12 headers when the flag is enabled.
+        if (stream_enable_rendering_backend) {
+          common_objc_headers += [
+            "objc/base/RTCNV12Buffer.h",
+            "objc/api/video_frame_buffer/RTCNativeNV12Buffer.h",
+          ]
+        }
 
         if (rtc_use_h265) {
           common_objc_headers += [
@@ -1542,6 +1601,7 @@ if (is_ios || is_mac) {
           common_objc_headers += [
             "objc/helpers/RTCCameraPreviewView.h",
             "objc/components/renderer/metal/RTCMTLVideoView.h",
+            "objc/components/renderer/metal/RTCVideoRenderingView.h",
           ]
         }
 
@@ -1692,6 +1752,7 @@ if (is_ios || is_mac) {
           "objc/components/capturer/RTCDesktopSource.h",
           "objc/components/capturer/RTCDesktopMediaList.h",
           "objc/components/renderer/metal/RTCMTLVideoView.h",
+          "objc/components/renderer/metal/RTCVideoRenderingView.h",
           "objc/components/renderer/metal/RTCMTLNSVideoView.h",
           "objc/components/renderer/opengl/RTCVideoViewShading.h",
           "objc/components/video_codec/RTCCodecSpecificInfoH264.h",
@@ -1714,6 +1775,13 @@ if (is_ios || is_mac) {
           "objc/components/audio/RTCAudioCustomProcessingDelegate.h",
           "objc/components/audio/RTCAudioProcessingConfig.h",
         ]
+        # Stream-only: export NV12 headers when the flag is enabled.
+        if (stream_enable_rendering_backend) {
+          sources += [
+            "objc/base/RTCNV12Buffer.h",
+            "objc/api/video_frame_buffer/RTCNativeNV12Buffer.h",
+          ]
+        }
         if (!build_with_chromium) {
           sources += [
             "objc/api/logging/RTCCallbackLogger.h",
@@ -1865,7 +1933,6 @@ if (is_ios || is_mac) {
     rtc_library("native_video") {
       sources = [
         "objc/native/src/objc_frame_buffer.h",
-        "objc/native/src/objc_frame_buffer.mm",
         "objc/native/src/objc_video_decoder_factory.h",
         "objc/native/src/objc_video_decoder_factory.mm",
         "objc/native/src/objc_video_encoder_factory.h",
@@ -1877,6 +1944,15 @@ if (is_ios || is_mac) {
         "objc/native/src/objc_video_track_source.h",
         "objc/native/src/objc_video_track_source.mm",
       ]
+      if (stream_enable_rendering_backend) {
+        sources += [
+          "objc/native/src/objc_frame_buffer_stream.mm",
+          "objc/native/src/objc_nv12_conversion.h",
+          "objc/native/src/objc_nv12_conversion.mm",
+        ]
+      } else {
+        sources += [ "objc/native/src/objc_frame_buffer.mm" ]
+      }
 
       configs += [ "..:common_objc" ]
 

sdk/objc/api/peerconnection/RTCPeerConnectionFactory.h

@@ -43,6 +43,13 @@ typedef NS_ENUM(NSInteger, RTC_OBJC_TYPE(RTCRtpMediaType));
 @protocol RTC_OBJC_TYPE
 (RTCAudioProcessingModule);
 
+typedef NS_ENUM(NSInteger, RTC_OBJC_TYPE(RTCFrameBufferPolicy)) {
+  RTC_OBJC_TYPE(RTCFrameBufferPolicyNone) = 0,
+  RTC_OBJC_TYPE(RTCFrameBufferPolicyWrapOnlyExistingNV12),
+  RTC_OBJC_TYPE(RTCFrameBufferPolicyCopyToNV12),
+  RTC_OBJC_TYPE(RTCFrameBufferPolicyConvertWithPoolToNV12)
+};
+
 RTC_OBJC_EXPORT
 @interface RTC_OBJC_TYPE (RTCPeerConnectionFactory) : NSObject
 
@@ -71,6 +78,20 @@ RTC_OBJC_EXPORT
 
 @property(nonatomic, readonly) RTC_OBJC_TYPE(RTCAudioDeviceModule) *audioDeviceModule;
 
+/**
+ * Controls how decoded frame buffers are bridged to Objective-C. Default is `none`.
+ * This can be toggled at runtime. It only takes effect when
+ * `stream_enable_rendering_backend=true` (RTC_STREAM_RENDERING_BACKEND).
+ *
+ * Note: the policy is evaluated per frame. Changing it mid-call can result in
+ * a mix of I420 and NV12 buffers for in-flight frames. For consistent format,
+ * set it before starting a call.
+ *
+ * Thread-safety: property access is not synchronized; set it from a single
+ * thread if you need strict consistency.
+ */
+@property(nonatomic, assign) RTC_OBJC_TYPE(RTCFrameBufferPolicy) frameBufferPolicy;
+
 /**
  * Valid kind values are kRTCMediaStreamTrackKindAudio and
  * kRTCMediaStreamTrackKindVideo.

sdk/objc/api/peerconnection/RTCPeerConnectionFactory.mm

@@ -57,6 +57,9 @@
 #include "sdk/objc/native/api/video_encoder_factory.h"
 #include "sdk/objc/native/src/objc_video_decoder_factory.h"
 #include "sdk/objc/native/src/objc_video_encoder_factory.h"
+#if defined(RTC_STREAM_RENDERING_BACKEND)
+#include "sdk/objc/native/src/objc_nv12_conversion.h"
+#endif
 
 #import "components/audio/RTCAudioProcessingModule.h"
 #import "components/audio/RTCDefaultAudioProcessingModule+Private.h"
@@ -73,6 +76,7 @@ @implementation RTC_OBJC_TYPE (RTCPeerConnectionFactory) {
   RTC_OBJC_TYPE(RTCDefaultAudioProcessingModule) *_defaultAudioProcessingModule;
 
   BOOL _hasStartedAecDump;
+  RTC_OBJC_TYPE(RTCFrameBufferPolicy) _frameBufferPolicy;
 }
 
 @synthesize nativeFactory = _nativeFactory;
@@ -196,6 +200,19 @@ - (instancetype)initWithNativeDependencies:
   return self;
 }
 
+- (RTC_OBJC_TYPE(RTCFrameBufferPolicy))frameBufferPolicy {
+  return _frameBufferPolicy;
+}
+
+- (void)setFrameBufferPolicy:(RTC_OBJC_TYPE(RTCFrameBufferPolicy))frameBufferPolicy {
+  _frameBufferPolicy = frameBufferPolicy;
+#if defined(RTC_STREAM_RENDERING_BACKEND)
+  // Only available in Stream builds with the shared backend enabled.
+  webrtc::SetObjCFrameBufferPolicy(
+      static_cast<webrtc::ObjCFrameBufferPolicy>(frameBufferPolicy));
+#endif
+}
+
 - (RTC_OBJC_TYPE(RTCRtpCapabilities) *)rtpSenderCapabilitiesFor:(RTC_OBJC_TYPE(RTCRtpMediaType))mediaType {
 
   webrtc::RtpCapabilities capabilities = _nativeFactory->GetRtpSenderCapabilities([RTC_OBJC_TYPE(RTCRtpReceiver) nativeMediaTypeForMediaType: mediaType]);

sdk/objc/api/video_frame_buffer/RTCNativeNV12Buffer+Private.h

@@ -0,0 +1,29 @@
+/*
+ *  Copyright 2026 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#import "RTCNativeNV12Buffer.h"
+
+#include "api/video/video_frame_buffer.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface RTC_OBJC_TYPE(RTCNV12Buffer) () {
+ @protected
+  webrtc::scoped_refptr<webrtc::NV12BufferInterface> _nv12Buffer;
+}
+
+/** Initialize an RTCNV12Buffer with its backing NV12BufferInterface. */
+- (instancetype)initWithFrameBuffer:
+    (webrtc::scoped_refptr<webrtc::NV12BufferInterface>)nv12Buffer;
+- (webrtc::scoped_refptr<webrtc::NV12BufferInterface>)nativeNV12Buffer;
+
+@end
+
+NS_ASSUME_NONNULL_END

sdk/objc/api/video_frame_buffer/RTCNativeNV12Buffer.h

@@ -0,0 +1,24 @@
+/*
+ *  Copyright 2026 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#import <AVFoundation/AVFoundation.h>
+
+#import "RTCNV12Buffer.h"
+#import "sdk/objc/base/RTCMacros.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+/** RTCNV12Buffer implements the RTCNV12Buffer protocol */
+RTC_OBJC_EXPORT
+@interface RTC_OBJC_TYPE(RTCNV12Buffer)
+    : NSObject<RTC_OBJC_TYPE(RTCNV12Buffer)>
+@end
+
+NS_ASSUME_NONNULL_END

sdk/objc/api/video_frame_buffer/RTCNativeNV12Buffer.mm

@@ -0,0 +1,93 @@
+/*
+ *  Copyright 2026 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#import "RTCNativeNV12Buffer+Private.h"
+#import "RTCNativeI420Buffer+Private.h"
+
+#include "api/video/nv12_buffer.h"
+
+@implementation RTC_OBJC_TYPE(RTCNV12Buffer)
+
+- (instancetype)initWithWidth:(int)width height:(int)height {
+  self = [super init];
+  if (self) {
+    _nv12Buffer = webrtc::NV12Buffer::Create(width, height);
+  }
+  return self;
+}
+
+- (instancetype)initWithWidth:(int)width
+                       height:(int)height
+                      strideY:(int)strideY
+                     strideUV:(int)strideUV {
+  self = [super init];
+  if (self) {
+    _nv12Buffer =
+        webrtc::NV12Buffer::Create(width, height, strideY, strideUV);
+  }
+  return self;
+}
+
+- (instancetype)initWithFrameBuffer:
+    (webrtc::scoped_refptr<webrtc::NV12BufferInterface>)nv12Buffer {
+  self = [super init];
+  if (self) {
+    _nv12Buffer = nv12Buffer;
+  }
+  return self;
+}
+
+- (int)width {
+  return _nv12Buffer->width();
+}
+
+- (int)height {
+  return _nv12Buffer->height();
+}
+
+- (int)strideY {
+  return _nv12Buffer->StrideY();
+}
+
+- (int)strideUV {
+  return _nv12Buffer->StrideUV();
+}
+
+- (int)chromaWidth {
+  return _nv12Buffer->ChromaWidth();
+}
+
+- (int)chromaHeight {
+  return _nv12Buffer->ChromaHeight();
+}
+
+- (const uint8_t *)dataY {
+  return _nv12Buffer->DataY();
+}
+
+- (const uint8_t *)dataUV {
+  return _nv12Buffer->DataUV();
+}
+
+- (id<RTC_OBJC_TYPE(RTCI420Buffer)>)toI420 {
+  webrtc::scoped_refptr<webrtc::I420BufferInterface> buffer =
+      _nv12Buffer->ToI420();
+  RTC_OBJC_TYPE(RTCI420Buffer) *result =
+      [[RTC_OBJC_TYPE(RTCI420Buffer) alloc] initWithFrameBuffer:buffer];
+  return result;
+}
+
+#pragma mark - Private
+
+- (webrtc::scoped_refptr<webrtc::NV12BufferInterface>)nativeNV12Buffer {
+  return _nv12Buffer;
+}
+
+@end