fix: implement CVPixelBufferPool for macOS

Author: peilinok

shared/darwin/AgoraCVPixelBufferUtils.h

@@ -2,6 +2,15 @@
 
 @interface AgoraCVPixelBufferUtils : NSObject
 
+/**
+ * Frees all CVPixelBuffer pools.
+ *
+ * We use a pool of CVPixelBuffers to avoid allocating and freeing them
+ * frequently. This method allows us to free all the CVPixelBuffers in the
+ * pool when needed.
+ */
++ (void)freeAllCVPixelBufferPools;
+
 /**
  * Creates a copy of a CVPixelBuffer.
  *

shared/darwin/AgoraCVPixelBufferUtils.mm

@@ -1,8 +1,132 @@
 #import "AgoraCVPixelBufferUtils.h"
+
+#include <mutex>
+#include <tuple>
+#include <unordered_map>
+
 #include <CoreVideo/CoreVideo.h>
+#import <Foundation/Foundation.h>
+
+#pragma mark - AgoraCVPixelBufferPool
+
+struct AgoraCVPixelBufferPoolKey {
+  OSType type;
+  size_t width;
+  size_t height;
+
+  bool operator==(const AgoraCVPixelBufferPoolKey &other) const {
+    return type == other.type && width == other.width && height == other.height;
+  }
+
+  bool operator<(const AgoraCVPixelBufferPoolKey &other) const {
+    return std::tie(type, width, height) <
+           std::tie(other.type, other.width, other.height);
+  }
+};
+
+struct AgoraCVPixelBufferPoolKeyHash {
+  std::size_t operator()(const AgoraCVPixelBufferPoolKey &key) const {
+    return std::hash<OSType>()(key.type) ^ std::hash<size_t>()(key.width) ^
+           std::hash<size_t>()(key.height);
+  }
+};
+
+@interface AgoraCVPixelBufferPool : NSObject
+
++ (instancetype)sharedInstance;
+
+- (CVPixelBufferRef)createPixelBuffer:(OSType)type
+                                width:(size_t)width
+                               height:(size_t)height;
+
+- (void)freeAllCVPixelBufferPools;
+
+@end
+
+@implementation AgoraCVPixelBufferPool {
+  std::mutex _mutex;
+  std::unordered_map<AgoraCVPixelBufferPoolKey, CVPixelBufferPoolRef,
+                     AgoraCVPixelBufferPoolKeyHash>
+      _pools;
+}
+
++ (instancetype)sharedInstance {
+  static AgoraCVPixelBufferPool *instance = nil;
+
+  // should we use this or just use a static global variable?
+  static dispatch_once_t onceToken;
+  dispatch_once(&onceToken, ^{
+    instance = [[AgoraCVPixelBufferPool alloc] init];
+  });
+
+  return instance;
+}
+
+- (CVPixelBufferRef)createPixelBuffer:(OSType)type
+                                width:(size_t)width
+                               height:(size_t)height {
+  std::lock_guard<std::mutex> lock(_mutex);
+  CVPixelBufferPoolRef pool = nil;
+
+  AgoraCVPixelBufferPoolKey key = {type, width, height};
+  auto it = _pools.find(key);
+  if (it == _pools.end()) {
+    NSMutableDictionary *attributes =
+        [NSMutableDictionary dictionaryWithDictionary:@{
+          (id)kCVPixelBufferIOSurfacePropertiesKey : @{},
+#if defined(WEBRTC_IOS)
+          (id)kCVPixelBufferOpenGLESCompatibilityKey : @YES,
+#elif defined(WEBRTC_MAC)
+          (id)kCVPixelBufferOpenGLCompatibilityKey : @YES,
+#endif
+          (id)kCVPixelBufferCGImageCompatibilityKey : @YES,
+          (id)kCVPixelBufferCGBitmapContextCompatibilityKey : @YES,
+          (id)kCVPixelBufferPixelFormatTypeKey : @(key.type),
+          (id)kCVPixelBufferWidthKey : @(key.width),
+          (id)kCVPixelBufferHeightKey : @(key.height)
+        }];
+
+    if (@available(macOS 10.11, *)) {
+      [attributes setObject:@YES
+                     forKey:(id)kCVPixelBufferMetalCompatibilityKey];
+    }
+    CVReturn status =
+        CVPixelBufferPoolCreate(kCFAllocatorDefault, nullptr,
+                                (__bridge CFDictionaryRef)attributes, &pool);
+    if (status != kCVReturnSuccess || !pool) {
+      return nil;
+    }
+
+    _pools[key] = pool;
+  } else {
+    pool = it->second;
+  }
+
+  CVPixelBufferRef pixelBuffer = nil;
+  CVPixelBufferPoolCreatePixelBuffer(kCFAllocatorDefault, pool, &pixelBuffer);
+
+  return pixelBuffer;
+}
+
+- (void)freeAllCVPixelBufferPools {
+  std::lock_guard<std::mutex> lock(_mutex);
+  for (auto &pool : _pools) {
+    CVPixelBufferPoolFlush(pool.second, kCVPixelBufferPoolFlushExcessBuffers);
+    CVPixelBufferPoolRelease(pool.second);
+  }
+  _pools.clear();
+}
+
+@end
+
+#pragma mark - AgoraCVPixelBufferUtils
 
 @implementation AgoraCVPixelBufferUtils
 
++ (void)freeAllCVPixelBufferPools {
+  [[AgoraCVPixelBufferPool sharedInstance] freeAllCVPixelBufferPools];
+}
+
 + (BOOL)copyNV12CVPixelBuffer:(CVPixelBufferRef _Nonnull)sourcePixelBuffer
               destPixelBuffer:(CVPixelBufferRef _Nonnull)destPixelBuffer {
   if (!sourcePixelBuffer || !destPixelBuffer) {
@@ -116,6 +240,8 @@ + (CVPixelBufferRef)copyCVPixelBuffer:
   size_t sourceHeight = CVPixelBufferGetHeight(sourcePixelBuffer);
   OSType sourceFormat = CVPixelBufferGetPixelFormatType(sourcePixelBuffer);
 
+// create pixel buffer directly
+#if 1
   // Create new buffer with Metal compatibility
   NSDictionary *pixelBufferAttributes = @{
     // This key is required to generate SKPicture with CVPixelBufferRef in
@@ -130,6 +256,16 @@ + (CVPixelBufferRef)copyCVPixelBuffer:
   if (status != kCVReturnSuccess || !destPixelBuffer) {
     return nil;
   }
+#else
+  // create pixel buffer from pool
+  CVPixelBufferRef destPixelBuffer =
+      [[AgoraCVPixelBufferPool sharedInstance] createPixelBuffer:sourceFormat
+                                                           width:sourceWidth
+                                                          height:sourceHeight];
+  if (!destPixelBuffer) {
+    return nil;
+  }
+#endif
 
   // Copy data based on format
   BOOL success = NO;

shared/darwin/VideoViewController.mm

@@ -1,6 +1,8 @@
 #import <Foundation/Foundation.h>
 #import "VideoViewController.h"
 #import "TextureRenderer.h"
+#import "AgoraCVPixelBufferUtils.h"
+
 #import <AgoraRtcWrapper/iris_engine_base.h>
 #import <AgoraRtcWrapper/iris_rtc_rendering_cxx.h>
 
@@ -234,8 +236,14 @@ - (BOOL)destroyTextureRender:(int64_t)textureId {
     if (textureRender != nil) {
       [textureRender dispose];
       [self.textureRenders removeObjectForKey:@(textureId)];
+        
+      if (self.textureRenders.count == 0) {
+        [AgoraCVPixelBufferUtils freeAllCVPixelBufferPools];
+      }
+
       return YES;
     }
+
     return NO;
 }