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IOS 技术分享| 在 iOS WebRTC 中添加美颜滤镜
发布于: 48 分钟前
在使用 WebRTC 的时候，对视频进行美颜处理一般有两种方式：替换 WebRTC 中的采集模块和对视频数据进行美颜。
一、替换 WebRTC 中的采集模块
替换 WebRTC 中的采集模块，相对比较简单，使用 GPUImageVideoCamera 替换 WebRTC 中的视频采集，得到经过 GPUImage 添加美颜处理后的图像，发送给 WebRTC 的 OnFrame 方法。
参考基于 WebRTC 框架开发的全平台推拉流 SDK：Github
设置美颜
- (void)setBeautyFace:(BOOL)beautyFace{ if(_beautyFace == beautyFace) return;
_beautyFace = beautyFace; [_emptyFilter removeAllTargets]; [_filter removeAllTargets]; [_videoCamera removeAllTargets];
if(_beautyFace){ _filter = [[GPUImageBeautifyFilter alloc] init]; _emptyFilter = [[GPUImageEmptyFilter alloc] init]; }else{ _filter = [[GPUImageEmptyFilter alloc] init]; }
__weak typeof(self) _self = self; [_filter setFrameProcessingCompletionBlock:^(GPUImageOutput *output, CMTime time) { [_self processVideo:output]; }]; [_videoCamera addTarget:_filter]; if (beautyFace) { [_filter addTarget:_emptyFilter]; if(_gpuImageView) [_emptyFilter addTarget:_gpuImageView]; } else { if(_gpuImageView) [_filter addTarget:_gpuImageView]; }}
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格式转换
GPUImage 处理后的 Pixel 格式为 BGRA,当处理完成后需要转换为 I420 格式，用于内部处理和渲染。
WebRTC 在编码的时候使用的是 NV12 格式的 Pixel，所以在编码的时候会进行二次格式转换
-(void) processVideo:(GPUImageOutput *)output{ rtc::CritScope cs(&cs_capture_); if (!_isRunning) { return; } @autoreleasepool { GPUImageFramebuffer *imageFramebuffer = output.framebufferForOutput;
size_t width = imageFramebuffer.size.width; size_t height = imageFramebuffer.size.height; uint32_t size = width * height * 3 / 2;
if(self.nWidth != width || self.nHeight != height) { self.nWidth = width; self.nHeight = height; if(_dst) delete[] _dst; _dst = NULL; } if(_dst == NULL) { _dst = new uint8_t[size]; } uint8_t* y_pointer = (uint8_t*)_dst; uint8_t* u_pointer = (uint8_t*)y_pointer + width*height; uint8_t* v_pointer = (uint8_t*)u_pointer + width*height/4; int y_pitch = width; int u_pitch = (width + 1) >> 1; int v_pitch = (width + 1) >> 1;
libyuv::ARGBToI420([imageFramebuffer byteBuffer], width * 4, y_pointer, y_pitch, u_pointer, u_pitch, v_pointer, v_pitch, width, height); if(self.bVideoEnable) libyuv::I420Rect(y_pointer, y_pitch, u_pointer, u_pitch, v_pointer, v_pitch, 0, 0, width, height, 32, 128, 128);
if(_capturer != nil) _capturer->CaptureYUVData(_dst, width, height, size); }}
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美颜后的数据发送给 WebRTC 的 OnFrame 方法
GPUImageVideoCapturer 类为 GPUImage 封装的摄像头类，跟 WebRTC 中的采集类功能保持一致，继承 cricket::VideoCapturer 类，便可以往 WebRTC 中塞入采集的音视频流。
namespace webrtc { // 继承cricket::VideoCapturer class GPUImageVideoCapturer : public cricket::VideoCapturer { ... }}
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void GPUImageVideoCapturer::CaptureYUVData(const webrtc::VideoFrame& frame, int width, int height){ VideoCapturer::OnFrame(frame, width, height);}
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二、对视频数据进行美颜
对视频数据美颜的思路就是传统的第三方美颜 SDK 的做法，对内部采集的音视频数据进行处理：内部采集的数据（CVPixelBufferRef）-》转换为纹理（GLuint）-》对纹理进行音视频的美颜-》美颜的纹理转换为 iOS 的采集数据（CVPixelBufferRef）-》返回给 WebRTC 内部进行渲染编码和传输。
同步线程
内部处理的一般都是使用同步线程，这样能够保证数据线性流动，参阅 GPUImage 中的代码片段
runSynchronouslyOnVideoProcessingQueue(^{ // 美颜处理 });
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把 CVPixelBufferRef 数据转换为纹理（GLuint）
RGB 格式类型的转换方式
CoreVideo框架的方法：使用此方法可以创建CVOpenGLESTextureRef纹理，并通过CVOpenGLESTextureGetName(texture)获取纹理 id。
- (GLuint)convertRGBPixelBufferToTexture:(CVPixelBufferRef)pixelBuffer { if (!pixelBuffer) { return 0; } CGSize textureSize = CGSizeMake(CVPixelBufferGetWidth(pixelBuffer), CVPixelBufferGetHeight(pixelBuffer)); CVOpenGLESTextureRef texture = nil; CVReturn status = CVOpenGLESTextureCacheCreateTextureFromImage(nil, [[GPUImageContext sharedImageProcessingContext] coreVideoTextureCache], pixelBuffer, nil, GL_TEXTURE_2D, GL_RGBA, textureSize.width, textureSize.height, GL_BGRA, GL_UNSIGNED_BYTE, 0, &texture); if (status != kCVReturnSuccess) { NSLog(@"Can't create texture"); } self.renderTexture = texture; return CVOpenGLESTextureGetName(texture); }
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OpenGL的方法：创建纹理对象，使用glTexImage2D方法上传CVPixelBufferRef中图像数据 data 到纹理对象中。
glBindTexture(GL_TEXTURE_2D, [outputFramebuffer texture]); glTexImage2D(GL_TEXTURE_2D, 0, _pixelFormat==GPUPixelFormatRGB ? GL_RGB : GL_RGBA, (int)uploadedImageSize.width, (int)uploadedImageSize.height, 0, (GLint)_pixelFormat, (GLenum)_pixelType, bytesToUpload);
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YUV 格式类型的转换方式
- (GLuint)convertYUVPixelBufferToTexture:(CVPixelBufferRef)pixelBuffer { if (!pixelBuffer) { return 0; } CGSize textureSize = CGSizeMake(CVPixelBufferGetWidth(pixelBuffer), CVPixelBufferGetHeight(pixelBuffer));
[EAGLContext setCurrentContext:self.context]; GLuint frameBuffer; GLuint textureID; // FBO glGenFramebuffers(1, &frameBuffer); glBindFramebuffer(GL_FRAMEBUFFER, frameBuffer); // texture glGenTextures(1, &textureID); glBindTexture(GL_TEXTURE_2D, textureID); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, textureSize.width, textureSize.height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, textureID, 0); glViewport(0, 0, textureSize.width, textureSize.height); // program glUseProgram(self.yuvConversionProgram); // texture CVOpenGLESTextureRef luminanceTextureRef = nil; CVOpenGLESTextureRef chrominanceTextureRef = nil;
CVReturn status = CVOpenGLESTextureCacheCreateTextureFromImage(kCFAllocatorDefault, self.textureCache, pixelBuffer, nil, GL_TEXTURE_2D, GL_LUMINANCE, textureSize.width, textureSize.height, GL_LUMINANCE, GL_UNSIGNED_BYTE, 0, &luminanceTextureRef); if (status != kCVReturnSuccess) { NSLog(@"Can't create luminanceTexture"); } status = CVOpenGLESTextureCacheCreateTextureFromImage(kCFAllocatorDefault, self.textureCache, pixelBuffer, nil, GL_TEXTURE_2D, GL_LUMINANCE_ALPHA, textureSize.width / 2, textureSize.height / 2, GL_LUMINANCE_ALPHA, GL_UNSIGNED_BYTE, 1, &chrominanceTextureRef); if (status != kCVReturnSuccess) { NSLog(@"Can't create chrominanceTexture"); } glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, CVOpenGLESTextureGetName(luminanceTextureRef)); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glUniform1i(glGetUniformLocation(self.yuvConversionProgram, "luminanceTexture"), 0); glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, CVOpenGLESTextureGetName(chrominanceTextureRef)); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glUniform1i(glGetUniformLocation(self.yuvConversionProgram, "chrominanceTexture"), 1); GLfloat kXDXPreViewColorConversion601FullRange[] = { 1.0, 1.0, 1.0, 0.0, -0.343, 1.765, 1.4, -0.711, 0.0, }; GLuint yuvConversionMatrixUniform = glGetUniformLocation(self.yuvConversionProgram, "colorConversionMatrix"); glUniformMatrix3fv(yuvConversionMatrixUniform, 1, GL_FALSE, kXDXPreViewColorConversion601FullRange); // VBO glBindBuffer(GL_ARRAY_BUFFER, self.VBO); GLuint positionSlot = glGetAttribLocation(self.yuvConversionProgram, "position"); glEnableVertexAttribArray(positionSlot); glVertexAttribPointer(positionSlot, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0); GLuint textureSlot = glGetAttribLocation(self.yuvConversionProgram, "inputTextureCoordinate"); glEnableVertexAttribArray(textureSlot); glVertexAttribPointer(textureSlot, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3* sizeof(float))); glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); glDeleteFramebuffers(1, &frameBuffer); glBindFramebuffer(GL_FRAMEBUFFER, 0); glBindBuffer(GL_ARRAY_BUFFER, 0); glFlush(); self.luminanceTexture = luminanceTextureRef; self.chrominanceTexture = chrominanceTextureRef; if (luminanceTextureRef) { CFRelease(luminanceTextureRef); } if (chrominanceTextureRef) { CFRelease(chrominanceTextureRef); } return textureID;}
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使用 GPUImageTextureInput 加载滤镜和使用 GPUImageTextureOutput 输出数据
[GPUImageContext setActiveShaderProgram:nil]; GPUImageTextureInput *textureInput = [[ARGPUImageTextureInput alloc] initWithTexture:textureID size:size]; GPUImageSmoothToonFilter *filter = [[GPUImageSmoothToonFilter alloc] init]; [textureInput addTarget:filter]; GPUImageTextureOutput *textureOutput = [[GPUImageTextureOutput alloc] init]; [filter addTarget:textureOutput]; [textureInput processTextureWithFrameTime:kCMTimeZero];
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得到 textureOutput，即得到输出的纹理。
GPUImageTextureOutput 纹理转化为 CVPixelBufferRef 数据
- (CVPixelBufferRef)convertTextureToPixelBuffer:(GLuint)texture textureSize:(CGSize)textureSize { [EAGLContext setCurrentContext:self.context]; CVPixelBufferRef pixelBuffer = [self createPixelBufferWithSize:textureSize]; GLuint targetTextureID = [self convertRGBPixelBufferToTexture:pixelBuffer]; GLuint frameBuffer; // FBO glGenFramebuffers(1, &frameBuffer); glBindFramebuffer(GL_FRAMEBUFFER, frameBuffer); // texture glBindTexture(GL_TEXTURE_2D, targetTextureID); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, textureSize.width, textureSize.height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, targetTextureID, 0); glViewport(0, 0, textureSize.width, textureSize.height); // program glUseProgram(self.normalProgram); // texture glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, texture); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glUniform1i(glGetUniformLocation(self.normalProgram, "renderTexture"), 0); // VBO glBindBuffer(GL_ARRAY_BUFFER, self.VBO); GLuint positionSlot = glGetAttribLocation(self.normalProgram, "position"); glEnableVertexAttribArray(positionSlot); glVertexAttribPointer(positionSlot, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0); GLuint textureSlot = glGetAttribLocation(self.normalProgram, "inputTextureCoordinate"); glEnableVertexAttribArray(textureSlot); glVertexAttribPointer(textureSlot, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3* sizeof(float))); glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); glDeleteFramebuffers(1, &frameBuffer); glBindFramebuffer(GL_FRAMEBUFFER, 0); glBindBuffer(GL_ARRAY_BUFFER, 0); glFlush(); return pixelBuffer;}
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把美颜后的 CVPixelBufferRef 同步返回给 SDK，进行渲染传输。
三、总结
对音视频的美颜，已经成为了音视频应用的常用功能，除了上述两种做法外，还可以使用第三方美颜，一般音视频厂商都有提供自采集功能，而第三方美颜功能则提供有采集美颜相机功能，二者正好可以无缝结合。如果自身的应用中对美颜要求不是很高，采用音视频 SDK 自带的美颜即可（美白、美颜、红润），如果用在娱乐场景，除了美颜，还要美型（廋脸，大眼）、贴纸（2D、3D）的，必须要集成第三方美颜 SDK 了。
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发布于: 48 分钟前阅读数: 2
版权声明: 本文为 InfoQ 作者【anyRTC开发者】的原创文章。
原文链接:【http://xie.infoq.cn/article/d3e19d59f40c7fe343279b5d2】。文章转载请联系作者。
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