Rust视频处理库core-video-sys的使用:跨平台视频编解码与硬件加速功能集成

use core_video_sys::{
    kCVPixelBufferLock_ReadOnly, 
    CVPixelBufferLockBaseAddress, 
    CVPixelBufferUnlockBaseAddress,
    // 其他必要的导入
};

fn main() {
    // 初始化视频处理环境
    unsafe {
        // 锁定像素缓冲区进行读取操作
        CVPixelBufferLockBaseAddress(pixel_buffer, kCVPixelBufferLock_ReadOnly);
        
        // 在这里进行视频编解码和硬件加速处理
        // 示例代码:访问像素数据
        let base_address = CVPixelBufferGetBaseAddress(pixel_buffer);
        let bytes_per_row = CVPixelBufferGetBytesPerRow(pixel_buffer);
        let width = CVPixelBufferGetWidth(pixel_buffer);
        let height = CVPixelBufferGetHeight(pixel_buffer);
        
        // 处理视频帧数据
        process_video_frame(base_address, bytes_per_row, width, height);
        
        // 解锁像素缓冲区
        CVPixelBufferUnlockBaseAddress(pixel_buffer, kCVPixelBufferLock_ReadOnly);
    }
}

fn process_video_frame(base_address: *mut std::ffi::c_void, bytes_per_row: usize, width: usize, height: usize) {
    // 视频帧处理逻辑
    // 这里可以实现编解码、滤镜、格式转换等功能
    println!("Processing video frame: {}x{}, stride: {}", width, height, bytes_per_row);
}
use std::ptr;
use core_foundation_sys::base::{CFRelease, CFRetain};
use core_video_sys::{
    kCVPixelBufferLock_ReadOnly,
    kCVPixelBufferLock_Exclude,
    CVPixelBufferLockBaseAddress,
    CVPixelBufferUnlockBaseAddress,
    CVPixelBufferGetBaseAddress,
    CVPixelBufferGetBytesPerRow,
    CVPixelBufferGetWidth,
    CVPixelBufferGetHeight,
    CVPixelBufferGetPixelFormatType,
    CVPixelBufferCreate,
    kCVPixelFormatType_32BGRA
};

// 视频帧处理函数
unsafe fn process_video_data(pixel_buffer: *mut std::ffi::c_void) {
    // 锁定像素缓冲区进行读取
    CVPixelBufferLockBaseAddress(pixel_buffer, kCVPixelBufferLock_ReadOnly);
    
    // 获取像素缓冲区信息
    let base_address = CVPixelBufferGetBaseAddress(pixel_buffer);
    let bytes_per_row = CVPixelBufferGetBytesPerRow(pixel_buffer) as usize;
    let width = CVPixelBufferGetWidth(pixel_buffer) as usize;
    let height = CVPixelBufferGetHeight(pixel_buffer) as usize;
    let format = CVPixelBufferGetPixelFormatType(pixel_buffer);
    
    println!("视频帧信息: {}x{}, 步长: {}, 格式: {}", width, height, bytes_per_row, format);
    
    // 处理视频帧数据(示例:简单的像素访问)
    if !base_address.is_null() {
        let data = std::slice::from_raw_parts(base_address as *const u8, height * bytes_per_row);
        // 这里可以添加具体的视频处理逻辑
        println!("成功访问像素数据,数据长度: {}", data.len());
    }
    
    // 解锁像素缓冲区
    CVPixelBufferUnlockBaseAddress(pixel_buffer, kCVPixelBufferLock_ReadOnly);
}

fn main() {
    // 创建测试用的像素缓冲区
    let width = 1920;
    let height = 1080;
    let pixel_format = kCVPixelFormatType_32BGRA;
    
    let mut pixel_buffer: *mut std::ffi::c_void = ptr::null_mut();
    
    unsafe {
        // 创建像素缓冲区
        let result = CVPixelBufferCreate(
            ptr::null_mut(),
            width as isize,
            height as isize,
            pixel_format,
            ptr::null_mut(),
            &mut pixel_buffer
        );
        
        if result == 0 && !pixel_buffer.is_null() {
            println!("成功创建像素缓冲区");
            
            // 处理视频数据
            process_video_data(pixel_buffer);
            
            // 释放资源
            CFRelease(pixel_buffer);
        } else {
            println!("创建像素缓冲区失败");
        }
    }
}

这个完整示例展示了如何使用core-video-sys库创建像素缓冲区、锁定访问像素数据以及进行基本的视频帧处理操作。代码包含了错误处理和资源管理,演示了该库提供的跨平台视频编解码和硬件加速功能集成支持。


1 回复

Rust视频处理库core-video-sys使用指南

概述

core-video-sys是Rust语言中用于跨平台视频处理的底层库,提供对系统级视频编解码和硬件加速功能的直接访问。该库封装了不同操作系统(macOS、iOS、Windows、Linux)的视频处理API,为开发者提供统一的接口。

主要功能

  • 硬件加速视频编解码
  • 跨平台视频帧处理
  • 内存管理和缓冲区操作
  • 色彩空间转换
  • 时间戳和帧率控制

安装方法

在Cargo.toml中添加依赖:

[dependencies]
core-video-sys = "0.1"

基本使用方法

1. 初始化视频会话

use core_video_sys::{
    CVReturn, 
    kCVReturnSuccess,
    CVImageBufferRef
};

fn init_video_session() -> Result<(), CVReturn> {
    // 初始化视频处理环境
    unsafe {
        let result = core_video_sys::CVPixelBufferCreate(
            std::ptr::null_mut(),
            1920,
            1080,
            core_video_sys::kCVPixelFormatType_32BGRA,
            std::ptr::null_mut(),
            std::ptr::null_mut()
        );
        
        if result != kCVReturnSuccess {
            return Err(result);
        }
    }
    Ok(())
}

2. 创建像素缓冲区

use std::ptr;

fn create_pixel_buffer() -> Result<CVImageBufferRef, CVReturn> {
    let mut pixel_buffer: CVImageBufferRef = ptr::null_mut();
    
    unsafe {
        let result = core_video_sys::CVPixelBufferCreate(
            ptr::null_mut(),
            1280,
            720,
            core_video_sys::kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange,
            ptr::null_mut(),
            &mut pixel_buffer
        );
        
        if result == kCVReturnSuccess {
            Ok(pixel_buffer)
        } else {
            Err(result)
        }
    }
}

3. 硬件加速编解码示例

use core_video_sys::{
    VTCompressionSessionRef,
    VTDecompressionSessionRef
};

fn setup_hardware_encoding() -> Result<VTCompressionSessionRef, CVReturn> {
    let mut compression_session: VTCompressionSessionRef = ptr::null_mut();
    
    unsafe {
        let result = core_video_sys::VTCompressionSessionCreate(
            ptr::null_mut(),
            1920,
            1080,
            core_video_sys::kCMVideoCodecType_H264,
            ptr::null_mut(),
            ptr::null_mut(),
            ptr::null_mut(),
            None,
            ptr::null_mut(),
            &mut compression_session
        );
        
        if result == 0 { // 0表示成功
            Ok(compression_session)
        } else {
            Err(result)
        }
    }
}

4. 跨平台视频处理

#[cfg(target_os = "macos")]
fn platform_specific_setup() {
    // macOS特定的初始化代码
    println!("Initializing for macOS...");
}

#[cfg(target_os = "windows")]
fn platform_specific_setup() {
    // Windows特定的初始化代码
    println!("Initializing for Windows...");
}

#[cfg(target_os = "linux")]
fn platform_specific_setup() {
    // Linux特定的初始化代码
    println!("Initializing for Linux...");
}

错误处理

fn handle_video_errors(result: CVReturn) -> Result<(), String> {
    match result {
        kCVReturnSuccess => Ok(()),
        core_video_sys::kCVReturnInvalidArgument => 
            Err("Invalid argument provided".to_string()),
        core_video_sys::kCVReturnAllocationFailed => 
            Err("Memory allocation failed".to_string()),
        _ => Err("Unknown error occurred".to_string())
    }
}

内存管理最佳实践

use std::ops::Drop;

struct VideoBuffer {
    buffer: CVImageBufferRef,
}

impl VideoBuffer {
    fn new() -> Result<Self, CVReturn> {
        let mut buffer: CVImageBufferRef = ptr::null_mut();
        unsafe {
            let result = core_video_sys::CVPixelBufferCreate(
                // ... 参数
            );
            if result == kCVReturnSuccess {
                Ok(Self { buffer })
            } else {
                Err(result)
            }
        }
    }
}

impl Drop for VideoBuffer {
    fn drop(&mut self) {
        if !self.buffer.is_null() {
            unsafe {
                core_video_sys::CFRelease(self.buffer as _);
            }
        }
    }
}

完整示例demo

use core_video_sys::{
    CVReturn, 
    kCVReturnSuccess,
    CVImageBufferRef,
    VTCompressionSessionRef,
    kCVPixelFormatType_32BGRA,
    kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange,
    kCMVideoCodecType_H264,
    kCVReturnInvalidArgument,
    kCVReturnAllocationFailed,
    CFRelease
};
use std::ptr;

// 视频处理会话结构体
struct VideoProcessingSession {
    compression_session: VTCompressionSessionRef,
    pixel_buffer: CVImageBufferRef,
}

impl VideoProcessingSession {
    // 创建新的视频处理会话
    fn new(width: i32, height: i32) -> Result<Self, CVReturn> {
        // 创建像素缓冲区
        let pixel_buffer = create_pixel_buffer_with_size(width, height)?;
        
        // 创建压缩会话
        let compression_session = create_compression_session(width, height)?;
        
        Ok(Self {
            compression_session,
            pixel_buffer,
        })
    }
    
    // 处理视频帧
    fn process_frame(&self) -> Result<(), CVReturn> {
        // 这里可以添加具体的视频帧处理逻辑
        unsafe {
            // 示例:设置会话属性
            let result = core_video_sys::VTSessionSetProperty(
                self.compression_session,
                core_video_sys::kVTCompressionPropertyKey_RealTime,
                ptr::null_mut()
            );
            
            if result != 0 {
                return Err(result);
            }
        }
        Ok(())
    }
}

impl Drop for VideoProcessingSession {
    fn drop(&mut self) {
        // 释放压缩会话
        if !self.compression_session.is_null() {
            unsafe {
                core_video_sys::VTCompressionSessionInvalidate(self.compression_session);
                core_video_sys::CFRelease(self.compression_session as _);
            }
        }
        
        // 释放像素缓冲区
        if !self.pixel_buffer.is_null() {
            unsafe {
                CFRelease(self.pixel_buffer as _);
            }
        }
    }
}

// 创建指定大小的像素缓冲区
fn create_pixel_buffer_with_size(width: i32, height: i32) -> Result<CVImageBufferRef, CVReturn> {
    let mut pixel_buffer: CVImageBufferRef = ptr::null_mut();
    
    unsafe {
        let result = core_video_sys::CVPixelBufferCreate(
            ptr::null_mut(),
            width,
            height,
            kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange,
            ptr::null_mut(),
            &mut pixel_buffer
        );
        
        if result == kCVReturnSuccess {
            Ok(pixel_buffer)
        } else {
            Err(result)
        }
    }
}

// 创建压缩会话
fn create_compression_session(width: i32, height: i32) -> Result<VTCompressionSessionRef, CVReturn> {
    let mut compression_session: VTCompressionSessionRef = ptr::null_mut();
    
    unsafe {
        let result = core_video_sys::VTCompressionSessionCreate(
            ptr::null_mut(),
            width,
            height,
            kCMVideoCodecType_H264,
            ptr::null_mut(),
            ptr::null_mut(),
            ptr::null_mut(),
            None,
            ptr::null_mut(),
            &mut compression_session
        );
        
        if result == 0 {
            Ok(compression_session)
        } else {
            Err(result)
        }
    }
}

// 错误处理函数
fn handle_cv_error(result: CVReturn) -> Result<(), String> {
    match result {
        kCVReturnSuccess => Ok(()),
        kCVReturnInvalidArgument => Err("提供了无效参数".to_string()),
        kCVReturnAllocationFailed => Err("内存分配失败".to_string()),
        _ => Err(format!("未知Core Video错误: {}", result))
    }
}

// 平台特定的初始化
fn initialize_platform() {
    #[cfg(target_os = "macos")]
    {
        println!("初始化macOS视频子系统...");
    }
    
    #[cfg(target_os = "windows")]
    {
        println!("初始化Windows视频子系统...");
    }
    
    #[cfg(target_os = "linux")]
    {
        println!("初始化Linux视频子系统...");
    }
}

// 主函数示例
fn main() -> Result<(), String> {
    // 平台初始化
    initialize_platform();
    
    // 创建视频处理会话
    let session = VideoProcessingSession::new(1920, 1080)
        .map_err(|e| handle_cv_error(e).unwrap_err())?;
    
    // 处理视频帧
    session.process_frame()
        .map_err(|e| handle_cv_error(e).unwrap_err())?;
    
    println!("视频处理会话创建并初始化成功!");
    
    Ok(())
}

// 单元测试
#[cfg(test)]
mod tests {
    use super::*;
    
    #[test]
    fn test_pixel_buffer_creation() {
        let result = create_pixel_buffer_with_size(640, 480);
        assert!(result.is_ok());
        
        let pixel_buffer = result.unwrap();
        assert!(!pixel_buffer.is_null());
        
        // 清理
        unsafe {
            CFRelease(pixel_buffer as _);
        }
    }
    
    #[test]
    fn test_error_handling() {
        let error = handle_cv_error(kCVReturnSuccess);
        assert!(error.is_ok());
        
        let error = handle_cv_error(kCVReturnInvalidArgument);
        assert!(error.is_err());
        assert_eq!(error.unwrap_err(), "提供了无效参数");
    }
}

注意事项

  1. 该库提供的是底层API,使用时需要谨慎处理内存管理和线程安全
  2. 不同平台的硬件加速支持可能有所差异
  3. 建议在使用前检查设备的能力和支持的编解码格式
  4. 注意错误处理和资源释放,避免内存泄漏

这个库为需要直接与系统视频处理功能交互的高级应用场景提供了强大的基础功能。

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