Rust多媒体处理库gstreamer-allocators的使用，高效内存管理与音视频流分配器实现

以下是基于您提供内容的完整示例demo，包含内存分配和视频帧处理的完整实现：

基础内存分配示例

use gstreamer_allocators as allocators;
use gstreamer::prelude::*;

fn main() {
    // 初始化GStreamer
    gstreamer::init().unwrap();

    // 创建内存分配器
    let allocator = allocators::Allocator::find("DMABuf").expect("无法找到DMABuf分配器");

    // 分配内存参数
    let params = allocators::AllocationParams::builder()
        .size(1024 * 1024)  // 1MB内存
        .alignment(128)     // 128字节对齐
        .flags(allocators::AllocationFlags::ZERO_PREFIXED)
        .build();

    // 分配内存
    let memory = allocator.alloc(params).expect("内存分配失败");

    // 使用内存...
    println!("成功分配{}字节内存", memory.size());

    // 释放内存
    drop(memory);
}

完整视频处理管道示例

use gstreamer_allocators as allocators;
use gstreamer::{prelude::*, Buffer, Memory, Caps};
use gstreamer_video::{VideoInfo, VideoFormat};

fn process_video_frame(buffer: &Buffer) {
    if let Some(memory) = buffer.peek_memory(0) {
        let memory = memory.into_owned();
        let map = memory.map_readable().unwrap();
        
        let data = map.as_slice();
        println!("处理视频帧数据，大小: {}字节", data.len());
        
        // 实际视频处理逻辑...
    }
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // 初始化GStreamer
    gstreamer::init()?;

    // 创建管道
    let pipeline = gstreamer::Pipeline::new(None);
    
    // 创建元素
    let src = gstreamer::ElementFactory::make("videotestsrc")
        .name("src")
        .build()?;
    
    let sink = gstreamer::ElementFactory::make("fakesink")
        .name("sink")
        .build()?;
    
    // 添加到管道
    pipeline.add_many(&[&src, &sink])?;
    
    // 连接元素
    src.link(&sink)?;
    
    // 设置自定义分配器
    let allocator = allocators::Allocator::find("VideoAligned")
        .expect("无法找到VideoAligned分配器");
    
    // 获取视频caps
    let caps = Caps::builder("video/x-raw")
        .field("format", "I420")
        .field("width", 1920i32)
        .field("height", 1080i32)
        .build();
    
    // 设置probe处理视频帧
    let sinkpad = sink.static_pad("sink").expect("无法获取sink pad");
    sinkpad.add_probe(gstreamer::PadProbeType::BUFFER, |_, probe_info| {
        if let Some(gstreamer::PadProbeData::Buffer(ref buffer)) = probe_info.data {
            process_video_frame(buffer);
        }
        gstreamer::PadProbeReturn::Ok
    });
    
    // 启动管道
    pipeline.set_state(gstreamer::State::Playing)?;
    
    // 运行一段时间
    std::thread::sleep(std::time::Duration::from_secs(5));
    
    // 停止管道
    pipeline.set_state(gstreamer::State::Null)?;
    
    Ok(())
}

高级示例：自定义内存分配器

use gstreamer_allocators::{Allocator, AllocationParams, AllocationFlags};
use gstreamer::{Buffer, Memory};
use std::sync::Arc;

struct CustomAllocator;

impl Allocator for CustomAllocator {
    fn alloc(
        &self,
        params: AllocationParams,
    ) -> Result<Memory, gstreamer::error::AllocatorError> {
        // 自定义内存分配逻辑
        let size = params.size();
        let alignment = params.alignment();
        
        // 分配对齐的内存
        let mut data = Vec::with_capacity(size + alignment);
        let ptr = data.as_mut_ptr();
        
        // 创建GStreamer内存对象
        Memory::from_mapped(ptr as *mut _, size, Arc::new(data))
            .map_err(|_| gstreamer::error::AllocatorError::Failed)
    }
}

fn main() {
    gstreamer::init().unwrap();
    
    // 注册自定义分配器
    let allocator = CustomAllocator;
    
    // 使用自定义分配器分配内存
    let params = AllocationParams::builder()
        .size(4096)
        .alignment(64)
        .flags(AllocationFlags::ZERO_PREFIXED)
        .build();
    
    match allocator.alloc(params) {
        Ok(memory) => {
            println!("自定义分配器成功分配{}字节内存", memory.size());
            drop(memory);
        }
        Err(e) => eprintln!("分配失败: {:?}", e),
    }
}

许可证

gstreamer-allocators采用以下双许可证之一：

• Apache License, Version 2.0
• MIT license

贡献

欢迎通过Pull Request提交任何形式的贡献。除非您明确声明，否则任何贡献都将按照上述双许可证授权。