Class RawFrame

rustcv-camera/src/backend/mod.rs:26–55

Raw frame data returned by a platform backend's `dequeue()`. 平台后端 `dequeue()` 返回的原始帧数据。 The lifetime `'a` is tied to the backend that produced it. For V4L2 this borrows directly from the mmap buffer; for AVFoundation it borrows from `AvfBackend::frame_buf`. 生命周期 `'a` 绑定到产生它的后端。 V4L2 中直接借用 mmap 缓冲区；AVFoundation 中借用 `AvfBackend::frame_buf`。

/// 生命周期 `'a` 绑定到产生它的后端。
/// V4L2 中直接借用 mmap 缓冲区；AVFoundation 中借用 `AvfBackend::frame_buf`。
pub(crate) struct RawFrame<'a> {
    /// Buffer index — used by V4L2 to re-queue the mmap buffer.
    /// Always 0 on AVFoundation (buffers managed internally).
    ///
    /// 缓冲区索引 —— V4L2 用于重新入队 mmap 缓冲区。
    /// AVFoundation 上始终为 0（缓冲区由内部管理）。
    #[allow(dead_code)]
    pub index: usize,

    /// Pixel data slice. Format is indicated by `pixel_format`.
    /// 像素数据切片。格式由 `pixel_format` 指示。
    pub data: &'a [u8],

    pub width: u32,
    pub height: u32,
    pub pixel_format: PixelFormat,

    /// Monotonically increasing frame counter.
    /// V4L2: kernel sequence number (gaps indicate dropped frames).
    /// AVFoundation: simple counter incremented by the delegate.
    ///
    /// 单调递增的帧计数器。
    /// V4L2：内核序号（间隔表示丢帧）。
    /// AVFoundation：delegate 递增的简单计数器。
    pub sequence: u64,

    /// Capture timestamp in microseconds.
    /// 采集时间戳（微秒）。
    pub timestamp_us: u64,
}

// ─── Platform backends ───────────────────────────────────────────────────────