Struct CMSampleBuffer

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pub struct CMSampleBuffer(/* private fields */);

Available on crate feature cm only.

Expand description

Owned reference to a CoreMedia CMSampleBufferRef.

Cloning increments the underlying refcount via CFRetain; dropping releases via CFRelease. The pointer is opaque to safe Rust — accessor methods on this type are the only sanctioned way to inspect it.

Implementations§

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impl CMSampleBuffer

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pub const unsafe fn from_ptr(ptr: *mut c_void) -> Self

Wrap a raw CMSampleBufferRef without bumping its refcount or checking for NULL.

§Safety

ptr must be a non-null, live CMSampleBufferRef of the exact type carrying one retain transferred to this wrapper. The caller must not release or separately adopt that retain. For NULL-tolerant construction prefer Self::from_raw.

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pub unsafe fn from_raw(ptr: *mut c_void) -> Option<Self>

Adopt a raw CMSampleBufferRef without bumping its refcount.

Use this when the caller has just received a +1 retained pointer (e.g. a Swift Unmanaged.passRetained(...).toOpaque()). The returned CMSampleBuffer will release the pointer when dropped.

Returns None for a NULL pointer.

§Safety

A non-null ptr must be a live CMSampleBufferRef of the exact type carrying one retain transferred to this wrapper. The caller must not release or separately adopt that transferred retain.

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pub unsafe fn from_raw_borrowed(ptr: *mut c_void) -> Option<Self>

Wrap a raw CMSampleBufferRef, calling CFRetain to bump its refcount before taking ownership.

Use this when the caller holds a borrowed (non-owning) reference and wants to take ownership without affecting the source.

§Safety

A non-null ptr must be a live CMSampleBufferRef of the exact type for the duration of the retain call.

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pub const fn as_ptr(&self) -> *mut c_void

Borrow the underlying +0 CMSampleBufferRef without changing its refcount. The pointer remains valid for the lifetime of self.

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pub fn is_valid(&self) -> bool

Whether the sample buffer is in a valid state.

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pub fn data_is_ready(&self) -> bool

Whether the sample buffer’s data is ready for consumption.

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pub fn num_samples(&self) -> i64

Number of samples carried by this buffer (1 for video, N for audio).

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pub fn presentation_timestamp(&self) -> CMTime

Presentation timestamp of the first sample.

Returns CMTime::INVALID if the buffer has no PTS.

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pub fn decode_timestamp(&self) -> CMTime

Decode timestamp of the first sample (matters when there’s B-frame reordering between PTS and DTS).

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pub fn duration(&self) -> CMTime

Total duration of all samples in this buffer.

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pub fn data_buffer(&self) -> Option<CMBlockBuffer>

The attached CMBlockBuffer holding the encoded sample data, if the sample buffer is data-bearing (as opposed to image-bearing).

Video frames from VTCompressionSession always have a data buffer (the encoded NAL units / ProRes frame data). Decoded video frames from a capture pipeline typically use an image buffer instead — see Self::image_buffer_ptr_borrowed.

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pub fn format_description(&self) -> Option<CMFormatDescription>

Format description (codec, dimensions, audio params, …) attached to this sample buffer.

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pub fn image_buffer_ptr_borrowed(&self) -> *mut c_void

Borrowed +0 CVImageBufferRef if the sample is image-bearing.

Returns NULL for sample buffers that don’t carry an image buffer (for example, compressed video or audio samples). The pointer remains valid only while self and the sample buffer’s image association remain alive. Retain it before storing or adopting it.

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