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

The caller must ensure ptr is a valid CMSampleBufferRef retained at +1 (the wrapper will release on drop). For NULL-tolerant construction prefer Self::from_raw.

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

Wrap 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.

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pub unsafe fn from_raw_retained(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

ptr must be a valid CMSampleBufferRef (or NULL). Passing a dangling or wrong-type pointer is undefined behaviour.

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

Borrow the underlying CMSampleBufferRef for hand-off to other Apple bindings 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.

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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(&self) -> *mut c_void

Raw CVImageBufferRef if the sample is image-bearing (decoded video frames from a capture pipeline). Use a CV crate’s wrapper to turn this into a safe CVPixelBuffer.

Returns NULL for sample buffers that don’t carry an image buffer (e.g. compressed video from VideoToolbox, audio samples).