Struct retina::codec::VideoParameters

pub struct VideoParameters { /* private fields */ }

Parameters which describe a video stream.

A video stream’s parameters are often, but not always, available immediately after DESCRIBE via crate::client::Stream::parameters. They should always be available after the first frame. They may change mid-stream.

Video streams’ parameters may change mid-stream; if so, the frame which changed them will have VideoFrame::new_parameters set, and subsequent calls to crate::client::Stream::parameters will return the new value.

Implementations

impl VideoParameters

pub fn rfc6381_codec(&self) -> &str

Returns a codec description in RFC-6381 form, eg avc1.4D401E.

pub fn pixel_dimensions(&self) -> (u32, u32)

Returns the overall dimensions of the video frame in pixels, as (width, height).

pub fn pixel_aspect_ratio(&self) -> Option<(u32, u32)>

Returns the displayed size of a pixel, if known, as a dimensionless ratio (h_spacing, v_spacing). This is as specified in ISO/IEC 14496-12:2015 section 12.1.4.

It’s common for IP cameras to use anamorphic sub streams. Eg a 16x9 camera may export the same video source as a 1920x1080 “main” stream and a 704x480 “sub” stream, without cropping. The former has a pixel aspect ratio of (1, 1) while the latter has a pixel aspect ratio of (40, 33).

pub fn frame_rate(&self) -> Option<(u32, u32)>

Returns the maximum frame rate in seconds as (numerator, denominator), if known.

May not be minimized, and may not be in terms of the clock rate. Eg 15 frames per second might be returned as (1, 15) or (6000, 90000). The standard NTSC framerate (roughly 29.97 fps) might be returned as (1001, 30000).

TODO: maybe return in clock rate units instead? TODO: expose fixed vs max distinction (see H.264 fixed_frame_rate_flag).

pub fn extra_data(&self) -> &[u8]

The codec-specific “extra data” to feed to eg ffmpeg to decode the video frames.

• H.264: an AvcDecoderConfig.

Trait Implementations

impl Clone for VideoParameters

fn clone(&self) -> VideoParameters

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for VideoParameters

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for VideoParameters

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for VideoParameters

fn eq(&self, other: &VideoParameters) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for VideoParameters

impl StructuralPartialEq for VideoParameters