Enum OutputFormat 

pub enum OutputFormat {
    Mp4H264Aac,
    Mp4H265Aac,
    WebmVp9Opus,
    WebmAv1Opus,
}

Output container + codec selection. Carries the (format → codec → muxer → file extension) tuple as one type so the rest of the pipeline can switch on a single value.

Default is OutputFormat::Mp4H264Aac — the universally- compatible “just give me an .mp4” choice. Other variants are opt-in via the M-EXPORT.4 format dropdown.

Variants

Mp4H264Aac

.mp4 container, H.264 video, AAC audio. The default for universal compatibility (QuickTime, every browser, every editor). macOS uses vtenc_h264_hw (hardware), Windows mfh264enc, Linux vaapih264enc / x264enc fallback.

Mp4H265Aac

.mp4 container, H.265 (HEVC) video, AAC audio. ~30% smaller files at equivalent quality vs. H.264; requires macOS 11+, Windows 10+, Linux with VAAPI HEVC support.

WebmVp9Opus

.webm container, VP9 video, Opus audio. Open codec (royalty-free), good browser support. macOS has no HW VP9 encoder so uses libvpx-vp9 (slow).

WebmAv1Opus

.webm container, AV1 video, Opus audio. Best compression of the four; HW encoders are M3+ Macs, Intel Arc, NVIDIA RTX 40+. Software fallback via svtav1enc (slow).

Implementations

impl OutputFormat

pub fn extension(self) -> &'static str

File extension this format writes (without leading .).

pub fn slug(self) -> &'static str

URL-safe slug for the M-EXPORT.4 format dropdown + RecordingConfig.format IPC field.

pub fn from_slug(slug: &str) -> Option<Self>

Parse the slug back to an OutputFormat. Inverse of Self::slug. Unknown slugs return None so the caller can surface a typed error.

pub const fn max_encode_edge(self) -> Option<u32>

Maximum encodable edge length (px) for this format’s hardware video encoder, or None when the encoder imposes no hard dimension cap.

Empirically probed on Apple Silicon (M1, GStreamer 1.26.8): VideoToolbox’s vtenc_h264_hw rejects caps negotiation (not-negotiated (-4), then the pipeline refuses to preroll) the instant either edge exceeds 4096 — the H.264 Level 5.2 frame-side ceiling. It is a per-axis cap, not a pixel-area cap (4096×4096 succeeds while the smaller 5120×1440 fails). vtenc_h265_hw accepts at least 8192×4320 (HEVC Level 6). The software WebM encoders (vp9enc / svtav1enc) have no hard cap — they only get slower. See AUT-334.

Trait Implementations

impl Clone for OutputFormat

fn clone(&self) -> OutputFormat

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for OutputFormat

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

Formats the value using the given formatter.

impl Default for OutputFormat

fn default() -> OutputFormat

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for OutputFormat

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for OutputFormat

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

Tests for self and other values to be equal, and is used by ==.

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

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

impl Serialize for OutputFormat

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Copy for OutputFormat

impl Eq for OutputFormat

impl StructuralPartialEq for OutputFormat