diff --git a/Cargo.lock b/Cargo.lock
index c7934100..8f8a55a2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1164,6 +1164,13 @@ dependencies = [
  "thiserror 2.0.21",
 ]
 
+[[package]]
+name = "effectcraft-av1enc"
+version = "0.1.0"
+dependencies = [
+ "filmcraft-av1",
+]
+
 [[package]]
 name = "effectcraft-cli"
 version = "0.1.0"
@@ -1301,6 +1308,13 @@ dependencies = [
  "wgpu",
 ]
 
+[[package]]
+name = "effectcraft-hevcenc"
+version = "0.1.0"
+dependencies = [
+ "filmcraft-hevc",
+]
+
 [[package]]
 name = "effectcraft-host"
 version = "0.1.0"
diff --git a/Cargo.toml b/Cargo.toml
index 22709f60..f12282d1 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -38,6 +38,8 @@ effectcraft-ui-egui = { path = "crates/ui-egui" }
 effectcraft-automation = { path = "crates/automation" }
 effectcraft-opusenc = { path = "crates/opusenc" }
 effectcraft-script = { path = "crates/script" }
+effectcraft-hevcenc = { path = "crates/hevcenc" }
+effectcraft-av1enc = { path = "crates/av1enc" }
 
 # foundation
 thiserror = "2"
@@ -76,6 +78,9 @@ filmcraft-isobmff = { git = "https://github.com/storytold/filmcraft", rev = "89c
 # decoder used as the round-trip oracle of effectcraft-opusenc (crates/export dev-dependency)
 filmcraft-opus = { git = "https://github.com/storytold/filmcraft", rev = "89cfbf24f698b0f0e538eb7795929f19bbfb1dbb" }
 filmcraft-vp9 = { git = "https://github.com/storytold/filmcraft", rev = "89cfbf24f698b0f0e538eb7795929f19bbfb1dbb" }
+# decoders used as the round-trip oracles of effectcraft-hevcenc / effectcraft-av1enc (dev-dependencies only)
+filmcraft-hevc = { git = "https://github.com/storytold/filmcraft", rev = "89cfbf24f698b0f0e538eb7795929f19bbfb1dbb" }
+filmcraft-av1 = { git = "https://github.com/storytold/filmcraft", rev = "89cfbf24f698b0f0e538eb7795929f19bbfb1dbb" }
 
 # gpu (the same wgpu eframe / egui-wgpu use)
 wgpu = { version = "30.0.1", features = ["fragile-send-sync-non-atomic-wasm"] }
@@ -148,6 +153,12 @@ opt-level = 3
 [profile.dev.package.effectcraft-vp9enc]
 opt-level = 3
 
+[profile.dev.package.effectcraft-hevcenc]
+opt-level = 3
+
+[profile.dev.package.effectcraft-av1enc]
+opt-level = 3
+
 # FilmCraft codec hot loops (same settings as FilmCraft's own workspace).
 [profile.dev.package.filmcraft-h264]
 opt-level = 3
diff --git a/crates/av1enc/Cargo.toml b/crates/av1enc/Cargo.toml
new file mode 100644
index 00000000..2a4c7ddf
--- /dev/null
+++ b/crates/av1enc/Cargo.toml
@@ -0,0 +1,15 @@
+[package]
+name = "effectcraft-av1enc"
+description = "Clean-room pure-Rust AV1 encoder (Main profile, key and inter frames) for MP4/WebM export, from the AV1 Bitstream & Decoding Process Specification"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+rust-version.workspace = true
+
+[lints]
+workspace = true
+
+[dependencies]
+
+[dev-dependencies]
+filmcraft-av1 = { workspace = true }
diff --git a/crates/av1enc/src/lib.rs b/crates/av1enc/src/lib.rs
new file mode 100644
index 00000000..7b2ee3bc
--- /dev/null
+++ b/crates/av1enc/src/lib.rs
@@ -0,0 +1,98 @@
+//! Clean-room pure-Rust AV1 encoder — API skeleton (implementation in progress).
+//!
+//! The public API below is the contract `crates/export` codes against; keep it stable.
+
+/// Rate control.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum RateControl {
+    /// Constant quantizer index (`base_q_idx`, 1–255; lower is better).
+    ConstantQ(u8),
+    /// Average bitrate target in kbit/s (frame-level quantizer adaptation).
+    Bitrate { kbps: u32 },
+}
+
+/// Encoder settings. Main profile (seq_profile 0), 4:2:0.
+#[derive(Clone, Debug, PartialEq)]
+pub struct EncoderConfig {
+    pub width: u32,
+    pub height: u32,
+    pub fps_num: u32,
+    pub fps_den: u32,
+    /// 8 or 10.
+    pub bit_depth: u8,
+    /// `seq_level_idx` (e.g. 8 = level 4.0); `None` picks the lowest level that fits.
+    pub level_idx: Option<u8>,
+    pub rate: RateControl,
+    /// Frames between key frames (1 = all key frames).
+    pub keyint: u32,
+    /// BT.709 limited range is signalled unless this is set.
+    pub full_range: bool,
+}
+
+impl EncoderConfig {
+    pub fn new(width: u32, height: u32, fps_num: u32, fps_den: u32) -> Self {
+        EncoderConfig { width, height, fps_num, fps_den, bit_depth: 8, level_idx: None, rate: RateControl::ConstantQ(100), keyint: 60, full_range: false }
+    }
+}
+
+/// One input picture, 4:2:0, samples at the configured bit depth.
+#[derive(Clone, Copy, Debug)]
+pub struct Frame<'a> {
+    pub y: &'a [u16],
+    pub u: &'a [u16],
+    pub v: &'a [u16],
+    pub y_stride: usize,
+    pub uv_stride: usize,
+}
+
+/// One temporal unit as stored in MP4 / WebM samples: OBUs with `obu_has_size_field` = 1 and
+/// no temporal delimiter (key frames start with the sequence header OBU).
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct Packet {
+    pub data: Vec<u8>,
+    pub keyframe: bool,
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum Error {
+    InvalidConfig(String),
+}
+
+impl std::fmt::Display for Error {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Error::InvalidConfig(s) => write!(f, "invalid AV1 encoder config: {s}"),
+        }
+    }
+}
+
+impl std::error::Error for Error {}
+
+/// AV1 encoder. Frames come out in input order (no hidden/reordered frames).
+pub struct Encoder {
+    cfg: EncoderConfig,
+}
+
+impl Encoder {
+    pub fn new(cfg: EncoderConfig) -> Result<Encoder, Error> {
+        if cfg.width == 0 || cfg.height == 0 {
+            return Err(Error::InvalidConfig("empty frame".into()));
+        }
+        Ok(Encoder { cfg })
+    }
+    pub fn config(&self) -> &EncoderConfig {
+        &self.cfg
+    }
+    /// The sequence header OBU (with size field).
+    pub fn sequence_header_obu(&self) -> Vec<u8> {
+        vec![]
+    }
+    /// AV1CodecConfigurationRecord (`av1C` payload, also the WebM CodecPrivate).
+    pub fn av1c(&self) -> Vec<u8> {
+        vec![]
+    }
+    /// Encodes one frame.
+    pub fn encode(&mut self, _frame: &Frame) -> Packet {
+        Packet { data: vec![], keyframe: true }
+    }
+}
diff --git a/crates/hevcenc/Cargo.toml b/crates/hevcenc/Cargo.toml
new file mode 100644
index 00000000..136611ff
--- /dev/null
+++ b/crates/hevcenc/Cargo.toml
@@ -0,0 +1,15 @@
+[package]
+name = "effectcraft-hevcenc"
+description = "Clean-room pure-Rust HEVC (H.265) encoder (Main / Main 10, I and P slices, CABAC) for MP4 export, from ITU-T H.265"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+rust-version.workspace = true
+
+[lints]
+workspace = true
+
+[dependencies]
+
+[dev-dependencies]
+filmcraft-hevc = { workspace = true }
diff --git a/crates/hevcenc/src/lib.rs b/crates/hevcenc/src/lib.rs
new file mode 100644
index 00000000..2d1b9968
--- /dev/null
+++ b/crates/hevcenc/src/lib.rs
@@ -0,0 +1,128 @@
+//! Clean-room pure-Rust HEVC (H.265) encoder — API skeleton (implementation in progress).
+//!
+//! The public API below is the contract `crates/export` codes against; keep it stable.
+
+/// Profile written in the parameter sets.
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
+pub enum Profile {
+    /// Main: 8-bit 4:2:0.
+    #[default]
+    Main,
+    /// Main 10: 10-bit 4:2:0.
+    Main10,
+}
+
+impl Profile {
+    pub fn bit_depth(self) -> u8 {
+        match self {
+            Profile::Main => 8,
+            Profile::Main10 => 10,
+        }
+    }
+}
+
+/// Rate control.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum RateControl {
+    /// Constant QP (0–51; lower is better).
+    ConstantQp(u8),
+    /// Average bitrate target in kbit/s (frame-level QP adaptation).
+    Bitrate { kbps: u32 },
+}
+
+/// Encoder settings.
+#[derive(Clone, Debug, PartialEq)]
+pub struct EncoderConfig {
+    pub width: u32,
+    pub height: u32,
+    /// Frame rate numerator / denominator (VUI timing and rate control).
+    pub fps_num: u32,
+    pub fps_den: u32,
+    pub profile: Profile,
+    /// `general_level_idc` (30 × level, e.g. 93 = level 3.1); `None` picks the lowest level that fits.
+    pub level_idc: Option<u8>,
+    pub rate: RateControl,
+    /// Frames between IDR pictures (1 = all intra).
+    pub keyint: u32,
+    /// BT.709 limited range is signalled in the VUI unless this is set.
+    pub full_range: bool,
+}
+
+impl EncoderConfig {
+    pub fn new(width: u32, height: u32, fps_num: u32, fps_den: u32) -> Self {
+        EncoderConfig {
+            width,
+            height,
+            fps_num,
+            fps_den,
+            profile: Profile::Main,
+            level_idc: None,
+            rate: RateControl::ConstantQp(28),
+            keyint: 60,
+            full_range: false,
+        }
+    }
+}
+
+/// One input picture, 4:2:0, samples at the profile's bit depth (8-bit values 0–255 for Main).
+#[derive(Clone, Copy, Debug)]
+pub struct Frame<'a> {
+    pub y: &'a [u16],
+    pub u: &'a [u16],
+    pub v: &'a [u16],
+    pub y_stride: usize,
+    pub uv_stride: usize,
+}
+
+/// One coded picture (an access unit): NAL units, each prefixed by a 4-byte big-endian length
+/// (ISO/IEC 14496-15 sample format; parameter sets are only in [`Encoder::hvcc`]).
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct Packet {
+    pub data: Vec<u8>,
+    /// IDR picture.
+    pub keyframe: bool,
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum Error {
+    InvalidConfig(String),
+}
+
+impl std::fmt::Display for Error {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Error::InvalidConfig(s) => write!(f, "invalid HEVC encoder config: {s}"),
+        }
+    }
+}
+
+impl std::error::Error for Error {}
+
+/// HEVC encoder. Pictures come out in input order (no reordering: I and P only).
+pub struct Encoder {
+    cfg: EncoderConfig,
+}
+
+impl Encoder {
+    pub fn new(cfg: EncoderConfig) -> Result<Encoder, Error> {
+        if cfg.width == 0 || cfg.height == 0 {
+            return Err(Error::InvalidConfig("empty frame".into()));
+        }
+        Ok(Encoder { cfg })
+    }
+    pub fn config(&self) -> &EncoderConfig {
+        &self.cfg
+    }
+    /// VPS, SPS, PPS NAL units (without start codes or length prefixes).
+    pub fn parameter_sets(&self) -> [Vec<u8>; 3] {
+        [vec![], vec![], vec![]]
+    }
+    /// HEVCDecoderConfigurationRecord (`hvcC` payload) with the parameter sets.
+    pub fn hvcc(&self) -> Vec<u8> {
+        vec![]
+    }
+    /// Encodes one picture.
+    pub fn encode(&mut self, _frame: &Frame) -> Packet {
+        Packet { data: vec![], keyframe: true }
+    }
+}
diff --git a/xtask/src/main.rs b/xtask/src/main.rs
index 21928b90..ac8e52d1 100644
--- a/xtask/src/main.rs
+++ b/xtask/src/main.rs
@@ -26,6 +26,8 @@ const LAYERS: &[(&str, u8)] = &[
     ("vp9enc", 0),
     ("testkit", 0),
     ("opusenc", 0),
+    ("hevcenc", 0),
+    ("av1enc", 0),
     ("raster", 1),
     ("keyframe", 1),
     ("path", 1),