diff --git a/crates/export/src/encode.rs b/crates/export/src/encode.rs
--- a/crates/export/src/encode.rs
+++ b/crates/export/src/encode.rs
@@ -7,7 +7,7 @@ use std::io::Write;
 use effectcraft_project::Comp;
 use effectcraft_project::render_queue::{AudioFormat, Channels, OutputFormat, ProResProfile};
 use effectcraft_time::{FrameRate, Tick};
-use filmcraft_isobmff::{Brand, FourCc, Mp4Writer, PcmConfig, SampleEntry, TrackConfig, WriteSample, WriterOptions};
+use filmcraft_isobmff::{Brand, ColorInfo, FourCc, Mp4Writer, PcmConfig, SampleEntry, TrackConfig, WriteSample, WriterOptions};
 use rayon::prelude::*;
 
 use crate::{Cx, ExportError, Report, Result, State, batch_size, wants_audio};
@@ -19,6 +19,17 @@ fn mux_err(e: impl std::fmt::Display) -> ExportError {
     ExportError::Io(e.to_string())
 }
 
+/// Tag a video [`SampleEntry`] with the BT.709 limited-range `colr` (nclx) box every video
+/// encoder here outputs (`rgba_to_yuv420`, `rgba_to_yuv_10` and `rgba_to_yuv420_bits` all use
+/// the 0.2126/0.7152/0.0722 luma and a 16–235 luma range). Without it a re-import falls back to
+/// the container's resolution-based `default_matrix` — BT.601 below 1024×577 — and shifts the
+/// colours (pure red came back as [232,0,1]).
+pub(crate) fn tag_bt709_limited(entry: &mut SampleEntry) {
+    if let Some(v) = entry.video.as_mut() {
+        v.color = Some(ColorInfo::Nclx { primaries: 1, transfer: 1, matrix: 1, full_range: false });
+    }
+}
+
 pub(crate) struct Packet {
     pub(crate) data: Vec<u8>,
     pub(crate) key: bool,
@@ -70,7 +81,9 @@ impl VideoEncoder for H264 {
             let (sps, pps) = self.enc.sps_pps();
             filmcraft_isobmff::AvcConfig::new(vec![sps], vec![pps], 4)
         });
-        SampleEntry::avc(cfg, self.w as u16, self.h as u16)
+        let mut entry = SampleEntry::avc(cfg, self.w as u16, self.h as u16);
+        tag_bt709_limited(&mut entry);
+        entry
     }
     fn encode(&mut self, rgba: &[u8], index: u64) -> Result<Vec<Packet>> {
         rgba_to_yuv420(rgba, self.w as usize, self.h as usize, &mut self.y, &mut self.u, &mut self.v);
diff --git a/crates/export/src/hevc_av1.rs b/crates/export/src/hevc_av1.rs
--- a/crates/export/src/hevc_av1.rs
+++ b/crates/export/src/hevc_av1.rs
@@ -92,7 +92,9 @@ impl Hevc {
 impl VideoEncoder for Hevc {
     fn sample_entry(&self) -> SampleEntry {
         let cfg = HevcConfig::parse(&self.enc.hvcc()).unwrap_or_default();
-        SampleEntry::hevc(cfg, self.w as u16, self.h as u16)
+        let mut entry = SampleEntry::hevc(cfg, self.w as u16, self.h as u16);
+        crate::encode::tag_bt709_limited(&mut entry);
+        entry
     }
     fn encode(&mut self, rgba: &[u8], _index: u64) -> Result<Vec<Packet>> {
         let (w, h) = (self.w as usize, self.h as usize);
@@ -148,7 +150,9 @@ impl Av1 {
 impl VideoEncoder for Av1 {
     fn sample_entry(&self) -> SampleEntry {
         let cfg = Av1Config::parse(&self.enc.av1c()).unwrap_or_default();
-        SampleEntry::video(FourCc(*b"av01"), CodecConfig::Av1(cfg), self.w as u16, self.h as u16)
+        let mut entry = SampleEntry::video(FourCc(*b"av01"), CodecConfig::Av1(cfg), self.w as u16, self.h as u16);
+        crate::encode::tag_bt709_limited(&mut entry);
+        entry
     }
     fn encode(&mut self, rgba: &[u8], _index: u64) -> Result<Vec<Packet>> {
         let (w, h) = (self.w as usize, self.h as usize);
diff --git a/crates/export/tests/it/hevc_av1_roundtrip.rs b/crates/export/tests/it/hevc_av1_roundtrip.rs
--- a/crates/export/tests/it/hevc_av1_roundtrip.rs
+++ b/crates/export/tests/it/hevc_av1_roundtrip.rs
@@ -123,7 +123,15 @@ fn ffprobe_video(path: &Path) -> Option<String> {
         .output()
         .expect("ffprobe");
     assert!(out.status.success() && out.stderr.is_empty(), "ffprobe rejected {}: {}", path.display(), String::from_utf8_lossy(&out.stderr));
-    Some(String::from_utf8_lossy(&out.stdout).trim().to_string())
+    let s = String::from_utf8_lossy(&out.stdout).trim().to_string();
+    // An ffprobe whose build lacks this codec's decoder (distro "free" builds) only parses the
+    // container: pix_fmt and the counted frames come back unknown/N/A, describing the build
+    // rather than our output. Skip the oracle, as when ffprobe is absent.
+    if s.contains("|unknown|") || s.ends_with("|N/A") {
+        eprintln!("ffprobe cannot decode this codec here: skipping the oracle ({s})");
+        return None;
+    }
+    Some(s)
 }
 
 /// Decode every frame with ffmpeg (no errors allowed) and check frames 0, 4, 5 and the last.
@@ -140,7 +148,14 @@ fn ffmpeg_check(path: &Path, decoder: Option<&str>, tol: f32) {
         cmd.args(["-c:v", d]);
     }
     let out = cmd.arg("-i").arg(path).args(["-pix_fmt", "rgba"]).arg(dir.join("f%03d.png")).output().expect("ffmpeg");
-    assert!(out.status.success() && out.stderr.is_empty(), "ffmpeg ({decoder:?}) failed on {}: {}", path.display(), String::from_utf8_lossy(&out.stderr));
+    let err = String::from_utf8_lossy(&out.stderr).to_string();
+    // Same as ffprobe: an ffmpeg without this codec's decoder cannot judge our output, so the
+    // oracle skips instead of failing (the in-repo decode above already proved the frames).
+    if !out.status.success() && err.contains("no decoder found") {
+        eprintln!("ffmpeg cannot decode this codec here: skipping the oracle decode ({err})");
+        return;
+    }
+    assert!(out.status.success() && err.is_empty(), "ffmpeg ({decoder:?}) failed on {}: {}", path.display(), err);
     for k in [0, 4, 5, FRAMES - 1] {
         let img = image::open(dir.join(format!("f{:03}.png", k + 1))).expect("ffmpeg frame").to_rgba8();
         check_frame(&Image::from_rgba8(img.width(), img.height(), img.as_raw()), k, tol);
diff --git a/crates/export/tests/it/roundtrip.rs b/crates/export/tests/it/roundtrip.rs
--- a/crates/export/tests/it/roundtrip.rs
+++ b/crates/export/tests/it/roundtrip.rs
@@ -23,6 +23,24 @@ const H: u32 = 48;
 const BG: [f32; 3] = [0.1, 0.1, 0.4];
 const FRAMES: u64 = 12;
 
+/// An H.264 encoder this ffmpeg build actually ships, or `None` when it has none. Distro "free"
+/// builds often omit `libx264` but ship an alternative (e.g. libopenh264), so pick the first
+/// present by name rather than hard-coding one that may be absent. The oracle only needs *an*
+/// H.264 encoder; the encoder identity is irrelevant to the assertion.
+fn h264_encoder() -> Option<&'static str> {
+    static ENC: std::sync::OnceLock<Option<&'static str>> = std::sync::OnceLock::new();
+    *ENC.get_or_init(|| {
+        let out = Command::new("ffmpeg").args(["-hide_banner", "-encoders"]).output().ok()?;
+        if !out.status.success() {
+            return None;
+        }
+        let text = String::from_utf8_lossy(&out.stdout);
+        ["libx264", "libopenh264", "h264_nvenc", "h264_vaapi", "h264_qsv", "h264_v4l2m2m", "h264_amf"]
+            .into_iter()
+            .find(|name| text.lines().any(|l| l.split_whitespace().any(|tok| tok == *name)))
+    })
+}
+
 fn out_dir(name: &str) -> PathBuf {
     let d = Path::new(env!("CARGO_MANIFEST_DIR")).join("../../target/test-out/export").join(name);
     let _ = std::fs::remove_dir_all(&d);
@@ -489,14 +507,18 @@ fn ffmpeg_audio(src: &Path) -> Vec<f32> {
 fn movies_carry_resampled_footage_audio() {
     let d = out_dir("audio-44k");
     let clip = d.join("clip.mp4");
+    let Some(enc) = h264_encoder() else {
+        eprintln!("ffmpeg has no H.264 encoder: skipping");
+        return;
+    };
     let made = Command::new("ffmpeg")
         .args(["-hide_banner", "-loglevel", "error", "-y", "-f", "lavfi", "-i", "testsrc2=size=64x48:rate=30000/1001:duration=3", "-f", "lavfi", "-i"])
-        .args(["aevalsrc=0.5*sin(2*PI*440*t)|0.5*sin(2*PI*(200+400*t/3)*t):s=44100:d=3", "-c:v", "libx264", "-pix_fmt", "yuv420p", "-c:a", "aac", "-shortest"])
+        .args(["aevalsrc=0.5*sin(2*PI*440*t)|0.5*sin(2*PI*(200+400*t/3)*t):s=44100:d=3", "-c:v", enc, "-pix_fmt", "yuv420p", "-c:a", "aac", "-shortest"])
         .arg(&clip)
         .status()
         .is_ok_and(|s| s.success());
     if !made {
-        eprintln!("ffmpeg not found: skipping");
+        eprintln!("ffmpeg could not make the H.264 fixture: skipping");
         return;
     }
     let fps = FrameRate::new(30000, 1001);
diff --git a/crates/hevcenc/tests/roundtrip.rs b/crates/hevcenc/tests/roundtrip.rs
--- a/crates/hevcenc/tests/roundtrip.rs
+++ b/crates/hevcenc/tests/roundtrip.rs
@@ -132,12 +132,36 @@ fn ffmpeg_available() -> bool {
     Command::new("ffmpeg").arg("-version").output().map(|o| o.status.success()).unwrap_or(false)
 }
 
+/// `true` when this ffmpeg/ffprobe build actually ships an HEVC decoder. Distro "free" builds
+/// (e.g. Fedora's ffmpeg-free) ship without one — the tools run but cannot decode our stream, so
+/// the external oracle means nothing and the test skips rather than failing on a gap in the tool.
+fn hevc_decoder_available() -> bool {
+    Command::new("ffmpeg")
+        .args(["-hide_banner", "-decoders"])
+        .output()
+        .map(|o| {
+            String::from_utf8_lossy(&o.stdout).lines().any(|l| {
+                // Decoder rows look like ` V....D hevc ...`; match the codec name, not the text.
+                // Every row of `-decoders` is a decoder, so the flags column says nothing about
+                // that — its trailing `D` is "supports direct rendering method 1", which a
+                // build's hevc decoder may well lack (requiring it would skip a working oracle).
+                let mut it = l.split_whitespace();
+                it.next().is_some() && it.next() == Some("hevc")
+            })
+        })
+        .unwrap_or(false)
+}
+
 /// Decode the Annex-B stream with ffmpeg and require bit-exact equality and an empty stderr.
 fn check_ffmpeg(run: &Run, w: usize, h: usize, bd: u32, tag: &str) {
     if !ffmpeg_available() {
         eprintln!("ffmpeg not found; skipping the ffmpeg oracle");
         return;
     }
+    if !hevc_decoder_available() {
+        eprintln!("ffmpeg has no HEVC decoder here; skipping the ffmpeg oracle");
+        return;
+    }
     let dir = std::env::temp_dir();
     let uniq = format!("{}-{}-{}", tag, std::process::id(), std::time::SystemTime::now().duration_since(std::time::UNIX_EPOCH).unwrap().as_nanos());
     let inp = dir.join(format!("hevcenc-{uniq}.hevc"));
@@ -197,6 +221,10 @@ fn ffprobe_stream_info() {
     if !ffmpeg_available() {
         return;
     }
+    if !hevc_decoder_available() {
+        eprintln!("ffmpeg has no HEVC decoder here; ffprobe cannot fully describe our stream, skipping");
+        return;
+    }
     let (w, h) = (130, 72);
     let pics: Vec<Pic> = (0..2).map(|i| synth(w, h, 10, i, 0)).collect();
     let mut c = cfg(w as u32, h as u32, 30, 30, Profile::Main10);
diff --git a/crates/media/tests/it/footage.rs b/crates/media/tests/it/footage.rs
--- a/crates/media/tests/it/footage.rs
+++ b/crates/media/tests/it/footage.rs
@@ -24,9 +24,40 @@ fn have_ffmpeg() -> bool {
     *HAVE.get_or_init(|| Command::new("ffmpeg").arg("-version").output().is_ok_and(|o| o.status.success()))
 }
 
+/// An H.264 encoder this ffmpeg build actually ships, or `None` when it has none. Distro "free"
+/// builds often omit `libx264` (the one named historically here) but ship an alternative, so pick
+/// the first present by name rather than hard-coding one that may be absent. These tests only
+/// need *an* H.264 encoder to make an oracle fixture; the encoder identity is irrelevant.
+fn h264_encoder() -> Option<&'static str> {
+    static ENC: std::sync::OnceLock<Option<&'static str>> = std::sync::OnceLock::new();
+    *ENC.get_or_init(|| {
+        let out = Command::new("ffmpeg").args(["-hide_banner", "-encoders"]).output().ok()?;
+        if !out.status.success() {
+            return None;
+        }
+        let text = String::from_utf8_lossy(&out.stdout);
+        ["libx264", "libopenh264", "h264_nvenc", "h264_vaapi", "h264_qsv", "h264_v4l2m2m", "h264_amf"]
+            .into_iter()
+            .find(|name| text.lines().any(|l| l.split_whitespace().any(|tok| tok == *name)))
+    })
+}
+
 /// Run ffmpeg to produce `name` (once; written to a temp name and renamed so concurrent test
 /// processes never see a partial file). `None` when ffmpeg is unavailable.
 fn ffmpeg_fixture(name: &str, args: &[&str]) -> Option<PathBuf> {
+    ffmpeg_fixture_inner(name, args, true)
+}
+
+/// Like [`ffmpeg_fixture`] for a fixture this build of ffmpeg may fail to make: an encoder found
+/// in the `-encoders` listing can still not run here (the hardware backends need their device,
+/// Fedora's `libopenh264` is the `noopenh264` stub), and fixtures built from one, like
+/// [`h264_mp4`], should skip with a note rather than fail on the packager's choice of ffmpeg —
+/// the same way every test here skips when ffmpeg is missing altogether.
+fn try_ffmpeg_fixture(name: &str, args: &[&str]) -> Option<PathBuf> {
+    ffmpeg_fixture_inner(name, args, false)
+}
+
+fn ffmpeg_fixture_inner(name: &str, args: &[&str], must_succeed: bool) -> Option<PathBuf> {
     if !have_ffmpeg() {
         eprintln!("ffmpeg not found: skipping");
         return None;
@@ -39,7 +70,14 @@ fn ffmpeg_fixture(name: &str, args: &[&str]) -> Option<PathBuf> {
     let ext = out.extension().map(|e| e.to_string_lossy().to_string()).unwrap_or_default();
     let tmp = out.with_file_name(format!("tmp-{}-{:?}.{ext}", std::process::id(), std::thread::current().id()).replace(['(', ')'], ""));
     let st = Command::new("ffmpeg").args(["-hide_banner", "-loglevel", "error", "-y"]).args(args).arg(&tmp).status().expect("run ffmpeg");
-    assert!(st.success(), "ffmpeg failed for {name}");
+    if !st.success() {
+        let _ = std::fs::remove_file(&tmp);
+        if must_succeed {
+            panic!("ffmpeg failed for {name}");
+        }
+        eprintln!("this ffmpeg build cannot make {name}: skipping");
+        return None;
+    }
     if std::fs::rename(&tmp, &out).is_err() {
         // Another test made it first; on Windows the rename fails while that test has it open.
         let _ = std::fs::remove_file(&tmp);
@@ -49,7 +87,10 @@ fn ffmpeg_fixture(name: &str, args: &[&str]) -> Option<PathBuf> {
 }
 
 fn h264_mp4() -> Option<PathBuf> {
-    ffmpeg_fixture(
+    // Made with whatever encoder this build has listed: a listed encoder can still fail at run
+    // time (the hardware ones without their device), so this may skip rather than fail.
+    let enc = h264_encoder()?;
+    try_ffmpeg_fixture(
         "testsrc2_1080p.mp4",
         &[
             "-f",
@@ -61,7 +102,7 @@ fn h264_mp4() -> Option<PathBuf> {
             "-i",
             "sine=frequency=440:sample_rate=48000:duration=2",
             "-c:v",
-            "libx264",
+            enc,
             "-pix_fmt",
             "yuv420p",
             "-preset",
@@ -281,7 +322,10 @@ fn h264_audio_samples() {
 /// H.264 + AAC at 44.1 kHz in MP4 (ffmpeg writes an edit list that skips the AAC priming):
 /// 440 Hz left, a 200 → 1000 Hz sweep right, 29.97 fps.
 fn aac_44k_mp4() -> Option<PathBuf> {
-    ffmpeg_fixture(
+    // Made with whatever encoder this build has listed: a listed encoder can still fail at run
+    // time (the hardware ones without their device), so this may skip rather than fail.
+    let enc = h264_encoder()?;
+    try_ffmpeg_fixture(
         "aac_44k.mp4",
         &[
             "-f",
@@ -293,7 +337,7 @@ fn aac_44k_mp4() -> Option<PathBuf> {
             "-i",
             "aevalsrc=0.5*sin(2*PI*440*t)|0.5*sin(2*PI*(200+400*t/3)*t):s=44100:d=3",
             "-c:v",
-            "libx264",
+            enc,
             "-pix_fmt",
             "yuv420p",
             "-c:a",
@@ -1098,7 +1142,7 @@ fn a_called_off_read_does_not_decode() {
 /// footage reports it (not a black frame without a word).
 #[test]
 fn an_unsupported_stream_reports_why_it_shows_no_picture() {
-    let Some(p) = ffmpeg_fixture(
+    let Some(p) = try_ffmpeg_fixture(
         "h264_high422_10bit.mp4",
         &["-f", "lavfi", "-i", "testsrc=size=320x180:rate=24:duration=1", "-c:v", "libx264", "-profile:v", "high422", "-pix_fmt", "yuv422p10le"],
     ) else {
diff --git a/crates/media/tests/it/open_in_place.rs b/crates/media/tests/it/open_in_place.rs
--- a/crates/media/tests/it/open_in_place.rs
+++ b/crates/media/tests/it/open_in_place.rs
@@ -19,8 +19,26 @@ fn fixtures() -> PathBuf {
     Path::new(env!("CARGO_MANIFEST_DIR")).join("../../target/fixtures/media")
 }
 
+/// An H.264 encoder this ffmpeg build actually ships, or `None` when it has none (see the same
+/// helper in `footage.rs`: distro "free" builds often omit `libx264` and ship an alternative).
+fn h264_encoder() -> Option<&'static str> {
+    static ENC: std::sync::OnceLock<Option<&'static str>> = std::sync::OnceLock::new();
+    *ENC.get_or_init(|| {
+        let out = Command::new("ffmpeg").args(["-hide_banner", "-encoders"]).output().ok()?;
+        if !out.status.success() {
+            return None;
+        }
+        let text = String::from_utf8_lossy(&out.stdout);
+        ["libx264", "libopenh264", "h264_nvenc", "h264_vaapi", "h264_qsv", "h264_v4l2m2m", "h264_amf"]
+            .into_iter()
+            .find(|name| text.lines().any(|l| l.split_whitespace().any(|tok| tok == *name)))
+    })
+}
+
 /// A 2 s 320×240 H.264 + AAC movie (written to a temp name and renamed, so concurrent test
-/// processes never see a partial file). `None` without ffmpeg.
+/// processes never see a partial file). `None` without ffmpeg, or when this build cannot encode
+/// H.264 at all — the test only measures how a movie is read, so it skips rather than asserting
+/// on the packager's choice of ffmpeg.
 fn small_mp4() -> Option<PathBuf> {
     let out = fixtures().join("in_place_small.mp4");
     if out.exists() {
@@ -29,16 +47,21 @@ fn small_mp4() -> Option<PathBuf> {
     if !Command::new("ffmpeg").arg("-version").output().is_ok_and(|o| o.status.success()) {
         return None;
     }
+    let enc = h264_encoder()?;
     std::fs::create_dir_all(fixtures()).unwrap();
     let tmp = fixtures().join(format!("in_place_tmp_{}.mp4", std::process::id()));
     let st = Command::new("ffmpeg")
         .args(["-hide_banner", "-loglevel", "error", "-y", "-f", "lavfi", "-i", "testsrc2=size=320x240:rate=30:duration=2"])
         .args(["-f", "lavfi", "-i", "sine=frequency=440:sample_rate=48000:duration=2"])
-        .args(["-c:v", "libx264", "-pix_fmt", "yuv420p", "-c:a", "aac", "-shortest"])
+        .args(["-c:v", enc, "-pix_fmt", "yuv420p", "-c:a", "aac", "-shortest"])
         .arg(&tmp)
         .status()
         .unwrap();
-    assert!(st.success(), "ffmpeg failed");
+    if !st.success() {
+        let _ = std::fs::remove_file(&tmp);
+        eprintln!("this ffmpeg build cannot make in_place_small.mp4: skipping");
+        return None;
+    }
     std::fs::rename(&tmp, &out).unwrap();
     Some(out)
 }
