Expose track_in_movie and track_in_preview flags on Tkhd

[iameli]

Ran into this while working on the MUXL spec; I think having track_in_movie set is probably a sensible default. Now we can do that!

From Claude:

The tkhd box has three flag bits: track_enabled (bit 0), track_in_movie (bit 1), and track_in_preview (bit 2). Previously only track_enabled was exposed as a public field. The other two were decoded but discarded, and always written as false on encode.

Add in_movie and in_preview fields to Tkhd so callers can read and write all three flags. Update all test expectations to match the actual flag values in their respective fixtures.

[coderabbitai]

Walkthrough

Two new public boolean fields, in_movie and in_preview, were added to the Tkhd struct. The Tkhd struct definition was extended in src/moov/trak/tkhd.rs with serialization and deserialization logic to populate these fields from the TkhdExt structure during encode and decode operations. All test files that construct Tkhd instances were updated to initialize these new fields with corresponding values, maintaining consistency across test expectations in modules such as av1, bbb, esds, flac, h264, hevc, libavif_anim, uncompressed, and vp9.

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the main change: exposing two previously hidden flag fields (track_in_movie and track_in_preview) on the Tkhd struct.
Description check	✅ Passed	The description provides clear context about the change, explaining what flags were previously hidden and why exposing them is useful (MUXL spec work and sensible defaults).
Docstring Coverage	✅ Passed	Docstring coverage is 85.71% which is sufficient. The required threshold is 80.00%.

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[coderabbitai]

🧹 Nitpick comments (1)

src/moov/trak/tkhd.rs (1)

198-199: Consider adding a direct serialized-flags assertion in unit tests.

Current tests are round-trip based; adding one direct assertion on the version+flags word would make bit-position regressions easier to catch.

Suggested test hardening

 #[test]
 fn test_tkhd32() {
     let expected = Tkhd {
         creation_time: 100,
         modification_time: 200,
         track_id: 1,
         duration: 634634,
         layer: 0,
         alternate_group: 0,
         volume: 1.into(),
         matrix: Matrix::default(),
         width: 512.into(),
         height: 288.into(),
         enabled: true,
         in_movie: true,
         in_preview: false,
     };
     let mut buf = Vec::new();
     expected.encode(&mut buf).unwrap();
+    // size(4) + kind(4) + version/flags(4)
+    assert_eq!(&buf[8..12], &[0x01, 0x00, 0x00, 0x03]);

     let mut buf = buf.as_ref();
     let decoded = Tkhd::decode(&mut buf).unwrap();
     assert_eq!(decoded, expected);
 }

Also applies to: 223-224

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@src/moov/trak/tkhd.rs` around lines 198 - 199, Tests currently only
round-trip the TrackHeaderBox; add a direct assertion that the packed
version+flags 32-bit word matches the expected literal to catch bit-position
regressions. In the unit test for TrackHeaderBox (the case that sets in_movie:
true and in_preview: false) call the serializer used (e.g.,
TrackHeaderBox::to_bytes / write_box / serialize) and extract the first 4 bytes
(version+flags) or use the helper that builds the version_and_flags word, then
assert equality against the expected u32 constant (computed from version and the
flag bits). Reference the fields in_movie and in_preview and the TrackHeaderBox
serialization path so the test fails if flag bit positions change.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@src/moov/trak/tkhd.rs`:
- Around line 198-199: Tests currently only round-trip the TrackHeaderBox; add a
direct assertion that the packed version+flags 32-bit word matches the expected
literal to catch bit-position regressions. In the unit test for TrackHeaderBox
(the case that sets in_movie: true and in_preview: false) call the serializer
used (e.g., TrackHeaderBox::to_bytes / write_box / serialize) and extract the
first 4 bytes (version+flags) or use the helper that builds the
version_and_flags word, then assert equality against the expected u32 constant
(computed from version and the flag bits). Reference the fields in_movie and
in_preview and the TrackHeaderBox serialization path so the test fails if flag
bit positions change.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 790684be-dab9-4ba2-ac19-d75021888af0

📥 Commits

Reviewing files that changed from the base of the PR and between 3073b3e and 622ca7d.

📒 Files selected for processing (11)

• src/moov/mod.rs
• src/moov/trak/tkhd.rs
• src/test/av1.rs
• src/test/bbb.rs
• src/test/esds.rs
• src/test/flac.rs
• src/test/h264.rs
• src/test/hevc.rs
• src/test/libavif_anim.rs
• src/test/uncompressed.rs
• src/test/vp9.rs

[bradh]

LGTM.

A round-trip test would be nice, but I can try to find some time for that later.