pq/libfreemkv
1
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Preserve interlaced scan type in label and MKV output

Browse Source 
Interlacing is detected upstream (PAL DVD -> R576i) but was dropped in
two places: the video label hardcoded a 'p' suffix, and the muxer never
wrote any scan-type flag, so MediaInfo inferred progressive and reported
576p for a 576i source.

- Add Resolution::is_interlaced() for the R*i variants.
- generate_video_label now branches i/p for the heights that can be
  interlaced (1080, 576, 480) instead of always emitting 'p'.
- MkvTrack carries interlaced + field_order; the video serializer emits
  FlagInterlaced (0x9A; 1=interlaced, 2=progressive) and, for interlaced
  content, FieldOrder (0x9D) - bottom-field-first for PAL 576i,
  top-field-first otherwise. Adds the EBML constants.
This commit is contained in:
Matthew Jackson
2026-06-24 09:47:16 -07:00
parent 2613a81f09
commit e0ce035765
4 changed files with 165 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/disc/mod.rs
+8
View File
@@ -655,6 +655,14 @@ impl Resolution {
matches!(self, Resolution::R2160p | Resolution::R4320p)
}
/// True if this is an interlaced resolution (the `R*i` variants).
pub fn is_interlaced(&self) -> bool {
matches!(
self,
Resolution::R480i | Resolution::R576i | Resolution::R1080i
)
}
/// True if this is an HD (720p+) resolution.
pub fn is_hd(&self) -> bool {
!matches!(
src/labels/mod.rs
+59 -5
View File
@@ -296,7 +296,13 @@ pub fn fill_defaults(titles: &mut [crate::disc::DiscTitle]) {
} else {
v.resolution.pixels()
};
v.label = generate_video_label(&v.codec, px, &v.hdr, v.secondary);
v.label = generate_video_label(
&v.codec,
px,
v.resolution.is_interlaced(),
&v.hdr,
v.secondary,
);
}
Stream::Subtitle(s) if s.forced => {
// Ensure forced subs are labeled even if BD-J didn't set a name
@@ -311,6 +317,7 @@ pub fn fill_defaults(titles: &mut [crate::disc::DiscTitle]) {
fn generate_video_label(
codec: &crate::disc::Codec,
pixels: (u32, u32),
interlaced: bool,
hdr: &crate::disc::HdrFormat,
secondary: bool,
) -> String {
@@ -331,20 +338,22 @@ fn generate_video_label(
// Codec
parts.push(codec.name().to_string());
// Resolution
// Resolution. Scan type (i/p) is honored for heights that can be
// interlaced on disc (1080 and SD 576/480); 720/4K/8K are always
// progressive.
let (w, h) = pixels;
let res = if w >= 7680 {
"8K"
} else if w >= 3840 {
"4K"
} else if w >= 1920 {
"1080p"
if interlaced { "1080i" } else { "1080p" }
} else if w >= 1280 {
"720p"
} else if h >= 576 {
"576p"
if interlaced { "576i" } else { "576p" }
} else if h >= 480 {
"480p"
if interlaced { "480i" } else { "480p" }
} else {
""
};
@@ -1736,6 +1745,51 @@ mod apply_tests {
}
}
/// Spec: an interlaced resolution (`R*i`) must surface the "i" scan type
/// in the generated label, not a hardcoded "p". PAL DVD is 576i.
/// Mutation: hardcode "p" → 576i video mislabeled as 576p.
#[test]
fn fill_defaults_video_label_honors_interlaced_scan_type() {
let interlaced = Stream::Video(VideoStream {
pid: 0x1011,
codec: Codec::Mpeg2,
resolution: Resolution::R576i,
frame_rate: FrameRate::F25,
hdr: HdrFormat::Sdr,
color_space: ColorSpace::Bt470bg,
display_aspect: None,
secondary: false,
label: String::new(),
});
let mut titles = vec![title_with(vec![interlaced])];
fill_defaults(&mut titles);
if let Stream::Video(v) = &titles[0].streams[0] {
assert!(v.label.contains("576i"), "expected 576i, got {}", v.label);
assert!(
!v.label.contains("576p"),
"must not say 576p, got {}",
v.label
);
}
let progressive = Stream::Video(VideoStream {
pid: 0x1011,
codec: Codec::Mpeg2,
resolution: Resolution::R576p,
frame_rate: FrameRate::F25,
hdr: HdrFormat::Sdr,
color_space: ColorSpace::Bt470bg,
display_aspect: None,
secondary: false,
label: String::new(),
});
let mut titles = vec![title_with(vec![progressive])];
fill_defaults(&mut titles);
if let Stream::Video(v) = &titles[0].streams[0] {
assert!(v.label.contains("576p"), "expected 576p, got {}", v.label);
}
}
// ── codec_hint_consistent hardening ───────────────────────────────────────
/// Spec: "Dolby Digital" (AC-3) hint is consistent ONLY with AC-3 streams;
src/mux/ebml.rs
+12
View File
@@ -424,6 +424,18 @@ pub const DEFAULT_DURATION: u32 = 0x23_E383;
pub const VIDEO: u32 = 0xE0;
pub const PIXEL_WIDTH: u32 = 0xB0;
pub const PIXEL_HEIGHT: u32 = 0xBA;
// Scan type (children of Video).
pub const FLAG_INTERLACED: u32 = 0x9A;
pub const FIELD_ORDER: u32 = 0x9D;
// FlagInterlaced values: 1 = interlaced, 2 = progressive (0 = undetermined).
pub const INTERLACED_INTERLACED: u64 = 1;
pub const INTERLACED_PROGRESSIVE: u64 = 2;
// FieldOrder values (Matroska): 0/2 = top-field-first, 1/9 = bottom-field-first.
// NTSC DVD (480i) and HD (1080i) are top-field-first; PAL DVD (576i) is
// bottom-field-first. 0xFF is our sentinel for "undetermined / omit".
pub const FIELD_ORDER_TFF: u8 = 2;
pub const FIELD_ORDER_BFF: u8 = 9;
pub const FIELD_ORDER_UNDETERMINED: u8 = 0xFF;
pub const DISPLAY_WIDTH: u32 = 0x54B0;
pub const DISPLAY_HEIGHT: u32 = 0x54BA;
pub const COLOUR: u32 = 0x55B0;
src/mux/mkv.rs
+86
View File
@@ -31,6 +31,11 @@ pub struct MkvTrack {
pub colour_transfer: u8, // TransferCharacteristics (16=smpte2084/PQ)
pub colour_primaries: u8, // Primaries (9=bt2020)
pub colour_range: u8, // Range (1=tv/limited)
// Scan type. `interlaced` drives FlagInterlaced (0x9A): true → 1
// (interlaced), false → 2 (progressive). `field_order` (0x9D) is only
// meaningful when interlaced; `FIELD_ORDER_UNDETERMINED` omits it.
pub interlaced: bool,
pub field_order: u8,
// Audio-specific
pub sample_rate: f64,
pub channels: u8,
@@ -125,6 +130,18 @@ impl MkvTrack {
colour_transfer: transfer,
colour_primaries: primaries,
colour_range: range,
interlaced: v.resolution.is_interlaced(),
// PAL DVD (576i) is bottom-field-first; NTSC DVD (480i) is
// top-field-first. HD interlaced (1080i) is top-field-first.
// Progressive content leaves the field order undetermined.
field_order: if v.resolution.is_interlaced() {
match v.resolution {
Resolution::R576i => ebml::FIELD_ORDER_BFF,
_ => ebml::FIELD_ORDER_TFF,
}
} else {
ebml::FIELD_ORDER_UNDETERMINED
},
sample_rate: 0.0,
channels: 0,
bit_depth: 0,
@@ -195,6 +212,8 @@ impl MkvTrack {
colour_transfer: 0,
colour_primaries: 0,
colour_range: 0,
interlaced: false,
field_order: ebml::FIELD_ORDER_UNDETERMINED,
sample_rate: sr,
channels: ch,
bit_depth: 0,
@@ -228,6 +247,8 @@ impl MkvTrack {
colour_transfer: 0,
colour_primaries: 0,
colour_range: 0,
interlaced: false,
field_order: ebml::FIELD_ORDER_UNDETERMINED,
sample_rate: 0.0,
channels: 0,
bit_depth: 0,
@@ -666,6 +687,21 @@ impl<W: Write + Seek> MkvMuxer<W> {
let vid_pos = ebml::start_master(&mut writer, ebml::VIDEO)?;
ebml::write_uint(&mut writer, ebml::PIXEL_WIDTH, track.pixel_width as u64)?;
ebml::write_uint(&mut writer, ebml::PIXEL_HEIGHT, track.pixel_height as u64)?;
// Scan type. FlagInterlaced: 1 = interlaced, 2 = progressive.
// FieldOrder is only written for interlaced content with a
// determined order (TFF=0/2/6/14, BFF=1/9/13...).
ebml::write_uint(
&mut writer,
ebml::FLAG_INTERLACED,
if track.interlaced {
ebml::INTERLACED_INTERLACED
} else {
ebml::INTERLACED_PROGRESSIVE
},
)?;
if track.interlaced && track.field_order != ebml::FIELD_ORDER_UNDETERMINED {
ebml::write_uint(&mut writer, ebml::FIELD_ORDER, track.field_order as u64)?;
}
if track.display_width > 0 && track.display_height > 0 {
ebml::write_uint(&mut writer, ebml::DISPLAY_WIDTH, track.display_width as u64)?;
ebml::write_uint(
@@ -1161,6 +1197,8 @@ mod tests {
colour_transfer: 0,
colour_primaries: 0,
colour_range: 0,
interlaced: false,
field_order: ebml::FIELD_ORDER_UNDETERMINED,
sample_rate: 0.0,
channels: 0,
bit_depth: 0,
@@ -1186,6 +1224,8 @@ mod tests {
colour_transfer: 0,
colour_primaries: 0,
colour_range: 0,
interlaced: false,
field_order: ebml::FIELD_ORDER_UNDETERMINED,
sample_rate: 48000.0,
channels: 6,
bit_depth: 0,
@@ -2944,6 +2984,52 @@ mod tests {
);
}
#[test]
fn video_emits_flag_interlaced_and_field_order() {
// An interlaced (576i PAL) track must emit FlagInterlaced=1 and
// FieldOrder=9 (bottom-field-first). A progressive track must emit
// FlagInterlaced=2 and NO FieldOrder.
let mut interlaced = make_video_track();
interlaced.interlaced = true;
interlaced.field_order = ebml::FIELD_ORDER_BFF;
let muxer = MkvMuxer::new(Cursor::new(Vec::new()), &[interlaced], None, 0.0, &[]).unwrap();
let data = muxer.writer.into_inner();
let fi = find_id(&data, ebml::FLAG_INTERLACED).expect("FlagInterlaced present");
// [id=0x9A][size=0x81][value]
assert_eq!(
data[fi + 2],
ebml::INTERLACED_INTERLACED as u8,
"FlagInterlaced must be 1 (interlaced)"
);
let fo = find_id(&data, ebml::FIELD_ORDER).expect("FieldOrder present");
assert_eq!(
data[fo + 2],
ebml::FIELD_ORDER_BFF,
"FieldOrder must be 9 (bottom-field-first) for PAL DVD"
);
// Progressive track: FlagInterlaced=2, no FieldOrder.
let muxer = MkvMuxer::new(
Cursor::new(Vec::new()),
&[make_video_track()],
None,
0.0,
&[],
)
.unwrap();
let data = muxer.writer.into_inner();
let fi = find_id(&data, ebml::FLAG_INTERLACED).expect("FlagInterlaced present");
assert_eq!(
data[fi + 2],
ebml::INTERLACED_PROGRESSIVE as u8,
"FlagInterlaced must be 2 (progressive)"
);
assert!(
find_id(&data, ebml::FIELD_ORDER).is_none(),
"no FieldOrder for progressive content"
);
}
#[test]
fn dolby_vision_track_emits_block_addition_mapping() {
// A DV track (dv_config set) must emit BlockAdditionMapping (0x41E4)