diff --git a/crates/meta/src/exif.rs b/crates/meta/src/exif.rs index ca8d7b7aa..51da692e8 100644 --- a/crates/meta/src/exif.rs +++ b/crates/meta/src/exif.rs @@ -16,8 +16,14 @@ pub fn read_exif(bytes: &[u8]) -> Metadata { /// Like [`read_exif`] but reports a structurally invalid TIFF header / IFD0. pub fn try_read_exif(bytes: &[u8]) -> Result { - let tiff = Tiff::parse(strip_exif_header(bytes))?; - Ok(from_tiff(&tiff)) + let data = strip_exif_header(bytes); + let tiff = Tiff::parse(data)?; + let mut m = from_tiff(&tiff); + // Panasonic writes no LensModel, only the name in its maker note (and in a RW2 that note is not in the raw's own Exif) + if m.lens_model.is_none() { + m.lens_model = panasonic_lens(data, &tiff).or_else(|| panasonic_jpg_from_raw_lens(&tiff)); + } + Ok(m) } fn text(ifd: Option<&Ifd>, tag: u16) -> Option { @@ -138,11 +144,104 @@ fn read_gps(g: &Ifd) -> Option { Some(Gps { latitude: lat, longitude: lon, altitude }) } +/// Panasonic maker note tag `0x0051` (LensType in the ExifTool Panasonic tag names): the lens name, ASCII. +const PANASONIC_LENS_TYPE: u16 = 0x0051; +/// RW2/RWL IFD0 tag `0x002E` (JpgFromRaw): a JPEG whose APP1 holds the full Exif, maker note included. +const PANASONIC_JPG_FROM_RAW: u16 = 0x002E; + +/// The lens name in a `Panasonic\0` maker note of this Exif stream (`data` starts at its TIFF header). +fn panasonic_lens(data: &[u8], tiff: &Tiff) -> Option { + let exif = tiff.exif()?; + if !exif.bytes(t::MAKER_NOTE)?.starts_with(b"Panasonic\0") { + return None; + } + let e = exif.get(t::MAKER_NOTE)?; + let make = tiff.ifds.first().and_then(|i| i.string(t::MAKE)).unwrap_or_default(); + let mn = lightcraft_tiff::makernote::parse_makernote(data, e.offset, e.count() as u64, tiff.order, &make)?; + text(Some(&mn.ifd), PANASONIC_LENS_TYPE) +} + +/// The lens name from the Exif of a RW2's (or Leica RWL's) embedded JpgFromRaw. +fn panasonic_jpg_from_raw_lens(tiff: &Tiff) -> Option { + let jpg = tiff.ifds.first()?.bytes(PANASONIC_JPG_FROM_RAW)?; + let exif = crate::jpeg_segments(jpg).exif?; + let data = strip_exif_header(&exif); + panasonic_lens(data, &Tiff::parse(data).ok()?) +} + #[cfg(test)] pub(crate) mod tests { use super::*; use lightcraft_tiff::{ByteOrder, IfdBuilder, TiffWriter, Value}; + /// An Exif block from a Panasonic body: no LensModel, the lens name in maker note tag 0x0051, whose value + /// lies outside the note's IFD at an offset relative to the Exif TIFF header (as Panasonic writes it). + fn panasonic_exif(order: ByteOrder, lens: Option<&str>, lens_model: Option<&str>) -> Vec { + let note = |at: u32| { + let mut v = b"Panasonic\0\0\0".to_vec(); + order.put_u16(&mut v, 1); + order.put_u16(&mut v, if lens.is_some() { PANASONIC_LENS_TYPE } else { 0x0001 }); + order.put_u16(&mut v, 2); + let name = format!("{:<34}\0", lens.unwrap_or("0210")); + order.put_u32(&mut v, name.len() as u32); + order.put_u32(&mut v, at + 30); + order.put_u32(&mut v, 0); + v.extend_from_slice(name.as_bytes()); + v + }; + let build = |at: u32| { + let mut exif = IfdBuilder::new(); + exif.set(t::MAKER_NOTE, Value::Undefined(note(at))); + exif.set(t::FOCAL_LENGTH, Value::Rational(vec![(25, 1)])); + if let Some(l) = lens_model { + exif.set(t::LENS_MODEL, Value::Ascii(l.into())); + } + let mut ifd0 = IfdBuilder::new(); + ifd0.set(t::MAKE, Value::Ascii("Panasonic".into())); + ifd0.set_child(t::EXIF_IFD, exif); + TiffWriter::new(order, false).write(&[ifd0]).unwrap() + }; + // the note's own offset is only known once it is laid out; its length doesn't change + let first = build(0); + let at = Tiff::parse(&first).unwrap().exif().unwrap().get(t::MAKER_NOTE).unwrap().offset as u32; + build(at) + } + + #[test] + fn panasonic_maker_note_names_the_lens() { + for order in [ByteOrder::Little, ByteOrder::Big] { + let m = read_exif(&panasonic_exif(order, Some("LUMIX G 25/F1.7"), None)); + assert_eq!(m.lens_model.as_deref(), Some("LUMIX G 25/F1.7")); + assert_eq!(m.focal_length, Some(25.0)); + } + // Exif's own LensModel wins, and a note without 0x0051 leaves the lens empty + let m = read_exif(&panasonic_exif(ByteOrder::Little, Some("LUMIX G 25/F1.7"), Some("Other 25mm"))); + assert_eq!(m.lens_model.as_deref(), Some("Other 25mm")); + assert_eq!(read_exif(&panasonic_exif(ByteOrder::Little, None, None)).lens_model, None); + } + + #[test] + fn rw2_reads_the_lens_from_its_jpg_from_raw() { + // a RW2 has the full Exif only in the APP1 of its JpgFromRaw (IFD0 0x002E), not in its own Exif IFD + let mut jpg = vec![0xff, 0xd8, 0xff, 0xe1]; + let mut app1 = b"Exif\0\0".to_vec(); + app1.extend(panasonic_exif(ByteOrder::Little, Some("LUMIX S 85/F1.8"), None)); + jpg.extend_from_slice(&((app1.len() + 2) as u16).to_be_bytes()); + jpg.extend(app1); + jpg.extend_from_slice(&[0xff, 0xda, 0, 2, 0xff, 0xd9]); + let mut exif = IfdBuilder::new(); + exif.set(t::FOCAL_LENGTH, Value::Rational(vec![(85, 1)])); + let mut ifd0 = IfdBuilder::new(); + ifd0.set(t::MAKE, Value::Ascii("Panasonic".into())); + ifd0.set(PANASONIC_JPG_FROM_RAW, Value::Undefined(jpg)); + ifd0.set_child(t::EXIF_IFD, exif); + let rw2 = TiffWriter::new(ByteOrder::Little, false).write(&[ifd0]).unwrap(); + let m = read_exif(&rw2); + assert_eq!(m.lens_model.as_deref(), Some("LUMIX S 85/F1.8")); + assert_eq!(m.focal_length, Some(85.0)); + assert_eq!(crate::extract(&rw2).lens_model.as_deref(), Some("LUMIX S 85/F1.8")); + } + pub(crate) fn sample_exif(order: ByteOrder) -> Vec { let mut exif = IfdBuilder::new(); exif.set(t::EXPOSURE_TIME, Value::Rational(vec![(1, 250)]));