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use crate::*;
/// Text track sample description format for tx3g
///
/// 3GPP TS 26.245 or ETSI TS 126 245 Section 5.16
/// See https://www.etsi.org/deliver/etsi_ts/126200_126299/126245/18.00.00_60/ts_126245v180000p.pdf
#[derive(Debug, Clone, PartialEq, Eq)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
pub struct Tx3g {
pub data_reference_index: u16,
pub display_flags: u32,
pub horizontal_justification: i8,
pub vertical_justification: i8,
pub bg_color_rgba: RgbaColor,
pub box_record: [i16; 4],
pub style_record: [u8; 12],
// Looks like this is supposed to be present, but we're relaxed about it.
pub ftab: Option<Ftab>,
// TODO: possibly there is a default disparity box here too, but never seen.
}
#[derive(Debug, Clone, PartialEq, Eq, Default)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
pub struct RgbaColor {
pub red: u8,
pub green: u8,
pub blue: u8,
pub alpha: u8,
}
impl Default for Tx3g {
fn default() -> Self {
Tx3g {
data_reference_index: 0,
display_flags: 0,
horizontal_justification: 1,
vertical_justification: -1,
bg_color_rgba: RgbaColor {
red: 0,
green: 0,
blue: 0,
alpha: 255,
},
box_record: [0, 0, 0, 0],
style_record: [0, 0, 0, 0, 0, 1, 0, 16, 255, 255, 255, 255],
ftab: None, // TODO: possibly a nice Serif?
}
}
}
impl Atom for Tx3g {
const KIND: FourCC = FourCC::new(b"tx3g");
fn decode_body<B: Buf>(buf: &mut B) -> Result<Self> {
u32::decode(buf)?; // reserved
u16::decode(buf)?; // reserved
let data_reference_index = u16::decode(buf)?;
let display_flags = u32::decode(buf)?;
let horizontal_justification = i8::decode(buf)?;
let vertical_justification = i8::decode(buf)?;
let bg_color_rgba = RgbaColor {
red: u8::decode(buf)?,
green: u8::decode(buf)?,
blue: u8::decode(buf)?,
alpha: u8::decode(buf)?,
};
let box_record: [i16; 4] = [
i16::decode(buf)?,
i16::decode(buf)?,
i16::decode(buf)?,
i16::decode(buf)?,
];
let style_record = <[u8; 12]>::decode(buf)?;
let mut ftab = None; // TODO
while let Some(atom) = Any::decode_maybe(buf)? {
match atom {
Any::Ftab(atom) => ftab = atom.into(),
unknown => Self::decode_unknown(&unknown)?,
}
}
Ok(Tx3g {
data_reference_index,
display_flags,
horizontal_justification,
vertical_justification,
bg_color_rgba,
box_record,
style_record,
ftab,
})
}
fn encode_body<B: BufMut>(&self, buf: &mut B) -> Result<()> {
0u32.encode(buf)?; // reserved
0u16.encode(buf)?; // reserved
self.data_reference_index.encode(buf)?;
self.display_flags.encode(buf)?;
self.horizontal_justification.encode(buf)?;
self.vertical_justification.encode(buf)?;
self.bg_color_rgba.red.encode(buf)?;
self.bg_color_rgba.green.encode(buf)?;
self.bg_color_rgba.blue.encode(buf)?;
self.bg_color_rgba.alpha.encode(buf)?;
for n in 0..4 {
(self.box_record[n]).encode(buf)?;
}
for n in 0..12 {
(self.style_record[n]).encode(buf)?;
}
self.ftab.encode(buf)?;
Ok(())
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_tx3g() {
let expected = Tx3g {
data_reference_index: 1,
display_flags: 0,
horizontal_justification: 1,
vertical_justification: -1,
bg_color_rgba: RgbaColor {
red: 0,
green: 0,
blue: 0,
alpha: 255,
},
box_record: [0, 0, 0, 0],
style_record: [0, 0, 0, 0, 0, 1, 0, 16, 255, 255, 255, 255],
ftab: None,
};
let mut buf = Vec::new();
expected.encode(&mut buf).unwrap();
let mut buf = buf.as_ref();
let decoded = Tx3g::decode(&mut buf).unwrap();
assert_eq!(decoded, expected);
}
// From the MPEG file format conformance test suite: isobmff/09_text.mp4
const ENCODED_TX3G_09: &[u8] = &[
0x00, 0x00, 0x00, 0x40, 0x74, 0x78, 0x33, 0x67, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x01, 0x00, 0x04, 0x00, 0x00, 0x01, 0xff, 0xff, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0x00,
0x00, 0x3c, 0x01, 0x90, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x12, 0xff, 0xff, 0xff,
0xff, 0x00, 0x00, 0x00, 0x12, 0x66, 0x74, 0x61, 0x62, 0x00, 0x01, 0x00, 0x01, 0x05, 0x53,
0x65, 0x72, 0x69, 0x66,
];
/* From isobmff/09_text_gpac.json:
"@Size": "64",
"@Type": "tx3g",
"@Specification": "3gpp",
"@Container": "stsd",
"@dataReferenceIndex": "1",
"@displayFlags": "40000",
"@horizontal-justification": "1",
"@vertical-justification": "-1",
"@backgroundColor": "ff 0 0 ff",
"DefaultBox": {
"BoxRecord": {
"@top": "0",
"@left": "0",
"@bottom": "60",
"@right": "400"
},
"FontTableBox": {
"@Size": "18",
"@Type": "ftab",
"@Specification": "3gpp",
"@Container": "tx3g text enct",
"FontRecord": {
"@ID": "1",
"@name": "Serif"
}
}
},
"DefaultStyle": {
"StyleRecord": {
"@startChar": "0",
"@endChar": "0",
"@fontID": "1",
"@styles": "Normal",
"@fontSize": "18",
"@textColor": "ff ff ff ff"
}
},
"FontTableBox": {
"@Size": "18",
"@Type": "ftab",
"@Specification": "3gpp",
"@Container": "tx3g text enct",
"FontRecord": {
"@ID": "1",
"@name": "Serif"
}
}
},
*/
fn get_reference_mpeg_09_tx3g() -> Tx3g {
Tx3g {
data_reference_index: 1,
display_flags: 0x00040000,
horizontal_justification: 1,
vertical_justification: -1,
bg_color_rgba: RgbaColor {
red: 0xFF,
green: 0x00,
blue: 0x00,
alpha: 0xFF,
},
box_record: [0, 0, 60, 400],
style_record: [0, 0, 0, 0, 0, 1, 0, 18, 255, 255, 255, 255],
ftab: Some(Ftab {
font_entries: vec![FontEntry {
font_id: 1,
font: "Serif".into(),
}],
}),
}
}
#[test]
fn test_mpeg_09_text_decode() {
let buf: &mut std::io::Cursor<&&[u8]> = &mut std::io::Cursor::new(&ENCODED_TX3G_09);
let tx3g = Tx3g::decode(buf).expect("failed to decode tx3g");
assert_eq!(tx3g, get_reference_mpeg_09_tx3g());
}
#[test]
fn test_mpeg_09_text_encode() {
let tx3g = get_reference_mpeg_09_tx3g();
let mut buf = Vec::new();
tx3g.encode(&mut buf).unwrap();
assert_eq!(buf.as_slice(), ENCODED_TX3G_09);
}
}