scuffle_mp4/boxes/types/
stts.rs

1use std::io;
2
3use byteorder::{BigEndian, ReadBytesExt, WriteBytesExt};
4use bytes::Bytes;
5
6use crate::boxes::header::{BoxHeader, FullBoxHeader};
7use crate::boxes::traits::BoxType;
8
9#[derive(Debug, Clone, PartialEq)]
10/// Decoding Time to Sample Box
11/// ISO/IEC 14496-12:2022(E) - 8.6.1.2
12pub struct Stts {
13    pub header: FullBoxHeader,
14    pub entries: Vec<SttsEntry>,
15}
16
17impl Stts {
18    pub fn new(entries: Vec<SttsEntry>) -> Self {
19        Self {
20            header: FullBoxHeader::new(Self::NAME, 0, 0),
21            entries,
22        }
23    }
24}
25
26#[derive(Debug, Clone, PartialEq)]
27/// Decoding Time to Sample Box Entry
28pub struct SttsEntry {
29    pub sample_count: u32,
30    pub sample_delta: u32,
31}
32
33impl BoxType for Stts {
34    const NAME: [u8; 4] = *b"stts";
35
36    fn demux(header: BoxHeader, data: Bytes) -> io::Result<Self> {
37        let mut reader = io::Cursor::new(data);
38
39        let header = FullBoxHeader::demux(header, &mut reader)?;
40
41        let entry_count = reader.read_u32::<BigEndian>()?;
42        let mut entries = Vec::with_capacity(entry_count as usize);
43        for _ in 0..entry_count {
44            let sample_count = reader.read_u32::<BigEndian>()?;
45            let sample_delta = reader.read_u32::<BigEndian>()?;
46            entries.push(SttsEntry {
47                sample_count,
48                sample_delta,
49            });
50        }
51
52        Ok(Self { header, entries })
53    }
54
55    fn primitive_size(&self) -> u64 {
56        let size = self.header.size();
57        let size = size + 4; // entry_count
58        // entries
59        size + (self.entries.len() as u64 * 8)
60    }
61
62    fn primitive_mux<T: io::Write>(&self, writer: &mut T) -> io::Result<()> {
63        self.header.mux(writer)?;
64
65        writer.write_u32::<BigEndian>(self.entries.len() as u32)?;
66        for entry in &self.entries {
67            writer.write_u32::<BigEndian>(entry.sample_count)?;
68            writer.write_u32::<BigEndian>(entry.sample_delta)?;
69        }
70
71        Ok(())
72    }
73
74    fn validate(&self) -> io::Result<()> {
75        if self.header.version != 0 {
76            return Err(io::Error::new(io::ErrorKind::InvalidData, "stts version must be 0"));
77        }
78
79        if self.header.flags != 0 {
80            return Err(io::Error::new(io::ErrorKind::InvalidData, "stts flags must be 0"));
81        }
82
83        Ok(())
84    }
85}
scuffle_mp4/boxes/types/stts.rs

scuffle_mp4/boxes/types/
stts.rs
