scuffle_mp4/boxes/types/
stsh.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/// Shadow Sync Sample Box
11/// ISO/IEC 14496-12:2022(E) - 8.6.3
12pub struct Stsh {
13    pub header: FullBoxHeader,
14    pub entries: Vec<StshEntry>,
15}
16
17#[derive(Debug, Clone, PartialEq)]
18/// Shadow Sync Sample Entry
19pub struct StshEntry {
20    pub shadowed_sample_count: u32,
21    pub sync_sample_number: u32,
22}
23
24impl BoxType for Stsh {
25    const NAME: [u8; 4] = *b"stsh";
26
27    fn demux(header: BoxHeader, data: Bytes) -> io::Result<Self> {
28        let mut reader = io::Cursor::new(data);
29
30        let header = FullBoxHeader::demux(header, &mut reader)?;
31
32        let entry_count = reader.read_u32::<BigEndian>()?;
33        let mut entries = Vec::with_capacity(entry_count as usize);
34        for _ in 0..entry_count {
35            let shadowed_sample_count = reader.read_u32::<BigEndian>()?;
36            let sync_sample_number = reader.read_u32::<BigEndian>()?;
37
38            entries.push(StshEntry {
39                shadowed_sample_count,
40                sync_sample_number,
41            });
42        }
43
44        Ok(Self { header, entries })
45    }
46
47    fn primitive_size(&self) -> u64 {
48        let size = self.header.size();
49        let size = size + 4; // entry_count
50        // entries
51        size + (self.entries.len() as u64 * 8)
52    }
53
54    fn primitive_mux<T: io::Write>(&self, writer: &mut T) -> io::Result<()> {
55        self.header.mux(writer)?;
56
57        writer.write_u32::<BigEndian>(self.entries.len() as u32)?;
58        for entry in &self.entries {
59            writer.write_u32::<BigEndian>(entry.shadowed_sample_count)?;
60            writer.write_u32::<BigEndian>(entry.sync_sample_number)?;
61        }
62
63        Ok(())
64    }
65
66    fn validate(&self) -> io::Result<()> {
67        if self.header.version != 0 {
68            return Err(io::Error::new(io::ErrorKind::InvalidData, "stsh version must be 0"));
69        }
70
71        if self.header.flags != 0 {
72            return Err(io::Error::new(io::ErrorKind::InvalidData, "stsh flags must be 0"));
73        }
74
75        Ok(())
76    }
77}
scuffle_mp4/boxes/types/stsh.rs

scuffle_mp4/boxes/types/
stsh.rs
