scuffle_mp4/boxes/types/
sdtp.rs

1use std::io;
2
3use byteorder::WriteBytesExt;
4use bytes::{Buf, Bytes};
5
6use crate::boxes::header::{BoxHeader, FullBoxHeader};
7use crate::boxes::traits::BoxType;
8
9#[derive(Debug, Clone, PartialEq)]
10/// Sample Dependency Type Box
11/// ISO/IEC 14496-12:2022(E) 8.6.4
12pub struct Sdtp {
13    pub header: FullBoxHeader,
14    pub entries: Vec<SdtpEntry>,
15}
16
17#[derive(Debug, Clone, PartialEq)]
18/// Sample Dependency Type Entry
19pub struct SdtpEntry {
20    pub sample_is_leading: u8,     // 2 bits
21    pub sample_depends_on: u8,     // 2 bits
22    pub sample_is_depended_on: u8, // 2 bits
23    pub sample_has_redundancy: u8, // 2 bits
24}
25
26impl BoxType for Sdtp {
27    const NAME: [u8; 4] = *b"sdtp";
28
29    fn demux(header: BoxHeader, data: Bytes) -> io::Result<Self> {
30        let mut reader = io::Cursor::new(data);
31
32        let header = FullBoxHeader::demux(header, &mut reader)?;
33
34        let mut entries = Vec::new();
35        while reader.has_remaining() {
36            let byte = reader.get_u8();
37            entries.push(SdtpEntry {
38                sample_is_leading: (byte & 0b11000000) >> 6,
39                sample_depends_on: (byte & 0b00110000) >> 4,
40                sample_is_depended_on: (byte & 0b00001100) >> 2,
41                sample_has_redundancy: byte & 0b00000011,
42            });
43        }
44
45        Ok(Self { header, entries })
46    }
47
48    fn primitive_size(&self) -> u64 {
49        let size = self.header.size();
50        // entries
51        size + (self.entries.len() as u64)
52    }
53
54    fn primitive_mux<T: io::Write>(&self, writer: &mut T) -> io::Result<()> {
55        self.header.mux(writer)?;
56
57        for entry in &self.entries {
58            let byte = (entry.sample_is_leading << 6)
59                | (entry.sample_depends_on << 4)
60                | (entry.sample_is_depended_on << 2)
61                | entry.sample_has_redundancy;
62            writer.write_u8(byte)?;
63        }
64
65        Ok(())
66    }
67
68    fn validate(&self) -> io::Result<()> {
69        if self.header.version != 0 {
70            return Err(io::Error::new(io::ErrorKind::InvalidData, "sdtp box version must be 0"));
71        }
72
73        if self.header.flags != 0 {
74            return Err(io::Error::new(io::ErrorKind::InvalidData, "sdtp box flags must be 0"));
75        }
76
77        Ok(())
78    }
79}
scuffle_mp4/boxes/types/sdtp.rs

scuffle_mp4/boxes/types/
sdtp.rs
