scuffle_mp4/boxes/types/
smhd.rs

1use std::io;
2
3use byteorder::{BigEndian, ReadBytesExt, WriteBytesExt};
4use bytes::Bytes;
5use fixed::FixedI16;
6use fixed::types::extra::U8;
7
8use crate::boxes::header::{BoxHeader, FullBoxHeader};
9use crate::boxes::traits::BoxType;
10
11#[derive(Debug, Clone, PartialEq)]
12/// Sound Media Header Box
13/// ISO/IEC 14496-12:2022(E) - 12.2.2
14pub struct Smhd {
15    pub header: FullBoxHeader,
16    pub balance: FixedI16<U8>,
17    pub reserved: u16,
18}
19
20impl Default for Smhd {
21    fn default() -> Self {
22        Self::new()
23    }
24}
25
26impl Smhd {
27    pub fn new() -> Self {
28        Self {
29            header: FullBoxHeader::new(Self::NAME, 0, 0),
30            balance: FixedI16::<U8>::from_num(0),
31            reserved: 0,
32        }
33    }
34}
35
36impl BoxType for Smhd {
37    const NAME: [u8; 4] = *b"smhd";
38
39    fn demux(header: BoxHeader, data: Bytes) -> io::Result<Self> {
40        let mut reader = io::Cursor::new(data);
41
42        let header = FullBoxHeader::demux(header, &mut reader)?;
43
44        let balance = reader.read_i16::<BigEndian>()?;
45        let reserved = reader.read_u16::<BigEndian>()?;
46
47        Ok(Self {
48            header,
49            balance: FixedI16::from_bits(balance),
50            reserved,
51        })
52    }
53
54    fn primitive_size(&self) -> u64 {
55        let size = self.header.size();
56        let size = size + 2; // balance
57        // reserved
58        size + 2
59    }
60
61    fn primitive_mux<T: io::Write>(&self, writer: &mut T) -> io::Result<()> {
62        self.header.mux(writer)?;
63
64        writer.write_i16::<BigEndian>(self.balance.to_bits())?;
65        writer.write_u16::<BigEndian>(self.reserved)?;
66
67        Ok(())
68    }
69
70    fn validate(&self) -> io::Result<()> {
71        if self.header.version != 0 {
72            return Err(io::Error::new(io::ErrorKind::InvalidData, "smhd version must be 0"));
73        }
74
75        if self.header.flags != 0 {
76            return Err(io::Error::new(io::ErrorKind::InvalidData, "smhd flags must be 0"));
77        }
78
79        if self.reserved != 0 {
80            return Err(io::Error::new(io::ErrorKind::InvalidData, "smhd reserved must be 0"));
81        }
82
83        Ok(())
84    }
85}
scuffle_mp4/boxes/types/smhd.rs

scuffle_mp4/boxes/types/
smhd.rs
