scuffle_mp4/boxes/types/
mdhd.rs

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use std::io;

use byteorder::{BigEndian, ReadBytesExt, WriteBytesExt};
use bytes::Bytes;

use crate::boxes::header::{BoxHeader, FullBoxHeader};
use crate::boxes::traits::BoxType;

#[derive(Debug, Clone, PartialEq)]
/// Media Header Box
/// ISO/IEC 14496-12:2022(E) - 8.4.2
pub struct Mdhd {
    pub header: FullBoxHeader,
    pub creation_time: u64,
    pub modification_time: u64,
    pub timescale: u32,
    pub duration: u64,
    pub language: u16,
    pub pre_defined: u16,
}

impl Mdhd {
    pub fn new(creation_time: u64, modification_time: u64, timescale: u32, duration: u64) -> Self {
        let version = if creation_time > u32::MAX as u64 || modification_time > u32::MAX as u64 || duration > u32::MAX as u64
        {
            1
        } else {
            0
        };

        Self {
            header: FullBoxHeader::new(Self::NAME, version, 0),
            creation_time,
            modification_time,
            timescale,
            duration,
            language: 0x55c4, // und
            pre_defined: 0,
        }
    }
}

impl BoxType for Mdhd {
    const NAME: [u8; 4] = *b"mdhd";

    fn demux(header: BoxHeader, data: Bytes) -> io::Result<Self> {
        let mut reader = io::Cursor::new(data);

        let header = FullBoxHeader::demux(header, &mut reader)?;

        let (creation_time, modification_time, timescale, duration) = if header.version == 1 {
            (
                reader.read_u64::<BigEndian>()?, // creation_time
                reader.read_u64::<BigEndian>()?, // modification_time
                reader.read_u32::<BigEndian>()?, // timescale
                reader.read_u64::<BigEndian>()?, // duration
            )
        } else {
            (
                reader.read_u32::<BigEndian>()? as u64, // creation_time
                reader.read_u32::<BigEndian>()? as u64, // modification_time
                reader.read_u32::<BigEndian>()?,        // timescale
                reader.read_u32::<BigEndian>()? as u64, // duration
            )
        };

        let language = reader.read_u16::<BigEndian>()?;
        let pre_defined = reader.read_u16::<BigEndian>()?;

        Ok(Self {
            header,
            creation_time,
            modification_time,
            timescale,
            duration,
            language,
            pre_defined,
        })
    }

    fn primitive_size(&self) -> u64 {
        self.header.size()
        + if self.header.version == 1 {
            8 + 8 + 4 + 8 // creation_time + modification_time + timescale + duration
        } else {
            4 + 4 + 4 + 4 // creation_time + modification_time + timescale + duration
        }
        + 2 // language
        + 2 // pre_defined
    }

    fn primitive_mux<T: io::Write>(&self, writer: &mut T) -> io::Result<()> {
        self.header.mux(writer)?;

        if self.header.version == 1 {
            writer.write_u64::<BigEndian>(self.creation_time)?;
            writer.write_u64::<BigEndian>(self.modification_time)?;
            writer.write_u32::<BigEndian>(self.timescale)?;
            writer.write_u64::<BigEndian>(self.duration)?;
        } else {
            writer.write_u32::<BigEndian>(self.creation_time as u32)?;
            writer.write_u32::<BigEndian>(self.modification_time as u32)?;
            writer.write_u32::<BigEndian>(self.timescale)?;
            writer.write_u32::<BigEndian>(self.duration as u32)?;
        }

        writer.write_u16::<BigEndian>(self.language)?;
        writer.write_u16::<BigEndian>(self.pre_defined)?;

        Ok(())
    }

    fn validate(&self) -> io::Result<()> {
        if self.header.flags != 0 {
            return Err(io::Error::new(io::ErrorKind::InvalidData, "mdhd box flags must be 0"));
        }

        if self.header.version > 1 {
            return Err(io::Error::new(io::ErrorKind::InvalidData, "mdhd box version must be 0 or 1"));
        }

        if self.header.version == 0 {
            if self.creation_time > u32::MAX as u64 {
                return Err(io::Error::new(
                    io::ErrorKind::InvalidData,
                    "mdhd box creation_time must be less than 2^32",
                ));
            }

            if self.modification_time > u32::MAX as u64 {
                return Err(io::Error::new(
                    io::ErrorKind::InvalidData,
                    "mdhd box modification_time must be less than 2^32",
                ));
            }

            if self.duration > u32::MAX as u64 {
                return Err(io::Error::new(
                    io::ErrorKind::InvalidData,
                    "mdhd box duration must be less than 2^32",
                ));
            }
        }

        if self.pre_defined != 0 {
            return Err(io::Error::new(io::ErrorKind::InvalidData, "mdhd box pre_defined must be 0"));
        }

        Ok(())
    }
}