scuffle_mp4/boxes/types/
stsz.rs

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)]
/// Sample Size Box
/// ISO/IEC 14496-12:2022(E) - 8.7.3.2
pub struct Stsz {
    pub header: FullBoxHeader,
    pub sample_size: u32,
    pub samples: Vec<u32>,
}

impl Stsz {
    pub fn new(sample_size: u32, samples: Vec<u32>) -> Self {
        Self {
            header: FullBoxHeader::new(Self::NAME, 0, 0),
            sample_size,
            samples,
        }
    }
}

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

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

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

        let sample_size = reader.read_u32::<BigEndian>()?;
        let sample_count = reader.read_u32::<BigEndian>()?;

        let mut samples = Vec::with_capacity(sample_count as usize);
        if sample_size == 0 {
            for _ in 0..sample_count {
                let size = reader.read_u32::<BigEndian>()?;
                samples.push(size);
            }
        }

        Ok(Self {
            header,
            sample_size,
            samples,
        })
    }

    fn primitive_size(&self) -> u64 {
        let size = self.header.size();
        let size = size + 8; // sample_size + sample_count

        if self.sample_size == 0 {
            size + (self.samples.len() as u64 * 4) // samples
        } else {
            size
        }
    }

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

        writer.write_u32::<BigEndian>(self.sample_size)?;
        writer.write_u32::<BigEndian>(self.samples.len() as u32)?;

        if self.sample_size == 0 {
            for size in &self.samples {
                writer.write_u32::<BigEndian>(*size)?;
            }
        }

        Ok(())
    }

    fn validate(&self) -> io::Result<()> {
        if self.sample_size != 0 && !self.samples.is_empty() {
            return Err(io::Error::new(
                io::ErrorKind::InvalidData,
                "stsz: sample_size is not 0 but samples are present",
            ));
        }

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

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

        Ok(())
    }
}
scuffle_mp4/boxes/types/stsz.rs

scuffle_mp4/boxes/types/
stsz.rs
