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|
use byteorder::{BigEndian, WriteBytesExt};
use four_cc::FourCC;
use bytes::{BufMut, BytesMut};
use std::mem::size_of;
use crate::{FullBoxHeader, Mp4Box, Mp4BoxError};
bitflags::bitflags! {
pub struct TrackFragmentRunFlags: u32 {
const DATA_OFFSET_PRESENT = 0x00000001;
const FIRST_SAMPLE_FLAGS_PRESENT = 0x00000004;
const SAMPLE_DURATION_PRESENT = 0x00000100;
const SAMPLE_SIZE_PRESENT = 0x00000200;
const SAMPLE_FLAGS_PRESENT = 0x00000400;
const SAMPLE_COMPOSITION_TIME_OFFSET_PRESENT = 0x00000800;
}
}
pub struct TrackFragmentSample {
pub duration: Option<u32>,
pub size: Option<u32>,
pub flags: Option<u32>,
pub composition_time_offset: Option<i32>,
}
pub struct TrackFragmentRunBox {
pub data_offset: Option<i32>,
pub first_sample_flags: Option<u32>,
pub samples: Vec<TrackFragmentSample>,
}
impl TrackFragmentRunBox {
fn sample_size(&self, flags: TrackFragmentRunFlags) -> u64 {
let mut sample_size = 0;
if flags.contains(TrackFragmentRunFlags::SAMPLE_DURATION_PRESENT) {
sample_size += 4; // sample_duration
}
if flags.contains(TrackFragmentRunFlags::SAMPLE_SIZE_PRESENT) {
sample_size += 4; // sample_size
}
if flags.contains(TrackFragmentRunFlags::SAMPLE_FLAGS_PRESENT) {
sample_size += 4; // sample_flags
}
if flags.contains(TrackFragmentRunFlags::SAMPLE_COMPOSITION_TIME_OFFSET_PRESENT) {
sample_size += 4; // sample_composition_time_offset
}
sample_size
}
fn flags_from_fields(&self) -> TrackFragmentRunFlags {
let mut flags = TrackFragmentRunFlags::empty();
if self.data_offset.is_some() {
flags.insert(TrackFragmentRunFlags::DATA_OFFSET_PRESENT);
}
if self.first_sample_flags.is_some() {
flags.insert(TrackFragmentRunFlags::FIRST_SAMPLE_FLAGS_PRESENT);
}
if let Some(sample) = self.samples.get(0) {
if sample.duration.is_some() {
flags.insert(TrackFragmentRunFlags::SAMPLE_DURATION_PRESENT);
}
if sample.size.is_some() {
flags.insert(TrackFragmentRunFlags::SAMPLE_SIZE_PRESENT);
}
if sample.flags.is_some() {
flags.insert(TrackFragmentRunFlags::SAMPLE_FLAGS_PRESENT);
}
if sample.composition_time_offset.is_some() {
flags.insert(TrackFragmentRunFlags::SAMPLE_COMPOSITION_TIME_OFFSET_PRESENT);
}
}
flags
}
}
impl Mp4Box for TrackFragmentRunBox {
const NAME: FourCC = FourCC(*b"trun");
fn get_full_box_header(&self) -> Option<FullBoxHeader> {
Some(FullBoxHeader::new(0, self.flags_from_fields().bits()))
}
fn content_size(&self) -> u64 {
let flags = self.flags_from_fields();
let mut size = 0;
size += size_of::<u32>() as u64; // sample_count
if flags.contains(TrackFragmentRunFlags::DATA_OFFSET_PRESENT) {
size += size_of::<i32>() as u64; // data_offset
}
if flags.contains(TrackFragmentRunFlags::FIRST_SAMPLE_FLAGS_PRESENT) {
size += size_of::<u32>() as u64; // first_sample_flags
}
size += self.sample_size(flags) * self.samples.len() as u64;
size
}
fn write_box_contents(&self, writer: &mut BytesMut) -> Result<(), Mp4BoxError> {
let mut v = Vec::new();
v.write_u32::<BigEndian>(self.samples.len() as u32)?; // TODO: check for truncation
if let Some(data_offset) = self.data_offset {
v.write_i32::<BigEndian>(data_offset)?;
}
if let Some(first_sample_flags) = self.first_sample_flags {
v.write_u32::<BigEndian>(first_sample_flags)?;
}
let flags = self.flags_from_fields();
for sample in &self.samples {
ensure_sample_fields_present(&sample, flags);
if let Some(duration) = sample.duration {
v.write_u32::<BigEndian>(duration)?;
}
if let Some(size) = sample.size {
v.write_u32::<BigEndian>(size)?;
}
if let Some(flags) = sample.flags {
v.write_u32::<BigEndian>(flags)?;
}
if let Some(composition_time_offset) = sample.composition_time_offset {
v.write_i32::<BigEndian>(composition_time_offset)?;
}
}
assert_eq!(v.len() as u64, self.content_size());
writer.put_slice(&v);
Ok(())
}
}
fn ensure_sample_fields_present(sample: &TrackFragmentSample, flags: TrackFragmentRunFlags) {
let duration_should_be_present = flags.contains(TrackFragmentRunFlags::SAMPLE_DURATION_PRESENT);
let size_should_be_present = flags.contains(TrackFragmentRunFlags::SAMPLE_SIZE_PRESENT);
let flags_should_be_present = flags.contains(TrackFragmentRunFlags::SAMPLE_FLAGS_PRESENT);
let composition_time_offset_should_be_present =
flags.contains(TrackFragmentRunFlags::SAMPLE_COMPOSITION_TIME_OFFSET_PRESENT);
let duration_is_present = sample.duration.is_some();
let size_is_present = sample.size.is_some();
let flags_is_present = sample.flags.is_some();
let composition_time_offset_is_present = sample.composition_time_offset.is_some();
// TODO: return error
assert_eq!(duration_should_be_present, duration_is_present);
assert_eq!(size_should_be_present, size_is_present);
assert_eq!(flags_should_be_present, flags_is_present);
assert_eq!(
composition_time_offset_should_be_present,
composition_time_offset_is_present
);
}
|
