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Remove Seek/File dependencies from stream readers

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Streams are streams — they take impl Read, not Read+Seek or File.

- MkvStream::open takes impl Read (was Read+Seek)
  - EBML element skipping uses skip_bytes() instead of seek(Current)
  - Byte position tracking uses remaining-bytes counter, not stream_position()
  - Removed file_size from open (progress is CLI concern)
- M2tsStream::open takes impl Read (was Read+Seek)
  - Buffers first 1MB for FMKV header / PMT scan
  - Uses chain reader (buffered head + rest) for sequential reading
  - Duration unknown without seeking (0.0) — CLI can set from metadata
- Removed ReadSeek trait (no longer needed)
- WriteSeek kept (MKV muxer container format requires seeking internally)
This commit is contained in:
MattJackson
2026-04-15 17:05:50 +00:00
parent 87342290c5
commit 404c005e0b
3 changed files with 89 additions and 87 deletions
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src/mux/mkvstream.rs
+44 -41
View File
@@ -7,11 +7,19 @@ use super::codec::{self, CodecParser};
use super::lookahead::{LookaheadBuffer, LookaheadState, DEFAULT_LOOKAHEAD_SIZE};
use super::mkv::{MkvMuxer, MkvTrack};
use super::ts::TsDemuxer;
use super::{ebml, IOStream, ReadSeek, WriteSeek};
use super::{ebml, IOStream, WriteSeek};
use std::io::Seek;
type MkvHeaderResult = io::Result<(crate::disc::DiscTitle, Vec<(u16, Vec<u8>)>)>;
/// Skip `n` bytes on a forward-only reader (no Seek required).
fn skip_bytes(r: &mut impl Read, n: u64) -> io::Result<()> {
io::copy(&mut r.take(n), &mut io::sink())?;
Ok(())
}
use crate::disc::*;
use std::io::{self, Read, Seek, SeekFrom, Write};
use std::io::{self, Read, Write};
/// Lookahead buffer for codec header detection (5 MB default).
const DEFAULT_MAX_BUFFER: usize = DEFAULT_LOOKAHEAD_SIZE;
@@ -35,7 +43,7 @@ struct WriteState {
}
struct ReadState {
reader: Box<dyn ReadSeek>,
reader: Box<dyn Read>,
buf: Vec<u8>,
pos: usize,
len: usize,
@@ -129,9 +137,7 @@ impl MkvStream {
}
/// Open an MKV file for reading.
pub fn open(mut reader: impl Read + Seek + 'static) -> io::Result<Self> {
let file_size = reader.seek(SeekFrom::End(0))?;
reader.seek(SeekFrom::Start(0))?;
pub fn open(mut reader: impl Read + 'static) -> io::Result<Self> {
let (disc_title, codec_privates) = parse_mkv_header(&mut reader)?;
Ok(Self {
disc_title,
@@ -146,7 +152,7 @@ impl MkvStream {
}),
max_buffer: 0,
finished: false,
file_size: Some(file_size),
file_size: None,
})
}
}
@@ -196,9 +202,7 @@ impl crate::pes::Stream for MkvStream {
}));
}
_ => {
// Skip unknown element
let mut skip = vec![0u8; size as usize];
let _ = rs.reader.read_exact(&mut skip);
skip_bytes(&mut rs.reader, size)?;
continue;
}
}
@@ -396,7 +400,7 @@ impl Read for MkvStream {
}
_ => {
if size != u64::MAX && size > 0 {
rs.reader.seek(SeekFrom::Current(size as i64))?;
skip_bytes(&mut rs.reader, size)?;
}
}
}
@@ -484,7 +488,7 @@ fn write_pes(
/// Returns (DiscTitle, codec_privates: Vec<(track_number, codec_private_bytes)>)
fn parse_mkv_header(
r: &mut (impl Read + Seek),
r: &mut impl Read,
) -> MkvHeaderResult {
let mut title = String::new();
let mut duration_ms = 0.0f64;
@@ -502,7 +506,7 @@ fn parse_mkv_header(
"EBML header too large",
));
}
r.seek(SeekFrom::Current(size as i64))?;
skip_bytes(r, size as u64)?;
let (id, _, _) = ebml::read_element_header(r)?;
if id != ebml::SEGMENT {
@@ -522,24 +526,24 @@ fn parse_mkv_header(
match id {
ebml::INFO => {
let end = r.stream_position()? + size;
while r.stream_position()? < end {
let (cid, cs, _) = ebml::read_element_header(r)?;
let mut remaining = size;
while remaining > 0 {
let (cid, cs, hlen) = ebml::read_element_header(r)?;
remaining = remaining.saturating_sub(hlen as u64 + cs);
match cid {
ebml::TIMESTAMP_SCALE => ts_scale = ebml::read_uint_val(r, cs as usize)?,
ebml::DURATION => duration_ms = ebml::read_float_val(r, cs as usize)?,
ebml::TITLE => title = ebml::read_string_val(r, cs as usize)?,
_ => {
r.seek(SeekFrom::Current(cs as i64))?;
}
_ => { skip_bytes(r, cs)?; }
}
}
got_info = true;
}
ebml::TRACKS => {
let end = r.stream_position()? + size;
while r.stream_position()? < end {
let (cid, cs, _) = ebml::read_element_header(r)?;
let mut remaining = size;
while remaining > 0 {
let (cid, cs, hlen) = ebml::read_element_header(r)?;
remaining = remaining.saturating_sub(hlen as u64 + cs);
if cid == ebml::TRACK_ENTRY {
let (stream, tnum, cp) = parse_track(r, cs)?;
if let Some(s) = stream {
@@ -549,14 +553,14 @@ fn parse_mkv_header(
codec_privates.push((tnum, cp));
}
} else {
r.seek(SeekFrom::Current(cs as i64))?;
skip_bytes(r, cs)?;
}
}
got_tracks = true;
}
ebml::CLUSTER => break,
_ if size != u64::MAX => {
r.seek(SeekFrom::Current(size as i64))?;
skip_bytes(r, size as u64)?;
}
_ => break,
}
@@ -573,17 +577,18 @@ fn parse_mkv_header(
/// Returns (stream, track_number, codec_private_bytes)
fn parse_track(
r: &mut (impl Read + Seek),
r: &mut impl Read,
size: u64,
) -> io::Result<(Option<crate::disc::Stream>, u16, Option<Vec<u8>>)> {
let end = r.stream_position()? + size;
let (mut ttype, mut tnum) = (0u64, 0u16);
let (mut codec_id, mut lang, mut name) = (String::new(), String::from("und"), String::new());
let (mut ph, mut sr, mut ch, mut forced) = (0u32, 0.0f64, 0u8, false);
let mut codec_priv: Option<Vec<u8>> = None;
while r.stream_position()? < end {
let (cid, cs, _) = ebml::read_element_header(r)?;
let mut remaining = size;
while remaining > 0 {
let (cid, cs, hlen) = ebml::read_element_header(r)?;
remaining = remaining.saturating_sub(hlen as u64 + cs);
match cid {
ebml::TRACK_NUMBER => tnum = ebml::read_uint_val(r, cs as usize)? as u16,
ebml::TRACK_TYPE => ttype = ebml::read_uint_val(r, cs as usize)?,
@@ -593,32 +598,30 @@ fn parse_track(
ebml::TRACK_NAME => name = ebml::read_string_val(r, cs as usize)?,
ebml::FLAG_FORCED => forced = ebml::read_uint_val(r, cs as usize)? != 0,
ebml::VIDEO => {
let ve = r.stream_position()? + cs;
while r.stream_position()? < ve {
let (vid, vs, _) = ebml::read_element_header(r)?;
let mut vrem = cs;
while vrem > 0 {
let (vid, vs, vhlen) = ebml::read_element_header(r)?;
vrem = vrem.saturating_sub(vhlen as u64 + vs);
if vid == ebml::PIXEL_HEIGHT {
ph = ebml::read_uint_val(r, vs as usize)? as u32;
} else {
r.seek(SeekFrom::Current(vs as i64))?;
skip_bytes(r, vs)?;
}
}
}
ebml::AUDIO => {
let ae = r.stream_position()? + cs;
while r.stream_position()? < ae {
let (aid, as_, _) = ebml::read_element_header(r)?;
let mut arem = cs;
while arem > 0 {
let (aid, as_, ahlen) = ebml::read_element_header(r)?;
arem = arem.saturating_sub(ahlen as u64 + as_);
match aid {
ebml::SAMPLING_FREQUENCY => sr = ebml::read_float_val(r, as_ as usize)?,
ebml::CHANNELS => ch = ebml::read_uint_val(r, as_ as usize)? as u8,
_ => {
r.seek(SeekFrom::Current(as_ as i64))?;
}
_ => { skip_bytes(r, as_)?; }
}
}
}
_ => {
r.seek(SeekFrom::Current(cs as i64))?;
}
_ => { skip_bytes(r, cs)?; }
}
}