mux/mp4: M2 — audio tracks + fit oracle (multi-track)
Generalize the sink to N tracks: one video + every MP4-mappable audio track. Audio sample entries built from the first frame's bitstream — AC-3 (ac-3/dac3) and E-AC-3 (ec-3/dec3), parsing the (E-)AC-3 BSI for fscod/bsid/bsmod/acmod/lfeon and the data rate. Per-sample audio durations from PTS deltas (no reorder → no ctts, all sync). Fit oracle (mp4_fit_report, exported): video HEVC/H264, audio AC-3/E-AC-3; TrueHD/DTS/LPCM and bitmap subs are excluded with a typed reason so the CLI can report exclusions — never a silent drop. Verified vs ffmpeg -c copy on real discs: AVC+AC3 and HEVC(HDR10)+AC3 both frame-exact on every track (video 2650/4270, audio 5567/3454), duration and colour identical, clean decode. On a pathological 4-clip title ffmpeg's OWN output emits the same DTS-monotonicity warnings (more of them) — source-inherent, not a muxer defect.
This commit is contained in:
Matthew Jackson
@@ -850,6 +850,11 @@ impl From<Error> for std::io::Error {
|
||||
// 9023 MuxEmpty: finish() reached with zero frames — the output
|
||||
// would be a header-only container. Treat as invalid output.
|
||||
E_MUX_EMPTY => std::io::ErrorKind::InvalidData,
|
||||
// 9048-9050 mp4:// track/codec/config mismatches: the requested
|
||||
// output can't hold this title's video — invalid output request.
|
||||
E_MP4_NO_VIDEO_TRACK | E_MP4_UNSUPPORTED_VIDEO_CODEC | E_MP4_MISSING_CODEC_PRIVATE => {
|
||||
std::io::ErrorKind::InvalidData
|
||||
}
|
||||
// 9030 ExtentNotUnitAligned: a malformed/non-AACS-aligned
|
||||
// extent was handed to the prefetch producer.
|
||||
9030 => std::io::ErrorKind::InvalidInput,
|
||||
|
||||
@@ -241,6 +241,7 @@ pub use mux::NullStream;
|
||||
pub use mux::StdioStream;
|
||||
pub use mux::WriteSeek;
|
||||
pub use mux::{InputOptions, StreamUrl, input, output, parse_url};
|
||||
pub use mux::{Mp4FitReport, Mp4SkipReason, mp4_fit_report};
|
||||
|
||||
// ─── Lower-level surfaces ───────────────────────────────────────────────────
|
||||
//
|
||||
|
||||
@@ -116,6 +116,7 @@ pub(crate) mod videomap;
|
||||
pub use disc::DiscStream;
|
||||
pub use m2ts::M2tsStream;
|
||||
pub use mkvstream::MkvStream;
|
||||
pub use mp4::{Mp4FitReport, Mp4SkipReason, fit_report as mp4_fit_report};
|
||||
pub use network::NetworkStream;
|
||||
pub use null::NullStream;
|
||||
pub use pipelined_stream::PipelinedPesStream;
|
||||
|
||||
@@ -0,0 +1,337 @@
|
||||
//! MP4 audio sample entries and codec-config boxes for the `mp4://` muxer.
|
||||
//!
|
||||
//! Covers the Dolby family that maps cleanly into MP4 and plays widely:
|
||||
//! **AC-3** (`ac-3` + `dac3`) and **E-AC-3 / Dolby Digital Plus** (`ec-3` +
|
||||
//! `dec3`, which also carries Atmos-in-DD+ JOC). The config boxes are derived
|
||||
//! from the first audio frame's bitstream (ISO/IEC 14496-12 amendments; ETSI TS
|
||||
//! 102 366 Annexes F/G). Codecs with no clean MP4 mapping (TrueHD, DTS family,
|
||||
//! LPCM, bitmap subtitles) are handled by the fit oracle in the sink, not here.
|
||||
|
||||
use super::boxes::bx;
|
||||
use crate::disc::Codec;
|
||||
|
||||
/// AC-3 / E-AC-3 sample rates indexed by `fscod` (byte-4 bits 7-6).
|
||||
const FSCOD_RATES: [u32; 3] = [48_000, 44_100, 32_000];
|
||||
/// E-AC-3 reduced rates indexed by `fscod2` (byte-4 bits 5-4) when `fscod == 3`.
|
||||
const EAC3_REDUCED_RATES: [u32; 4] = [24_000, 22_050, 16_000, 48_000];
|
||||
/// Base channel count per `acmod` (A/52 Table 5.8), before the LFE.
|
||||
const ACMOD_CHANNELS: [u8; 8] = [2, 1, 2, 3, 3, 4, 4, 5];
|
||||
|
||||
/// A big-endian MSB-first bit reader over a byte slice.
|
||||
struct BitReader<'a> {
|
||||
data: &'a [u8],
|
||||
bit: usize,
|
||||
}
|
||||
|
||||
impl<'a> BitReader<'a> {
|
||||
fn new(data: &'a [u8]) -> Self {
|
||||
Self { data, bit: 0 }
|
||||
}
|
||||
fn skip(&mut self, n: usize) {
|
||||
self.bit += n;
|
||||
}
|
||||
/// Read `n` bits (n ≤ 32). Returns 0 past end of data (callers pre-check len).
|
||||
fn read(&mut self, n: usize) -> u32 {
|
||||
let mut v = 0u32;
|
||||
for _ in 0..n {
|
||||
let byte = self.data.get(self.bit / 8).copied().unwrap_or(0);
|
||||
let shift = 7 - (self.bit % 8);
|
||||
v = (v << 1) | ((byte >> shift) & 1) as u32;
|
||||
self.bit += 1;
|
||||
}
|
||||
v
|
||||
}
|
||||
}
|
||||
|
||||
/// Decoded (E-)AC-3 stream parameters needed for the `dac3`/`dec3` config box
|
||||
/// and the audio sample entry.
|
||||
pub(super) struct DolbyConfig {
|
||||
pub fscod: u8,
|
||||
pub bsid: u8,
|
||||
pub bsmod: u8,
|
||||
pub acmod: u8,
|
||||
pub lfeon: bool,
|
||||
/// AC-3 only: `bit_rate_code` (= `frmsizecod >> 1`). Unused for E-AC-3.
|
||||
pub bit_rate_code: u8,
|
||||
/// E-AC-3 only: nominal data rate in kbps (for `dec3`). 0 for AC-3.
|
||||
pub data_rate_kbps: u16,
|
||||
pub sample_rate: u32,
|
||||
pub channels: u16,
|
||||
}
|
||||
|
||||
impl DolbyConfig {
|
||||
fn channel_count(acmod: u8, lfeon: bool) -> u16 {
|
||||
ACMOD_CHANNELS[acmod as usize] as u16 + lfeon as u16
|
||||
}
|
||||
}
|
||||
|
||||
/// Parse the first (E-)AC-3 frame starting at the 0x0B77 syncword. Returns
|
||||
/// `None` if the frame is too short or the syncword is absent.
|
||||
pub(super) fn parse_dolby(frame: &[u8]) -> Option<DolbyConfig> {
|
||||
let start =
|
||||
(0..frame.len().saturating_sub(1)).find(|&i| frame[i] == 0x0B && frame[i + 1] == 0x77)?;
|
||||
let f = &frame[start..];
|
||||
if f.len() < 6 {
|
||||
return None;
|
||||
}
|
||||
// bsid lives in byte 5 bits 7-3 for both AC-3 and E-AC-3.
|
||||
let bsid = (f[5] >> 3) & 0x1F;
|
||||
if bsid >= 11 {
|
||||
parse_eac3(f)
|
||||
} else {
|
||||
parse_ac3(f)
|
||||
}
|
||||
}
|
||||
|
||||
/// Legacy AC-3 (A/52 §5.3.2): syncword | crc(16) | fscod(2) frmsizecod(6) |
|
||||
/// bsid(5) bsmod(3) | acmod(3) …optional… lfeon.
|
||||
fn parse_ac3(f: &[u8]) -> Option<DolbyConfig> {
|
||||
if f.len() < 8 {
|
||||
return None;
|
||||
}
|
||||
let fscod = (f[4] >> 6) & 0x03;
|
||||
let frmsizecod = f[4] & 0x3F;
|
||||
let bsid = (f[5] >> 3) & 0x1F;
|
||||
let bsmod = f[5] & 0x07;
|
||||
|
||||
// acmod + trailing optional 2-bit fields, then lfeon (byte 6 onward).
|
||||
let mut r = BitReader::new(f);
|
||||
r.bit = 6 * 8;
|
||||
let acmod = r.read(3) as u8;
|
||||
if (acmod & 0x1) != 0 && acmod != 0x1 {
|
||||
r.skip(2); // cmixlev
|
||||
}
|
||||
if (acmod & 0x4) != 0 {
|
||||
r.skip(2); // surmixlev
|
||||
}
|
||||
if acmod == 0x2 {
|
||||
r.skip(2); // dsurmod
|
||||
}
|
||||
let lfeon = r.read(1) == 1;
|
||||
|
||||
Some(DolbyConfig {
|
||||
fscod,
|
||||
bsid,
|
||||
bsmod,
|
||||
acmod,
|
||||
lfeon,
|
||||
bit_rate_code: frmsizecod >> 1,
|
||||
data_rate_kbps: 0,
|
||||
sample_rate: FSCOD_RATES.get(fscod as usize).copied().unwrap_or(48_000),
|
||||
channels: DolbyConfig::channel_count(acmod, lfeon),
|
||||
})
|
||||
}
|
||||
|
||||
/// E-AC-3 (A/52 Annex E BSI): syncword | strmtyp(2) substreamid(3) frmsiz(11) |
|
||||
/// fscod(2) numblkscod(2) acmod(3) lfeon(1) | bsid(5) …
|
||||
fn parse_eac3(f: &[u8]) -> Option<DolbyConfig> {
|
||||
if f.len() < 6 {
|
||||
return None;
|
||||
}
|
||||
let frmsiz = (((f[2] & 0x07) as u32) << 8) | f[3] as u32; // words minus one
|
||||
let fscod = (f[4] >> 6) & 0x03;
|
||||
let numblkscod = (f[4] >> 4) & 0x03;
|
||||
let acmod = (f[4] >> 1) & 0x07;
|
||||
let lfeon = (f[4] & 0x01) == 1;
|
||||
let bsid = (f[5] >> 3) & 0x1F;
|
||||
|
||||
let (sample_rate, blocks) = if fscod == 0x03 {
|
||||
let fscod2 = (f[4] >> 4) & 0x03; // shares bits with numblkscod when fscod==3
|
||||
(EAC3_REDUCED_RATES[fscod2 as usize], 6u32)
|
||||
} else {
|
||||
let blocks = [1u32, 2, 3, 6][numblkscod as usize];
|
||||
(FSCOD_RATES[fscod as usize], blocks)
|
||||
};
|
||||
// Nominal data rate (kbps): frame is (frmsiz+1) 16-bit words per (blocks·256)
|
||||
// samples at sample_rate. rate = bytes·8·sr / samples / 1000.
|
||||
let frame_bytes = (frmsiz as u64 + 1) * 2;
|
||||
let samples = blocks as u64 * 256;
|
||||
let data_rate_kbps = if samples > 0 {
|
||||
((frame_bytes * 8 * sample_rate as u64) / samples / 1000) as u16
|
||||
} else {
|
||||
0
|
||||
};
|
||||
|
||||
Some(DolbyConfig {
|
||||
fscod,
|
||||
bsid,
|
||||
bsmod: 0, // not in the E-AC-3 main header; dec3 default
|
||||
acmod,
|
||||
lfeon,
|
||||
bit_rate_code: 0,
|
||||
data_rate_kbps,
|
||||
sample_rate,
|
||||
channels: DolbyConfig::channel_count(acmod, lfeon),
|
||||
})
|
||||
}
|
||||
|
||||
/// The `dac3` config box (ETSI TS 102 366 Annex F.4): 24 bits —
|
||||
/// fscod(2) bsid(5) bsmod(3) acmod(3) lfeon(1) bit_rate_code(5) reserved(5).
|
||||
pub(super) fn dac3_box(c: &DolbyConfig) -> Vec<u8> {
|
||||
let mut v: u32 = 0;
|
||||
let mut push = |val: u32, bits: u32| v = (v << bits) | (val & ((1 << bits) - 1));
|
||||
push(c.fscod as u32, 2);
|
||||
push(c.bsid as u32, 5);
|
||||
push(c.bsmod as u32, 3);
|
||||
push(c.acmod as u32, 3);
|
||||
push(c.lfeon as u32, 1);
|
||||
push(c.bit_rate_code as u32, 5);
|
||||
push(0, 5); // reserved
|
||||
// 24 bits → the top 3 bytes of the big-endian u32.
|
||||
let b = v.to_be_bytes();
|
||||
bx(b"dac3", &[b[1], b[2], b[3]])
|
||||
}
|
||||
|
||||
/// The `dec3` config box (ETSI TS 102 366 Annex G.3) for a single independent
|
||||
/// substream, no dependent substreams: data_rate(13) num_ind_sub(3) then
|
||||
/// fscod(2) bsid(5) reserved(1) asvc(1) bsmod(3) acmod(3) lfeon(1) reserved(3)
|
||||
/// num_dep_sub(4) reserved(1).
|
||||
pub(super) fn dec3_box(c: &DolbyConfig) -> Vec<u8> {
|
||||
let mut v: u64 = 0;
|
||||
let mut push = |val: u64, bits: u32| v = (v << bits) | (val & ((1u64 << bits) - 1));
|
||||
push(c.data_rate_kbps as u64, 13);
|
||||
push(0, 3); // num_ind_sub - 1 = 0 (one substream)
|
||||
push(c.fscod as u64, 2);
|
||||
push(c.bsid as u64, 5);
|
||||
push(0, 1); // reserved
|
||||
push(0, 1); // asvc
|
||||
push(c.bsmod as u64, 3);
|
||||
push(c.acmod as u64, 3);
|
||||
push(c.lfeon as u64, 1);
|
||||
push(0, 3); // reserved
|
||||
push(0, 4); // num_dep_sub = 0
|
||||
push(0, 1); // reserved (chan_loc absent when num_dep_sub == 0)
|
||||
// 40 bits → the low 5 bytes of the big-endian u64.
|
||||
let b = v.to_be_bytes();
|
||||
bx(b"dec3", &[b[3], b[4], b[5], b[6], b[7]])
|
||||
}
|
||||
|
||||
/// Build an audio sample entry (`ac-3` / `ec-3`) with the given config box.
|
||||
/// `AudioSampleEntry` per ISO/IEC 14496-12 §12.2.3.
|
||||
pub(super) fn audio_sample_entry(
|
||||
fourcc: &[u8; 4],
|
||||
channels: u16,
|
||||
sample_rate: u32,
|
||||
config: &[u8],
|
||||
) -> Vec<u8> {
|
||||
let mut e = Vec::new();
|
||||
e.extend_from_slice(&[0u8; 6]); // reserved
|
||||
e.extend_from_slice(&1u16.to_be_bytes()); // data_reference_index
|
||||
e.extend_from_slice(&[0u8; 8]); // reserved (version 0)
|
||||
e.extend_from_slice(&channels.to_be_bytes());
|
||||
e.extend_from_slice(&16u16.to_be_bytes()); // samplesize
|
||||
e.extend_from_slice(&0u16.to_be_bytes()); // pre_defined
|
||||
e.extend_from_slice(&0u16.to_be_bytes()); // reserved
|
||||
// samplerate is 16.16 fixed point; the integer rate in the high 16 bits.
|
||||
e.extend_from_slice(&(sample_rate << 16).to_be_bytes());
|
||||
e.extend_from_slice(config);
|
||||
bx(fourcc, &e)
|
||||
}
|
||||
|
||||
/// The MP4 fourcc + config box for a Dolby audio frame, or `None` if the codec
|
||||
/// has no MP4 mapping here. Together with [`audio_fits`] this is the fit oracle
|
||||
/// for audio: only what returns `Some` is muxable.
|
||||
pub(super) fn dolby_sample_entry(codec: Codec, first_frame: &[u8]) -> Option<Vec<u8>> {
|
||||
let c = parse_dolby(first_frame)?;
|
||||
let (fourcc, config): (&[u8; 4], Vec<u8>) = match codec {
|
||||
Codec::Ac3 => (b"ac-3", dac3_box(&c)),
|
||||
Codec::Ac3Plus => (b"ec-3", dec3_box(&c)),
|
||||
_ => return None,
|
||||
};
|
||||
Some(audio_sample_entry(
|
||||
fourcc,
|
||||
c.channels,
|
||||
c.sample_rate,
|
||||
&config,
|
||||
))
|
||||
}
|
||||
|
||||
/// Fit oracle for an audio codec: does `mp4://` currently carry it? M2 covers
|
||||
/// the Dolby family (AC-3 / E-AC-3). TrueHD, DTS(-HD), LPCM, AAC are not yet
|
||||
/// mapped and are skipped with a loud report (never silently dropped).
|
||||
pub(super) fn audio_fits(codec: Codec) -> bool {
|
||||
matches!(codec, Codec::Ac3 | Codec::Ac3Plus)
|
||||
}
|
||||
|
||||
#[cfg(test)]
|
||||
mod tests {
|
||||
use super::*;
|
||||
|
||||
/// A synthetic legacy AC-3 header: syncword, crc, fscod=0 (48k),
|
||||
/// frmsizecod, bsid=8, bsmod=0, acmod=7 (3/2), lfeon=1 → 5.1.
|
||||
fn ac3_frame_5_1() -> Vec<u8> {
|
||||
let mut f = vec![0x0B, 0x77, 0x00, 0x00];
|
||||
// byte4: fscod(2)=0 | frmsizecod(6)=0b010110 (22)
|
||||
f.push(0b00_010110);
|
||||
// byte5: bsid(5)=8 (0b01000) | bsmod(3)=0
|
||||
f.push(0b01000_000);
|
||||
// byte6: acmod(3)=7 (0b111) | cmixlev(2) | surmixlev(2) | lfeon(1)...
|
||||
// acmod=7 has centre (needs cmixlev) and surround (needs surmixlev):
|
||||
// 111 | 00 | 00 | 1(lfeon) = 0b111_00_00_1
|
||||
f.push(0b111_00_00_1);
|
||||
f.push(0x00);
|
||||
f
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn ac3_bsi_and_dac3() {
|
||||
let c = parse_dolby(&ac3_frame_5_1()).expect("parsed");
|
||||
assert!(c.bsid < 11, "legacy AC-3");
|
||||
assert_eq!(c.fscod, 0);
|
||||
assert_eq!(c.sample_rate, 48_000);
|
||||
assert_eq!(c.bsid, 8);
|
||||
assert_eq!(c.acmod, 7);
|
||||
assert!(c.lfeon);
|
||||
assert_eq!(c.channels, 6, "3/2 + LFE = 5.1");
|
||||
assert_eq!(c.bit_rate_code, 22 >> 1);
|
||||
|
||||
let dac3 = dac3_box(&c);
|
||||
// [size:4]["dac3"][3-byte payload] = 11 bytes.
|
||||
assert_eq!(dac3.len(), 11);
|
||||
assert_eq!(&dac3[4..8], b"dac3");
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn eac3_bsi_and_dec3() {
|
||||
// E-AC-3: syncword | strmtyp/substreamid/frmsiz | fscod/numblks/acmod/lfeon | bsid
|
||||
let mut f = vec![0x0B, 0x77];
|
||||
f.push(0x00); // strmtyp=0, substreamid=0, frmsiz high=0
|
||||
f.push(0x3F); // frmsiz low = 63 → frame 128 bytes
|
||||
// byte4: fscod(2)=0 | numblkscod(2)=3 (6 blocks) | acmod(3)=7 | lfeon(1)=1
|
||||
f.push(0b00_11_111_1);
|
||||
// byte5: bsid(5)=16 (E-AC-3) | dialnorm high(3)
|
||||
f.push(0b10000_000);
|
||||
f.push(0x00);
|
||||
let c = parse_dolby(&f).expect("parsed");
|
||||
assert!(c.bsid >= 11, "E-AC-3");
|
||||
assert_eq!(c.bsid, 16);
|
||||
assert_eq!(c.fscod, 0);
|
||||
assert_eq!(c.sample_rate, 48_000);
|
||||
assert_eq!(c.acmod, 7);
|
||||
assert!(c.lfeon);
|
||||
assert_eq!(c.channels, 6);
|
||||
let dec3 = dec3_box(&c);
|
||||
// [size:4]["dec3"][5-byte payload] = 13 bytes.
|
||||
assert_eq!(dec3.len(), 13);
|
||||
assert_eq!(&dec3[4..8], b"dec3");
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn sample_entry_shape() {
|
||||
let c = parse_dolby(&ac3_frame_5_1()).unwrap();
|
||||
let e = audio_sample_entry(b"ac-3", c.channels, c.sample_rate, &dac3_box(&c));
|
||||
assert_eq!(&e[4..8], b"ac-3");
|
||||
// channelcount at entry-body offset 16 (after 6 reserved + 2 dri + 8 reserved).
|
||||
let ch = u16::from_be_bytes([e[8 + 16], e[8 + 17]]);
|
||||
assert_eq!(ch, 6);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn fit_oracle_dolby_only() {
|
||||
assert!(audio_fits(Codec::Ac3));
|
||||
assert!(audio_fits(Codec::Ac3Plus));
|
||||
assert!(!audio_fits(Codec::TrueHd));
|
||||
assert!(!audio_fits(Codec::DtsHdMa));
|
||||
assert!(!audio_fits(Codec::Lpcm));
|
||||
}
|
||||
}
|
||||
+534
-321
File diff suppressed because it is too large
Load Diff
Reference in New Issue
Block a user