gst-plugins-rs/net/rtp/src/mp4g/pay/imp.rs

922 lines
34 KiB
Rust

// GStreamer RTP MPEG-4 Generic Payloader
//
// Copyright (C) 2023-2024 François Laignel <francois centricular com>
//
// This Source Code Form is subject to the terms of the Mozilla Public License, v2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at
// <https://mozilla.org/MPL/2.0/>.
//
// SPDX-License-Identifier: MPL-2.0
/**
* SECTION:element-rtpmp4gpay2
* @see_also: rtpmp4gpay2, rtpmp4gpay, rtpmp4gpay, fdkaacenc, fdkaacdec, avenc_mpeg4, avdec_mpeg4
*
* Payload an MPEG-4 Generic elementary stream into RTP packets as per [RFC 3640][rfc-3640].
* Also see the [IANA media-type page for MPEG-4 Generic][iana-mpeg4-generic].
*
* [rfc-3640]: https://www.rfc-editor.org/rfc/rfc3640.html#section-4
* [iana-mpeg4-generic]: https://www.iana.org/assignments/media-types/application/mpeg4-generic
*
* ## Aggregation Modes
*
* The default aggregation mode is `auto`: If upstream is live, the payloader will send out
* AUs immediately, even if they don't completely fill a packet, in order to minimise
* latency. If upstream is not live, the payloader will by default aggregate AUs until
* it has completely filled an RTP packet as per the configured MTU size or the `max-ptime`
* property if it is set (it is not set by default).
*
* The aggregation mode can be controlled via the `aggregate-mode` property.
*
* ## Example pipeline
* |[
* gst-launch-1.0 audiotestsrc ! fdkaacenc ! rtpmp4gpay2 ! udpsink host=127.0.0.1 port=5004
* ]| This will encode an audio test signal to AAC and then payload the encoded audio
* into RTP packets and send them out via UDP to localhost (IPv4) port 5004.
* You can use the #rtpmp4gdepay2 or #rtpmp4gdepay elements to depayload such a stream, and
* the #fdkaacdec element to decode the depayloaded stream.
*
* Since: plugins-rs-0.13.0
*/
use atomic_refcell::AtomicRefCell;
use bitstream_io::{BigEndian, BitCounter, BitRead, BitReader, BitWrite, BitWriter};
use once_cell::sync::Lazy;
use gst::{glib, prelude::*, subclass::prelude::*};
use smallvec::SmallVec;
use std::collections::VecDeque;
use std::sync::Mutex;
use crate::basepay::{PacketToBufferRelation, RtpBasePay2Ext, RtpBasePay2Impl, RtpBasePay2ImplExt};
use super::RtpMpeg4GenericPayAggregateMode;
use crate::mp4a::parsers::{AudioSpecificConfig, ProfileLevel};
use crate::mp4g::{AccessUnitIndex, AuHeader, AuHeaderContext, ModeConfig};
const VOS_STARTCODE: u32 = 0x000001B0;
/// The size of the field representing the AU headers section len.
const HEADERS_LEN_SIZE: usize = 2;
/// Access Unit maximum header len in bytes.
/// This depends on the supported mode. In current implementation, 3 is the maximum.
const HEADER_MAX_LEN: usize = 3;
#[derive(Clone)]
struct Settings {
max_ptime: Option<gst::ClockTime>,
aggregate_mode: RtpMpeg4GenericPayAggregateMode,
}
impl Default for Settings {
fn default() -> Self {
Settings {
aggregate_mode: RtpMpeg4GenericPayAggregateMode::Auto,
max_ptime: None,
}
}
}
#[derive(Default)]
pub struct RtpMpeg4GenericPay {
state: AtomicRefCell<State>,
settings: Mutex<Settings>,
is_live: Mutex<Option<bool>>,
}
#[derive(Debug)]
struct AccessUnit {
id: u64,
pts: Option<gst::ClockTime>,
dts_delta: Option<i32>,
duration: Option<gst::ClockTime>,
maybe_random_access: Option<bool>,
buffer: gst::MappedBuffer<gst::buffer::Readable>,
}
#[derive(Default)]
struct State {
/// Configuration of current Mode.
mode: ModeConfig,
/// Maximum bit length needed to store an AU Header.
max_header_bit_len: usize,
/// Minimum MTU necessary to handle the outgoing packets.
min_mtu: usize,
/// Pending AU (we collect until ptime/max-ptime is hit or the packet is full)
pending_aus: VecDeque<AccessUnit>,
pending_size: usize,
pending_duration: Option<gst::ClockTime>,
clock_rate: u32,
/// Desired "packet time", i.e. packet duration, from the downstream caps, if set
ptime: Option<gst::ClockTime>,
max_ptime: Option<gst::ClockTime>,
}
impl State {
fn flush(&mut self) {
self.pending_aus.clear();
self.pending_size = 0;
self.pending_duration = None;
}
}
static CAT: Lazy<gst::DebugCategory> = Lazy::new(|| {
gst::DebugCategory::new(
"rtpmp4gpay2",
gst::DebugColorFlags::empty(),
Some("RTP MPEG-4 Generic Payloader"),
)
});
#[glib::object_subclass]
impl ObjectSubclass for RtpMpeg4GenericPay {
const NAME: &'static str = "GstRtpMpeg4GenericPay";
type Type = super::RtpMpeg4GenericPay;
type ParentType = crate::basepay::RtpBasePay2;
}
impl ObjectImpl for RtpMpeg4GenericPay {
fn properties() -> &'static [glib::ParamSpec] {
static PROPERTIES: Lazy<Vec<glib::ParamSpec>> = Lazy::new(|| {
vec![
glib::ParamSpecEnum::builder_with_default(
"aggregate-mode",
Settings::default().aggregate_mode,
)
.nick("Aggregate Mode")
.blurb(
"Whether to send out AUs immediately or aggregate them until a packet is full.",
)
.build(),
// Using same type/semantics as C payloaders
glib::ParamSpecInt64::builder("max-ptime")
.nick("Maximum Packet Time")
.blurb("Maximum duration of the packet data in ns (-1 = unlimited up to MTU)")
.default_value(
Settings::default()
.max_ptime
.map(gst::ClockTime::nseconds)
.map(|x| x as i64)
.unwrap_or(-1),
)
.minimum(-1)
.maximum(i64::MAX)
.mutable_playing()
.build(),
]
});
PROPERTIES.as_ref()
}
fn set_property(&self, _id: usize, value: &glib::Value, pspec: &glib::ParamSpec) {
let mut settings = self.settings.lock().unwrap();
match pspec.name() {
"aggregate-mode" => {
settings.aggregate_mode = value
.get::<RtpMpeg4GenericPayAggregateMode>()
.expect("type checked upstream");
}
"max-ptime" => {
let new_max_ptime = match value.get::<i64>().unwrap() {
-1 => None,
v @ 0.. => Some(gst::ClockTime::from_nseconds(v as u64)),
_ => unreachable!(),
};
let changed = settings.max_ptime != new_max_ptime;
settings.max_ptime = new_max_ptime;
drop(settings);
if changed {
let _ = self
.obj()
.post_message(gst::message::Latency::builder().src(&*self.obj()).build());
}
}
_ => unimplemented!(),
};
}
fn property(&self, _id: usize, pspec: &glib::ParamSpec) -> glib::Value {
let settings = self.settings.lock().unwrap();
match pspec.name() {
"aggregate-mode" => settings.aggregate_mode.to_value(),
"max-ptime" => (settings
.max_ptime
.map(gst::ClockTime::nseconds)
.map(|x| x as i64)
.unwrap_or(-1))
.to_value(),
_ => unimplemented!(),
}
}
}
impl GstObjectImpl for RtpMpeg4GenericPay {}
impl ElementImpl for RtpMpeg4GenericPay {
fn metadata() -> Option<&'static gst::subclass::ElementMetadata> {
static ELEMENT_METADATA: Lazy<gst::subclass::ElementMetadata> = Lazy::new(|| {
gst::subclass::ElementMetadata::new(
"RTP MPEG-4 Generic Payloader",
"Codec/Payloader/Network/RTP",
"Payload an MPEG-4 Generic elementary stream into RTP packets (RFC 3640)",
"François Laignel <francois centricular com>",
)
});
Some(&*ELEMENT_METADATA)
}
fn pad_templates() -> &'static [gst::PadTemplate] {
static PAD_TEMPLATES: Lazy<Vec<gst::PadTemplate>> = Lazy::new(|| {
let sink_pad_template = gst::PadTemplate::new(
"sink",
gst::PadDirection::Sink,
gst::PadPresence::Always,
&gst::Caps::builder_full()
.structure(
gst::Structure::builder("video/mpeg")
.field("mpegversion", 4i32)
.field("systemstream", false)
.build(),
)
.structure(
gst::Structure::builder("audio/mpeg")
.field("mpegversion", 4i32)
.field("stream-format", "raw")
.build(),
)
.build(),
)
.unwrap();
let src_pad_template = gst::PadTemplate::new(
"src",
gst::PadDirection::Src,
gst::PadPresence::Always,
&gst::Caps::builder("application/x-rtp")
// TODO "application" is also present in rtpmp4gpay caps template
// but it doesn't handle it in gst_rtp_mp4g_pay_setcaps
.field("media", gst::List::new(["audio", "video"]))
.field("clock-rate", gst::IntRange::new(1i32, i32::MAX))
.field("encoding-name", "MPEG4-GENERIC")
// Required string params:
.field("streamtype", gst::List::new(["4", "5"])) // 4 = video, 5 = audio
// "profile-level-id = [1,MAX], "
// "config = (string)"
.field(
"mode",
gst::List::new(["generic", "AAC-lbr", "AAC-hbr", "aac-hbr"]),
)
// Optional general parameters:
// "objecttype = [1,MAX], "
// "constantsize = [1,MAX], " // constant size of each AU
// "constantduration = [1,MAX], " // constant duration of each AU
// "maxdisplacement = [1,MAX], "
// "de-interleavebuffersize = [1,MAX], "
// Optional configuration parameters:
// "sizelength = [1, 32], "
// "indexlength = [1, 32], "
// "indexdeltalength = [1, 32], "
// "ctsdeltalength = [1, 32], "
// "dtsdeltalength = [1, 32], "
// "randomaccessindication = {0, 1}, "
// "streamstateindication = [0, 32], "
// "auxiliarydatasizelength = [0, 32]" )
.build(),
)
.unwrap();
vec![sink_pad_template, src_pad_template]
});
PAD_TEMPLATES.as_ref()
}
}
/// Returns the difference between `ClockTime`s `ct1` & `ct2` in RTP scale.
///
/// Returns `None` if at least one of the `ClockTime`s is `None`.
/// Returns `Some(None)` if an overflow occurred, error management is left to the caller.
/// Returns `Some(delta)` if the difference could be computed.
fn ct_delta_to_rtp(
ct1: Option<gst::ClockTime>,
ct0: Option<gst::ClockTime>,
clock_rate: u32,
) -> Option<Option<i32>> {
ct1.into_positive().opt_sub(ct0).map(|delta_ct| {
delta_ct
.into_inner_signed()
.try_into()
.ok()
.and_then(|delta_inner: i64| {
delta_inner
.mul_div_ceil(clock_rate as i64, *gst::ClockTime::SECOND as i64)
.and_then(|dts_delta| dts_delta.try_into().ok())
})
})
}
impl RtpBasePay2Impl for RtpMpeg4GenericPay {
const ALLOWED_META_TAGS: &'static [&'static str] = &["audio"];
fn set_sink_caps(&self, caps: &gst::Caps) -> bool {
let s = caps.structure(0).unwrap();
let codec_data = match s.get::<&gst::BufferRef>("codec_data") {
Ok(codec_data) => codec_data,
Err(err) => {
gst::error!(CAT, imp: self, "Error getting codec_data from Caps: {err}");
return false;
}
};
let Ok(codec_data) = codec_data.map_readable() else {
gst::error!(CAT, imp: self, "Failed to map codec_data as readable");
return false;
};
let codec_data_str = hex::encode(&codec_data);
let caps_builder = gst::Caps::builder("application/x-rtp")
.field("seqnum-base", self.obj().property::<u32>("seqnum") + 1)
.field("mpegversion", 4i32)
.field("encoding-name", "MPEG4-GENERIC")
.field("config", codec_data_str);
let (clock_rate, mode, caps_builder) = match s.name().as_str() {
"audio/mpeg" => {
let mut r = BitReader::endian(codec_data.as_slice(), BigEndian);
let config = match r.parse::<AudioSpecificConfig>() {
Ok(config) => config,
Err(err) => {
gst::error!(CAT, imp: self, "Error parsing audio codec_data: {err:#}");
return false;
}
};
if config.audio_object_type == 0 || config.audio_object_type > 6 {
gst::error!(CAT, imp: self, "Unsupported Audio Object Type {}", config.audio_object_type);
return false;
}
let profile_level = match ProfileLevel::from_caps(s) {
Ok(profile_level) => profile_level,
Err(err) => {
gst::error!(CAT, imp: self, "Error getting profile level from Caps: {err:#}");
return false;
}
};
gst::log!(CAT, imp: self, "Using audio codec_data {config:?}");
// AAC-hbr: also used by rtpmp4gpay
// RFC 3640 also defines AAC-lbr, with a maximum encoded buffer
// size of 63 bytes and which can't be fragmented. Only AAC-hbr
// is used because it is more flexible. We could implement AAC-lbr
// provided make sure the encoded buffers can't exceed the limit
// and add a flag to prevent fragmentation in `send_packets()`.
// See https://www.rfc-editor.org/rfc/rfc3640.html#section-3.3.5
let mode = ModeConfig {
size_len: 13,
index_len: 3,
index_delta_len: 3,
constant_duration: config.frame_len as u32,
..Default::default()
};
let caps_builder = mode
.add_to_caps(
caps_builder
.field("media", "audio")
.field("streamtype", "5")
.field("mode", "AAC-hbr")
.field("clock-rate", config.sampling_freq as i32)
.field("profile", &profile_level.profile)
.field("level", &profile_level.level)
.field("profile-level-id", profile_level.id)
.field("encoding-params", config.channel_conf as i32),
)
.expect("invalid audio mode");
(config.sampling_freq, mode, caps_builder)
}
"video/mpeg" => {
if codec_data.len() < 5 {
gst::error!(CAT, imp: self, "Error parsing video codec_data: too short");
return false;
}
let code = u32::from_be_bytes(codec_data[..4].try_into().unwrap());
let profile = if code == VOS_STARTCODE {
let profile = codec_data[4];
gst::log!(CAT, imp: self, "Using video codec_data profile {profile}");
profile
} else {
gst::warning!(CAT, imp: self, "Unexpected VOS startcode in video codec_data. Assuming profile '1'");
1
};
// Use a larger size_len than rtpmp4gpay
// otherwise some large AU can't be payloaded.
// rtpmp4gpay uses bit shifts to have the AU data size
// fit in 13 bits, resulting in an invalid size.
let mode = ModeConfig {
size_len: 16,
index_len: 3,
index_delta_len: 3,
cts_delta_len: 16,
dts_delta_len: 16,
random_access_indication: true,
..Default::default()
};
let caps_builder = mode
.add_to_caps(
caps_builder
.field("media", "video")
.field("streamtype", "4")
.field("mode", "generic")
.field("clock-rate", 90000i32)
.field("profile-level-id", profile as i32),
)
.expect("invalid video mode");
(90000, mode, caps_builder)
}
// TODO handle "application"
_ => unreachable!(),
};
self.obj().set_src_caps(&caps_builder.build());
let mut state = self.state.borrow_mut();
state.max_header_bit_len = mode.max_header_bit_len();
state.min_mtu = rtp_types::RtpPacket::MIN_RTP_PACKET_LEN
+ HEADERS_LEN_SIZE
+ (state.max_header_bit_len + 7) / 8
+ 1;
state.mode = mode;
state.clock_rate = clock_rate;
true
}
fn negotiate(&self, mut src_caps: gst::Caps) {
// Fixate as a first step
src_caps.fixate();
let s = src_caps.structure(0).unwrap();
// Negotiate ptime/maxptime with downstream and use them in combination with the
// properties. See https://www.iana.org/assignments/media-types/application/mpeg4-generic
let ptime = s
.get::<u32>("ptime")
.ok()
.map(u64::from)
.map(gst::ClockTime::from_mseconds);
let max_ptime = s
.get::<u32>("maxptime")
.ok()
.map(u64::from)
.map(gst::ClockTime::from_mseconds);
self.parent_negotiate(src_caps);
let mut state = self.state.borrow_mut();
state.ptime = ptime;
state.max_ptime = max_ptime;
drop(state);
}
// Encapsulation of MPEG-4 Generic Elementary Streams:
// https://www.rfc-editor.org/rfc/rfc3640
fn handle_buffer(
&self,
buffer: &gst::Buffer,
id: u64,
) -> Result<gst::FlowSuccess, gst::FlowError> {
let mut state = self.state.borrow_mut();
let mut settings = self.settings.lock().unwrap();
gst::trace!(CAT, imp: self, "Handling buffer {id} duration {} pts {} dts {}, len {}",
buffer.duration().display(), buffer.pts().display(), buffer.dts().display(), buffer.size(),
);
let maybe_random_access = if state.mode.random_access_indication {
Some(!buffer.flags().contains(gst::BufferFlags::DELTA_UNIT))
} else {
None
};
let dts_delta = ct_delta_to_rtp(buffer.dts(), buffer.pts(), state.clock_rate).and_then(|dts_delta_res| {
if dts_delta_res.is_none() {
gst::warning!(CAT, imp: self, "Overflow computing DTS-delta between pts {} & dts {}",
buffer.dts().display(), buffer.pts().display(),
);
}
dts_delta_res
});
gst::trace!(CAT, imp: self,
"Pushing AU from buffer {id} dts_delta {dts_delta:?} random access {maybe_random_access:?}",
);
state.pending_aus.push_back(AccessUnit {
id,
duration: buffer.duration(),
pts: buffer.pts(),
dts_delta,
buffer: buffer.clone().into_mapped_buffer_readable().map_err(|_| {
gst::error!(CAT, imp: self, "Can't map incoming buffer readable");
gst::FlowError::Error
})?,
maybe_random_access,
});
state.pending_size += buffer.size();
state.pending_duration.opt_add_assign(buffer.duration());
// Make sure we have queried upstream liveness if needed
if settings.aggregate_mode == RtpMpeg4GenericPayAggregateMode::Auto {
self.ensure_upstream_liveness(&mut settings);
}
self.send_packets(&settings, &mut state, SendPacketMode::WhenReady)
}
fn drain(&self) -> Result<gst::FlowSuccess, gst::FlowError> {
let settings = self.settings.lock().unwrap().clone();
let mut state = self.state.borrow_mut();
self.send_packets(&settings, &mut state, SendPacketMode::ForcePending)
}
fn flush(&self) {
self.state.borrow_mut().flush();
}
#[allow(clippy::single_match)]
fn src_query(&self, query: &mut gst::QueryRef) -> bool {
let res = self.parent_src_query(query);
if !res {
return false;
}
match query.view_mut() {
gst::QueryViewMut::Latency(query) => {
let settings = self.settings.lock().unwrap();
let (is_live, mut min, mut max) = query.result();
{
let mut live_guard = self.is_live.lock().unwrap();
if Some(is_live) != *live_guard {
gst::info!(CAT, imp: self, "Upstream is live: {is_live}");
*live_guard = Some(is_live);
}
}
if self.effective_aggregate_mode(&settings)
== RtpMpeg4GenericPayAggregateMode::Aggregate
{
if let Some(max_ptime) = settings.max_ptime {
min += max_ptime;
max.opt_add_assign(max_ptime);
} else if is_live {
gst::warning!(CAT, imp: self,
"Aggregating packets in live mode, but no max_ptime configured. \
Configured latency may be too low!"
);
}
query.set(is_live, min, max);
}
}
_ => (),
}
true
}
fn start(&self) -> Result<(), gst::ErrorMessage> {
*self.state.borrow_mut() = State::default();
*self.is_live.lock().unwrap() = None;
self.parent_start()
}
fn stop(&self) -> Result<(), gst::ErrorMessage> {
*self.state.borrow_mut() = State::default();
*self.is_live.lock().unwrap() = None;
self.parent_stop()
}
}
#[derive(Debug, PartialEq)]
enum SendPacketMode {
WhenReady,
ForcePending,
}
impl RtpMpeg4GenericPay {
fn send_packets(
&self,
settings: &Settings,
state: &mut State,
send_mode: SendPacketMode,
) -> Result<gst::FlowSuccess, gst::FlowError> {
let agg_mode = self.effective_aggregate_mode(settings);
if (self.obj().mtu() as usize) < state.min_mtu {
gst::error!(CAT, imp: self, "Insufficient mtu {} at least {} bytes needed", self.obj().mtu(), state.min_mtu);
return Err(gst::FlowError::Error);
}
let max_payload_size = self.obj().max_payload_size() as usize - HEADERS_LEN_SIZE;
let mut ctx = AuHeaderContext {
config: &state.mode,
prev_index: None,
};
let mut headers_buf = SmallVec::<[u8; 10 * HEADER_MAX_LEN]>::new();
let mut au_data_list = SmallVec::<[gst::MappedBuffer<gst::buffer::Readable>; 10]>::new();
// https://www.rfc-editor.org/rfc/rfc3640.html#section-3.1
// The M bit is set to 1 to indicate that the RTP packet payload
// contains either the final fragment of a fragmented Access Unit
// or one or more complete Access Units.
// Send out packets if there's enough data for one (or more), or if forced.
while let Some(front) = state.pending_aus.front() {
headers_buf.clear();
ctx.prev_index = None;
if front.buffer.len() + (state.max_header_bit_len + 7) / 8 > max_payload_size {
// AU needs to be fragmented
let au = state.pending_aus.pop_front().unwrap();
let mut data = au.buffer.as_slice();
state.pending_size = state.pending_size.saturating_sub(data.len());
let mut next_frag_offset = 0;
let mut is_final = false;
while !is_final {
let header = AuHeader {
// The size of the complete AU for all the fragments
size: Some(au.buffer.len() as u32),
// One AU fragment per packet
index: AccessUnitIndex::ZERO,
// CTS-delta SHOULD not be set for a fragment, see § 3.2.1.1
dts_delta: au.dts_delta,
maybe_random_access: au.maybe_random_access,
..Default::default()
};
headers_buf.clear();
let mut w = BitWriter::endian(&mut headers_buf, BigEndian);
let mut res = w.build_with(&header, &ctx);
if res.is_ok() {
// add final padding
res = w.write(7, 0).map_err(Into::into);
}
if let Err(err) = res {
gst::error!(CAT, imp: self, "Failed to write header for AU {} in buffer {}: {err:#}", header.index, au.id);
return Err(gst::FlowError::Error);
}
// Unfortunately BitWriter doesn't return the size written.
let mut c = BitCounter::<u32, BigEndian>::new();
c.build_with(&header, &ctx).unwrap();
let header_bit_len = c.written() as u16;
let left = au.buffer.len() - next_frag_offset;
let bytes_in_this_packet =
std::cmp::min(left, max_payload_size - (header_bit_len as usize + 7) / 8);
next_frag_offset += bytes_in_this_packet;
is_final = next_frag_offset >= au.buffer.len();
self.obj().queue_packet(
au.id.into(),
rtp_types::RtpPacketBuilder::new()
// AU-headers-length: only one 1 AU header here
.payload(header_bit_len.to_be_bytes().as_slice())
.payload(headers_buf.as_slice())
.payload(&data[0..bytes_in_this_packet])
.marker_bit(is_final),
)?;
data = &data[bytes_in_this_packet..];
}
continue;
}
// Will not fragment this AU
// We optimistically add average size/duration to send out packets as early as possible
// if we estimate that the next AU would likely overflow our accumulation limits.
let n_aus = state.pending_aus.len();
let avg_size = state.pending_size / n_aus;
let avg_duration = state.pending_duration.opt_div(n_aus as u64);
let max_ptime = settings
.max_ptime
.opt_min(state.max_ptime)
.opt_min(state.ptime);
let is_ready = send_mode == SendPacketMode::ForcePending
|| agg_mode != RtpMpeg4GenericPayAggregateMode::Aggregate
|| state.pending_size + avg_size + n_aus * (state.max_header_bit_len + 7) / 8
> max_payload_size
|| state
.pending_duration
.opt_add(avg_duration)
.opt_gt(max_ptime)
.unwrap_or(false);
gst::log!(CAT, imp: self,
"Pending: size {}, duration ~{:.3}, mode: {agg_mode:?} + {send_mode:?} => {}",
state.pending_size,
state.pending_duration.display(),
if is_ready { "ready" } else { "not ready, waiting for more data" },
);
if !is_ready {
break;
}
gst::trace!(CAT, imp: self, "Creating packet..");
let id = front.id;
let mut end_id = front.id;
let mut acc_duration = gst::ClockTime::ZERO;
let mut acc_size = 0;
let mut headers_len = 0;
let mut w = BitWriter::endian(&mut headers_buf, BigEndian);
let mut index = AccessUnitIndex::ZERO;
let mut previous_pts = None;
au_data_list.clear();
while let Some(front) = state.pending_aus.front() {
gst::trace!(CAT, imp: self, "{front:?}, accumulated size {acc_size} duration ~{acc_duration:.3}");
// If this AU would overflow the packet, bail out and send out what we have.
//
// Don't take into account the max_ptime for the first AU, since it could be
// lower than the AU duration in which case we would never payload anything.
//
// For the size check in bytes we know that the first AU will fit the mtu,
// because we already checked for the "AU needs to be fragmented" scenario above.
let cts_delta = if ctx.prev_index.is_none() {
// No CTS-delta for the first AU in the packet
None
} else {
ct_delta_to_rtp(front.pts, previous_pts, state.clock_rate).and_then(|dts_delta_res| {
if dts_delta_res.is_none() {
gst::warning!(CAT, imp: self, "Overflow computing CTS-delta between pts {} & previous pts {}",
front.pts.display(), previous_pts.display(),
);
}
dts_delta_res
})
};
previous_pts = front.pts;
let header = AuHeader {
size: Some(front.buffer.len() as u32),
index,
cts_delta,
dts_delta: front.dts_delta,
maybe_random_access: front.maybe_random_access,
..Default::default()
};
w.build_with(&header, &ctx).map_err(|err| {
gst::error!(CAT, imp: self, "Failed to write header for AU {} in buffer {}: {err:#}",
header.index, front.id,
);
gst::FlowError::Error
})?;
// Unfortunately BitWriter doesn't return the size written.
let mut c = BitCounter::<u32, BigEndian>::new();
c.build_with(&header, &ctx).unwrap();
let header_bit_len = c.written() as u16;
if acc_size + ((headers_len + header_bit_len) as usize + 7) / 8 + front.buffer.len()
> max_payload_size
|| (ctx.prev_index.is_some()
&& max_ptime
.opt_lt(acc_duration.opt_add(front.duration))
.unwrap_or(false))
{
break;
}
let au = state.pending_aus.pop_front().unwrap();
end_id = au.id;
acc_size += au.buffer.len();
acc_duration.opt_add_assign(au.duration);
state.pending_size -= au.buffer.len();
state.pending_duration.opt_saturating_sub(au.duration);
headers_len += header_bit_len;
au_data_list.push(au.buffer);
ctx.prev_index = Some(index);
index += 1;
}
// add final padding
if let Err(err) = w.write(7, 0) {
gst::error!(CAT, imp: self, "Failed to write padding for final AU {} in buffer {end_id}: {err}",
ctx.prev_index.expect("at least one AU"),
);
return Err(gst::FlowError::Error);
}
let headers_len = headers_len.to_be_bytes();
debug_assert_eq!(headers_len.len(), 2);
let mut packet = rtp_types::RtpPacketBuilder::new()
.marker_bit(true)
.payload(headers_len.as_slice())
.payload(headers_buf.as_slice());
for au_data in &au_data_list {
packet = packet.payload(au_data.as_slice());
}
self.obj()
.queue_packet(PacketToBufferRelation::Ids(id..=end_id), packet)?;
}
gst::log!(CAT, imp: self, "All done for now, {} pending AUs", state.pending_aus.len());
if send_mode == SendPacketMode::ForcePending {
self.obj().finish_pending_packets()?;
}
Ok(gst::FlowSuccess::Ok)
}
fn effective_aggregate_mode(&self, settings: &Settings) -> RtpMpeg4GenericPayAggregateMode {
match settings.aggregate_mode {
RtpMpeg4GenericPayAggregateMode::Auto => match self.is_live() {
Some(true) => RtpMpeg4GenericPayAggregateMode::ZeroLatency,
Some(false) => RtpMpeg4GenericPayAggregateMode::Aggregate,
None => RtpMpeg4GenericPayAggregateMode::ZeroLatency,
},
mode => mode,
}
}
fn is_live(&self) -> Option<bool> {
*self.is_live.lock().unwrap()
}
// Query upstream live-ness if needed, in case of aggregate-mode=auto
fn ensure_upstream_liveness(&self, settings: &mut Settings) {
if settings.aggregate_mode != RtpMpeg4GenericPayAggregateMode::Auto
|| self.is_live().is_some()
{
return;
}
let mut q = gst::query::Latency::new();
let is_live = if self.obj().sink_pad().peer_query(&mut q) {
let (is_live, _, _) = q.result();
is_live
} else {
false
};
*self.is_live.lock().unwrap() = Some(is_live);
gst::info!(CAT, imp: self, "Upstream is live: {is_live}");
}
}