mirror of
https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs.git
synced 2024-11-25 04:51:26 +00:00
closedcaption: Add Closed Caption to ST2038 element
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests/1777>
This commit is contained in:
Sebastian Dröge
GStreamer Marge Bot
parent
c1b364696c
commit
593cb6c7fc
4 changed files with 450 additions and 0 deletions
351
video/closedcaption/src/cctost2038anc/imp.rs
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351
video/closedcaption/src/cctost2038anc/imp.rs
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@ -0,0 +1,351 @@
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// Copyright (C) 2024 Sebastian Dröge <sebastian@centricular.com>
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//
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// This Source Code Form is subject to the terms of the Mozilla Public License, v2.0.
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// If a copy of the MPL was not distributed with this file, You can obtain one at
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// <https://mozilla.org/MPL/2.0/>.
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//
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// SPDX-License-Identifier: MPL-2.0
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use std::sync::Mutex;
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use gst::glib;
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use gst::prelude::*;
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use gst::subclass::prelude::*;
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use atomic_refcell::AtomicRefCell;
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use once_cell::sync::Lazy;
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use crate::st2038anc_utils::convert_to_st2038_buffer;
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#[derive(Clone, Copy, Debug, PartialEq, Eq)]
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enum Format {
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Cea608,
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Cea708,
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}
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#[derive(Default)]
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struct State {
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format: Option<Format>,
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}
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#[derive(Clone)]
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struct Settings {
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c_not_y_channel: bool,
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line_number: u16,
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horizontal_offset: u16,
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}
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impl Default for Settings {
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fn default() -> Self {
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Settings {
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c_not_y_channel: false,
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line_number: 9,
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horizontal_offset: 0,
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}
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}
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}
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pub struct CcToSt2038Anc {
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sinkpad: gst::Pad,
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srcpad: gst::Pad,
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state: AtomicRefCell<State>,
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settings: Mutex<Settings>,
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}
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static CAT: Lazy<gst::DebugCategory> = Lazy::new(|| {
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gst::DebugCategory::new(
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"cctost2038anc",
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gst::DebugColorFlags::empty(),
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Some("Closed Caption to ST-2038 ANC Element"),
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)
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});
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impl CcToSt2038Anc {
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fn sink_chain(
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&self,
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pad: &gst::Pad,
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buffer: gst::Buffer,
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) -> Result<gst::FlowSuccess, gst::FlowError> {
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gst::trace!(CAT, obj = pad, "Handling buffer {:?}", buffer);
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let state = self.state.borrow_mut();
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let settings = self.settings.lock().unwrap().clone();
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let map = buffer.map_readable().map_err(|_| {
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gst::error!(CAT, obj = pad, "Can't map buffer readable");
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gst::FlowError::Error
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})?;
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let (did, sdid) = match state.format {
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Some(Format::Cea608) => (0x61, 0x02),
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Some(Format::Cea708) => (0x61, 0x01),
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None => {
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gst::error!(CAT, imp = self, "No caps set");
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return Err(gst::FlowError::NotNegotiated);
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}
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};
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let mut outbuf = match convert_to_st2038_buffer(
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settings.c_not_y_channel,
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settings.line_number,
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settings.horizontal_offset,
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did,
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sdid,
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&map,
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) {
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Ok(outbuf) => outbuf,
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Err(err) => {
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gst::error!(
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CAT,
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imp = self,
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"Can't convert Closed Caption buffer: {err}"
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);
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return Err(gst::FlowError::Error);
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}
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};
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drop(map);
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{
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let outbuf = outbuf.get_mut().unwrap();
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let _ = buffer.copy_into(outbuf, gst::BUFFER_COPY_METADATA, ..);
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}
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drop(state);
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self.srcpad.push(outbuf)
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}
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#[allow(clippy::single_match)]
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fn sink_event(&self, pad: &gst::Pad, event: gst::Event) -> bool {
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use gst::EventView;
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gst::log!(CAT, obj = pad, "Handling event {:?}", event);
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match event.view() {
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EventView::Caps(ev) => {
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let caps = ev.caps();
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let s = caps.structure(0).unwrap();
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let format = match s.name().as_str() {
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"closedcaption/x-cea-608" => Format::Cea608,
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"closedcaption/x-cea-708" => Format::Cea708,
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_ => {
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gst::error!(CAT, imp = self, "Unsupported caps {caps:?}");
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return false;
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}
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};
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gst::debug!(CAT, imp = self, "Configuring format {format:?}");
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let mut state = self.state.borrow_mut();
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state.format = Some(format);
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drop(state);
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return self.srcpad.push_event(
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gst::event::Caps::builder(&self.srcpad.pad_template_caps())
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.seqnum(ev.seqnum())
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.build(),
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);
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}
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_ => (),
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}
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gst::Pad::event_default(pad, Some(&*self.obj()), event)
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}
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}
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#[glib::object_subclass]
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impl ObjectSubclass for CcToSt2038Anc {
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const NAME: &'static str = "GstCcToSt2038Anc";
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type Type = super::CcToSt2038Anc;
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type ParentType = gst::Element;
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fn with_class(klass: &Self::Class) -> Self {
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let templ = klass.pad_template("sink").unwrap();
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let sinkpad = gst::Pad::builder_from_template(&templ)
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.chain_function(|pad, parent, buffer| {
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CcToSt2038Anc::catch_panic_pad_function(
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parent,
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|| Err(gst::FlowError::Error),
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|this| this.sink_chain(pad, buffer),
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)
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})
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.event_function(|pad, parent, event| {
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CcToSt2038Anc::catch_panic_pad_function(
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parent,
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|| false,
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|this| this.sink_event(pad, event),
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)
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})
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.flags(gst::PadFlags::FIXED_CAPS)
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.build();
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let templ = klass.pad_template("src").unwrap();
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let srcpad = gst::Pad::builder_from_template(&templ)
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.flags(gst::PadFlags::FIXED_CAPS)
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.build();
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Self {
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sinkpad,
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srcpad,
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state: AtomicRefCell::new(State::default()),
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settings: Mutex::new(Settings::default()),
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}
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}
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}
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impl ObjectImpl for CcToSt2038Anc {
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fn properties() -> &'static [glib::ParamSpec] {
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static PROPERTIES: Lazy<Vec<glib::ParamSpec>> = Lazy::new(|| {
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vec![
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glib::ParamSpecBoolean::builder("c-not-y-channel")
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.nick("Y Not C Channel")
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.blurb("Set the y_not_c_channel flag in the output")
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.default_value(Settings::default().c_not_y_channel)
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.mutable_playing()
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.build(),
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glib::ParamSpecUInt::builder("line-number")
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.nick("Line Number")
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.blurb("Line Number of the output")
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.default_value(Settings::default().line_number as u32)
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.maximum(2047)
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.mutable_playing()
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.build(),
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glib::ParamSpecUInt::builder("horizontal-offset")
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.nick("Horizontal Offset")
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.blurb("Horizontal offset of the output")
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.default_value(Settings::default().horizontal_offset as u32)
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.maximum(4095)
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.mutable_playing()
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.build(),
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]
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});
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PROPERTIES.as_ref()
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}
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fn set_property(&self, _id: usize, value: &glib::Value, pspec: &glib::ParamSpec) {
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match pspec.name() {
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"c-not-y-channel" => {
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let mut settings = self.settings.lock().unwrap();
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settings.c_not_y_channel = value.get().expect("type checked upstream");
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}
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"line-number" => {
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let mut settings = self.settings.lock().unwrap();
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settings.line_number = value.get::<u32>().expect("type checked upstream") as u16;
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}
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"horizontal-offset" => {
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let mut settings = self.settings.lock().unwrap();
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settings.horizontal_offset =
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value.get::<u32>().expect("type checked upstream") as u16;
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}
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_ => unimplemented!(),
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}
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}
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fn property(&self, _id: usize, pspec: &glib::ParamSpec) -> glib::Value {
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match pspec.name() {
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"c-not-y-channel" => {
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let settings = self.settings.lock().unwrap();
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settings.c_not_y_channel.to_value()
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}
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"line-number" => {
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let settings = self.settings.lock().unwrap();
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(settings.line_number as u32).to_value()
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}
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"horizontal-offset" => {
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let settings = self.settings.lock().unwrap();
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(settings.horizontal_offset as u32).to_value()
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}
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_ => unimplemented!(),
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}
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}
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fn constructed(&self) {
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self.parent_constructed();
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let obj = self.obj();
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obj.add_pad(&self.sinkpad).unwrap();
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obj.add_pad(&self.srcpad).unwrap();
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}
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}
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impl GstObjectImpl for CcToSt2038Anc {}
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impl ElementImpl for CcToSt2038Anc {
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fn metadata() -> Option<&'static gst::subclass::ElementMetadata> {
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static ELEMENT_METADATA: Lazy<gst::subclass::ElementMetadata> = Lazy::new(|| {
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gst::subclass::ElementMetadata::new(
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"CC to ST-2038 ANC",
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"Generic",
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"Converts Closed Captions to ST-2038 ANC",
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"Sebastian Dröge <sebastian@centricular.com>",
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)
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});
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Some(&*ELEMENT_METADATA)
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}
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fn pad_templates() -> &'static [gst::PadTemplate] {
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static PAD_TEMPLATES: Lazy<Vec<gst::PadTemplate>> = Lazy::new(|| {
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let src_pad_template = gst::PadTemplate::new(
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"src",
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gst::PadDirection::Src,
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gst::PadPresence::Sometimes,
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&gst::Caps::builder("meta/x-st-2038").build(),
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)
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.unwrap();
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let sink_pad_template = gst::PadTemplate::new(
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"sink",
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gst::PadDirection::Sink,
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gst::PadPresence::Always,
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&[
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gst::Structure::builder("closedcaption/x-cea-608")
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.field("format", "s334-1a")
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.build(),
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gst::Structure::builder("closedcaption/x-cea-708")
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.field("format", "cdp")
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.build(),
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]
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.into_iter()
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.collect::<gst::Caps>(),
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)
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.unwrap();
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vec![src_pad_template, sink_pad_template]
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});
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PAD_TEMPLATES.as_ref()
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}
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#[allow(clippy::single_match)]
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fn change_state(
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&self,
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transition: gst::StateChange,
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) -> Result<gst::StateChangeSuccess, gst::StateChangeError> {
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gst::trace!(CAT, imp = self, "Changing state {:?}", transition);
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match transition {
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gst::StateChange::ReadyToPaused => {
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*self.state.borrow_mut() = State::default();
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}
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_ => (),
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}
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let ret = self.parent_change_state(transition)?;
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match transition {
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gst::StateChange::PausedToReady => {
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*self.state.borrow_mut() = State::default();
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}
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_ => (),
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}
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Ok(ret)
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}
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}
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25
video/closedcaption/src/cctost2038anc/mod.rs
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25
video/closedcaption/src/cctost2038anc/mod.rs
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@ -0,0 +1,25 @@
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// Copyright (C) 2024 Sebastian Dröge <sebastian@centricular.com>
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//
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// This Source Code Form is subject to the terms of the Mozilla Public License, v2.0.
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// If a copy of the MPL was not distributed with this file, You can obtain one at
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// <https://mozilla.org/MPL/2.0/>.
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//
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// SPDX-License-Identifier: MPL-2.0
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use gst::glib;
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use gst::prelude::*;
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mod imp;
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glib::wrapper! {
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pub struct CcToSt2038Anc(ObjectSubclass<imp::CcToSt2038Anc>) @extends gst::Element, gst::Object;
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}
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pub fn register(plugin: &gst::Plugin) -> Result<(), glib::BoolError> {
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gst::Element::register(
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Some(plugin),
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"cctost2038anc",
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gst::Rank::NONE,
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CcToSt2038Anc::static_type(),
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)
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}
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@ -18,6 +18,7 @@ use gst::glib;
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use gst::prelude::*;
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mod ccdetect;
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mod cctost2038anc;
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mod ccutils;
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mod cea608overlay;
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mod cea608tocea708;
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@ -69,6 +70,7 @@ fn plugin_init(plugin: &gst::Plugin) -> Result<(), glib::BoolError> {
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st2038ancdemux::register(plugin)?;
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st2038ancmux::register(plugin)?;
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st2038anctocc::register(plugin)?;
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cctost2038anc::register(plugin)?;
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Ok(())
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}
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@ -68,3 +68,75 @@ impl AncDataHeader {
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})
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}
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}
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fn extend_with_even_odd_parity(v: u8, checksum: &mut u16) -> u16 {
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let parity = v.count_ones() & 1;
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let res = if parity == 0 {
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0x1_00 | (v as u16)
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} else {
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0x2_00 | (v as u16)
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};
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*checksum = checksum.wrapping_add(res);
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res
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}
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pub(crate) fn convert_to_st2038_buffer(
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c_not_y_channel: bool,
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line_number: u16,
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horizontal_offset: u16,
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did: u8,
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sdid: u8,
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payload: &[u8],
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) -> Result<gst::Buffer, anyhow::Error> {
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if payload.len() > 255 {
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anyhow::bail!(
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"Payload needs to be less than 256 bytes, got {}",
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payload.len()
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);
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}
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use anyhow::Context;
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use bitstream_io::{BigEndian, BitWrite, BitWriter};
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let mut output = Vec::with_capacity((70 + payload.len() * 10) / 8 + 1);
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let mut w = BitWriter::endian(&mut output, BigEndian);
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w.write::<u8>(6, 0b00_0000).context("zero bits")?;
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w.write_bit(c_not_y_channel).context("c_not_y_channel")?;
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w.write::<u16>(11, line_number).context("line number")?;
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w.write::<u16>(12, horizontal_offset)
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.context("horizontal offset")?;
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let mut checksum = 0u16;
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w.write::<u16>(10, extend_with_even_odd_parity(did, &mut checksum))
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.context("DID")?;
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w.write::<u16>(10, extend_with_even_odd_parity(sdid, &mut checksum))
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.context("SDID")?;
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w.write::<u16>(
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10,
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extend_with_even_odd_parity(payload.len() as u8, &mut checksum),
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)
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.context("data count")?;
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for &b in payload {
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w.write::<u16>(10, extend_with_even_odd_parity(b, &mut checksum))
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.context("payload")?;
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}
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checksum &= 0x1_ff;
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checksum |= ((!(checksum >> 8)) & 0x0_01) << 9;
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w.write::<u16>(10, checksum).context("checksum")?;
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while !w.byte_aligned() {
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w.write_bit(true).context("padding")?;
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}
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w.flush().context("flushing")?;
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Ok(gst::Buffer::from_mut_slice(output))
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}
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