closedcaption: implement cea608overlay

Useful complement to cea708overlay, that can only render native
708.

The element isn't an aggregator, and simply parses and renders
closed caption meta on its input video buffers.

No property is exposed, the rendering is done using a monospace
font, over a 32 x 15 grid with the font size fitted to fill as
much of the viewport as possible.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests/343>

video/closedcaption/Cargo.toml

@@ -15,20 +15,24 @@ uuid = { version = "0.8", features = ["v4"] }
 chrono = "0.4"
 lazy_static = "1.2"
 atomic_refcell = "0.1"
+cairo-rs = { git = "https://github.com/gtk-rs/cairo", features=["use_glib"] }
+cairo-sys-rs = { git = "https://github.com/gtk-rs/cairo" }
+pango = { git = "https://github.com/gtk-rs/pango" }
+pangocairo = { git = "https://github.com/gtk-rs/pangocairo" }
 
 [dependencies.gst]
 git = "https://gitlab.freedesktop.org/gstreamer/gstreamer-rs"
-features = ["v1_12"]
+features = ["v1_16"]
 package="gstreamer"
 
 [dependencies.gst-base]
 git = "https://gitlab.freedesktop.org/gstreamer/gstreamer-rs"
-features = ["v1_12"]
+features = ["v1_16"]
 package="gstreamer-base"
 
 [dependencies.gst-video]
 git = "https://gitlab.freedesktop.org/gstreamer/gstreamer-rs"
-features = ["v1_12"]
+features = ["v1_16"]
 package="gstreamer-video"
 
 [dev-dependencies]

video/closedcaption/src/c/caption.c

@@ -412,7 +412,7 @@ caption_frame_from_text (caption_frame_t * frame, const utf8_char_t * data)
 
 ////////////////////////////////////////////////////////////////////////////////
 size_t
-caption_frame_to_text (caption_frame_t * frame, utf8_char_t * data)
+caption_frame_to_text (caption_frame_t * frame, utf8_char_t * data, int full)
 {
   int r, c, uln, crlf = 0, count = 0;
   size_t s, size = 0;
@@ -425,8 +425,9 @@ caption_frame_to_text (caption_frame_t * frame, utf8_char_t * data)
       const utf8_char_t *chr =
           caption_frame_read_char (frame, r, c, &sty, &uln);
       // dont start a new line until we encounter at least one printable character
-      if (0 < utf8_char_length (chr) && (0 < count
-              || !utf8_char_whitespace (chr))) {
+      if (full ||
+          (0 < utf8_char_length (chr) && (0 < count
+              || !utf8_char_whitespace (chr)))) {
         if (0 < crlf) {
           memcpy (data, "\r\n\0", 3);
           data += 2, size += 2, crlf = 0;

video/closedcaption/src/c/caption.h

@@ -131,7 +131,7 @@ int caption_frame_from_text(caption_frame_t* frame, const utf8_char_t* data);
     \param
 */
 #define CAPTION_FRAME_TEXT_BYTES (4 * ((SCREEN_COLS + 2) * SCREEN_ROWS) + 1)
-size_t caption_frame_to_text(caption_frame_t* frame, utf8_char_t* data);
+size_t caption_frame_to_text(caption_frame_t* frame, utf8_char_t* data, int full);
 /*! \brief
     \param
 */

video/closedcaption/src/caption_frame.rs

@@ -0,0 +1,71 @@
+// Copyright (C) 2020 Sebastian Dröge <sebastian@centricular.com>
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use super::cea608tott_ffi as ffi;
+use std::mem;
+
+#[derive(Copy, Clone, Debug)]
+#[allow(unused)]
+pub enum Status {
+    Ok,
+    Ready,
+    Clear,
+}
+
+#[derive(Copy, Clone, Debug)]
+pub struct Error;
+
+pub struct CaptionFrame(ffi::caption_frame_t);
+
+unsafe impl Send for CaptionFrame {}
+unsafe impl Sync for CaptionFrame {}
+
+impl CaptionFrame {
+    pub fn new() -> Self {
+        unsafe {
+            let mut frame = mem::MaybeUninit::uninit();
+            ffi::caption_frame_init(frame.as_mut_ptr());
+            Self(frame.assume_init())
+        }
+    }
+
+    #[allow(unused)]
+    pub fn decode(&mut self, cc_data: u16, timestamp: f64) -> Result<Status, Error> {
+        unsafe {
+            let res = ffi::caption_frame_decode(&mut self.0, cc_data, timestamp);
+            match res {
+                ffi::libcaption_stauts_t_LIBCAPTION_OK => Ok(Status::Ok),
+                ffi::libcaption_stauts_t_LIBCAPTION_READY => Ok(Status::Ready),
+                ffi::libcaption_stauts_t_LIBCAPTION_CLEAR => Ok(Status::Clear),
+                _ => Err(Error),
+            }
+        }
+    }
+
+    #[allow(unused)]
+    pub fn to_text(&self, full: bool) -> Result<String, Error> {
+        unsafe {
+            let mut data = Vec::with_capacity(ffi::CAPTION_FRAME_TEXT_BYTES as usize);
+
+            let len = ffi::caption_frame_to_text(
+                &self.0 as *const _ as *mut _,
+                data.as_ptr() as *mut _,
+                if full { 1 } else { 0 },
+            );
+            data.set_len(len as usize);
+
+            String::from_utf8(data).map_err(|_| Error)
+        }
+    }
+}
+
+impl Default for CaptionFrame {
+    fn default() -> Self {
+        Self::new()
+    }
+}

video/closedcaption/src/cea608overlay.rs

@@ -0,0 +1,503 @@
+// Copyright (C) 2020 Mathieu Duponchelle <mathieu@centricular.com>
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Library General Public
+// License as published by the Free Software Foundation; either
+// version 2 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Library General Public License for more details.
+//
+// You should have received a copy of the GNU Library General Public
+// License along with this library; if not, write to the
+// Free Software Foundation, Inc., 51 Franklin Street, Suite 500,
+// Boston, MA 02110-1335, USA.
+
+// Example command-line:
+//
+// gst-launch-1.0 cccombiner name=ccc ! cea608overlay ! autovideosink \
+//   videotestsrc ! video/x-raw, width=1280, height=720 ! queue ! ccc.sink \
+//   filesrc location=input.srt ! subparse ! tttocea608 ! queue ! ccc.caption
+
+use glib::prelude::*;
+use glib::subclass;
+use glib::subclass::prelude::*;
+use gst::prelude::*;
+use gst::subclass::prelude::*;
+use gst_video::prelude::*;
+
+use std::sync::Mutex;
+
+use pango::prelude::*;
+
+use crate::caption_frame::{CaptionFrame, Status};
+
+lazy_static! {
+    static ref CAT: gst::DebugCategory = {
+        gst::DebugCategory::new(
+            "cea608overlay",
+            gst::DebugColorFlags::empty(),
+            Some("CEA 608 overlay element"),
+        )
+    };
+}
+
+struct State {
+    video_info: Option<gst_video::VideoInfo>,
+    layout: Option<pango::Layout>,
+    caption_frame: CaptionFrame,
+    composition: Option<gst_video::VideoOverlayComposition>,
+    left_alignment: i32,
+    attach: bool,
+}
+
+impl Default for State {
+    fn default() -> Self {
+        Self {
+            video_info: None,
+            layout: None,
+            caption_frame: CaptionFrame::default(),
+            composition: None,
+            left_alignment: 0,
+            attach: false,
+        }
+    }
+}
+
+unsafe impl Send for State {}
+
+struct Cea608Overlay {
+    srcpad: gst::Pad,
+    sinkpad: gst::Pad,
+    state: Mutex<State>,
+}
+
+impl Cea608Overlay {
+    fn set_pad_functions(sinkpad: &gst::Pad, _srcpad: &gst::Pad) {
+        sinkpad.set_chain_function(|pad, parent, buffer| {
+            Cea608Overlay::catch_panic_pad_function(
+                parent,
+                || Err(gst::FlowError::Error),
+                |overlay, element| overlay.sink_chain(pad, element, buffer),
+            )
+        });
+        sinkpad.set_event_function(|pad, parent, event| {
+            Cea608Overlay::catch_panic_pad_function(
+                parent,
+                || false,
+                |overlay, element| overlay.sink_event(pad, element, event),
+            )
+        });
+    }
+
+    // FIXME: we want to render the text in the largest 32 x 15 characters
+    // that will fit the viewport. This is a truly terrible way to determine
+    // the appropriate font size, but we only need to run that on resolution
+    // changes, and the API that would allow us to precisely control the
+    // line height has not yet been exposed by the bindings:
+    //
+    // https://blogs.gnome.org/mclasen/2019/07/27/more-text-rendering-updates/
+    //
+    // TODO: switch to the API presented in this post once it's been exposed
+    fn recalculate_layout(
+        &self,
+        element: &gst::Element,
+        state: &mut State,
+    ) -> Result<gst::FlowSuccess, gst::FlowError> {
+        let video_info = state.video_info.as_ref().unwrap();
+        let fontmap = match pangocairo::FontMap::new() {
+            Some(fontmap) => Ok(fontmap),
+            None => {
+                gst_element_error!(
+                    element,
+                    gst::LibraryError::Failed,
+                    ["Failed to create pangocairo font map"]
+                );
+                Err(gst::FlowError::Error)
+            }
+        }?;
+        let context = match fontmap.create_context() {
+            Some(context) => Ok(context),
+            None => {
+                gst_element_error!(
+                    element,
+                    gst::LibraryError::Failed,
+                    ["Failed to create font map context"]
+                );
+                Err(gst::FlowError::Error)
+            }
+        }?;
+        context.set_language(&pango::Language::from_string("en_US"));
+        context.set_base_dir(pango::Direction::Ltr);
+        let layout = pango::Layout::new(&context);
+        layout.set_alignment(pango::Alignment::Left);
+        let mut font_desc = pango::FontDescription::from_string(&"monospace");
+
+        let mut font_size = 1;
+        let mut left_alignment = 0;
+        loop {
+            font_desc.set_size(font_size * pango::SCALE);
+            layout.set_font_description(Some(&font_desc));
+            layout.set_text(
+                &"12345678901234567890123456789012\n2\n3\n4\n5\n6\n7\n8\n9\n0\n1\n2\n3\n4\n5",
+            );
+            let (_ink_rect, logical_rect) = layout.get_extents();
+            if logical_rect.width > video_info.width() as i32 * pango::SCALE
+                || logical_rect.height > video_info.height() as i32 * pango::SCALE
+            {
+                font_desc.set_size((font_size - 1) * pango::SCALE);
+                layout.set_font_description(Some(&font_desc));
+                break;
+            }
+            left_alignment = (video_info.width() as i32 - logical_rect.width / pango::SCALE) / 2;
+            font_size += 1;
+        }
+
+        state.left_alignment = left_alignment;
+        state.layout = Some(layout);
+
+        Ok(gst::FlowSuccess::Ok)
+    }
+
+    fn overlay_text(&self, text: &str, state: &mut State) {
+        let video_info = state.video_info.as_ref().unwrap();
+        let layout = state.layout.as_ref().unwrap();
+        layout.set_text(text);
+        let (_ink_rect, logical_rect) = layout.get_extents();
+        let height = logical_rect.height / pango::SCALE;
+        let width = logical_rect.width / pango::SCALE;
+
+        // No text actually needs rendering
+        if width == 0 || height == 0 {
+            state.composition = None;
+            return;
+        }
+
+        let mut buffer = gst::Buffer::with_size((width * height) as usize * 4).unwrap();
+
+        gst_video::VideoMeta::add(
+            buffer.get_mut().unwrap(),
+            gst_video::VideoFrameFlags::NONE,
+            #[cfg(target_endian = "little")]
+            gst_video::VideoFormat::Bgra,
+            #[cfg(target_endian = "big")]
+            gst_video::VideoFormat::Argb,
+            width as u32,
+            height as u32,
+        );
+        let buffer = buffer.into_mapped_buffer_writable().unwrap();
+        let buffer = {
+            let buffer_ptr = unsafe { buffer.get_buffer().as_ptr() };
+            let surface = cairo::ImageSurface::create_for_data(
+                buffer,
+                cairo::Format::ARgb32,
+                width as i32,
+                height,
+                width as i32 * 4,
+            )
+            .unwrap();
+
+            let cr = cairo::Context::new(&surface);
+
+            // Clear background
+            cr.set_operator(cairo::Operator::Source);
+            cr.set_source_rgba(0.0, 0.0, 0.0, 0.0);
+            cr.paint();
+
+            // Render text outline
+            cr.save();
+            cr.set_operator(cairo::Operator::Over);
+
+            cr.set_source_rgba(0.0, 0.0, 0.0, 1.0);
+
+            pangocairo::functions::layout_path(&cr, &layout);
+            cr.stroke();
+            cr.restore();
+
+            // Render text
+            cr.save();
+            cr.set_source_rgba(255.0, 255.0, 255.0, 1.0);
+
+            pangocairo::functions::show_layout(&cr, &layout);
+
+            cr.restore();
+            drop(cr);
+
+            // Safety: The surface still owns a mutable reference to the buffer but our reference
+            // to the surface here is the last one. After dropping the surface the buffer would be
+            // freed, so we keep an additional strong reference here before dropping the surface,
+            // which is then returned. As such it's guaranteed that nothing is using the buffer
+            // anymore mutably.
+            unsafe {
+                assert_eq!(
+                    cairo_sys::cairo_surface_get_reference_count(surface.to_raw_none()),
+                    1
+                );
+                let buffer = glib::translate::from_glib_none(buffer_ptr);
+                drop(surface);
+                buffer
+            }
+        };
+
+        let rect = gst_video::VideoOverlayRectangle::new_raw(
+            &buffer,
+            state.left_alignment,
+            (video_info.height() as i32 - height) / 2,
+            width as u32,
+            height as u32,
+            gst_video::VideoOverlayFormatFlags::PREMULTIPLIED_ALPHA,
+        );
+
+        state.composition = match gst_video::VideoOverlayComposition::new(Some(&rect)) {
+            Ok(composition) => Some(composition),
+            Err(_) => None,
+        };
+    }
+
+    fn negotiate(
+        &self,
+        element: &gst::Element,
+        state: &mut State,
+    ) -> Result<gst::FlowSuccess, gst::FlowError> {
+        let video_info = match state.video_info.as_ref() {
+            Some(video_info) => Ok(video_info),
+            None => {
+                gst_element_error!(
+                    element,
+                    gst::CoreError::Negotiation,
+                    ["Element hasn't received valid video caps at negotiation time"]
+                );
+                Err(gst::FlowError::NotNegotiated)
+            }
+        }?;
+
+        let mut caps = video_info.to_caps().unwrap();
+        let mut downstream_accepts_meta = false;
+
+        let upstream_has_meta = caps
+            .get_features(0)
+            .map(|f| f.contains(&gst_video::CAPS_FEATURE_META_GST_VIDEO_OVERLAY_COMPOSITION))
+            .unwrap_or(false);
+
+        if !upstream_has_meta {
+            let mut caps_clone = caps.clone();
+            let overlay_caps = caps_clone.make_mut();
+
+            if let Some(features) = overlay_caps.get_mut_features(0) {
+                features.add(&gst_video::CAPS_FEATURE_META_GST_VIDEO_OVERLAY_COMPOSITION);
+                if let Some(peercaps) = self.srcpad.peer_query_caps(Some(&caps_clone)) {
+                    downstream_accepts_meta = !peercaps.is_empty();
+                    if downstream_accepts_meta {
+                        caps = caps_clone;
+                    }
+                }
+            }
+        }
+
+        state.attach = upstream_has_meta || downstream_accepts_meta;
+
+        self.recalculate_layout(element, state)?;
+
+        if !self.srcpad.push_event(gst::Event::new_caps(&caps).build()) {
+            Err(gst::FlowError::NotNegotiated)
+        } else {
+            Ok(gst::FlowSuccess::Ok)
+        }
+    }
+
+    fn sink_chain(
+        &self,
+        pad: &gst::Pad,
+        element: &gst::Element,
+        mut buffer: gst::Buffer,
+    ) -> Result<gst::FlowSuccess, gst::FlowError> {
+        gst_log!(CAT, obj: pad, "Handling buffer {:?}", buffer);
+
+        let mut state = self.state.lock().unwrap();
+
+        if self.srcpad.check_reconfigure() {
+            self.negotiate(element, &mut state)?;
+        }
+
+        for meta in buffer.iter_meta::<gst_video::VideoCaptionMeta>() {
+            if meta.get_caption_type() == gst_video::VideoCaptionType::Cea608Raw {
+                let data = meta.get_data();
+                assert!(data.len() % 2 == 0);
+                for i in 0..data.len() / 2 {
+                    match state
+                        .caption_frame
+                        .decode((data[i * 2] as u16) << 8 | data[i * 2 + 1] as u16, 0.0)
+                    {
+                        Ok(Status::Ready) => {
+                            let text = match state.caption_frame.to_text(true) {
+                                Ok(text) => text,
+                                Err(_) => {
+                                    gst_error!(
+                                        CAT,
+                                        obj: pad,
+                                        "Failed to convert caption frame to text"
+                                    );
+                                    continue;
+                                }
+                            };
+
+                            self.overlay_text(&text, &mut state);
+                        }
+                        _ => (),
+                    }
+                }
+            }
+        }
+
+        if let Some(composition) = &state.composition {
+            let buffer = buffer.make_mut();
+            if state.attach {
+                gst_video::VideoOverlayCompositionMeta::add(buffer, &composition);
+            } else {
+                let mut frame = gst_video::VideoFrameRef::from_buffer_ref_writable(
+                    buffer,
+                    state.video_info.as_ref().unwrap(),
+                )
+                .unwrap();
+                match composition.blend(&mut frame) {
+                    Err(_) => {
+                        gst_error!(CAT, obj: pad, "Failed to blend composition");
+                    }
+                    _ => (),
+                }
+            }
+        }
+        drop(state);
+
+        self.srcpad.push(buffer)
+    }
+
+    fn sink_event(&self, pad: &gst::Pad, element: &gst::Element, event: gst::Event) -> bool {
+        use gst::EventView;
+
+        gst_log!(CAT, obj: pad, "Handling event {:?}", event);
+        match event.view() {
+            EventView::Caps(c) => {
+                let mut state = self.state.lock().unwrap();
+                state.video_info = gst_video::VideoInfo::from_caps(c.get_caps()).ok();
+                self.srcpad.check_reconfigure();
+                match self.negotiate(element, &mut state) {
+                    Ok(_) => true,
+                    Err(_) => {
+                        self.srcpad.mark_reconfigure();
+                        true
+                    }
+                }
+            }
+            EventView::FlushStop(..) => {
+                let mut state = self.state.lock().unwrap();
+                state.caption_frame = CaptionFrame::default();
+                state.composition = None;
+                pad.event_default(Some(element), event)
+            }
+            _ => pad.event_default(Some(element), event),
+        }
+    }
+}
+
+impl ObjectSubclass for Cea608Overlay {
+    const NAME: &'static str = "RsCea608Overlay";
+    type ParentType = gst::Element;
+    type Instance = gst::subclass::ElementInstanceStruct<Self>;
+    type Class = subclass::simple::ClassStruct<Self>;
+
+    glib_object_subclass!();
+
+    fn new_with_class(klass: &subclass::simple::ClassStruct<Self>) -> Self {
+        let templ = klass.get_pad_template("sink").unwrap();
+        let sinkpad = gst::Pad::new_from_template(&templ, Some("sink"));
+        sinkpad.set_pad_flags(gst::PadFlags::PROXY_CAPS);
+        let templ = klass.get_pad_template("src").unwrap();
+        let srcpad = gst::Pad::new_from_template(&templ, Some("src"));
+        srcpad.set_pad_flags(gst::PadFlags::PROXY_CAPS);
+
+        Cea608Overlay::set_pad_functions(&sinkpad, &srcpad);
+
+        Self {
+            srcpad,
+            sinkpad,
+            state: Mutex::new(State::default()),
+        }
+    }
+
+    fn class_init(klass: &mut subclass::simple::ClassStruct<Self>) {
+        klass.set_metadata(
+            "Cea 608 overlay",
+            "Video/Overlay/Subtitle",
+            "Renders CEA 608 closed caption meta over raw video frames",
+            "Mathieu Duponchelle <mathieu@centricular.com>",
+        );
+
+        let caps = gst_video::VideoFormat::iter_raw()
+            .into_video_caps()
+            .unwrap()
+            .build();
+
+        let sink_pad_template = gst::PadTemplate::new(
+            "sink",
+            gst::PadDirection::Sink,
+            gst::PadPresence::Always,
+            &caps,
+        )
+        .unwrap();
+        klass.add_pad_template(sink_pad_template);
+
+        let src_pad_template = gst::PadTemplate::new(
+            "src",
+            gst::PadDirection::Src,
+            gst::PadPresence::Always,
+            &caps,
+        )
+        .unwrap();
+        klass.add_pad_template(src_pad_template);
+    }
+}
+
+impl ObjectImpl for Cea608Overlay {
+    glib_object_impl!();
+
+    fn constructed(&self, obj: &glib::Object) {
+        self.parent_constructed(obj);
+
+        let element = obj.downcast_ref::<gst::Element>().unwrap();
+        element.add_pad(&self.sinkpad).unwrap();
+        element.add_pad(&self.srcpad).unwrap();
+    }
+}
+
+impl ElementImpl for Cea608Overlay {
+    fn change_state(
+        &self,
+        element: &gst::Element,
+        transition: gst::StateChange,
+    ) -> Result<gst::StateChangeSuccess, gst::StateChangeError> {
+        gst_trace!(CAT, obj: element, "Changing state {:?}", transition);
+
+        match transition {
+            gst::StateChange::ReadyToPaused | gst::StateChange::PausedToReady => {
+                // Reset the whole state
+                let mut state = self.state.lock().unwrap();
+                *state = State::default();
+            }
+            _ => (),
+        }
+
+        self.parent_change_state(element, transition)
+    }
+}
+
+pub fn register(plugin: &gst::Plugin) -> Result<(), glib::BoolError> {
+    gst::Element::register(
+        Some(plugin),
+        "cea608overlay",
+        gst::Rank::Primary,
+        Cea608Overlay::get_type(),
+    )
+}

video/closedcaption/src/cea608tott.rs

@@ -12,7 +12,7 @@ use glib::subclass::prelude::*;
 use gst::prelude::*;
 use gst::subclass::prelude::*;
 
-use super::cea608tott_ffi as ffi;
+use crate::caption_frame::{CaptionFrame, Status};
 use atomic_refcell::AtomicRefCell;
 
 #[derive(Copy, Clone, Debug)]
@@ -109,7 +109,7 @@ impl Cea608ToTt {
             }
             Ok(Status::Ready) => {
                 gst_debug!(CAT, obj: pad, "Have new closed caption packet");
-                let text = match state.caption_frame.to_text() {
+                let text = match state.caption_frame.to_text(false) {
                     Ok(text) => text,
                     Err(_) => {
                         gst_error!(CAT, obj: pad, "Failed to convert caption frame to text");
@@ -509,60 +509,3 @@ pub fn register(plugin: &gst::Plugin) -> Result<(), glib::BoolError> {
         Cea608ToTt::get_type(),
     )
 }
-
-use std::mem;
-
-#[derive(Copy, Clone, Debug)]
-enum Status {
-    Ok,
-    Ready,
-    Clear,
-}
-
-#[derive(Copy, Clone, Debug)]
-struct Error;
-
-struct CaptionFrame(ffi::caption_frame_t);
-
-unsafe impl Send for CaptionFrame {}
-unsafe impl Sync for CaptionFrame {}
-
-impl CaptionFrame {
-    fn new() -> Self {
-        unsafe {
-            let mut frame = mem::MaybeUninit::uninit();
-            ffi::caption_frame_init(frame.as_mut_ptr());
-            Self(frame.assume_init())
-        }
-    }
-
-    fn decode(&mut self, cc_data: u16, timestamp: f64) -> Result<Status, Error> {
-        unsafe {
-            let res = ffi::caption_frame_decode(&mut self.0, cc_data, timestamp);
-            match res {
-                ffi::libcaption_stauts_t_LIBCAPTION_OK => Ok(Status::Ok),
-                ffi::libcaption_stauts_t_LIBCAPTION_READY => Ok(Status::Ready),
-                ffi::libcaption_stauts_t_LIBCAPTION_CLEAR => Ok(Status::Clear),
-                _ => Err(Error),
-            }
-        }
-    }
-
-    fn to_text(&self) -> Result<String, Error> {
-        unsafe {
-            let mut data = Vec::with_capacity(ffi::CAPTION_FRAME_TEXT_BYTES as usize);
-
-            let len =
-                ffi::caption_frame_to_text(&self.0 as *const _ as *mut _, data.as_ptr() as *mut _);
-            data.set_len(len as usize);
-
-            String::from_utf8(data).map_err(|_| Error)
-        }
-    }
-}
-
-impl Default for CaptionFrame {
-    fn default() -> Self {
-        Self::new()
-    }
-}

video/closedcaption/src/cea608tott_ffi.rs

@@ -805,7 +805,11 @@ extern "C" {
     ) -> ::std::os::raw::c_int;
 }
 extern "C" {
-    pub fn caption_frame_to_text(frame: *mut caption_frame_t, data: *mut utf8_char_t) -> usize;
+    pub fn caption_frame_to_text(
+        frame: *mut caption_frame_t,
+        data: *mut utf8_char_t,
+        full: ::std::os::raw::c_int,
+    ) -> usize;
 }
 extern "C" {
     pub fn caption_frame_dump_buffer(frame: *mut caption_frame_t, buf: *mut utf8_char_t) -> usize;

video/closedcaption/src/lib.rs

@@ -33,6 +33,8 @@ extern crate lazy_static;
 #[macro_use]
 extern crate pretty_assertions;
 
+mod caption_frame;
+mod cea608overlay;
 mod cea608tott;
 #[allow(non_camel_case_types, non_upper_case_globals)]
 #[allow(clippy::redundant_static_lifetimes, clippy::unreadable_literal)]
@@ -54,6 +56,7 @@ fn plugin_init(plugin: &gst::Plugin) -> Result<(), glib::BoolError> {
     scc_enc::register(plugin)?;
     cea608tott::register(plugin)?;
     tttocea608::register(plugin)?;
+    cea608overlay::register(plugin)?;
     Ok(())
 }