Add VideoFrameRef API

This is like VideoFrame, but can work on gst::BufferRefs and borrows
from it. VideoFrames can be converted into this by borrowing.

gstreamer-video/src/lib.rs

@@ -54,8 +54,8 @@ mod video_format_info;
 pub use video_format_info::*;
 mod video_info;
 pub use video_info::*;
-mod video_frame;
-pub use video_frame::VideoFrame;
+pub mod video_frame;
+pub use video_frame::{VideoFrame, VideoFrameRef};
 mod video_overlay;
 pub use video_overlay::VideoOverlayExtManual;
 mod video_event;

gstreamer-video/src/video_frame.rs

@@ -18,6 +18,7 @@ use std::mem;
 use std::ptr;
 use std::marker::PhantomData;
 use std::slice;
+use std::ops;
 
 pub struct Readable;
 pub struct Writable;
@@ -219,6 +220,12 @@ impl VideoFrame<Readable> {
             }
         }
     }
+
+    pub fn as_video_frame_ref(&self) -> VideoFrameRef<&gst::BufferRef> {
+        let vframe = unsafe { ptr::read(&self.0) };
+        let info = self.2.clone();
+        VideoFrameRef(vframe, Some(self.buffer()), info, true)
+    }
 }
 
 impl VideoFrame<Writable> {
@@ -311,6 +318,304 @@ impl VideoFrame<Writable> {
             ))
         }
     }
+
+    pub fn as_mut_video_frame_ref(&mut self) -> VideoFrameRef<&mut gst::BufferRef> {
+        let vframe = unsafe { ptr::read(&self.0) };
+        let info = self.2.clone();
+        VideoFrameRef(vframe, Some(self.buffer_mut()), info, true)
+    }
+}
+
+pub struct VideoFrameRef<T>(ffi::GstVideoFrame, Option<T>, ::VideoInfo, bool);
+
+impl<'a> VideoFrameRef<&'a gst::BufferRef> {
+    pub fn from_buffer_ref_readable<'b>(
+        buffer: &'a gst::BufferRef,
+        info: &'b ::VideoInfo,
+    ) -> Option<VideoFrameRef<&'a gst::BufferRef>> {
+        skip_assert_initialized!();
+
+        unsafe {
+            let mut frame = mem::zeroed();
+            let res: bool = from_glib(ffi::gst_video_frame_map(
+                &mut frame,
+                info.to_glib_none().0 as *mut _,
+                buffer.as_mut_ptr(),
+                mem::transmute(
+                    ffi::GST_VIDEO_FRAME_MAP_FLAG_NO_REF.bits() | gst_ffi::GST_MAP_READ.bits(),
+                ),
+            ));
+
+            if !res {
+                None
+            } else {
+                let info = ::VideoInfo(ptr::read(&frame.info));
+                Some(VideoFrameRef(frame, Some(buffer), info, false))
+            }
+        }
+    }
+
+    pub fn from_buffer_ref_id_readable<'b>(
+        buffer: &'a gst::BufferRef,
+        id: i32,
+        info: &'b ::VideoInfo,
+    ) -> Option<VideoFrameRef<&'a gst::BufferRef>> {
+        skip_assert_initialized!();
+
+        unsafe {
+            let mut frame = mem::zeroed();
+            let res: bool = from_glib(ffi::gst_video_frame_map_id(
+                &mut frame,
+                info.to_glib_none().0 as *mut _,
+                buffer.as_mut_ptr(),
+                id,
+                mem::transmute(
+                    ffi::GST_VIDEO_FRAME_MAP_FLAG_NO_REF.bits() | gst_ffi::GST_MAP_READ.bits(),
+                ),
+            ));
+
+            if !res {
+                None
+            } else {
+                let info = ::VideoInfo(ptr::read(&frame.info));
+                Some(VideoFrameRef(frame, Some(buffer), info, false))
+            }
+        }
+    }
+
+    pub fn info(&self) -> &::VideoInfo {
+        &self.2
+    }
+
+    pub fn flags(&self) -> ::VideoFrameFlags {
+        from_glib(self.0.flags)
+    }
+
+    pub fn id(&self) -> i32 {
+        self.0.id
+    }
+
+    pub fn copy(&self, dest: &mut VideoFrame<Writable>) -> Result<(), glib::BoolError> {
+        unsafe {
+            let res: bool = from_glib(ffi::gst_video_frame_copy(&mut dest.0, &self.0));
+            if res {
+                Ok(())
+            } else {
+                Err(glib::BoolError("Failed to copy video frame"))
+            }
+        }
+    }
+
+    pub fn copy_plane(
+        &self,
+        dest: &mut VideoFrame<Writable>,
+        plane: u32,
+    ) -> Result<(), glib::BoolError> {
+        skip_assert_initialized!();
+
+        unsafe {
+            let res: bool = from_glib(ffi::gst_video_frame_copy_plane(&mut dest.0, &self.0, plane));
+            if res {
+                Ok(())
+            } else {
+                Err(glib::BoolError("Failed to copy video frame plane"))
+            }
+        }
+    }
+
+    pub fn format(&self) -> ::VideoFormat {
+        self.info().format()
+    }
+
+    pub fn format_info(&self) -> ::VideoFormatInfo {
+        self.info().format_info()
+    }
+
+    pub fn width(&self) -> u32 {
+        self.info().width()
+    }
+
+    pub fn height(&self) -> u32 {
+        self.info().height()
+    }
+
+    pub fn size(&self) -> usize {
+        self.info().size()
+    }
+
+    pub fn is_interlaced(&self) -> bool {
+        self.flags().contains(::VideoFrameFlags::INTERLACED)
+    }
+
+    pub fn is_tff(&self) -> bool {
+        self.flags().contains(::VideoFrameFlags::TFF)
+    }
+
+    pub fn is_rff(&self) -> bool {
+        self.flags().contains(::VideoFrameFlags::RFF)
+    }
+
+    pub fn is_onefield(&self) -> bool {
+        self.flags().contains(::VideoFrameFlags::ONEFIELD)
+    }
+
+    pub fn n_planes(&self) -> u32 {
+        self.info().n_planes()
+    }
+
+    pub fn n_components(&self) -> u32 {
+        self.info().n_components()
+    }
+
+    pub fn plane_stride(&self) -> &[i32] {
+        self.info().stride()
+    }
+
+    pub fn plane_offset(&self) -> &[usize] {
+        self.info().offset()
+    }
+
+    pub fn buffer(&self) -> &gst::BufferRef {
+        self.1.as_ref().unwrap()
+    }
+
+    pub fn plane_data(&self, plane: u32) -> Option<&[u8]> {
+        if plane >= self.n_planes() {
+            return None;
+        }
+
+        let format_info = self.format_info();
+
+        // Just get the palette
+        if format_info.has_palette() && plane == 1 {
+            unsafe {
+                return Some(slice::from_raw_parts(self.0.data[1] as *const u8, 256 * 4));
+            }
+        }
+
+        let w = self.plane_stride()[plane as usize] as u32;
+        // FIXME: This assumes that the horizontal subsampling of all
+        // components in the plane is the same, which is probably safe
+        let h = format_info.scale_height(plane as u8, self.height());
+
+        unsafe {
+            Some(slice::from_raw_parts(
+                self.0.data[plane as usize] as *const u8,
+                (w * h) as usize,
+            ))
+        }
+    }
+}
+
+impl<'a> VideoFrameRef<&'a mut gst::BufferRef> {
+    pub fn from_buffer_ref_writable<'b>(
+        buffer: &'a mut gst::BufferRef,
+        info: &'b ::VideoInfo,
+    ) -> Option<VideoFrameRef<&'a mut gst::BufferRef>> {
+        skip_assert_initialized!();
+
+        unsafe {
+            let mut frame = mem::zeroed();
+            let res: bool = from_glib(ffi::gst_video_frame_map(
+                &mut frame,
+                info.to_glib_none().0 as *mut _,
+                buffer.as_mut_ptr(),
+                mem::transmute(
+                    ffi::GST_VIDEO_FRAME_MAP_FLAG_NO_REF.bits() | gst_ffi::GST_MAP_READ.bits()
+                        | gst_ffi::GST_MAP_WRITE.bits(),
+                ),
+            ));
+
+            if !res {
+                None
+            } else {
+                let info = ::VideoInfo(ptr::read(&frame.info));
+                Some(VideoFrameRef(frame, Some(buffer), info, false))
+            }
+        }
+    }
+
+    pub fn from_buffer_ref_id_writable<'b>(
+        buffer: &'a mut gst::BufferRef,
+        id: i32,
+        info: &'b ::VideoInfo,
+    ) -> Option<VideoFrameRef<&'a mut gst::BufferRef>> {
+        skip_assert_initialized!();
+
+        unsafe {
+            let mut frame = mem::zeroed();
+            let res: bool = from_glib(ffi::gst_video_frame_map_id(
+                &mut frame,
+                info.to_glib_none().0 as *mut _,
+                buffer.as_mut_ptr(),
+                id,
+                mem::transmute(
+                    ffi::GST_VIDEO_FRAME_MAP_FLAG_NO_REF.bits() | gst_ffi::GST_MAP_READ.bits()
+                        | gst_ffi::GST_MAP_WRITE.bits(),
+                ),
+            ));
+
+            if !res {
+                None
+            } else {
+                let info = ::VideoInfo(ptr::read(&frame.info));
+                Some(VideoFrameRef(frame, Some(buffer), info, false))
+            }
+        }
+    }
+
+    pub fn buffer_mut(&mut self) -> &mut gst::BufferRef {
+        self.1.as_mut().unwrap()
+    }
+
+    pub fn plane_data_mut(&mut self, plane: u32) -> Option<&mut [u8]> {
+        if plane >= self.n_planes() {
+            return None;
+        }
+
+        let format_info = self.format_info();
+
+        // Just get the palette
+        if format_info.has_palette() && plane == 1 {
+            unsafe {
+                return Some(slice::from_raw_parts_mut(
+                    self.0.data[1] as *mut u8,
+                    256 * 4,
+                ));
+            }
+        }
+
+        let w = self.plane_stride()[plane as usize] as u32;
+        // FIXME: This assumes that the horizontal subsampling of all
+        // components in the plane is the same, which is probably safe
+        let h = format_info.scale_height(plane as u8, self.height());
+
+        unsafe {
+            Some(slice::from_raw_parts_mut(
+                self.0.data[plane as usize] as *mut u8,
+                (w * h) as usize,
+            ))
+        }
+    }
+}
+
+impl<'a> ops::Deref for VideoFrameRef<&'a mut gst::BufferRef> {
+    type Target = VideoFrameRef<&'a gst::BufferRef>;
+
+    fn deref(&self) -> &Self::Target {
+        use std::mem;
+        unsafe { mem::transmute(self) }
+    }
+}
+
+impl<T> Drop for VideoFrameRef<T> {
+    fn drop(&mut self) {
+        if !self.3 {
+            unsafe {
+                ffi::gst_video_frame_unmap(&mut self.0);
+            }
+        }
+    }
 }
 
 #[cfg(test)]