diff --git a/gstreamer-audio/src/audio_ring_buffer_spec.rs b/gstreamer-audio/src/audio_ring_buffer_spec.rs
index ce55f59f7..47f7ebbbd 100644
--- a/gstreamer-audio/src/audio_ring_buffer_spec.rs
+++ b/gstreamer-audio/src/audio_ring_buffer_spec.rs
@@ -87,6 +87,9 @@ impl Drop for AudioRingBufferSpec {
     }
 }
 
+unsafe impl Send for AudioRingBufferSpec {}
+unsafe impl Sync for AudioRingBufferSpec {}
+
 impl fmt::Debug for AudioRingBufferSpec {
     fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
         f.debug_struct("AudioRingBufferSpec")
diff --git a/gstreamer-base/src/base_parse_frame.rs b/gstreamer-base/src/base_parse_frame.rs
index 49fd7781f..4154d981b 100644
--- a/gstreamer-base/src/base_parse_frame.rs
+++ b/gstreamer-base/src/base_parse_frame.rs
@@ -23,6 +23,9 @@ pub struct BaseParseFrame<'a>(
     PhantomData<&'a BaseParse>,
 );
 
+unsafe impl<'a> Send for BaseParseFrame<'a> {}
+unsafe impl<'a> Sync for BaseParseFrame<'a> {}
+
 #[derive(Debug)]
 pub enum Overhead {
     None,
diff --git a/gstreamer-check/src/harness.rs b/gstreamer-check/src/harness.rs
index 936326066..c082e7070 100644
--- a/gstreamer-check/src/harness.rs
+++ b/gstreamer-check/src/harness.rs
@@ -36,6 +36,7 @@ impl Drop for Harness {
 }
 
 unsafe impl Send for Harness {}
+unsafe impl Sync for Harness {}
 
 impl Harness {
     pub fn add_element_full<P: IsA<gst::Element>>(
@@ -792,7 +793,7 @@ impl Harness {
 }
 
 #[derive(Debug)]
-pub struct Ref<'a>(Option<Harness>, PhantomData<&'a gst_check_sys::GstHarness>);
+pub struct Ref<'a>(Option<Harness>, PhantomData<&'a Harness>);
 
 impl<'a> ops::Deref for Ref<'a> {
     type Target = Harness;
@@ -810,10 +811,7 @@ impl<'a> Drop for Ref<'a> {
 }
 
 #[derive(Debug)]
-pub struct RefMut<'a>(
-    Option<Harness>,
-    PhantomData<&'a mut gst_check_sys::GstHarness>,
-);
+pub struct RefMut<'a>(Option<Harness>, PhantomData<&'a mut Harness>);
 
 impl<'a> ops::Deref for RefMut<'a> {
     type Target = Harness;
diff --git a/gstreamer-gl/src/gl_sync_meta.rs b/gstreamer-gl/src/gl_sync_meta.rs
index fb48a4062..5f0fd95d3 100644
--- a/gstreamer-gl/src/gl_sync_meta.rs
+++ b/gstreamer-gl/src/gl_sync_meta.rs
@@ -11,6 +11,9 @@ use GLContext;
 #[repr(C)]
 pub struct GLSyncMeta(gst_gl_sys::GstGLSyncMeta);
 
+unsafe impl Send for GLSyncMeta {}
+unsafe impl Sync for GLSyncMeta {}
+
 impl GLSyncMeta {
     pub fn add<'a, C: IsA<GLContext>>(
         buffer: &'a mut gst::BufferRef,
diff --git a/gstreamer-net/src/net_address_meta.rs b/gstreamer-net/src/net_address_meta.rs
index 4e157742f..3e0c18dc6 100644
--- a/gstreamer-net/src/net_address_meta.rs
+++ b/gstreamer-net/src/net_address_meta.rs
@@ -10,6 +10,9 @@ use gst_net_sys;
 #[repr(C)]
 pub struct NetAddressMeta(gst_net_sys::GstNetAddressMeta);
 
+unsafe impl Send for NetAddressMeta {}
+unsafe impl Sync for NetAddressMeta {}
+
 impl NetAddressMeta {
     pub fn add<'a, A: IsA<gio::SocketAddress>>(
         buffer: &'a mut gst::BufferRef,
diff --git a/gstreamer-rtp/src/rtp_buffer.rs b/gstreamer-rtp/src/rtp_buffer.rs
index 0baa24375..9b0415e44 100644
--- a/gstreamer-rtp/src/rtp_buffer.rs
+++ b/gstreamer-rtp/src/rtp_buffer.rs
@@ -11,6 +11,9 @@ pub enum Writable {}
 #[repr(C)]
 pub struct RTPBuffer<'a, T>(gst_rtp_sys::GstRTPBuffer, &'a gst::Buffer, PhantomData<T>);
 
+unsafe impl<'a, T> Send for RTPBuffer<'a, T> {}
+unsafe impl<'a, T> Sync for RTPBuffer<'a, T> {}
+
 impl<'a> RTPBuffer<'a, Readable> {
     pub fn from_buffer_readable(
         buffer: &gst::Buffer,
diff --git a/gstreamer-sdp/src/sdp_attribute.rs b/gstreamer-sdp/src/sdp_attribute.rs
index 3d504280f..af78855cf 100644
--- a/gstreamer-sdp/src/sdp_attribute.rs
+++ b/gstreamer-sdp/src/sdp_attribute.rs
@@ -16,6 +16,9 @@ use gst_sdp_sys;
 #[repr(C)]
 pub struct SDPAttribute(pub(crate) gst_sdp_sys::GstSDPAttribute);
 
+unsafe impl Send for SDPAttribute {}
+unsafe impl Sync for SDPAttribute {}
+
 impl SDPAttribute {
     pub fn new(key: &str, value: Option<&str>) -> Self {
         assert_initialized_main_thread!();
diff --git a/gstreamer-sdp/src/sdp_bandwidth.rs b/gstreamer-sdp/src/sdp_bandwidth.rs
index 67149fd1e..f1e97c43d 100644
--- a/gstreamer-sdp/src/sdp_bandwidth.rs
+++ b/gstreamer-sdp/src/sdp_bandwidth.rs
@@ -16,6 +16,9 @@ use gst_sdp_sys;
 #[repr(C)]
 pub struct SDPBandwidth(pub(crate) gst_sdp_sys::GstSDPBandwidth);
 
+unsafe impl Send for SDPBandwidth {}
+unsafe impl Sync for SDPBandwidth {}
+
 impl SDPBandwidth {
     pub fn new(bwtype: &str, bandwidth: u32) -> Self {
         assert_initialized_main_thread!();
diff --git a/gstreamer-sdp/src/sdp_connection.rs b/gstreamer-sdp/src/sdp_connection.rs
index 45f2385d1..55eacae42 100644
--- a/gstreamer-sdp/src/sdp_connection.rs
+++ b/gstreamer-sdp/src/sdp_connection.rs
@@ -16,6 +16,9 @@ use gst_sdp_sys;
 #[repr(C)]
 pub struct SDPConnection(pub(crate) gst_sdp_sys::GstSDPConnection);
 
+unsafe impl Send for SDPConnection {}
+unsafe impl Sync for SDPConnection {}
+
 impl SDPConnection {
     pub fn new(nettype: &str, addrtype: &str, address: &str, ttl: u32, addr_number: u32) -> Self {
         assert_initialized_main_thread!();
diff --git a/gstreamer-sdp/src/sdp_key.rs b/gstreamer-sdp/src/sdp_key.rs
index f7c9867e9..737120fe6 100644
--- a/gstreamer-sdp/src/sdp_key.rs
+++ b/gstreamer-sdp/src/sdp_key.rs
@@ -14,6 +14,9 @@ use gst_sdp_sys;
 #[repr(C)]
 pub struct SDPKey(gst_sdp_sys::GstSDPKey);
 
+unsafe impl Send for SDPKey {}
+unsafe impl Sync for SDPKey {}
+
 impl SDPKey {
     pub fn type_(&self) -> Option<&str> {
         unsafe {
diff --git a/gstreamer-sdp/src/sdp_origin.rs b/gstreamer-sdp/src/sdp_origin.rs
index beb5a8973..d016eb525 100644
--- a/gstreamer-sdp/src/sdp_origin.rs
+++ b/gstreamer-sdp/src/sdp_origin.rs
@@ -14,6 +14,9 @@ use gst_sdp_sys;
 #[repr(C)]
 pub struct SDPOrigin(pub(crate) gst_sdp_sys::GstSDPOrigin);
 
+unsafe impl Send for SDPOrigin {}
+unsafe impl Sync for SDPOrigin {}
+
 impl SDPOrigin {
     pub fn username(&self) -> Option<&str> {
         unsafe {
diff --git a/gstreamer-sdp/src/sdp_time.rs b/gstreamer-sdp/src/sdp_time.rs
index f638064c2..5fc5d436f 100644
--- a/gstreamer-sdp/src/sdp_time.rs
+++ b/gstreamer-sdp/src/sdp_time.rs
@@ -18,6 +18,9 @@ use gst_sdp_sys;
 #[repr(C)]
 pub struct SDPTime(pub(crate) gst_sdp_sys::GstSDPTime);
 
+unsafe impl Send for SDPTime {}
+unsafe impl Sync for SDPTime {}
+
 impl SDPTime {
     pub fn new(start: &str, stop: &str, repeat: &[&str]) -> Self {
         assert_initialized_main_thread!();
diff --git a/gstreamer-sdp/src/sdp_zone.rs b/gstreamer-sdp/src/sdp_zone.rs
index fc6a673d1..8868058df 100644
--- a/gstreamer-sdp/src/sdp_zone.rs
+++ b/gstreamer-sdp/src/sdp_zone.rs
@@ -16,6 +16,9 @@ use gst_sdp_sys;
 #[repr(C)]
 pub struct SDPZone(pub(crate) gst_sdp_sys::GstSDPZone);
 
+unsafe impl Send for SDPZone {}
+unsafe impl Sync for SDPZone {}
+
 impl SDPZone {
     pub fn new(time: &str, typed_time: &str) -> Self {
         assert_initialized_main_thread!();
diff --git a/gstreamer-video/src/video_frame.rs b/gstreamer-video/src/video_frame.rs
index 0d9e83b71..cd3fe5bdc 100644
--- a/gstreamer-video/src/video_frame.rs
+++ b/gstreamer-video/src/video_frame.rs
@@ -663,6 +663,9 @@ impl<'a> ops::Deref for VideoFrameRef<&'a mut gst::BufferRef> {
     }
 }
 
+unsafe impl<T> Send for VideoFrameRef<T> {}
+unsafe impl<T> Sync for VideoFrameRef<T> {}
+
 impl<T> Drop for VideoFrameRef<T> {
     fn drop(&mut self) {
         if !self.3 {
diff --git a/gstreamer-video/src/video_meta.rs b/gstreamer-video/src/video_meta.rs
index 35ee619d8..d7abd2403 100644
--- a/gstreamer-video/src/video_meta.rs
+++ b/gstreamer-video/src/video_meta.rs
@@ -18,6 +18,9 @@ use gst_video_sys;
 #[repr(C)]
 pub struct VideoMeta(gst_video_sys::GstVideoMeta);
 
+unsafe impl Send for VideoMeta {}
+unsafe impl Sync for VideoMeta {}
+
 impl VideoMeta {
     pub fn add(
         buffer: &mut gst::BufferRef,
@@ -134,6 +137,9 @@ impl fmt::Debug for VideoMeta {
 #[repr(C)]
 pub struct VideoOverlayCompositionMeta(gst_video_sys::GstVideoOverlayCompositionMeta);
 
+unsafe impl Send for VideoOverlayCompositionMeta {}
+unsafe impl Sync for VideoOverlayCompositionMeta {}
+
 impl VideoOverlayCompositionMeta {
     pub fn add<'a>(
         buffer: &'a mut gst::BufferRef,
@@ -186,6 +192,11 @@ impl fmt::Debug for VideoOverlayCompositionMeta {
 #[repr(C)]
 pub struct VideoCaptionMeta(gst_video_sys::GstVideoCaptionMeta);
 
+#[cfg(any(feature = "v1_16", feature = "dox"))]
+unsafe impl Send for VideoCaptionMeta {}
+#[cfg(any(feature = "v1_16", feature = "dox"))]
+unsafe impl Sync for VideoCaptionMeta {}
+
 #[cfg(any(feature = "v1_16", feature = "dox"))]
 impl VideoCaptionMeta {
     pub fn add<'a>(
diff --git a/gstreamer-video/src/video_time_code.rs b/gstreamer-video/src/video_time_code.rs
index 9ea10cf93..227402767 100644
--- a/gstreamer-video/src/video_time_code.rs
+++ b/gstreamer-video/src/video_time_code.rs
@@ -525,6 +525,9 @@ impl From<ValidVideoTimeCode> for VideoTimeCode {
 #[repr(C)]
 pub struct VideoTimeCodeMeta(gst_video_sys::GstVideoTimeCodeMeta);
 
+unsafe impl Send for VideoTimeCodeMeta {}
+unsafe impl Sync for VideoTimeCodeMeta {}
+
 impl VideoTimeCodeMeta {
     pub fn add<'a>(
         buffer: &'a mut gst::BufferRef,
diff --git a/gstreamer/src/allocation_params.rs b/gstreamer/src/allocation_params.rs
index e5c6e7f6b..7fe794d04 100644
--- a/gstreamer/src/allocation_params.rs
+++ b/gstreamer/src/allocation_params.rs
@@ -15,6 +15,9 @@ use MemoryFlags;
 #[derive(Debug, Clone)]
 pub struct AllocationParams(gst_sys::GstAllocationParams);
 
+unsafe impl Send for AllocationParams {}
+unsafe impl Sync for AllocationParams {}
+
 impl AllocationParams {
     pub fn get_flags(&self) -> MemoryFlags {
         from_glib(self.0.flags)
diff --git a/gstreamer/src/buffer.rs b/gstreamer/src/buffer.rs
index 325ce8949..b3c09a15e 100644
--- a/gstreamer/src/buffer.rs
+++ b/gstreamer/src/buffer.rs
@@ -604,6 +604,9 @@ macro_rules! define_iter(
         items: PhantomData<$mtyp>,
     }
 
+    unsafe impl<'a, T: MetaAPI> Send for $name<'a, T> { }
+    unsafe impl<'a, T: MetaAPI> Sync for $name<'a, T> { }
+
     impl<'a, T: MetaAPI> $name<'a, T> {
         fn new(buffer: $typ) -> $name<'a, T> {
             skip_assert_initialized!();
@@ -778,6 +781,9 @@ impl<'a, T> Drop for BufferMap<'a, T> {
     }
 }
 
+unsafe impl<'a, T> Send for BufferMap<'a, T> {}
+unsafe impl<'a, T> Sync for BufferMap<'a, T> {}
+
 impl<T> MappedBuffer<T> {
     pub fn as_slice(&self) -> &[u8] {
         unsafe { slice::from_raw_parts(self.map_info.data as *const u8, self.map_info.size) }
@@ -860,6 +866,7 @@ impl<T> PartialEq for MappedBuffer<T> {
 impl<T> Eq for MappedBuffer<T> {}
 
 unsafe impl<T> Send for MappedBuffer<T> {}
+unsafe impl<T> Sync for MappedBuffer<T> {}
 
 lazy_static! {
     pub static ref BUFFER_COPY_METADATA: ::BufferCopyFlags =
diff --git a/gstreamer/src/buffer_pool.rs b/gstreamer/src/buffer_pool.rs
index cf08b2e44..720e7995f 100644
--- a/gstreamer/src/buffer_pool.rs
+++ b/gstreamer/src/buffer_pool.rs
@@ -187,6 +187,9 @@ impl BufferPoolConfig {
 #[derive(Debug)]
 pub struct BufferPoolAcquireParams(gst_sys::GstBufferPoolAcquireParams);
 
+unsafe impl Send for BufferPoolAcquireParams {}
+unsafe impl Sync for BufferPoolAcquireParams {}
+
 impl BufferPoolAcquireParams {
     pub fn with_flags(flags: ::BufferPoolAcquireFlags) -> Self {
         BufferPoolAcquireParams(gst_sys::GstBufferPoolAcquireParams {
diff --git a/gstreamer/src/iterator.rs b/gstreamer/src/iterator.rs
index 2e8d4dd16..a4bbad28d 100644
--- a/gstreamer/src/iterator.rs
+++ b/gstreamer/src/iterator.rs
@@ -326,6 +326,7 @@ where
 }
 
 unsafe impl<T> Send for Iterator<T> {}
+unsafe impl<T> Sync for Iterator<T> {}
 
 unsafe extern "C" fn filter_trampoline<T>(value: gconstpointer, func: gconstpointer) -> i32
 where
diff --git a/gstreamer/src/memory.rs b/gstreamer/src/memory.rs
index 64b682511..1f6809d5d 100644
--- a/gstreamer/src/memory.rs
+++ b/gstreamer/src/memory.rs
@@ -380,6 +380,9 @@ impl<'a, T> Drop for MemoryMap<'a, T> {
     }
 }
 
+unsafe impl<'a, T> Send for MemoryMap<'a, T> {}
+unsafe impl<'a, T> Sync for MemoryMap<'a, T> {}
+
 impl<T> MappedMemory<T> {
     pub fn as_slice(&self) -> &[u8] {
         unsafe { slice::from_raw_parts(self.map_info.data as *const u8, self.map_info.size) }
@@ -462,3 +465,4 @@ impl<T> PartialEq for MappedMemory<T> {
 impl<T> Eq for MappedMemory<T> {}
 
 unsafe impl<T> Send for MappedMemory<T> {}
+unsafe impl<T> Sync for MappedMemory<T> {}
diff --git a/gstreamer/src/meta.rs b/gstreamer/src/meta.rs
index cea0f18cf..1cebfee29 100644
--- a/gstreamer/src/meta.rs
+++ b/gstreamer/src/meta.rs
@@ -27,7 +27,7 @@ use glib::translate::{from_glib, from_glib_none, FromGlib, ToGlibPtr};
 use glib_sys;
 use gst_sys;
 
-pub unsafe trait MetaAPI: Sized {
+pub unsafe trait MetaAPI: Sync + Send + Sized {
     type GstType;
 
     fn get_meta_api() -> glib::Type;
@@ -210,6 +210,9 @@ impl<'a, U> MetaRefMut<'a, Meta, U> {
 #[repr(C)]
 pub struct Meta(gst_sys::GstMeta);
 
+unsafe impl Send for Meta {}
+unsafe impl Sync for Meta {}
+
 impl Meta {
     fn get_api(&self) -> glib::Type {
         unsafe { glib::Type::from_glib((*self.0.info).api) }
@@ -235,6 +238,9 @@ impl fmt::Debug for Meta {
 #[repr(C)]
 pub struct ParentBufferMeta(gst_sys::GstParentBufferMeta);
 
+unsafe impl Send for ParentBufferMeta {}
+unsafe impl Sync for ParentBufferMeta {}
+
 impl ParentBufferMeta {
     pub fn add<'a>(buffer: &'a mut BufferRef, parent: &Buffer) -> MetaRefMut<'a, Self, Standalone> {
         unsafe {
@@ -276,6 +282,11 @@ impl fmt::Debug for ParentBufferMeta {
 #[repr(C)]
 pub struct ReferenceTimestampMeta(gst_sys::GstReferenceTimestampMeta);
 
+#[cfg(any(feature = "v1_14", feature = "dox"))]
+unsafe impl Send for ReferenceTimestampMeta {}
+#[cfg(any(feature = "v1_14", feature = "dox"))]
+unsafe impl Sync for ReferenceTimestampMeta {}
+
 #[cfg(any(feature = "v1_14", feature = "dox"))]
 impl ReferenceTimestampMeta {
     pub fn add<'a>(
diff --git a/gstreamer/src/pad.rs b/gstreamer/src/pad.rs
index 183947e0c..69da1d6ec 100644
--- a/gstreamer/src/pad.rs
+++ b/gstreamer/src/pad.rs
@@ -99,6 +99,9 @@ pub enum PadProbeData<'a> {
     __Unknown(*mut gst_sys::GstMiniObject),
 }
 
+unsafe impl<'a> Send for PadProbeData<'a> {}
+unsafe impl<'a> Sync for PadProbeData<'a> {}
+
 #[derive(Debug)]
 pub struct StreamLock(Pad);
 impl Drop for StreamLock {
diff --git a/gstreamer/src/parse_context.rs b/gstreamer/src/parse_context.rs
index 63d2183c4..0badea107 100644
--- a/gstreamer/src/parse_context.rs
+++ b/gstreamer/src/parse_context.rs
@@ -25,6 +25,9 @@ glib_wrapper! {
     }
 }
 
+unsafe impl Send for ParseContext {}
+unsafe impl Sync for ParseContext {}
+
 impl ParseContext {
     pub fn new() -> Self {
         unsafe { from_glib_full(gst_sys::gst_parse_context_new()) }
diff --git a/gstreamer/src/segment.rs b/gstreamer/src/segment.rs
index 6b880b16a..8e3482696 100644
--- a/gstreamer/src/segment.rs
+++ b/gstreamer/src/segment.rs
@@ -508,6 +508,7 @@ impl<T: FormattedValue> PartialEq for FormattedSegment<T> {
 impl<T: FormattedValue> Eq for FormattedSegment<T> {}
 
 unsafe impl<T: FormattedValue> Send for FormattedSegment<T> {}
+unsafe impl<T: FormattedValue> Sync for FormattedSegment<T> {}
 
 impl<T: FormattedValue> Clone for FormattedSegment<T> {
     fn clone(&self) -> Self {
diff --git a/gstreamer/src/subclass/plugin_1_12.rs b/gstreamer/src/subclass/plugin_1_12.rs
index 924604433..de804a9ff 100644
--- a/gstreamer/src/subclass/plugin_1_12.rs
+++ b/gstreamer/src/subclass/plugin_1_12.rs
@@ -25,6 +25,7 @@ macro_rules! gst_plugin_define(
 
             #[repr(C)]
             pub struct GstPluginDesc($crate::gst_sys::GstPluginDesc);
+            unsafe impl Send for GstPluginDesc {}
             unsafe impl Sync for GstPluginDesc {}
 
             #[no_mangle]
diff --git a/gstreamer/src/subclass/plugin_1_14.rs b/gstreamer/src/subclass/plugin_1_14.rs
index db2aedf77..7bccedf36 100644
--- a/gstreamer/src/subclass/plugin_1_14.rs
+++ b/gstreamer/src/subclass/plugin_1_14.rs
@@ -23,6 +23,7 @@ macro_rules! gst_plugin_define(
 
             #[repr(C)]
             pub struct GstPluginDesc($crate::gst_sys::GstPluginDesc);
+            unsafe impl Send for GstPluginDesc {}
             unsafe impl Sync for GstPluginDesc {}
 
             static GST_PLUGIN_DESC: GstPluginDesc = GstPluginDesc($crate::gst_sys::GstPluginDesc {
diff --git a/gstreamer/src/typefind.rs b/gstreamer/src/typefind.rs
index 7f2d168b3..a062fdec2 100644
--- a/gstreamer/src/typefind.rs
+++ b/gstreamer/src/typefind.rs
@@ -96,8 +96,6 @@ impl<'a> TypeFind<'a> {
     }
 }
 
-unsafe impl<'a> Send for TypeFind<'a> {}
-
 impl TypeFindFactory {
     pub fn call_function(&self, find: &mut dyn TypeFindImpl) {
         unsafe {