diff --git a/src/decode/mod.rs b/src/decode/mod.rs
index 094ac03..72d9556 100644
--- a/src/decode/mod.rs
+++ b/src/decode/mod.rs
@@ -10,7 +10,7 @@ pub fn spawn(
         (
             mpsc::Receiver<util::RawMedia>,
             mpsc::Receiver<util::RawMedia>,
-            mpsc::Receiver<Box<dyn Error>>
+            mpsc::Receiver<Box<dyn Error + Send + Sync>>
         ),
         Box<dyn Error>
     > {
diff --git a/src/demux/flv.rs b/src/demux/flv.rs
index 97cb56e..15a2ce2 100644
--- a/src/demux/flv.rs
+++ b/src/demux/flv.rs
@@ -74,7 +74,7 @@ impl input::FileReader for FLVReader {
         self.skip_init_header()?;
         return self.read_metadata()
     }
-    fn read_nalu(&mut self, metadata: &util::Metadata) -> Result<util::NALUPacket, Box<dyn Error>> {
+    fn read_nalu(&mut self, metadata: &util::Metadata) -> Result<util::NALUPacket, Box<dyn Error + Send + Sync>> {
         todo!();
     }
 }
diff --git a/src/demux/input.rs b/src/demux/input.rs
index a4dece6..b5843d5 100644
--- a/src/demux/input.rs
+++ b/src/demux/input.rs
@@ -8,8 +8,8 @@ use crate::demux::flv;
 
 pub trait FileReader {
     fn init(&mut self) -> Result<util::Metadata, Box<dyn Error>>;
-    fn read_nalu(&mut self, metadata: &util::Metadata) -> Result<util::NALUPacket, Box<dyn Error>>;
-    fn data_loop(&mut self, v_in: mpsc::Sender<util::NALUPacket>, a_in: mpsc::Sender<util::NALUPacket>, metadata: &util::Metadata, err_in: mpsc::Sender<Box<dyn Error>>) {
+    fn read_nalu(&mut self, metadata: &util::Metadata) -> Result<util::NALUPacket, Box<dyn Error + Send + Sync>>;
+    fn data_loop(&mut self, v_in: mpsc::Sender<util::NALUPacket>, a_in: mpsc::Sender<util::NALUPacket>, metadata: &util::Metadata, err_in: mpsc::Sender<Box<dyn Error + Send + Sync>>) {
         loop {
             let nalu = match self.read_nalu(metadata) {
                 Ok(x) => x,
diff --git a/src/demux/mod.rs b/src/demux/mod.rs
index 7faa5cb..8985850 100644
--- a/src/demux/mod.rs
+++ b/src/demux/mod.rs
@@ -13,7 +13,7 @@ pub fn spawn() -> Result<
         mpsc::Receiver<util::NALUPacket>,
         mpsc::Receiver<util::NALUPacket>,
         util::Metadata,
-        mpsc::Receiver<Box<dyn Error>>
+        mpsc::Receiver<Box<dyn Error + Send + Sync>>
     ),
     Box<dyn Error>
     > {
diff --git a/src/encode/mod.rs b/src/encode/mod.rs
index 9572052..07fa3d6 100644
--- a/src/encode/mod.rs
+++ b/src/encode/mod.rs
@@ -11,7 +11,7 @@ pub fn spawn(
         (
             mpsc::Receiver<util::NALUPacket>,
             mpsc::Receiver<util::NALUPacket>,
-            mpsc::Receiver<Box<dyn Error>>
+            mpsc::Receiver<Box<dyn Error + Send + Sync>>
         ),
         Box<dyn Error>
     > {
diff --git a/src/main.rs b/src/main.rs
index e1e45c4..59f5411 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -7,7 +7,7 @@ mod muxer;
 use std::process::exit;
 use std::sync::mpsc;
 
-fn init() -> Result<[mpsc::Receiver<Box<dyn std::error::Error>>; 4], Box<dyn std::error::Error>>{
+fn init() -> Result<[mpsc::Receiver<Box<dyn std::error::Error + Send + Sync>>; 4], Box<dyn std::error::Error>>{
     let (v_out, a_out, metadata, demux_err_recv) = demux::spawn()?;
     let (raw_v_out, raw_a_out, decode_err_recv) = decode::spawn(v_out, a_out, &metadata)?;
     let (enc_v_out, enc_a_out, encode_err_recv) = encode::spawn(raw_v_out, raw_a_out, &metadata)?;
@@ -15,7 +15,7 @@ fn init() -> Result<[mpsc::Receiver<Box<dyn std::error::Error>>; 4], Box<dyn std
     return Ok([demux_err_recv, decode_err_recv, encode_err_recv, muxer_err_recv]);
 }
 
-fn process(error_handles: [mpsc::Receiver<Box<dyn std::error::Error>>; 4]) -> Result<(), Box<dyn std::error::Error>> {
+fn process(error_handles: [mpsc::Receiver<Box<dyn std::error::Error + Send + Sync>>; 4]) -> Result<(), Box<dyn std::error::Error>> {
     todo!();
 }
 
diff --git a/src/muxer/mod.rs b/src/muxer/mod.rs
index b5540f8..6a9e922 100644
--- a/src/muxer/mod.rs
+++ b/src/muxer/mod.rs
@@ -8,7 +8,7 @@ pub fn spawn(
         a: mpsc::Receiver<util::NALUPacket>,
         metadata: &util::Metadata
     ) -> Result< 
-        mpsc::Receiver<Box<dyn Error>>,
+        mpsc::Receiver<Box<dyn Error + Send + Sync>>,
         Box<dyn Error>
     > {
     todo!();
diff --git a/src/util/mod.rs b/src/util/mod.rs
index f6a3ce2..6f11f5e 100644
--- a/src/util/mod.rs
+++ b/src/util/mod.rs
@@ -113,7 +113,7 @@ impl fmt::Display for DemuxerError {
 
 // funcs
 
-pub fn thread_freeze(err_sender: mpsc::Sender<Box<dyn Error>>, err: Box<dyn Error>) {
+pub fn thread_freeze(err_sender: mpsc::Sender<Box<dyn Error + Send + Sync>>, err: Box<dyn Error + Send + Sync>) {
     err_sender.send(err).unwrap();
     thread::park();
 }