diff --git a/Cargo.lock b/Cargo.lock
index 95b1cb5dd..28a5b6b98 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2069,6 +2069,15 @@ dependencies = [
  "thiserror",
 ]
 
+[[package]]
+name = "h263-rs-deblock"
+version = "0.1.0"
+source = "git+https://github.com/ruffle-rs/h263-rs?rev=128cdbd85455d19783c88927bb535e8a26fe5220#128cdbd85455d19783c88927bb535e8a26fe5220"
+dependencies = [
+ "itertools",
+ "wide",
+]
+
 [[package]]
 name = "h263-rs-yuv"
 version = "0.1.0"
@@ -2363,6 +2372,15 @@ dependencies = [
  "waker-fn",
 ]
 
+[[package]]
+name = "itertools"
+version = "0.10.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b0fd2260e829bddf4cb6ea802289de2f86d6a7a690192fbe91b3f46e0f2c8473"
+dependencies = [
+ "either",
+]
+
 [[package]]
 name = "itoa"
 version = "1.0.8"
@@ -4030,6 +4048,7 @@ dependencies = [
  "flate2",
  "generational-arena",
  "h263-rs",
+ "h263-rs-deblock",
  "log",
  "nihav_codec_support",
  "nihav_core",
diff --git a/video/software/Cargo.toml b/video/software/Cargo.toml
index ecf948361..581808ac4 100644
--- a/video/software/Cargo.toml
+++ b/video/software/Cargo.toml
@@ -17,12 +17,13 @@ flate2 = "1.0.26"
 log = "0.4"
 
 h263-rs = { git = "https://github.com/ruffle-rs/h263-rs", rev = "128cdbd85455d19783c88927bb535e8a26fe5220", optional = true }
+h263-rs-deblock = { git = "https://github.com/ruffle-rs/h263-rs", rev = "128cdbd85455d19783c88927bb535e8a26fe5220", optional = true }
 nihav_core = { git = "https://github.com/ruffle-rs/nihav-vp6", rev = "9416fcc9fc8aab8f4681aa9093b42922214abbd3", optional = true }
 nihav_codec_support = { git = "https://github.com/ruffle-rs/nihav-vp6", rev = "9416fcc9fc8aab8f4681aa9093b42922214abbd3", optional = true }
 nihav_duck = { git = "https://github.com/ruffle-rs/nihav-vp6", rev = "9416fcc9fc8aab8f4681aa9093b42922214abbd3", optional = true }
 
 [features]
 default = ["h263", "vp6", "screenvideo"]
-h263 = ["h263-rs"]
+h263 = ["h263-rs", "h263-rs-deblock"]
 vp6 = ["nihav_core", "nihav_codec_support", "nihav_duck"]
 screenvideo = []
diff --git a/video/software/src/backend.rs b/video/software/src/backend.rs
index 4d4dc5629..3f59bcdf3 100644
--- a/video/software/src/backend.rs
+++ b/video/software/src/backend.rs
@@ -35,11 +35,11 @@ impl VideoBackend for SoftwareVideoBackend {
         _num_frames: u32,
         size: (u16, u16),
         codec: VideoCodec,
-        _filter: VideoDeblocking,
+        filter: VideoDeblocking,
     ) -> Result<VideoStreamHandle, Error> {
         let decoder: Box<dyn VideoDecoder> = match codec {
             #[cfg(feature = "h263")]
-            VideoCodec::H263 => Box::new(crate::decoder::h263::H263Decoder::new()),
+            VideoCodec::H263 => Box::new(crate::decoder::h263::H263Decoder::new(filter)),
             #[cfg(feature = "vp6")]
             VideoCodec::Vp6 => Box::new(crate::decoder::vp6::Vp6Decoder::new(false, size)),
             #[cfg(feature = "vp6")]
diff --git a/video/software/src/decoder/h263.rs b/video/software/src/decoder/h263.rs
index 2abd35027..eade4bce9 100644
--- a/video/software/src/decoder/h263.rs
+++ b/video/software/src/decoder/h263.rs
@@ -1,9 +1,11 @@
 use crate::decoder::VideoDecoder;
 use h263_rs::parser::H263Reader;
-use h263_rs::{DecoderOption, H263State, PictureTypeCode};
+use h263_rs::{DecoderOption, H263State, PictureOption, PictureTypeCode};
+use h263_rs_deblock::deblock::{deblock, QUANT_TO_STRENGTH};
 use ruffle_render::bitmap::BitmapFormat;
 use ruffle_video::error::Error;
 use ruffle_video::frame::{DecodedFrame, EncodedFrame, FrameDependency};
+use swf::VideoDeblocking;
 
 #[derive(thiserror::Error, Debug)]
 pub enum H263Error {
@@ -27,11 +29,14 @@ impl From<H263Error> for Error {
 }
 
 /// H263 video decoder.
-pub struct H263Decoder(H263State);
+pub struct H263Decoder(H263State, VideoDeblocking);
 
 impl H263Decoder {
-    pub fn new() -> Self {
-        Self(H263State::new(DecoderOption::SORENSON_SPARK_BITSTREAM))
+    pub fn new(deblock: VideoDeblocking) -> Self {
+        Self(
+            H263State::new(DecoderOption::SORENSON_SPARK_BITSTREAM),
+            deblock,
+        )
     }
 }
 
@@ -70,21 +75,49 @@ impl VideoDecoder for H263Decoder {
             .ok_or(H263Error::MissingWidthHeight)?;
         let (y, b, r) = picture.as_yuv();
 
-        let mut data = y.to_vec();
-        data.extend(b);
-        data.extend(r);
+        let hdr = picture.as_header();
 
-        Ok(DecodedFrame::new(
-            width as u32,
-            height as u32,
-            BitmapFormat::Yuv420p,
-            data,
-        ))
+        if self.1 == VideoDeblocking::Level1
+            || (self.1 == VideoDeblocking::UseVideoPacketValue
+                && hdr.options.contains(PictureOption::USE_DEBLOCKER))
+        {
+            let chroma_width = picture.chroma_samples_per_row();
+            let quantizer = hdr.quantizer as usize;
+            let strength = QUANT_TO_STRENGTH[quantizer];
+
+            let y = deblock(y, width as usize, strength);
+            let b = deblock(b, chroma_width, strength);
+            let r = deblock(r, chroma_width, strength);
+
+            let mut data = Vec::with_capacity(y.len() + b.len() + r.len());
+            data.extend_from_slice(&y);
+            data.extend_from_slice(&b);
+            data.extend_from_slice(&r);
+
+            Ok(DecodedFrame::new(
+                width as u32,
+                height as u32,
+                BitmapFormat::Yuv420p,
+                data,
+            ))
+        } else {
+            let mut data = Vec::with_capacity(y.len() + b.len() + r.len());
+            data.extend_from_slice(y);
+            data.extend_from_slice(b);
+            data.extend_from_slice(r);
+
+            Ok(DecodedFrame::new(
+                width as u32,
+                height as u32,
+                BitmapFormat::Yuv420p,
+                data,
+            ))
+        }
     }
 }
 
 impl Default for H263Decoder {
     fn default() -> Self {
-        Self::new()
+        Self::new(VideoDeblocking::UseVideoPacketValue)
     }
 }