diff --git a/docs/plugins/gst_plugins_cache.json b/docs/plugins/gst_plugins_cache.json
index 32e764750..c0880b619 100644
--- a/docs/plugins/gst_plugins_cache.json
+++ b/docs/plugins/gst_plugins_cache.json
@@ -2100,7 +2100,7 @@
                 "long-name": "CMAFMux",
                 "pad-templates": {
                     "sink": {
-                        "caps": "video/x-h264:\n  stream-format: { (string)avc, (string)avc3 }\n      alignment: au\n          width: [ 1, 65535 ]\n         height: [ 1, 65535 ]\nvideo/x-av1:\n  stream-format: obu-stream\n      alignment: tu\n        profile: { (string)main, (string)high, (string)professional }\n  chroma-format: { (string)4:0:0, (string)4:2:0, (string)4:2:2, (string)4:4:4 }\n bit-depth-luma: { (uint)8, (uint)10, (uint)12 }\nbit-depth-chroma: { (uint)8, (uint)10, (uint)12 }\n          width: [ 1, 65535 ]\n         height: [ 1, 65535 ]\nvideo/x-h265:\n  stream-format: { (string)hvc1, (string)hev1 }\n      alignment: au\n          width: [ 1, 65535 ]\n         height: [ 1, 65535 ]\naudio/mpeg:\n    mpegversion: 4\n  stream-format: raw\n       channels: [ 1, 65535 ]\n           rate: [ 1, 2147483647 ]\n",
+                        "caps": "video/x-h264:\n  stream-format: { (string)avc, (string)avc3 }\n      alignment: au\n          width: [ 1, 65535 ]\n         height: [ 1, 65535 ]\nvideo/x-av1:\n  stream-format: obu-stream\n      alignment: tu\n        profile: { (string)main, (string)high, (string)professional }\n  chroma-format: { (string)4:0:0, (string)4:2:0, (string)4:2:2, (string)4:4:4 }\n bit-depth-luma: { (uint)8, (uint)10, (uint)12 }\nbit-depth-chroma: { (uint)8, (uint)10, (uint)12 }\n          width: [ 1, 65535 ]\n         height: [ 1, 65535 ]\nvideo/x-h265:\n  stream-format: { (string)hvc1, (string)hev1 }\n      alignment: au\n          width: [ 1, 65535 ]\n         height: [ 1, 65535 ]\naudio/mpeg:\n    mpegversion: 4\n  stream-format: raw\n       channels: [ 1, 65535 ]\n           rate: [ 1, 2147483647 ]\naudio/x-opus:\nchannel-mapping-family: [ 0, 255 ]\n       channels: [ 1, 8 ]\n           rate: [ 1, 2147483647 ]\n",
                         "direction": "sink",
                         "presence": "always",
                         "type": "GstFMP4MuxPad"
diff --git a/mux/fmp4/src/fmp4mux/boxes.rs b/mux/fmp4/src/fmp4mux/boxes.rs
index fd6ed1893..88d1cd09b 100644
--- a/mux/fmp4/src/fmp4mux/boxes.rs
+++ b/mux/fmp4/src/fmp4mux/boxes.rs
@@ -161,6 +161,9 @@ fn cmaf_brands_from_caps(caps: &gst::CapsRef, compatible_brands: &mut Vec<&'stat
         "audio/mpeg" => {
             compatible_brands.push(b"caac");
         }
+        "audio/x-opus" => {
+            compatible_brands.push(b"opus");
+        }
         "video/x-av1" => {
             compatible_brands.push(b"av01");
             compatible_brands.push(b"cmf2");
diff --git a/mux/fmp4/src/fmp4mux/imp.rs b/mux/fmp4/src/fmp4mux/imp.rs
index e9fb8cfdd..7df90c95e 100644
--- a/mux/fmp4/src/fmp4mux/imp.rs
+++ b/mux/fmp4/src/fmp4mux/imp.rs
@@ -3707,6 +3707,11 @@ impl ElementImpl for CMAFMux {
                         .field("channels", gst::IntRange::new(1, u16::MAX as i32))
                         .field("rate", gst::IntRange::new(1, i32::MAX))
                         .build(),
+                    gst::Structure::builder("audio/x-opus")
+                        .field("channel-mapping-family", gst::IntRange::new(0i32, 255))
+                        .field("channels", gst::IntRange::new(1i32, 8))
+                        .field("rate", gst::IntRange::new(1, i32::MAX))
+                        .build(),
                 ]
                 .into_iter()
                 .collect::<gst::Caps>(),