mediatype-audio-raw: document GstAudioMeta

diff --git a/markdown/design/mediatype-audio-raw.md b/markdown/design/mediatype-audio-raw.md
index 603ee91..dade166 100644 (file)
--- a/markdown/design/mediatype-audio-raw.md
+++ b/markdown/design/mediatype-audio-raw.md
@@ -21,6 +21,10 @@ Use `GstAudioInfo` and related helper API to create and parse raw audio caps.
 
 ## Metadata
 
+ - `GstAudioMeta`: Metadata that describes the layout of the data inside
+   the buffer. It is a requirement for buffers with non-interleaved layout
+   to have this metadata attached.
+
  - `GstAudioDownmixMeta`: A matrix for downmixing multichannel audio to a
    lower numer of channels.