Could you provide a sample file please?

Oh, nevermind, you are talking about the muxer.

Created attachment 205270 [details] [review]
basic adpcm support

I'm sure some bits are still missing however I can mux with:

gst-launch -e -v audiotestsrc ! adpcmenc ! matroskamux ! filesink location=/tmp/test.mkv

and playback with:

gst-launch -v filesrc location=/tmp/test.mkv ! matroskademux ! adpcmdec ! pulsesink

Steve Lhomme suggested to use A_MS/ACM for codec mapping,

Nicola

commit 4baf8080f2cbd2b6cebdefd4f6d723c762dc1ef9
Author: Sebastian Dröge <sebastian@centricular.com>
Date:   Mon Dec 23 15:46:48 2013 +0100

    matroskamux: Use correct codec id for ADPCM/DVI

commit 7cae8922cb1d622cd9fcf2563e165ec81465f8a8
Author: Sebastian Dröge <sebastian@centricular.com>
Date:   Mon Dec 23 15:44:30 2013 +0100

    matroskademux: Check for the correct size of codec_data in the ACM case

commit 00ea1cb00398ac79f14f771f00ba4cfbaeb1ca34
Author: Nicola Murino <nicola.murino@gmail.com>
Date:   Sat Jan 14 19:58:17 2012 +0100

    matroskamux: basic adpcm support
    
    https://bugzilla.gnome.org/show_bug.cgi?id=664339

Created attachment 264825 [details] [review]
correct max block align is 8192 not 8096

Comment on attachment 264825 [details] [review]
correct max block align is 8192 not 8096

commit 5b1108dd5f88bfa67655f90d7de9a8308a183f19
Author: Nicola Murino <nicola.murino@gmail.com>
Date:   Tue Dec 24 00:43:39 2013 +0100

    matroskamux: adpcm max block align is 8192