diff --git a/CHANGELOG.md b/CHANGELOG.md
index eed7d10..8565587 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@
 - Padding after data chunks in bw64 files was not written, and this error was silently ignored in the reader. This can be fixed with the new `ear-utils rewrite` command.
 - Mutable default parameters in ADMBuilder could cause unexpected extra blocks to be added when this was used from other programs.
 - ADM elements outside the `audioFormatExtended` were parsed, causing errors for some files containing non-standard ADM data.
+- Generated IDs for audioStreamFormat and audioTrackFormat included the format (i.e. always PCM, or 0001), but should include the type of the linked channel/pack format. See [#78].
 
 ### Changed
 - Added a warning for audioBlockFormats which have a duration but no rtime; previously these were fixed silently. See [#54].
@@ -163,6 +164,7 @@ Initial release.
 [#62]: https://github.com/ebu/ebu_adm_renderer/pull/62
 [#59]: https://github.com/ebu/ebu_adm_renderer/pull/59
 [#58]: https://github.com/ebu/ebu_adm_renderer/issues/58
+[#78]: https://github.com/ebu/ebu_adm_renderer/pull/78
 [34b738a]: https://github.com/ebu/ebu_adm_renderer/commit/34b738a
 [04533fc]: https://github.com/ebu/ebu_adm_renderer/commit/04533fc
 [222374a]: https://github.com/ebu/ebu_adm_renderer/commit/222374a
diff --git a/ear/fileio/adm/generate_ids.py b/ear/fileio/adm/generate_ids.py
index f1e7812..2cacf2d 100644
--- a/ear/fileio/adm/generate_ids.py
+++ b/ear/fileio/adm/generate_ids.py
@@ -10,6 +10,19 @@ def _stream_track_formats(adm, stream_format):
             yield track_format
 
 
+def _stream_type_definition(stream_format):
+    """get the TypeDefinition from the channel or pack format linked to a stream format"""
+    if stream_format.audioChannelFormat is not None:
+        return stream_format.audioChannelFormat.type
+    elif stream_format.audioPackFormat is not None:
+        return stream_format.audioPackFormat.type
+    else:
+        assert False, (
+            "can not generate IDs for an audioStreamFormat not linked"
+            "to an audioChannelFormat or an audioPackFormat; run validation first"
+        )
+
+
 def generate_ids(adm):
     """regenerate ids for all elements in adm
 
@@ -42,10 +55,14 @@ def generate_ids(adm):
             block.id = "AB_{type.value:04X}{id:04X}_{block_id:08X}".format(id=id, type=element.type, block_id=block_id)
 
     for id, element in enumerate(non_common(adm.audioStreamFormats), 0x1001):
-        element.id = "AS_{format.value:04X}{id:04X}".format(id=id, format=element.format)
+        type_id = _stream_type_definition(element).value
+
+        element.id = "AS_{type_id:04X}{id:04X}".format(id=id, type_id=type_id)
 
         for track_id, element in enumerate(_stream_track_formats(adm, element), 0x1):
-            element.id = "AT_{format.value:04X}{id:04X}_{track_id:02X}".format(id=id, format=element.format, track_id=track_id)
+            element.id = "AT_{type_id:04X}{id:04X}_{track_id:02X}".format(
+                id=id, type_id=type_id, track_id=track_id
+            )
 
     for id, element in enumerate(adm.audioTrackUIDs, 0x1):
         element.id = "ATU_{id:08X}".format(id=id)
diff --git a/ear/fileio/adm/test/test_adm_files/defaults_v1.xml b/ear/fileio/adm/test/test_adm_files/defaults_v1.xml
index 41d26c4..3ae038f 100644
--- a/ear/fileio/adm/test/test_adm_files/defaults_v1.xml
+++ b/ear/fileio/adm/test/test_adm_files/defaults_v1.xml
@@ -21,15 +21,15 @@
         <audioPackFormat audioPackFormatID="AP_00031001" audioPackFormatName="MyObject 1" typeLabel="0003" typeDefinition="Objects">
           <audioChannelFormatIDRef>AC_00031001</audioChannelFormatIDRef>
         </audioPackFormat>
-        <audioStreamFormat audioStreamFormatID="AS_00011001" audioStreamFormatName="MyObject 1" formatLabel="0001" formatDefinition="PCM">
-          <audioTrackFormatIDRef>AT_00011001_01</audioTrackFormatIDRef>
+        <audioStreamFormat audioStreamFormatID="AS_00031001" audioStreamFormatName="MyObject 1" formatLabel="0001" formatDefinition="PCM">
+          <audioTrackFormatIDRef>AT_00031001_01</audioTrackFormatIDRef>
           <audioChannelFormatIDRef>AC_00031001</audioChannelFormatIDRef>
         </audioStreamFormat>
-        <audioTrackFormat audioTrackFormatID="AT_00011001_01" audioTrackFormatName="MyObject 1" formatLabel="0001" formatDefinition="PCM">
-          <audioStreamFormatIDRef>AS_00011001</audioStreamFormatIDRef>
+        <audioTrackFormat audioTrackFormatID="AT_00031001_01" audioTrackFormatName="MyObject 1" formatLabel="0001" formatDefinition="PCM">
+          <audioStreamFormatIDRef>AS_00031001</audioStreamFormatIDRef>
         </audioTrackFormat>
         <audioTrackUID UID="ATU_00000001">
-          <audioTrackFormatIDRef>AT_00011001_01</audioTrackFormatIDRef>
+          <audioTrackFormatIDRef>AT_00031001_01</audioTrackFormatIDRef>
           <audioPackFormatIDRef>AP_00031001</audioPackFormatIDRef>
         </audioTrackUID>
       </audioFormatExtended>
diff --git a/ear/fileio/adm/test/test_generate_ids.py b/ear/fileio/adm/test/test_generate_ids.py
index 978b230..ffb0709 100644
--- a/ear/fileio/adm/test/test_generate_ids.py
+++ b/ear/fileio/adm/test/test_generate_ids.py
@@ -36,8 +36,8 @@ def test_generate_ids():
     assert acf.id == "AC_00031001"
     assert acf.audioBlockFormats[0].id == "AB_00031001_00000001"
 
-    assert builder.adm.audioStreamFormats[0].id == "AS_00011001"
+    assert builder.adm.audioStreamFormats[0].id == "AS_00031001"
 
-    assert builder.adm.audioTrackFormats[0].id == "AT_00011001_01"
+    assert builder.adm.audioTrackFormats[0].id == "AT_00031001_01"
 
     assert builder.adm.audioTrackUIDs[0].id == "ATU_00000001"
diff --git a/ear/test/data/test_bwf.wav b/ear/test/data/test_bwf.wav
index d601d0f..e67e02d 100644
Binary files a/ear/test/data/test_bwf.wav and b/ear/test/data/test_bwf.wav differ