ADM support

wavinfo/wave_adm_reader.py

@@ -3,35 +3,19 @@ ADM Reader
 """
 
 from struct import unpack, unpack_from, calcsize
-from dataclasses import dataclass
 from io import BytesIO
+from collections import namedtuple
+from typing import Iterable, Tuple
 
 from lxml import etree as ET
 
-@dataclass
-class ChannelEntry:
-    """
-    A `chna` chunk table entry.
-    """
-
-    track_index: int
-    "Track index (indexed from 1)"
-
-    uid: str
-    "audioTrackUID"
-
-    track_ref: str
-    "audioTrackFormatID"
-
-    pack_ref: str
-    "audioPackFormatID"
-
-
 class WavADMReader:
     """
     Reads XML data from an EBU ADM (Audio Definiton Model) WAV File.
     """
 
+    ChannelEntry = namedtuple('ChannelEntry', "track_index uid track_ref pack_ref")
+
     def __init__(self, axml_data: bytes, chna_data: bytes):
         header_fmt = "<HH"
         uid_fmt = "<H12s14s11sx"
@@ -49,7 +33,54 @@ class WavADMReader:
 
             # these values are either ascii or all null
 
-            self.channel_uids.append(ChannelEntry(track_index,
+            self.channel_uids.append(WavADMReader.ChannelEntry(track_index,
                 uid.decode('ascii') , track_ref.decode('ascii'), pack_ref.decode('ascii')))
 
             offset += calcsize(uid_fmt)
+
+
+    def track_info(self, index):
+        """
+        Information about a track in the WAV file.
+
+        :param index: index of audio track (indexed from zero) 
+        :returns: a dictionary with content_name, object_name, pack_format_name, pack_type, 
+                  channel_format_name
+        """
+        channel_info = next((x for x in self.channel_uids if x.track_index == index + 1), None)
+        
+        if channel_info is None:
+            return None
+
+        ret_dict = {}
+
+        nsmap = self.axml.getroot().nsmap
+
+        trackformat_elem = self.axml.find(".//audioFormatExtended/audioTrackFormat[@audioTrackFormatID='%s']" % channel_info.track_ref, namespaces=nsmap)
+
+        stream_id = trackformat_elem[0].text
+
+        channelformatref_elem = self.axml.find(".//audioFormatExtended/audioStreamFormat[@audioStreamFormatID='%s']/audioChannelFormatIDRef" % stream_id, namespaces=nsmap)
+        channelformat_id = channelformatref_elem.text
+
+        packformatref_elem = self.axml.find(".//audioFormatExtended/audioStreamFormat[@audioStreamFormatID='%s']/audioPackFormatIDRef" % stream_id, namespaces=nsmap)
+        packformat_id = packformatref_elem.text
+
+        channelformat_elem = self.axml.find(".//audioFormatExtended/audioChannelFormat[@audioChannelFormatID='%s']" % channelformat_id, namespaces=nsmap)
+        ret_dict['channel_format_name'] = channelformat_elem.get("audioChannelFormatName")
+
+        packformat_elem = self.axml.find(".//audioFormatExtended/audioPackFormat[@audioPackFormatID='%s']" % packformat_id, namespaces=nsmap)
+        ret_dict['pack_type'] = packformat_elem.get("typeDefinition")
+        ret_dict['pack_format_name'] = packformat_elem.get("audioPackFormatName")
+
+        object_elem = self.axml.find(".//audioFormatExtended/audioObject[audioPackFormatIDRef = '%s']" % packformat_id, namespaces=nsmap)
+        ret_dict['audio_object_name'] = object_elem.get("audioObjectName")
+        object_id = object_elem.get("audioObjectID")
+
+        content_elem = self.axml.find(".//audioFormatExtended/audioContent/[audioObjectIDRef = '%s']" % object_id, namespaces=nsmap)
+        ret_dict['content_name'] = content_elem.get("audioContentName")
+
+        return ret_dict
+
+    def to_dict(self):
+        return dict(channel_entries=list(map(lambda z: z._asdict(), self.channel_uids)))