Add shortcuts to tracks (audio_tracks, video_tracks…), fixes #95

Also add the following to improve tests:
* Chapters to sample.mkv.
* An image test file.
* A MediaInfo XML output for a file containing tracks of type "Other".

docs/index.rst

@@ -40,15 +40,20 @@ Getting information from an image
   from pymediainfo import MediaInfo
 
   media_info = MediaInfo.parse("/home/user/image.jpg")
-  for track in media_info.tracks:
-      if track.track_type == "Image":
-          print(f"{track.format} of {track.width}×{track.height} pixels.")
+  # Tracks can be accessed via the 'tracks' attribute or through shortcuts
+  # such as 'image_tracks', 'audio_tracks', 'video_tracks', etc.
+  general_track = media_info.general_tracks[0]
+  image_track = media_info.image_tracks[0]
+  print(
+      f"{image_track.format} of {image_track.width}×{image_track.height} pixels"
+      f" and {general_track.file_size} bytes."
+  )
 
 Will return something like:
 
 .. code-block:: none
 
-  JPEG of 828×828 pixels.
+  JPEG of 828×828 pixels and 19098 bytes.
 
 Getting information from a video
 --------------------------------

pymediainfo/__init__.py

@@ -10,7 +10,7 @@
 import sys
 import warnings
 import xml.etree.ElementTree as ET
-from typing import Any, Dict, Optional, Tuple, Union
+from typing import Any, Dict, List, Optional, Tuple, Union
 
 from pkg_resources import DistributionNotFound, get_distribution
 
@@ -25,7 +25,7 @@ class Track:
     An object associated with a media file track.
 
     Each :class:`Track` attribute corresponds to attributes parsed from MediaInfo's output.
-    All attributes are lower case. Attributes that are present several times such as Duration
+    All attributes are lower case. Attributes that are present several times such as `Duration`
     yield a second attribute starting with `other_` which is a list of all alternative
     attribute values.
 
@@ -38,7 +38,7 @@ class Track:
     <Track track_id='None', track_type='General'>
     >>> t.duration
     3000
-    >>> t.to_data()["other_duration"]
+    >>> t.other_duration
     ['3 s 0 ms', '3 s 0 ms', '3 s 0 ms',
         '00:00:03.000', '00:00:03.000']
     >>> type(t.non_existing)
@@ -166,6 +166,65 @@ def __init__(self, xml: str, encoding_errors: str = "strict"):
         for xml_track in xml_dom.iterfind(xpath):
             self.tracks.append(Track(xml_track))
 
+    def _tracks(self, track_type: str) -> List[Track]:
+        return [track for track in self.tracks if track.track_type == track_type]
+
+    @property
+    def general_tracks(self) -> List[Track]:
+        """
+        :return: All :class:`Track`\\s of type ``General``.
+        :rtype: list of :class:`Track`\\s
+        """
+        return self._tracks("General")
+
+    @property
+    def video_tracks(self) -> List[Track]:
+        """
+        :return: All :class:`Track`\\s of type ``Video``.
+        :rtype: list of :class:`Track`\\s
+        """
+        return self._tracks("Video")
+
+    @property
+    def audio_tracks(self) -> List[Track]:
+        """
+        :return: All :class:`Track`\\s of type ``Audio``.
+        :rtype: list of :class:`Track`\\s
+        """
+        return self._tracks("Audio")
+
+    @property
+    def text_tracks(self) -> List[Track]:
+        """
+        :return: All :class:`Track`\\s of type ``Text``.
+        :rtype: list of :class:`Track`\\s
+        """
+        return self._tracks("Text")
+
+    @property
+    def other_tracks(self) -> List[Track]:
+        """
+        :return: All :class:`Track`\\s of type ``Other``.
+        :rtype: list of :class:`Track`\\s
+        """
+        return self._tracks("Other")
+
+    @property
+    def image_tracks(self) -> List[Track]:
+        """
+        :return: All :class:`Track`\\s of type ``Image``.
+        :rtype: list of :class:`Track`\\s
+        """
+        return self._tracks("Image")
+
+    @property
+    def menu_tracks(self) -> List[Track]:
+        """
+        :return: All :class:`Track`\\s of type ``Menu``.
+        :rtype: list of :class:`Track`\\s
+        """
+        return self._tracks("Menu")
+
     @staticmethod
     def _normalize_filename(filename: Any) -> Any:
         # TODO: wait for https://github.com/python/typeshed/pull/4582 pylint: disable=fixme
@@ -264,6 +323,8 @@ def can_parse(cls, library_file: Optional[str] = None) -> bool:
         """
         Checks whether media files can be analyzed using libmediainfo.
 
+        :param str library_file: path to the libmediainfo library, this should only be used if
+            the library cannot be auto-detected.
         :rtype: bool
         """
         try:

tests/data/other_track.xml

@@ -0,0 +1,35 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Mediainfo version="20.09">
+  <File>
+    <track type="General">
+      <Complete_name>test.mxf</Complete_name>
+    </track>
+    <track type="Video">
+      <ID>2</ID>
+      <Format>MPEG Video</Format>
+      <Format_version>Version 2</Format_version>
+    </track>
+    <track type="Audio">
+      <ID>3</ID>
+      <Format>PCM</Format>
+    </track>
+    <track type="Other" typeorder="1">
+      <ID>1-Material</ID>
+      <Type>Time code</Type>
+      <Format>MXF TC</Format>
+      <Frame_rate>25.000 FPS</Frame_rate>
+      <Time_code_of_first_frame>00:00:00:00</Time_code_of_first_frame>
+      <Time_code_settings>Material Package</Time_code_settings>
+      <Time_code__striped>Yes</Time_code__striped>
+    </track>
+    <track type="Other" typeorder="2">
+      <ID>1-Source</ID>
+      <Type>Time code</Type>
+      <Format>MXF TC</Format>
+      <Frame_rate>25.000 FPS</Frame_rate>
+      <Time_code_of_first_frame>00:00:00:00</Time_code_of_first_frame>
+      <Time_code_settings>Source Package</Time_code_settings>
+      <Time_code__striped>Yes</Time_code__striped>
+    </track>
+  </File>
+</Mediainfo>

tests/test_pymediainfo.py

@@ -368,3 +368,43 @@ def test_parameter_output(self):
             os.path.join(data_dir, "sample.mp4"), output="General;%FileSize%"
         )
         self.assertEqual(media_info, "404567")
+
+
+class MediaInfoTrackShortcutsTests(unittest.TestCase):
+    def setUp(self):
+        self.mi_audio = MediaInfo.parse(os.path.join(data_dir, "sample.mp4"))
+        self.mi_text = MediaInfo.parse(os.path.join(data_dir, "sample.mkv"))
+        self.mi_image = MediaInfo.parse(os.path.join(data_dir, "empty.gif"))
+        with open(os.path.join(data_dir, "other_track.xml")) as f:
+            self.mi_other = MediaInfo(f.read())
+
+    def test_empty_list(self):
+        self.assertEqual(self.mi_audio.text_tracks, [])
+
+    def test_general_tracks(self):
+        self.assertEqual(len(self.mi_audio.general_tracks), 1)
+        self.assertIsNotNone(self.mi_audio.general_tracks[0].file_name)
+
+    def test_video_tracks(self):
+        self.assertEqual(len(self.mi_audio.video_tracks), 1)
+        self.assertIsNotNone(self.mi_audio.video_tracks[0].display_aspect_ratio)
+
+    def test_audio_tracks(self):
+        self.assertEqual(len(self.mi_audio.audio_tracks), 1)
+        self.assertIsNotNone(self.mi_audio.audio_tracks[0].sampling_rate)
+
+    def test_text_tracks(self):
+        self.assertEqual(len(self.mi_text.text_tracks), 1)
+        self.assertEqual(self.mi_text.text_tracks[0].kind_of_stream, "Text")
+
+    def test_other_tracks(self):
+        self.assertEqual(len(self.mi_other.other_tracks), 2)
+        self.assertEqual(self.mi_other.other_tracks[0].type, "Time code")
+
+    def test_image_tracks(self):
+        self.assertEqual(len(self.mi_image.image_tracks), 1)
+        self.assertEqual(self.mi_image.image_tracks[0].width, 1)
+
+    def test_menu_tracks(self):
+        self.assertEqual(len(self.mi_text.menu_tracks), 1)
+        self.assertEqual(self.mi_text.menu_tracks[0].kind_of_stream, "Menu")