Merge pull request #113 from blokfyuh/add-time-offset-support

Add time offset support

m3u8/model.py

@@ -8,6 +8,7 @@
 import errno
 import math
 
+from m3u8.protocol import ext_x_start
 from m3u8.parser import parse, format_date_time
 from m3u8.mixins import BasePathMixin, GroupedBasePathMixin
 
@@ -178,6 +179,9 @@ def _initialize_attributes(self):
                                         )
         self.segment_map = self.data.get('segment_map')
 
+        start = self.data.get('start', None)
+        self.start = start and Start(**start)
+
     def __unicode__(self):
         return self.dumps()
 
@@ -251,6 +255,8 @@ def dumps(self):
             output.append('#EXT-X-PROGRAM-DATE-TIME:' + format_date_time(self.program_date_time))
         if not (self.playlist_type is None or self.playlist_type == ''):
             output.append('#EXT-X-PLAYLIST-TYPE:%s' % str(self.playlist_type).upper())
+        if self.start:
+            output.append(str(self.start))
         if self.is_i_frames_only:
             output.append('#EXT-X-I-FRAMES-ONLY')
         if self.is_variant:
@@ -676,6 +682,22 @@ def __str__(self):
         return '\n'.join(output)
 
 
+class Start(object):
+
+    def __init__(self, time_offset, precise=None):
+        self.time_offset = float(time_offset)
+        self.precise = precise
+
+    def __str__(self):
+        output = [
+            'TIME-OFFSET=' + str(self.time_offset)
+        ]
+        if self.precise and self.precise in ['YES', 'NO']:
+            output.append('PRECISE=' + str(self.precise))
+
+        return ext_x_start + ':' + ','.join(output)
+
+
 def find_key(keydata, keylist):
     if not keydata:
         return None

m3u8/parser.py

@@ -51,7 +51,7 @@ def parse(content, strict=False):
         'segments': [],
         'iframe_playlists': [],
         'media': [],
-        'keys': [],
+        'keys': []
     }
 
     state = {
@@ -141,6 +141,13 @@ def parse(content, strict=False):
             segment_map_info = _parse_attribute_list(protocol.ext_x_map, line, quoted_parser)
             data['segment_map'] = segment_map_info
 
+        elif line.startswith(protocol.ext_x_start):
+            attribute_parser = {
+                "time_offset": lambda x: float(x)
+            }
+            start_info = _parse_attribute_list(protocol.ext_x_start, line, attribute_parser)
+            data['start'] = start_info
+
         # Comments and whitespace
         elif line.startswith('#'):
             # comment

m3u8/protocol.py

@@ -26,3 +26,4 @@
 ext_x_cue_end = '#EXT-X-CUE-IN'
 ext_x_cue_span = '#EXT-X-CUE-SPAN'
 ext_x_map = '#EXT-X-MAP'
+ext_x_start = '#EXT-X-START'

tests/playlists.py

@@ -15,6 +15,24 @@
 #EXT-X-ENDLIST
 '''
 
+SIMPLE_PLAYLIST_WITH_START_NEGATIVE_OFFSET = '''
+#EXTM3U
+#EXT-X-TARGETDURATION:5220
+#EXT-X-START:TIME-OFFSET=-2.0
+#EXTINF:5220,
+http://media.example.com/entire.ts
+#EXT-X-ENDLIST
+'''
+
+SIMPLE_PLAYLIST_WITH_START_PRECISE = '''
+#EXTM3U
+#EXT-X-TARGETDURATION:5220
+#EXT-X-START:TIME-OFFSET=10.5,PRECISE=YES
+#EXTINF:5220,
+http://media.example.com/entire.ts
+#EXT-X-ENDLIST
+'''
+
 SIMPLE_PLAYLIST_FILENAME = abspath(
     join(dirname(__file__), 'playlists/simple-playlist.m3u8'))
 

tests/test_model.py

@@ -8,6 +8,9 @@
 
 import arrow
 import datetime
+
+from m3u8.protocol import ext_x_start
+
 import m3u8
 import playlists
 from m3u8.model import Segment, Key, Media
@@ -712,6 +715,21 @@ def test_segment_map_uri_attribute_with_byterange():
     obj = m3u8.M3U8(playlists.MAP_URI_PLAYLIST_WITH_BYTERANGE)
     assert obj.segment_map['uri'] == "main.mp4"
 
+
+def test_start_with_negative_offset():
+    obj = m3u8.M3U8(playlists.SIMPLE_PLAYLIST_WITH_START_NEGATIVE_OFFSET)
+    assert obj.start.time_offset == -2.0
+    assert obj.start.precise is None
+    assert ext_x_start + ':TIME-OFFSET=-2.0\n' in obj.dumps()
+
+
+def test_start_with_precise():
+    obj = m3u8.M3U8(playlists.SIMPLE_PLAYLIST_WITH_START_PRECISE)
+    assert obj.start.time_offset == 10.5
+    assert obj.start.precise == 'YES'
+    assert ext_x_start + ':TIME-OFFSET=10.5,PRECISE=YES\n' in obj.dumps()
+
+
 # custom asserts
 
 

tests/test_parser.py

@@ -275,3 +275,15 @@ def test_should_parse_empty_uri_with_base_path():
     assert media.uri is None
     assert media.base_path is None
     assert 'base_uri/' == media.base_uri
+
+
+def test_should_parse_start_with_negative_time_offset():
+    data = m3u8.parse(playlists.SIMPLE_PLAYLIST_WITH_START_NEGATIVE_OFFSET)
+    assert data['start']['time_offset'] == -2.0
+    assert not hasattr(data['start'], 'precise')
+
+
+def test_should_parse_start_with_precise():
+    data = m3u8.parse(playlists.SIMPLE_PLAYLIST_WITH_START_PRECISE)
+    assert data['start']['time_offset'] == 10.5
+    assert data['start']['precise'] == 'YES'