diff --git a/downloader/downloader/hls_playlist.py b/downloader/downloader/hls_playlist.py
index b05f9f8..96163f1 100644
--- a/downloader/downloader/hls_playlist.py
+++ b/downloader/downloader/hls_playlist.py
@@ -253,7 +253,7 @@ class M3U8Parser(object):
         elif line.startswith("#EXT-X-MAP"):
             attr = self.parse_tag(line, self.parse_attributes)
             byterange = self.parse_byterange(attr.get("BYTERANGE", ""))
-            self.state["map"] = Map(attr.get("URI"), byterange)
+            self.state["map"] = Map(self.uri(attr.get("URI")), byterange)
         elif line.startswith("#EXT-X-I-FRAME-STREAM-INF"):
             attr = self.parse_tag(line, self.parse_attributes)
             streaminf = self.state.pop("streaminf", attr)
diff --git a/downloader/downloader/main.py b/downloader/downloader/main.py
index d7ea2a8..d434836 100644
--- a/downloader/downloader/main.py
+++ b/downloader/downloader/main.py
@@ -305,6 +305,11 @@ class StreamWorker(object):
 		# This worker's SegmentGetters will use its session by default for performance,
 		# but will fall back to a new one if something goes wrong.
 		self.session = common.requests.InstrumentedSession()
+		# Map cache is a simple cache to avoid re-downloading the same map URI for every segment,
+		# since it's generally the same but may occasionally change.
+		# We expect the map data to be very small so there is no eviction here.
+		# {uri: data}
+		self.map_cache = {}
 
 	def __repr__(self):
 		return "<{} at 0x{:x} for stream {!r}>".format(type(self).__name__, id(self), self.quality)
@@ -387,6 +392,7 @@ class StreamWorker(object):
 						self.quality,
 						segment,
 						date,
+						self.map_cache,
 					)
 					gevent.spawn(self.getters[segment.uri].run)
 				if date is not None:
@@ -442,13 +448,14 @@ class SegmentGetter(object):
 	# or so, to be paranoid we set it to considerably longer than that.
 	GIVE_UP_TIMEOUT = 20 * 60
 
-	def __init__(self, parent_logger, session, base_dir, channel, quality, segment, date):
+	def __init__(self, parent_logger, session, base_dir, channel, quality, segment, date, map_cache):
 		self.logger = parent_logger.getChild("SegmentGetter@{:x}".format(id(self)))
 		self.base_dir = base_dir
 		self.channel = channel
 		self.quality = quality
 		self.segment = segment
 		self.date = date
+		self.map_cache = map_cache
 		self.prefix = self.make_path_prefix()
 		self.retry = None # Event, set to begin retrying
 		self.done = gevent.event.Event() # set when file exists or we give up
@@ -554,6 +561,15 @@ class SegmentGetter(object):
 		try:
 			self.logger.debug("Downloading segment {} to {}".format(self.segment, temp_path))
 			start_time = monotonic()
+			map_data = None
+			if self.segment.map and self.segment.map.uri:
+				# Usage of map cache is racy here as multiple SegmentGetters can fill it at once, but we don't care.
+				if self.segment.map.uri not in self.map_cache:
+					with soft_hard_timeout(self.logger, "getting map data", self.FETCH_HEADERS_TIMEOUTS, retry.set):
+						resp = self.session.get(self.segment.map.uri, metric_name='get_map_data')
+						resp.raise_for_status()
+						self.map_cache[self.segment.map.uri] = resp.content
+				map_data = self.map_cache[self.segment.map.uri]
 			with soft_hard_timeout(self.logger, "getting and writing segment", self.FETCH_FULL_TIMEOUTS, retry.set):
 				with soft_hard_timeout(self.logger, "getting segment headers", self.FETCH_HEADERS_TIMEOUTS, retry.set):
 					resp = self.session.get(self.segment.uri, stream=True, metric_name='get_segment')
@@ -566,6 +582,8 @@ class SegmentGetter(object):
 				common.ensure_directory(temp_path)
 				with open(temp_path, 'wb') as f:
 					file_created = True
+					if map_data is not None:
+						common.writeall(f.write, map_data)
 					# We read chunk-wise in 8KiB chunks. Note that if the connection cuts halfway,
 					# we may lose part of the last chunk even though we did receive it.
 					# This is a small enough amount of data that we don't really care.