Remove empty representations from dash manifests

src/invidious.cr

@@ -4401,8 +4401,13 @@ get "/api/manifest/dash/id/:id" do |env|
         i = 0
 
         {"audio/mp4", "audio/webm"}.each do |mime_type|
+          mime_streams = audio_streams.select { |stream| stream["type"].starts_with? mime_type }
+          if mime_streams.empty?
+            next
+          end
+
           xml.element("AdaptationSet", id: i, mimeType: mime_type, startWithSAP: 1, subsegmentAlignment: true) do
-            audio_streams.select { |stream| stream["type"].starts_with? mime_type }.each do |fmt|
+            mime_streams.each do |fmt|
               codecs = fmt["type"].split("codecs=")[1].strip('"')
               bandwidth = fmt["bitrate"].to_i * 1000
               itag = fmt["itag"]
@@ -4423,9 +4428,14 @@ get "/api/manifest/dash/id/:id" do |env|
         end
 
         {"video/mp4", "video/webm"}.each do |mime_type|
+          mime_streams = video_streams.select { |stream| stream["type"].starts_with? mime_type }
+          if mime_streams.empty?
+            next
+          end
+
           heights = [] of Int32
           xml.element("AdaptationSet", id: i, mimeType: mime_type, startWithSAP: 1, subsegmentAlignment: true, scanType: "progressive") do
-            video_streams.select { |stream| stream["type"].starts_with? mime_type }.each do |fmt|
+            mime_streams.each do |fmt|
               codecs = fmt["type"].split("codecs=")[1].strip('"')
               bandwidth = fmt["bitrate"]
               itag = fmt["itag"]