* VRFS-2605 - compute offset and seek based on client info

ruby/lib/jam_ruby/app/mailers/admin_mailer.rb

@@ -1,6 +1,6 @@
 module JamRuby
   # sends out a boring ale
-  class AdminMailer < ActionMailer::Base
+  class   AdminMailer < ActionMailer::Base
     include SendGrid
 
 

ruby/lib/jam_ruby/models/mix.rb

@@ -137,15 +137,37 @@ module JamRuby
       one_day = 60 * 60 * 24
 
       jam_track_offset = 0
+      jam_track_seek = 0
 
       if recording.timeline
         recording_timeline_data = JSON.parse(recording.timeline)
 
+        # did the jam track play at all?
+        jam_track_isplaying = recording_timeline_data["jam_track_isplaying"]
         recording_start_time = recording_timeline_data["recording_start_time"]
         jam_track_play_start_time = recording_timeline_data["jam_track_play_start_time"]
         jam_track_recording_start_play_offset = recording_timeline_data["jam_track_recording_start_play_offset"]
 
-        jam_track_offset = -jam_track_recording_start_play_offset
+        # how long did the JamTrack play? not needed because we limit on the input tracks, which represents how long the recording is, too
+        jam_track_play_time = recording_timeline_data["jam_track_play_time"]
+
+        offset = jam_track_play_start_time - recording_start_time
+
+        if offset >= 0
+          # jamtrack started after recording, so buffer with silence as necessary
+          jam_track_offset = offset
+        else
+          # jamtrack started before recording, so we can seek into it to make up for the missing parts
+          jam_track_seek = -offset
+        end
+
+        if jam_track_recording_start_play_offset < 0
+          # we don't know how to handle this ! alert ops
+          AdminMailer.alerts({subject: "negative jam_track_recording_start_play_offset mix.id=#{self.id}"})
+          jam_track_recording_start_play_offset = 0
+        end
+
+        jam_track_seek = jam_track_seek + jam_track_recording_start_play_offset
       end
 
       manifest = { "files" => [], "timeline" => [] }
@@ -171,27 +193,29 @@ module JamRuby
         mix_params << { "level" => 1.0, "balance" => 0 }
       end
 
-      recording.recorded_jam_track_tracks.each do |recorded_jam_track_track|
-        manifest["files"] << { "filename" => recorded_jam_track_track.jam_track_track.sign_url(one_day), "codec" => "vorbis", "offset" => jam_track_offset }
-        # let's look for level info from the client
-        level = 1.0 # default value - means no effect
-        if recorded_jam_track_track.timeline
+      if recording.is_jamtrack_recording?
+        recording.recorded_jam_track_tracks.each do |recorded_jam_track_track|
+          manifest["files"] << { "filename" => recorded_jam_track_track.jam_track_track.sign_url(one_day), "codec" => "vorbis", "offset" => jam_track_offset, "seek" => jam_track_seek }
+          # let's look for level info from the client
+          level = 1.0 # default value - means no effect
+          if recorded_jam_track_track.timeline
 
-          timeline_data = JSON.parse(recorded_jam_track_track.timeline)
+            timeline_data = JSON.parse(recorded_jam_track_track.timeline)
 
-          # always take the 1st entry for now
-          first = timeline_data[0]
+            # always take the 1st entry for now
+            first = timeline_data[0]
 
-          if first["mute"]
-            # mute equates to no noise
-            level = 0.0
-          else
-            # otherwise grab the left channel...
-            level = first["vol_l"]
+            if first["mute"]
+              # mute equates to no noise
+              level = 0.0
+            else
+              # otherwise grab the left channel...
+              level = first["vol_l"]
+            end
           end
-        end
 
-        mix_params << { "level" => level, "balance" => 0 }
+          mix_params << { "level" => level, "balance" => 0 }
+        end
       end
 
       manifest["timeline"] << { "timestamp" => 0, "mix" => mix_params }

ruby/lib/jam_ruby/models/recording.rb

@@ -51,7 +51,11 @@ module JamRuby
     end
 
     def is_jamtrack_recording?
-      !jam_track_id.nil?
+      !jam_track_id.nil? && parsed_timeline['jam_track_isplaying']
+    end
+
+    def parsed_timeline
+      timeline ? JSON.parse(timeline) : {}
     end
 
     def high_quality_mix?