[PATCH] splitfx: add "offset" option for all track times

[PATCH] splitfx: add "offset" option for all track times

[Eric Wong]

This option is intended to make it easy to reuse track splits
from one audio recording of a given source (e.g. a live
performance or vinyl rip) for another audio recording of
the same source.
---
 Documentation/dtas-splitfx.pod |  5 +++++
 lib/dtas/splitfx.rb            | 13 ++++++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/Documentation/dtas-splitfx.pod b/Documentation/dtas-splitfx.pod
index b5dadfd..ff3d8cb 100644
--- a/Documentation/dtas-splitfx.pod
+++ b/Documentation/dtas-splitfx.pod
@@ -117,6 +117,11 @@ highest-numbered track.  Default: true
 
 =item command - used only by L<dtas-player(1)>
 
+=item offset - time offset to apply to each track
+
+This is useful for reusing track offsets between different recordings
+of the same source or live performance.  May be a negative value.
+
 =back
 
 =head1 TRACKS
diff --git a/lib/dtas/splitfx.rb b/lib/dtas/splitfx.rb
index c0c7ac9..e310300 100644
--- a/lib/dtas/splitfx.rb
+++ b/lib/dtas/splitfx.rb
@@ -92,6 +92,7 @@ def initialize
     @infmt = nil # wait until input is assigned
     @cuebp = nil # for playback
     @command = nil # top-level, for playback
+    @offset = 0
   end
 
   def _bool(hash, key)
@@ -145,6 +146,16 @@ def import(hash, overrides = {})
       end
     end
 
+    if offset = hash["offset"]
+      offset = offset.dup
+      sign = 1
+      if offset.sub!(/\A-/, '')
+        sign = -1
+      else
+        offset.sub!(/\A\+/, '') # drop "+"
+      end
+      @offset = @t2s.call(offset) * sign
+    end
     load_input!(hash)
     load_tracks!(hash)
     @command = hash["command"] # nil by default
@@ -343,7 +354,7 @@ def t2s_cdda(time)
   end
 
   def t2s(time)
-    @infmt.hhmmss_to_samples(time)
+    @infmt.hhmmss_to_samples(time) + @offset
   end
 
   def run(target, opts = {})