[pitivi] factories/base.py: preserve any existing alpha channel

[Edward Hervey <edwardrv src gnome org>]

commit 2e25a4b18091cb57da677e2edd537df90e6a4f91
Author: Brandon Lewis <brandon_lewis alum berkeley edu>
Date:   Fri Jan 15 15:09:40 2010 -0800

    factories/base.py: preserve any existing alpha channel

 pitivi/factories/base.py |   19 ++++++++++++++++++-
 1 files changed, 18 insertions(+), 1 deletions(-)
---
diff --git a/pitivi/factories/base.py b/pitivi/factories/base.py
index e2c0328..0c59a81 100644
--- a/pitivi/factories/base.py
+++ b/pitivi/factories/base.py
@@ -374,8 +374,25 @@ class SourceFactory(ObjectFactory):
             b.queue.props.max_size_bytes = 0
             b.queue.props.max_size_time = 0
             b.queue.props.max_size_buffers = 3
-            b.csp = gst.element_factory_make("ffmpegcolorspace", "internal-colorspace")
+
+            # all video needs to be AYUV, but the colorspace conversion
+            # element depends on the input. if there is no alpha we need to
+            # add ffmpegcolorspace. if we have an argb or rgba stream, we need
+            # alphacolor to preserve the alpha channel (ffmpeg clobbers it).
+            # if we have an ayuv stream we don't want any colorspace
+            # converter.
+
+            if not output_stream.has_alpha(): 
+                b.csp = gst.element_factory_make("ffmpegcolorspace",
+                    "internal-colorspace") 
+            elif output_stream.videotype == 'video/x-raw-rgb': 
+                b.csp = gst.element_factory_make("alphacolor", 
+                    "internal-alphacolor")
+            else: 
+                b.csp = gst.element_factory_make("identity")
+
             b.alpha = gst.element_factory_make("alpha", "internal-alpha")
+
             b.add(b.queue, b.csp, b.alpha)
             gst.element_link_many(b.queue, b.csp)
             if child_bin: