[gst-devel] Alpha plugin in GStreamer not working properly

[Miguel Escriva]

Hi!

I'm trying to compose two videos, and I'm using the alpha plug-in to make
the white color transparent.
To test the alpha plug-in I'm creating the pipeline with gst-launch.

The first test I done was:

gst-launch videotestsrc pattern=smpte75  \
    ! alpha method=custom target-r=255 target-g=255 target-b=255 angle=10 \
    ! videomixer name=mixer ! ffmpegcolorspace ! autovideosink  \
    videotestsrc pattern=snow ! mixer.

and it works great! Then I created two videos with those lines:

gst-launch videotestsrc pattern=snow ! ffmpegcolorspace ! theoraenc ! oggmux
! filesink location=snow.ogv
gst-launch videotestsrc pattern=smpte75 ! ffmpegcolorspace ! theoraenc !
oggmux ! filesink location=bars75.ogv

And changed the videotestsrc to a filesrc and it continues working

gst-launch filesrc location=bars75.ogv ! decodebin2 \
    ! alpha method=custom target-r=255 target-g=255 target-b=255 angle=10 \
    ! videomixer name=mixer ! ffmpegcolorspace ! autovideosink  \
    filesrc location=snow.ogv ! decodebin2 ! alpha ! mixer.


But, when I use the ideo I want to compose, I'm not able to make the white
color transparent

gst-launch filesrc location=video.ogv ! decodebin2 \
    ! alpha method=custom target-r=255 target-g=255 target-b=255 angle=10 \
    ! videomixer name=mixer ! ffmpegcolorspace ! autovideosink  \
    filesrc location=snow.ogv ! decodebin2 ! alpha ! mixer.


Can you help me? Any idea what is happening?
I'm using GStreamer 0.10.28


You can download the test videos from here:
http://polimedia.upv.es/pub/gst/gst.zip



Thanks in advance,
  Miguel Escriva
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