[FFmpeg-user] There is maybe still a bug with the videofilter "split"

[PixelPartner]

I want to process both halves of a 3D-movie seperately and then recombine them in another layout.
The video filter option seems perfect for this, except that since 7 months the split filter does not work as documented.
When I call ... 

ffmpeg
    -i "Tangled_3D_Trailer.wmv" \
    -vf "[in] split [a][b];[a] crop=960:1080:0:0,scale=768:432,pad=768:1024:0:40 [L]; \
         [b] crop=960:1080:0:0,scale=768:432 [R]; [L][R] overlay=0:552 [out]" \
    -b 8500K -y out.mp4

I get the message, that the split buffer is not accessible for the given frame number
"request_frame() called with no available frame!"
Here comes the full listing : 
 
ffmpeg -i "Tangled_3D_Trailer.wmv" -vf "[in] select=1,split [a][b];[a] crop=960:1080:960:0,scale=768:432,pad=768:1024:0:552 [L];[b] crop=960:1080:0:0,scale=768:432 [R]; [L][R] overlay=0:40 [out]" -b 8500K -y out.mp4

ffmpeg version N-31461-g371888c, Copyright (c) 2000-2011 the FFmpeg developers
  built on Jul 14 2011 15:01:44 with gcc 4.6.1
  configuration: --enable-gpl --enable-version3 --enable-memalign-hack --enable-runtime-cpudetect --enable-avisynth --enable-
bzlib --enable-frei0r --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libfreetype --enable-libgsm --enable-lib
mp3lame --enable-libopenjpeg --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbi
s --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
  libavutil    51. 11. 0 / 51. 11. 0
  libavcodec   53.  7. 0 / 53.  7. 0
  libavformat  53.  5. 0 / 53.  5. 0
  libavdevice  53.  2. 0 / 53.  2. 0
  libavfilter   2. 25. 0 /  2. 25. 0
  libswscale    2.  0. 0 /  2.  0. 0
  libpostproc  51.  2. 0 / 51.  2. 0

Seems stream 0 codec frame rate differs from container frame rate: 1000.00 (1000/1) -> 25.00 (25/1)
Input #0, asf, from 'Tangled_3D_Trailer.wmv':
  Duration: 00:02:15.40, start: 0.000000, bitrate: 11414 kb/s
    Stream #0.0: Video: wmv2, yuv420p, 1920x1080, 25 tbr, 1k tbn, 1k tbc
    Stream #0.1: Audio: wmav2, 48000 Hz, 2 channels, s16, 160 kb/s
[buffer @ 039FA040] w:1920 h:1080 pixfmt:yuv420p tb:1/1000000 sar:0/1 sws_param:
[crop @ 01D3E4E0] w:1920 h:1080 -> w:960 h:1080
[scale @ 01D3E280] w:960 h:1080 fmt:yuv420p -> w:768 h:432 fmt:yuv420p flags:0x4
[pad @ 01D3EF80] w:768 h:432 -> w:768 h:1024 x:0 y:552 color:0x108080FF[yuva]
[crop @ 01D3F6C0] w:1920 h:1080 -> w:960 h:1080
[scale @ 01D3FD00] w:960 h:1080 fmt:yuv420p -> w:768 h:432 fmt:yuva420p flags:0x4
[overlay @ 01D3FEC0] main w:768 h:1024 fmt:yuv420p overlay x:0 y:40 w:768 h:432 fmt:yuva420p
[overlay @ 01D3FEC0] main_tb:1/1000000 overlay_tb:1/1000000 -> tb:1/1000000 exact:1
Output #0, mp4, to 'out.mp4':
  Metadata:
    encoder         : Lavf53.5.0
    Stream #0.0: Video: mpeg4, yuv420p, 768x1024, q=2-31, 8500 kb/s, 25 tbn, 25 tbc
    Stream #0.1: Audio: aac, 48000 Hz, 2 channels, s16, 64 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
  Stream #0.1 -> #0.1
Press [q] to stop, [?] for help
[buffer @ 039FA040] request_frame() called with no available frame!
    Last message repeated 621 times7933kB time=00:00:24.68 bitrate=2633.1kbits/s
request_frame() called with no available frame!
frame=  623 fps= 17 q=2.0 Lsize=    8010kB time=00:00:24.91 bitrate=2633.3kbits/s
video:7797kB audio:197kB global headers:0kB muxing overhead 0.192338%
Received signal 2: terminating.
 
^^^^^ Aborted with Ctrl.C ^^^^^^ 
 
Does anyone have a hint what to do else, or is it a bug (planned, but not yet implemented feature) as I suspect. 
 
best wishes to the team and community 
 
Thomas Kumlehn