Something

mencoder mf://*.png -ovc lavc -lavcopts vcodec=xvid -of avi -o lightturn.avi
MEncoder 1.0rc1-4.1.1 (C) 2000-2006 MPlayer Team
CPU: AMD Athlon(tm) XP 2600+ (Family: 6, Model: 10, Stepping: 0)
CPUflags: Type: 6 MMX: 1 MMX2: 1 3DNow: 1 3DNow2: 1 SSE: 1 SSE2: 0
Compiled for x86 CPU with extensions: MMX MMX2 3DNow 3DNowEx SSE

success: format: 16  data: 0x0 - 0x0
MF file format detected.
[mf] search expr: *.png
[mf] number of files: 101 (404)
[demux_mf] file type was not set! trying 'type=png'...
VIDEO:  [MPNG]  0x0  24bpp  25.000 fps    0.0 kbps ( 0.0 kbyte/s)
[V] filefmt:16  fourcc:0x474E504D  size:0x0  fps:25.00  ftime:=0.0400
Opening video filter: [expand osd=1]
Expand: -1 x -1, -1 ; -1, osd: 1, aspect: 0.000000, round: 1
==========================================================================
Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
Selected video codec: [ffpng] vfm: ffmpeg (FFmpeg PNG decoder)
==========================================================================
VDec: vo config request - 480 x 352 (preferred colorspace: RGB 24-bit)
Could not find matching colorspace - retrying with -vf scale...
Opening video filter: [scale]
VDec: using RGB 24-bit as output csp (no 5)
Movie-Aspect is undefined - no prescaling applied.
SwScaler: reducing / aligning filtersize 1 -> 4
SwScaler: reducing / aligning filtersize 1 -> 4
SwScaler: reducing / aligning filtersize 1 -> 1
SwScaler: reducing / aligning filtersize 9 -> 8

SwScaler: BICUBIC scaler, from rgb24 to yuv420p using MMX2
SwScaler: using 4-tap MMX scaler for horizontal luminance scaling
SwScaler: using 4-tap MMX scaler for horizontal chrominance scaling
SwScaler: using 1-tap MMX "scaler" for vertical scaling (YV12 like)
SwScaler: 480x352 -> 480x352
videocodec: libavcodec (480x352 fourcc=64697678 [xvid])
New_Face failed. Maybe the font path is wrong.
Please supply the text font file (~/.mplayer/subfont.ttf).
subtitle font: load_sub_face failed.
Writing header...
ODML: Aspect information not (yet?) available or unspecified, not writing vprp header.
Writing header...
ODML: Aspect information not (yet?) available or unspecified, not writing vprp header.
VDec: vo config request - 3 x 3 (preferred colorspace: BGRA)0.000 [818:0]
VDec: using BGRA as output csp (no 0)
Movie-Aspect is undefined - no prescaling applied.
swScaler: 3x3 -> 480x352 is invalid scaling dimension
Couldn't init SwScaler for this setup
FATAL: Cannot initialize video driver.

Exiting...