Problem with Motion JPEG B

[Mr.Ash]

I have here a Quicktime .mov movie. It uses "Motion JPEG B" for video and "uncompressed" for audio.
How can i convert this movie to a mpeg4 .avi file? When i hit the "DivX" preset and start the encoding process ffmpegX say's:

Encoding started on Thu May 20 19:33:59 CEST 2004
Using GNU internationalization
Original domain: messages
Original dirname: /sw/share/locale
Current domain: mplayer
Current dirname: /usr/local/share/locale
MEncoder dev-CVS-030226-15:00-3.1 (C) 2000-2003 Arpad Gereoffy (see DOCS)
AltiVec found
Reading /Users/mrash/.mplayer/codecs.conf: Reading /usr/local/etc/mplayer/codecs.conf: Using built-in default codecs.conf
File not found: 'frameno.avi'
success: format: 0 data: 0x0 - 0x67D40634
QuickTime/MOV file format detected.
--------------
MOV track #0: 23298 chunks, 49350 samples
MOV: Found unsupported Field-Handling movie atom (10)!
MOV: Found unsupported Gamma-Correction movie atom (12)!
Image size: 752 x 576 (24 bpp)
Display size: 752 x 576
Fourcc: bpjm Codec: 'Motion JPEG B'
--------------
MOV track #1: 2026 chunks, 0 samples
Audio bits: 16 chans: 2 rate: 32000
Audio extra header: len=38 fcc=0x77617665
Fourcc: sowt
--------------
MOV: longest streams: A: #1 (2026 samples) V: #0 (49350 samples)
[V] filefmt:7 fourcc:0x62706A6D size:752x576 fps: 8.70 ftime:=0.1150
================================================== ========================
Requested video codec family [m3jpeg] (vfm=vfw) not available (enable it at compilation)
Opening audio decoder: [pcm] Uncompressed PCM audio decoder
AUDIO: 32000 Hz, 2 ch, 16 bit (0x20), ratio: 128000->128000 (1024.0 kbit)
Selected audio codec: [pcm] afmcm (Uncompressed PCM)
================================================== ========================
Opening video filter: [expand=-1:-1:-1:-1:1]
Expand: -1 x -1, -1 ; -1 (-1=autodetect) osd: 1
Opening video filter: [scale=720:540]
Opening video filter: [lavcdeint]
Opening video filter: [denoise3d]
Requested video codec family [mjpeg] (vfm=vfw) not available (enable it at compilation)
Cannot find codec matching selected -vo and video format 0x62706A6D.
============================
*** Try to upgrade /Users/mrash/.mplayer/codecs.conf from etc/codecs.conf
*** If it still does not work, read DOCS/codecs.html!
================================================== ========================
Exiting...

How can i convert this movie?

[major]

You could use Quicktime Player to export it to Motion JPEG A first.

[Mr.Ash]

Does this mean that motion JPEG B isn't supported? I just fear that the quality could suffer when i export the video again. Will it work with motion JPEG A? If yes, i will give it a try.