Got libavcodec CVS with MPlayer-20020325
./configure --disable-mencoder --enable-linux-devfs --enable-gui --disable-tv --disable-tv-v41 --enable-3dfx --enable-tdfxfb --disable-alsa --disable-sunaudio --disable-mad --enable-aa --enable-mmx --enable-mmx2 --enable-sse --disable-runtime-cpudetection --enable-debug

Config files successfully generated by ./configure !

  Install prefix: /usr/local
  Data directory: /usr/local/share/mplayer
  Config direct.: /usr/local/share/mplayer

  Enabled optional drivers:
    Input: network dvdread vcd
    Codecs: divx4linux libavcodec directshow win32
    Audio output: oss sdl
    Video output: xvidix sdl vesa png mpegpes(file) svga aa opengl dga xv x11 tdfxfb 3dfx
  Disabled optional drivers:
    Input: tv-v4l tv-bsdbt848 tv dvdcss
    Codecs: xvid xanim
    Audio output: sgi sun alsa nas
    Video output: zr dxr3 fbdev ggi xmga mga directfb

(btw, /dev/sound/dspW doesn't exist with a SBLive and default devfsd installation. /dev/sound/dsp however does ... (maybe an error at your side or SBLive entry is diffrent?)

make;
rm /usr/local/bin/mplayer
make install
(i dind't rm the /etc/mplayer.conf since it hasn't changed in MPLayer-0.60 and in a CVS that was released shortly after that, it changes were made to it's design, it must have been somewere around 20020322)
rm /usr/local/share/mplayer/codecs.conf

running mplayer sample.avi works fine, as always. Window aspect ratio is weird, and it changes resolution (but not desktop/movie size) so that's annoying however it works, returning to a windowed mode is weird resolution too, however it works.
running gmplayer crashes. here is a snip from the crashlog.



init (ok)
<snip>
Reading /usr/local/share/mplayer/codecs.conf: 30 audio & 81 video codecs
font: can't open file: /home/oliver/.mplayer/font/font.desc
Font /usr/local/share/mplayer/font/font.desc loaded successfully! (206 chars)

GLib-CRITICAL **: file ghash.c: line 138 (g_hash_table_lookup): assertion `hash_table != NULL' failed.

Gtk-WARNING **: gtk_type_create(): unknown parent type `21'.

GLib-CRITICAL **: file ghash.c: line 138 (g_hash_table_lookup): assertion `hash_table != NULL' failed.
<snip>
Linux RTC init error: Permission denied
Using usleep() timing

Gtk-WARNING **: invalid cast from (NULL) pointer to `GtkLabel'

Gtk-CRITICAL **: file gtklabel.c: line 260 (gtk_label_set_text): assertion `GTK_IS_LABEL (label)' failed.

Gtk-CRITICAL **: file gtkwidget.c: line 1510 (gtk_widget_hide): assertion `widget != NULL' failed.

Gtk-WARNING **: invalid cast from (NULL) pointer to `GtkWindow'
<snip>
Gtk-CRITICAL **: file gtkwidget.c: line 1427 (gtk_widget_show): assertion `widget != NULL' failed.
- MPlayer crashed. This shouldn't happen. It can be a bug in the MPlayer code _or_ in your drivers _or_ in your gcc version. If you think it's MPlayer's fault, please read DOCS/bugreports.html and follow instructions there. We can't and won't help unless you provide these informations when reporting a possible bug.

Trying to use gdb, I get the following:
gdb gmplayer
This GDB was configured as "i386-slackware-linux"...
(no debugging symbols found)...
(gdb) 
i tried it anyhow.
(no debugging symbols found)...
Program received signal SIGSEGV, Segmentation fault.
0x40212b4c in _gdk_pixmap_create_from_xpm (window=0x40225f60, 
    colormap=0x832f520, mask=0xbfffe730, transparent_color=0x40, 
    get_buf=0x40213080 <mem_buffer>, handle=0xbfffe6e4) at gdkpixmap.c:526
526     gdkpixmap.c: No such file or directory.
(gdb) 

I haven't changed anything in my system configuration, and it worked before. it stopped working with the last few CVS builds.

System Info, Slackware 8.0 Updated with security fixes, 2.4.18, XFree 4.2.0, libc-2.2.3, gcc 2.95.3 (20010315 release), ld 2.11.90.0.19, as, 2.11.90.0.19
CPU  PIII (Cu) 1Ghz Family 6, model 8, stepping 10, GPU VooDoo3 using XV or X11, SBLive kernel driver built in (no module)
00:0a.1 Input device controller: Creative Labs SB Live! (rev 01)
        Subsystem: Creative Labs Gameport Joystick
        Control: I/O+ Mem- BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
        Status: Cap+ 66Mhz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR-
        Latency: 32
        Region 0: I/O ports at a800 [size=8]
        Capabilities: [dc] Power Management version 1
                Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
                Status: D0 PME-Enable- DSel=0 DScale=0 PME-

01:00.0 VGA compatible controller: 3Dfx Interactive, Inc. Voodoo 3 (rev 01) (prog-if 00 [VGA])
        Subsystem: 3Dfx Interactive, Inc. Voodoo3 AGP
        Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B-
        Status: Cap+ 66Mhz+ UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR+
        Interrupt: pin A routed to IRQ 10
        Region 0: Memory at ca000000 (32-bit, non-prefetchable) [size=32M]
        Region 1: Memory at ce000000 (32-bit, prefetchable) [size=32M]
        Region 2: I/O ports at d800 [size=256]
        Expansion ROM at cdff0000 [disabled] [size=64K]
        Capabilities: [54] AGP version 1.0
                Status: RQ=7 SBA+ 64bit+ FW- Rate=x1,x2
                Command: RQ=0 SBA- AGP- 64bit- FW- Rate=<none>
        Capabilities: [60] Power Management version 1
                Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
                Status: D0 PME-Enable- DSel=0 DScale=0 PME-