Video screws up after a bit, if using ffmpeg for decoding

mplayer output:
MPlayer CVS-020805-07:05-2.95.4 (C) 2000-2002 Arpad Gereoffy (see DOCS!)

CPU: Advanced Micro Devices Athlon TB Thunderbird (Family: 6, Stepping: 2)
CPUflags:  MMX: 1 MMX2: 1 3DNow: 1 3DNow2: 1 SSE: 0 SSE2: 0
Compiled for x86 CPU with extensions: MMX MMX2 3DNow 3DNowEx

Reading /root/.mplayer/codecs.conf: can't open '/root/.mplayer/codecs.conf': No such file or directory
Reading /etc/mplayer/codecs.conf: 36 audio & 103 video codecs
CommandLine: '-v' 'test3.avi'
get_path('font/font.desc') -> '/root/.mplayer/font/font.desc'
Font /root/.mplayer/font/font.desc loaded successfully! (206 chars)
Using MMX (with tiny bit MMX2) Optimized OnScreenDisplay
Using Linux's hardware RTC timing (1024Hz)
get_path('input.conf') -> '/root/.mplayer/input.conf'
Can't open input config file /root/.mplayer/input.conf : No such file or directory
Can't open input config file /etc/mplayer/input.conf : No such file or directory
Falling back on default (hardcoded) input config

Playing test3.avi
Not an URL!
File size is 14585856 bytes
Detected AVI file format!
list_end=0x22C8
======= AVI Header =======
us/frame: 40000  (fps=25.000)
max bytes/sec: 0
padding: 0
MainAVIHeader.dwFlags: (272) HAS_INDEX IS_INTERLEAVED
frames  total: 261   initial: 0
streams: 2
Suggested BufferSize: 0
Size:  512 x 384
list_end=0x1138
==> Found video stream: 0
======= STREAM Header =======
Type: vids   FCC: xvid (64697678)
Flags: 0
Priority: 0   Language: 0
InitialFrames: 0
Rate: 25/1 = 25.000
Start: 0   Len: 261
Suggested BufferSize: 92735
Quality 10000
Sample size: 0
found 'bih', 108 bytes of 40
======= VIDEO Format ======
  biSize 40
    biWidth 512
      biHeight 384
        biPlanes 1
	  biBitCount 24
	    biCompression 1145656920='XVID'
	      biSizeImage 589824
	      ===========================
	      list_end=0x21BC
	      ==> Found audio stream: 1
	      ======= STREAM Header =======
	      Type: auds   FCC:  (0)
	      Flags: 0
	      Priority: 0   Language: 0
	      InitialFrames: 1
	      Rate: 176400/4 = 44100.000
	      Start: 0   Len: 441000
	      Suggested BufferSize: 88200
	      Quality -1
	      Sample size: 4
	      found 'wf', 16 bytes of 20
	      ======= WAVE Format =======
	      Format Tag: 1 (0x1)
	      Channels: 2
	      Samplerate: 44100
	      avg byte/sec: 176400
	      Block align: 4
	      bits/sample: 16
	      cbSize: 0
	      list_end=0x22C8
	      Broken chunk?  chunksize=1328  (id=JUNK)
	      list_end=0xDE6BE6
	      Found movie at 0x280C - 0xDE6BE6
	      Reading INDEX block, 500 chunks for 261 frames
	      Broken chunk?  chunksize=0  (id=idx1)
	      Reading INDEX block, 500 chunks for 261 frames
	      AVI index offset: 0x2808 (movi=0x280C idx0=0x4 idx1=0x15894)
	      Auto-selected AVI audio ID = 1
	      Auto-selected AVI video ID = 0
	      AVI: Searching for audio stream (id:1)
	      AVI video length=14121370
	      VIDEO:  [XVID]  512x384  24bpp  25.00 fps  10821.0 kbps (1320.9 kbyte/s)
	      [V] filefmt:3  fourcc:0x44495658  size:512x384  fps:25.00  ftime:=0.0400
	      get_path('sub/') -> '/root/.mplayer/sub/'
	      Detected audio codec: [pcm] afm:2 (Uncompressed PCM)
	      Initializing audio codec...
	      Opening audio decoder: [pcm] Uncompressed PCM audio decoder
	      dec_audio: Allocating 2048 + 65536 = 67584 bytes for output buffer
	      AUDIO: 44100 Hz, 2 ch, sfmt: 0x10 (2 bps), ratio: 176400->176400 (1411.2 kbit)
	      X11 opening display: :0.0
	      vo: X11 color mask:  FFFFFF  (R:FF0000 G:FF00 B:FF)
	      vo: X11 running at 1280x960 with depth 24 and 32 bpp (":0.0" => local display)
	      ==========================================================================
	      Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
	      libavcodec: CPU flags: mmx mmxext 3dnow
	      INFO: libavcodec init OK!
	      Detected video codec: [ffodivx] vfm:5 (FFmpeg MPEG-4)
	      ==========================================================================
	      AO: [oss] 44100Hz 2ch Signed 16-bit (Little-Endian)
	      AO: Description: OSS/ioctl audio output
	      AO: Author: A'rpi
	      ao2: 44100 Hz  2 chans  Signed 16-bit (Little-Endian)
	      audio_setup: using '/dev/dsp' dsp device
	      audio_setup: sample format: Signed 16-bit (Little-Endian) (requested: Signed 16-bit (Little-Endian))
	      audio_setup: using 2 channels (requested: 2)
	      audio_setup: using 44100 Hz samplerate (requested: 44100)
	      audio_setup: frags:   8/8  (8192 bytes/frag)  free:  65536
	      Start playing...
	      looks like this file was encoded with (divx4/(old)xvid/opendivx) -> forcing low_delay flag
	      VDec: vo config request - 512 x 384 (preferred csp: Planar YV12)
	      vo_debug: query(Planar YV12) returned 0x437 (i=0)
	      Movie-Aspect is undefined - no prescaling applied.
	      video_out->init(512x384->512x384,flags=0,'MPlayer',0x32315659)
	      VO: [xv] 512x384 => 512x384 Planar YV12
	      VO: Description: X11/Xv
	      VO: Author: Gerd Knorr <kraxel@goldbach.in-berlin.de> and others
	      Xvideo image format: 0x32595559 (YUY2) packed
	      Xvideo image format: 0x32315659 (YV12) planar
	      Xvideo image format: 0x59565955 (UYVY) packed
	      Xvideo image format: 0x30323449 (I420) planar
	      using Xvideo port 76 for hw scaling
	      [xv] dx: 0 dy: 0 dw: 512 dh: 384
	      *** [vo] Allocating mp_image_t, 512x384x12bpp YUV planar, 294912 bytes
	      [xv] dx: 0 dy: 0 dw: 512 dh: 384
	      XXX initial  v_pts=0.000  a_pos=88200 (0.500)   1   0%  0%  0.0% 0 0 0%
	      *** [vo] Allocating mp_image_t, 512x384x12bpp YUV planar, 294912 bytes
	      |level| overflow in 3. esc000 ct:  0.002  100/100  16%  4%  0.1% 0 0 0%
	      Error at MB: 693
	      concealing errors
	      |level| overflow in 3. esc000 ct:  0.002  132/132  15%  4%  0.1% 0 0 0%
	      Error at MB: 39
	      concealing errors
	      |level| overflow in 3. esc000 ct:  0.002  136/136  15%  4%  0.1% 0 0 0%
	      Error at MB: 151
	      concealing errors
	      |level| overflow in 3. esc000 ct:  0.002  140/140  15%  4%  0.1% 0 0 0%
	      Error at MB: 89
	      concealing errors
	      |level| overflow in 3. esc000 ct:  0.002  147/147  15%  4%  0.1% 0 0 0%
	      Error at MB: 47
	      concealing errors
	      |level| overflow in 3. esc000 ct:  0.002  149/149  15%  4%  0.1% 0 0 0%
	      Error at MB: 57
	      concealing errors
	      |level| overflow in 3. esc000 ct:  0.002  151/151  15%  4%  0.1% 0 0 0%
	      Error at MB: 13
	      concealing errors
	      |level| overflow in 3. esc001 ct:  0.002  153/153  15%  4%  0.1% 0 0 0%
	      Error at MB: 39
	      concealing errors
	      vo: uninit ...6.2 A-V:  0.005 ct:  0.003  157/157  15%  4%  0.1% 0 0 0%