[MEncoder-users] Skipped and duplicate frames

[Peter]

I'm trying to convert some movies from a digital camera at 30fps from MJPEG to 
XVID to save space. I'm getting lots of skipped frames and duplicate frame 
messages, although the input file seems fine, and indeed the output file seems 
fine, too.

The messages seem serious, in that I would have expected to see doubled and 
missing frames (but I don't).

Can anyone help me understand why I'm getting these errors, when apparently 
there's nothing wrong?

I've reduced my command line to the minimum.

D:\Samsung\2009_03_12>\me\mencoder -oac mp3lame -lameopts preset=standard:fast -
ovc xvid -xvidencopts bitrate=2000000 -ofps 30 -o ".\XVID\S6301641.AVI" "S630164
1.AVI"
MEncoder Sherpya-SVN-r27811-4.2.5 (C) 2000-2008 MPlayer Team
CPU: Intel(R) Core(TM)2 Quad CPU    Q6600  @ 2.40GHz (Family: 6, Model: 15, Step
ping: 11)
CPUflags: Type: 6 MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1
Compiled for x86 CPU with extensions: MMX MMX2 SSE SSE2

success: format: 0  data: 0x0 - 0x2e5fc54
AVI file format detected.
[aviheader] Video stream found, -vid 0
[aviheader] Audio stream found, -aid 1
VIDEO:  [MJPG]  640x480  24bpp  30.000 fps  9337.0 kbps (1139.8 kbyte/s)
[V] filefmt:3  fourcc:0x47504A4D  size:640x480  fps:30.000  ftime:=0.0333
==========================================================================
Opening audio decoder: [pcm] Uncompressed PCM audio decoder
AUDIO: 22050 Hz, 1 ch, s16le, 352.8 kbit/100.00% (ratio: 44100->44100)
Selected audio codec: [pcm] afm: pcm (Uncompressed PCM)
==========================================================================
xvid: using library version 1.1.3 (build xvid-1.1.3)
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: [ffmjpeg] vfm: ffmpeg (FFmpeg MJPEG decoder)
==========================================================================
MP3 audio selected.
VDec: vo config request - 640 x 480 (preferred colorspace: Planar 422P)
Could not find matching colorspace - retrying with -vf scale...
Opening video filter: [scale]
VDec: using Planar 422P as output csp (no 1)
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 @ 00DAB6F4]BICUBIC scaler, from yuv422p to yuv420p using MMX2
[swscaler @ 00DAB6F4]using 4-tap MMX scaler for horizontal luminance scaling
[swscaler @ 00DAB6F4]using 4-tap MMX scaler for horizontal chrominance scaling
[swscaler @ 00DAB6F4]using 1-tap MMX "scaler" for vertical scaling (YV12 like)
[swscaler @ 00DAB6F4]640x480 -> 640x480
videocodec: XviD (640x480 fourcc=44495658 [XVID])
xvid: par=0/0 (vga11), displayed=640x480, sampled=640x480
xvid: CBR Rate Control -- bitrate=2000kbit/s
Writing header...
ODML: vprp aspect is 4:3.
Setting audio delay to 0.026s.
Writing header...
ODML: vprp aspect is 4:3.
Setting audio delay to 0.026s.
Pos:   0.7s     22f ( 3%)  0.00fps Trem:   0min   3mb  A-V:0.070 [0:60]
Skipping frame!
Pos:   1.0s     33f ( 4%)  0.00fps Trem:   0min   4mb  A-V:0.069 [0:60]
Skipping frame!
Pos:   3.8s    117f (12%) 41.79fps Trem:   0min   6mb  A-V:0.069 [1581:66]
Skipping frame!
Pos:   4.1s    127f (12%) 41.19fps Trem:   0min   6mb  A-V:0.069 [1626:62]
Skipping frame!
Pos:   4.4s    137f (13%) 40.85fps Trem:   0min   6mb  A-V:0.069 [1618:58]
Skipping frame!
Pos:   4.7s    147f (14%) 40.34fps Trem:   0min   6mb  A-V:0.069 [1618:56]
Skipping frame!
Pos:   5.0s    157f (14%) 39.55fps Trem:   0min   6mb  A-V:0.069 [1662:53]
Skipping frame!
Pos:   5.5s    175f (15%) 39.02fps Trem:   0min   7mb  A-V:0.025 [1686:50]