При оцифровке VHS Mencoder'ом пропускаются кадры

mencoder -o /home/dmitry/1.avi -tv driver=v4l2:width=512:height=384:device=/dev/video0:freq=471.25 tv:// norm=PAL-BG -oac mp3lame -ovc raw

MEncoder SVN-r31774-4.5.0 (C) 2000-2010 MPlayer Team
158 audio & 340 video codecs
success: format: 9  data: 0x0 - 0x0
TV file format detected.
Selected driver: v4l2
 name: Video 4 Linux 2 input
 author: Martin Olschewski <olschewski@zpr.uni-koeln.de>
 comment: first try, more to come ;-)
Selected device: ASUS TV-FM 7135
 Tuner cap: STEREO LANG1 LANG2
 Tuner rxs: MONO
 Capabilites:  video capture  video overlay  VBI capture device  tuner  read/write  streaming
 supported norms: 0 = NTSC; 1 = NTSC-M; 2 = NTSC-M-JP; 3 = NTSC-M-KR; 4 = PAL; 5 = PAL-BG; 6 = PAL-H; 7 = PAL-I; 8 = PAL-DK; 9 = PAL-M; 10 = PAL-N; 11 = PAL-Nc; 12 = PAL-60; 13 = SECAM; 14 = SECAM-B; 15 = SECAM-G; 16 = SECAM-H; 17 = SECAM-DK; 18 = SECAM-L; 19 = SECAM-Lc;
 inputs: 0 = Television; 1 = Composite1; 2 = S-Video;
 Current input: 0
 Current format: BGR24
v4l2: current audio mode is : MONO
Audio block size too low, setting to 8192!
[V] filefmt:9  fourcc:0x32315659  size:512x384  fps:25.000  ftime:=0.0400
==========================================================================
Opening audio decoder: [pcm] Uncompressed PCM audio decoder
AUDIO: 44100 Hz, 1 ch, s16le, 705.6 kbit/100.00% (ratio: 88200->88200)
Selected audio codec: [pcm] afm: pcm (Uncompressed PCM)
==========================================================================
Opening video filter: [expand osd=1]
Expand: -1 x -1, -1 ; -1, osd: 1, aspect: 0.000000, round: 1
==========================================================================
Opening video decoder: [raw] RAW Uncompressed Video
Movie-Aspect is undefined - no prescaling applied.
Selected video codec: [rawyv12] vfm: raw (RAW YV12)
==========================================================================
MP3 audio selected.
Forcing audio preload to 0, max pts correction to 0.

3 duplicate frame(s)!
Pos:   0.2s      1f ( 0%)  0.00fps Trem:   0min   0mb  A-V:0.000 [0:0]
Writing header...
ODML: vprp aspect is 4:3.
Writing header...
ODML: vprp aspect is 4:3.
Pos:   0.7s     14f ( 0%)  0.00fps Trem:   0min   0mb  A-V:0.000 [0:0]

1 duplicate frame(s)!
Pos:   0.8s     15f ( 0%)  0.00fps Trem:   0min   0mb  A-V:0.000 [0:0]

1 duplicate frame(s)!
Pos:   0.8s     16f ( 0%)  0.00fps Trem:   0min   0mb  A-V:0.000 [0:0]

2 duplicate frame(s)!
Pos:   1.2s     24f ( 0%) 18.32fps Trem:   0min   0mb  A-V:0.000 [45663:127]

3 duplicate frame(s)!
Pos:   1.4s     25f ( 0%) 17.33fps Trem:   0min   0mb  A-V:0.000 [42130:129]

2 duplicate frame(s)!
Pos:   1.7s     31f ( 0%) 17.45fps Trem:   0min   0mb  A-V:0.000 [42522:127]