[MEncoder-users] Trying to cut/copy mpeg file from Tivo, seeing errors

[Brian Mathis]

Hello,

I used my Tivo as a simple capturing device to record from VHS->Tivo.
Now I'm trying to process it.  Initially I'm just trying to cut it up,
and here's the command line I'm using:
    mencoder file.mpg -ovc copy -oac copy -of mpeg -endpos 00:01:00 -o test.mpg

The output is (truncated for readability):

MEncoder 1.0rc2-4.2.1 (C) 2000-2007 MPlayer Team
CPU: Intel(R) Core(TM)2 Duo CPU     T7300  @ 2.00GHz (Family: 6,
Model: 15, Stepping: 10)
CPUflags: Type: 6 MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1
Compiled with runtime CPU detection.
success: format: 0  data: 0x0 - 0xe9b89292
MPEG-PS file format detected.
VIDEO:  MPEG2  480x480  (aspect 2)  29.970 fps  8700.0 kbps (1087.5 kbyte/s)
[V] filefmt:2  fourcc:0x10000002  size:480x480  fps:29.97  ftime:=0.0334
==========================================================================
Opening audio decoder: [mp3lib] MPEG layer-2, layer-3
AUDIO: 48000 Hz, 2 ch, s16le, 192.0 kbit/12.50% (ratio: 24000->192000)
Selected audio codec: [mp3] afm: mp3lib (mp3lib MPEG layer-2, layer-3)
==========================================================================
PACKET SIZE: 2048 bytes, deltascr: 245760
videocodec: framecopy (480x480 24bpp fourcc=10000002)
audiocodec: framecopy (format=50 chans=2 rate=48000 bits=16 B/s=24000 sample-1)
Limiting audio preload to 0.4s.
Increasing audio density to 4.
Writing header...
INITV: 0.200, 0.167, fps: 29.970
Pos:   0.0s      1f ( 0%)  0.00fps Trem:   0min   0mb  A-V:0.000 [0:0]
Pos:   0.1s      2f ( 0%)  0.00fps Trem:   0min   0mb  A-V:0.003 [0:0]
Pos:   0.1s      3f ( 0%)  0.00fps Trem:   0min   0mb  A-V:0.007 [0:0]
(...)
BUFFER UNDEFLOW at stream 0, raising muxrate to 1980 kb/s, delta_scr: 223418
BUFFER UNDEFLOW at stream 1, raising muxrate to 2178 kb/s, delta_scr: 203107
BUFFER UNDEFLOW at stream 0, raising muxrate to 2395 kb/s, delta_scr: 184643
BUFFER UNDEFLOW at stream 0, raising muxrate to 2635 kb/s, delta_scr: 167857
BUFFER UNDEFLOW at stream 1, raising muxrate to 2898 kb/s, delta_scr: 152597
BUFFER UNDEFLOW at stream 0, raising muxrate to 3188 kb/s, delta_scr: 138725
ERROR: scr 1.544, dts 0.000, pts 1.433
ERROR: scr 1.668, dts 1.501, pts 1.601
BUFFER UNDEFLOW at stream 0, raising muxrate to 3507 kb/s, delta_scr: 126114
ERROR: scr 1.673, dts 0.000, pts 1.505
ERROR: scr 1.855, dts 0.000, pts 1.601
ERROR: scr 1.860, dts 1.601, pts 1.702
(...)
Writing index...
Overhead: 1.418% (653432 / 46075784)
Writing header...
Video stream: 5988.216 kbit/s  (748527 B/s)  size: 44931556 bytes
60.027 secs  1802 frames
Audio stream:  192.000 kbit/s  (24000 B/s)  size: 1440000 bytes  60.000 secs


Can anyone give pointers on what I need to do to prevent the errors
and buffer underflows?  I think I need to mess with -mpegopts, but I
have no idea where to start with that.  Has anyone successfully edited
tivotogo files with mencoder?  Have a command-line to share?

Thanks.