[MEncoder-users] help with simple task: crop, scale, encode

[Molle Bestefich]

Hi

I'd like to take an input file from a PVR, crop it, scale it to half
size, and MPEG4 encode it.

It's for a buddy on Windows, so I chose AVI and MSMPEG4v2.

First try:
# mencoder input.vob \
-vf crop=700:428:8:74 \
-vf scale=350:-2 \
-ovc lavc -lavcopts vcodec=msmpeg4v2 \
-oac mp3lame \
-vo null -of avi -o output.avi

It dies with "-vo is not an MEncoder option".
Ok, fine (although -vo is in "man mencoder", hmm).  I try without -vo:

MEncoder dev-CVS-060415-00:32-3.3.6 (C) 2000-2006 MPlayer Team
# [...snip...]
success: format: 0  data: 0x0 - 0xf9c8000
MPEG-PS file format detected.
VIDEO:  MPEG2  720x576  (aspect 2)  25.000 fps  4096.0 kbps (512.0 kbyte/s)
[V] filefmt:2  fourcc:0x10000002  size:720x576  fps:25.00  ftime:=0.0400
==========================================================================
Opening audio decoder: [liba52] AC3 decoding with liba52
# [...no audio probs, snip...]
==========================================================================
Opening video filter: [expand osd=1]
Expand: -1 x -1, -1 ; -1, osd: 1, aspect: 0.000000, round: 1
Opening video filter: [scale w=350 h=-2]

# Ok, here I wonder, why is the 'expand' filter loaded?
# And why in the same "========" block as the 'scale' filter?
#
# Carrying on...

==========================================================================
Opening video decoder: [mpegpes] MPEG 1/2 Video passthrough
VDec: vo config request - 720 x 576 (preferred colorspace: Mpeg PES)
The selected video_out device is incompatible with this codec.
Try adding the scale filter, e.g. -vf spp,scale instead of -vf spp.
VDecoder init failed :(

# Doesn't look too god.
# Not sure what it means by "vo config request",
# I haven't requested any vo config.
#
# I haven't selected a video_out device either, as
# mencoder did not accept my "-vo null" option.
# So how do I tell it to not try to output anything?
#
# It tells me to try adding the scale filter, but the scale
# filter is already added since I want to downscale the video.

Opening video decoder: [libmpeg2] MPEG 1/2 Video decoder libmpeg2-v0.4.0b
Selected video codec: [mpeg12] vfm: libmpeg2 (MPEG-1 or 2 (libmpeg2))
==========================================================================
MP3 audio selected
VDec: vo config request - 720 x 576 (preferred colorspace: Planar YV12)
VDec: using Planar YV12 as output csp (no 0)
Movie-Aspect is 1.33:1 - prescaling to correct movie aspect.

SwScaler: BICUBIC scaler, from Planar YV12 to Planar YV12 using MMX
videocodec: libavcodec (350x262 fourcc=3234504d [MP42])

# Argh!!
#  After cropping, the video should be 700x428, ergo
# after scaling, it should be 350x214 - NOT 350x262...
#
# Why, oh why does it not what I tell it to?

Writing header...2f ( 0%)  0.00fps Trem:   0min   0mb  A-V:0.004 [0:0]
ODML: Aspect information not (yet?) available or unspecified, not
writing vprp header.
Writing header...
ODML: Aspect information not (yet?) available or unspecified, not
writing vprp header.

1 duplicate frame(s)!
Pos:   0.8s     22f ( 0%)  0.00fps Trem:   2min  29mb  A-V:0.084 [0:165]
Skipping frame!
Pos:   1.2s     32f ( 0%)  0.00fps Trem:   2min  29mb  A-V:0.084 [684:165]
Skipping frame!
Pos:   1.6s     42f ( 0%)  0.00fps Trem:   2min  32mb  A-V:0.084 [667:166]
Skipping frame!
Pos:   2.3s     62f ( 0%) 57.73fps Trem:   2min  32mb  A-V:0.084 [646:166]
Skipping frame!
Pos:   2.8s     75f ( 0%) 58.00fps Trem:   2min  34mb  A-V:0.083 [649:166]
Skipping frame!
Pos:  21.6s    547f ( 5%) 55.80fps Trem:   2min  38mb  A-V:0.017 [667:171]
Flushing video frames
Writing index...
Writing header...
ODML: Aspect information not (yet?) available or unspecified, not
writing vprp header.

Video stream:  667.485 kbit/s  (83435 B/s)  size: 1798871 bytes 
21.560 secs  547 frames
Audio stream:  171.190 kbit/s  (21398 B/s)  size: 471456 bytes  22.032 secs

# The ODML: warnings doesn't look too good either, what do they mean?
# Why does it skip frames?

Thanks :)