Спасибо. В общем-то, crop делается и в ffmpeg и mencoder, но первый падает в корку, а второй сообщает об ошибке.
ffmpeg -i test.ogv -croptop 20 -cropbottom 20 tt.ogv
[cas@c249 share]$ mencoder test.ogv -vf crop=800:620:20:20 -o tt.ogv -ovc lavc
MEncoder dev-SVN-r27654-4.3.2 (C) 2000-2008 MPlayer Team
CPU: Intel(R) Core(TM)2 Duo CPU T7250 @ 2.00GHz (Family: 6, Model: 15, Stepping: 13)
CPUflags: Type: 6 MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1
Compiled with runtime CPU detection.
129 audio & 259 video codecs
WARNING: OUTPUT FILE FORMAT IS _AVI_. See -of help.
success: format: 0 data: 0x0 - 0x1465933
Ogg stream 0 is of an unknown type
[Ogg] stream 1: video (Theora v3.2.1), -vid 0
Ogg file format detected.
VIDEO: [theo] 800x640 24bpp 15,000 fps 0,0 kbps ( 0,0 kbyte/s)
[V] filefmt:18 fourcc:0x6F656874 size:800x640 fps:15,000 ftime:=0,0667
Opening video filter: [expand osd=1]
Expand: -1 x -1, -1 ; -1, osd: 1, aspect: 0,000000, round: 1
Opening video filter: [crop w=800 h=620 x=20 y=20]
Crop: 800 x 620, 20 ; 20
==========================================================================
Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
[theora @ 0x8d28a40]Missing extradata!
Could not open codec.
VDecoder init failed :(
Opening video decoder: [theora] Theora/VP3
VDec: vo config request - 800 x 640 (preferred colorspace: Planar YV12)
VDec: using Planar YV12 as output csp (no 0)
Movie-Aspect is 1,25:1 - prescaling to correct movie aspect.
[CROP] Bad position/width/height - cropped area outside of the original!
FATAL: Cannot initialize video driver.
VDecoder init failed :(
Cannot find codec matching selected -vo and video format 0x6F656874.
Read DOCS/HTML/en/codecs.html!
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Кстати, следуя по твоему совету:
1. через ffmpeg — ужасное качество и сегфолт при использовании crop
2. через mencoder — вообще полученный файл не открывается: [theora @ 0x89b1d10]Missing extradata!
Could not open codec.