[gentoo-user] mencoder did nothing all night at 100% CPU!

[Iain Buchanan <iaindb@netspace.net.au>]

Hi all,

I'm trying out mencoder to try a few different codecs and formats for 1.
dvd authoring and 2. just compressing to keep on my HD.

This is what I tried last night:

mencoder 2006.06.24_09-26-48.dv -o 2006.06.24_09-26-48.avi -ovc lavc -oac lavc

that was ok, GREAT file size (original 350MB dv went down to 13MB), but
crappy quality - I could see all the compression "squares".  Then I
tried:

mencoder 2006.06.24_09-26-48.dv -o 2006.06.24_09-26-48.avi -ovc lavc -lavcopts vcodec=mpeg4:mbd=2:mv0:trell:v4mv:cbp:last_pred=3:predia=2:dia=2:vmax_b_frames=2:vb_strategy=1:precmp=2:cmp=2:subcmp=2:preme=2:qns=2 -oac lavc

which was better quality, and still a great file size, but I could still
see some quit noticeable compression artifacts.

THEN I thought, well if I'm going to encode for DVD, lets try: 

$ mencoder 2006.06.24_09-26-48.dv -of mpeg -ovc lavc -lavcopts vcodec=mpeg2video -oac pcm -o 2006.06.24_09-26-48.mpeg	

which went straight to 100% CPU.  I then went to bed, and when I got up
in the morning 7 1/2 hours later, it was in the same spot at 100% cpu!
The file size was 0 bytes.  Heres the output:

$ mencoder 2006.06.24_09-26-48.dv -of mpeg -ovc lavc -lavcopts
vcodec=mpeg2video -oac pcm -o 2006.06.24_09-26-48.mpeg
MEncoder 1.0pre8-3.4.6 (C) 2000-2006 MPlayer Team
CPU:               Intel(R) Pentium(R) 4 CPU 3.00GHz (Family: 15, Model:
2, Stepping: 9)
MMX supported but disabled
MMX2 supported but disabled
CPUflags: Type: 15 MMX: 0 MMX2: 0 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1
Compiled with runtime CPU detection.
93 audio & 211 video codecs
success: format: 0  data: 0x0 - 0x15fd6500
RAWDV file format detected.
VIDEO:  [DVSD]  720x576  24bpp  25.000 fps    0.0 kbps ( 0.0 kbyte/s)
[V] filefmt:22  fourcc:0x44535644  size:720x576  fps:25.00
ftime:=0.0400
==========================================================================
Opening audio decoder: [libdv] Raw DV Audio Decoder
AUDIO: 32000 Hz, 2 ch, s16le, 28800.0 kbit/2812.50% (ratio:
3600000->128000)
Selected audio codec: [libdv] afm: libdv (raw DV audio decoder (libdv))
==========================================================================
PACKET SIZE: 2048 bytes, deltascr: 245760
Opening video filter: [expand osd=1]
Expand: -1 x -1, -1 ; -1, osd: 1, aspect: 0.000000, round: 1
==========================================================================
Opening video decoder: [dshow] DirectShow video codecs
Decoder supports the following YUV formats: YUY2 UYVY
Decoder is capable of YUV output (flags 0x9)
VDec: vo config request - 720 x 576 (preferred colorspace: Packed YUY2)
[PP] Using codec's postprocessing, max q = 4.
Could not find matching colorspace - retrying with -vf scale...
Opening video filter: [scale]
VDec: using Packed YUY2 as output csp (no 0)
Movie-Aspect is undefined - no prescaling applied.

SwScaler: BICUBIC scaler, from Packed YUY2 to Planar YV12 using C
videocodec: libavcodec (720x576 fourcc=3267706d [mpg2])
Selected video codec: [qdv] vfm: dshow (Sony Digital Video (DV))
==========================================================================
Limiting audio preload to 0.4s.
Increasing audio density to 4.
Writing header...
Killed

(I killed it :)  So, firstly, why didn't that work?

And secondly, how should I encode if I want to write the movie to a DVD,
and have really good quality (close to the original dv)?

Lastly, how about storing on disk - what codec should I use there?  As I
said, I didn't like the quality of the first two attempts, so something
a bit nicer, (at the expense of file size) would be good.


Well, there are some big asks in this email - I appreciate anyone
looking into it and offering tips.  Thanks!

(PS I've been reading:
http://gentoo-wiki.com/HOWTO_Mencoder_Introduction_Guide
http://www.mplayerhq.hu/DOCS/HTML/en/menc-feat-dvd-mpeg4.html#menc-feat-dvd-mpeg4-muxing-avi-limitations
http://www.mplayerhq.hu/DOCS/HTML/en/menc-feat-enc-libavcodec.html
http://www.mplayerhq.hu/DOCS/HTML/en/menc-feat-mpeg.html
thanks.)
-- 
Iain Buchanan <iaindb at netspace dot net dot au>

Four fifths of the perjury in the world is expended on tombstones, women
and competitors.
		-- Lord Thomas Dewar

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