[MPlayer-users] XviD 2-pass problems

kmn c15zyx at hotmail.com
Sun Apr 11 21:26:35 CEST 2004


Hi,
I've run into a problem (bug?) with XviD 2-pass in recent versions-
for some files it creates an empty 1st pass logfile (except for the header
w/ the XviD version and the do not modify notice), which makes the
second pass useless. During these passes data is being written to the
pass file OK, but when it completes mencoder does something and the log
gets reset to empty. I've been trying to track down the conditions for this
problem, but have been unsuccessful, all I know so far is that it tends to
affect large files (DVD vobs) more  than smaller ones. What is unusual is
that at the end of the encode, the last few lines of the problem pass are:

Pos:   3.8s    112f ( 0%)  58fps Trem:   0min   0mb  A-V:0.000 [2:0]
demux_mpg: 24fps progressive NTSC content detected, switching framerate.
VDec: vo config request - 720 x 480 (preferred csp: Planar YV12)7:0]
VDec: using Planar YV12 as output csp (no 0)
Movie-Aspect is 1.78:1 - prescaling to correct movie aspect.
videocodec: XviD (16x16 fourcc=44495658 [DIVX])
xvid: 2Pass Rate Control -- 1st pass
Pos:7011.2s 168122f (99%)  39fps Trem:   0min   7mb  A-V:0.000 [7:0]
Writing AVI index...
Fixing AVI header...
ODML: vprp aspect is 16384:9362.

Video stream:    7.278 kbit/s  (909 bps)  size: 6378460 bytes  7011.171
   secs  168122 frames


While the end output for an OK pass is:


Pos:   3.8s    112f (13%)  60fps Trem:   0min   0mb  A-V:0.000 [2:0]
demux_mpg: 24fps progressive NTSC content detected, switching framerate.
Pos:  28.3s    701f (99%)  65fps Trem:   0min   0mb  A-V:0.000 [4:0]
Writing AVI index...
Fixing AVI header...
ODML: vprp aspect is 16384:9362.

Video stream:    4.627 kbit/s  (578 bps)  size: 16381 bytes  28.320 secs
   701 frames


Apparently mencoder is repeating some steps from the start of the encode
at the end, and this is clearing the 1st pass log file. Any suggestions to get
around this? Also, another problem I've been experiencing with XviD is that
constant quantizer seems to be broken... it encodes but its bitrates are huge,
roughly 3x previous versions, although 1 or 2 pass works fine, the quantizers
produce bitrates like they should.




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