[MPlayer-users] XviD 2-pass problems

[Nico Sabbi]

kmn wrote:

>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.
>
>  
>
it's an old and still unsolved problem: libmpeg2 (the decoding library) 
sometimes reinitializes
the decoding and filtering pipeline, at the end of which is xvid that 
overwrites the logfile.
I never experienced this problem when using  -vc ffmpeg12