[MEncoder-users] unexpected bitrate warning with x264

[Christian Ebert]

Hi,

When encoding for the iPod for some movies I get the following
warning when the second pass is started:

x264 [warning]: target: 384.00 kbit/s, expected: 359.05 kbit/s, avg QP: 25.5253

Could it be the relatively hight setting of qcomp=0.8?

I actually would like to use the _full_ bitrate I am specifying.

I don't get this for all movies, and not with different scripts
using x264 (with bframes, higher frameref etc.).

I am using the latest x264, but this has always happened -- well,
since I am running this script.

Command and output (the raw video is later muxed with audio by MP4Box):

mencoder -nosound -mc 0 -noskip -sws 10 -vfm ffmpeg \
-fps 25 -ofps 25 -fielddominance 1 \
-vf \
scale,pp=lb/ha:164:7/va/dr,fmt=yv12,softskip,scale=320:240,harddup \
-aspect 4/3 -of rawvideo -ovc x264 \
-x264encopts \
bitrate=384:pass=2:turbo=1:keyint=250:keyint_min=25\
scenecut=40:frameref=1:bframes=0:nocabac\
qp_min=10:qp_max=51:vbv_maxrate=768:vbv_bufsize=500\
qcomp=0.8:direct_pred=none:noweight_b:no8x8dct:me=tesa\
me_range=64:subq=8:chroma_me:nomixed_refs:trellis=0\
partitions=p8x8,p4x4,i4x4:psy-rd=0.6,0.0:aq_mode=2:nofast_pskip\
dct_decimate:level_idc=13:threads=auto:psnr:ssim"
-o test.raw test.mov

MEncoder SVN-r29437-4.0.1 (C) 2000-2009 MPlayer Team
success: format: 0  data: 0x0 - 0xea3325c1
libavformat file format detected.
[lavf] Video stream found, -vid 0
[lavf] Audio stream found, -aid 1
VIDEO:  [dvcp]  720x576  24bpp  25.000 fps    0.0 kbps ( 0.0 kbyte/s)
[V] filefmt:44  fourcc:0x70637664  size:720x576  fps:25.000  ftime:=0.0400
Input fps will be interpreted as 25.000 instead.
Opening video filter: [expand osd=1]
Expand: -1 x -1, -1 ; -1, osd: 1, aspect: 0.000000, round: 1
Opening video filter: [harddup]
Opening video filter: [scale w=320 h=240]
Opening video filter: [softskip]
Opening video filter: [format fmt=yv12]
Opening video filter: [pp=lb/ha:164:7/va/dr]
Opening video filter: [scale]
==========================================================================
Trying to force video codec driver family ffmpeg...
Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
Unsupported PixelFormat -1
Selected video codec: [ffdv] vfm: ffmpeg (FFmpeg DV)
==========================================================================
VDec: vo config request - 720 x 576 (preferred colorspace: Planar YV12)
[PP] Using external postprocessing filter, max q = 6.
VDec: using Planar YV12 as output csp (no 2)
Movie-Aspect is 1.33:1 - prescaling to correct movie aspect.
[swscaler @ 0x802660]using unscaled yuv420p -> yuv420p special converter
x264 [info]: using SAR=1/1
x264 [info]: using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle SSE4.1 Cache64
x264 [warning]: target: 384.00 kbit/s, expected: 359.05 kbit/s, avg QP: 25.5253
x264 [info]: profile Baseline, level 1.3
x264 [error]: 2nd pass has more frames than 1st pass (167473)000 [358:0]
x264 [error]: continuing anyway, at constant QP=25
Pos:6698.9s 167475f (94%) 15.90fps Trem:   9min 301mb  A-V:0.000 [358:0]
Flushing video frames.

The error I always get with these paramaters, but they do not
seem to affect the result.

c
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