[x264-devel] x264 bug/feature: interlaced video problem - height of the frame is larger than original frame and is padded with cloned pixels

[Lauri Ahonen]

Hello everyone! Great efforts on a superb project, thank you!

I've been experimenting with DVD -> H264 conversion script which uses 
Avisynth and x264 for the video processing. I tried to implement 
cropping of the interlaced frame by removing 8 pixels from the edges of 
the video frame resolution 720x576i resulting in a 704x560i frame. 
However, after encoding the frame is 568i and pixels of the extra lines 
are cloned much like they would be with non Mod16 resolutions. If I try 
to resize the frame to 704x568i, the resulting frame is 572i and the 
problem persists.

Is there some other restrictions apart from the Mod16 that I'm not 
aware? Should I just revert to full frame with interlaced frames and not 
to crop at all - or is this possibly a bug? Vertical resolution of 544i 
seems to work ok.

Thanks you in advance,
zk.

Here is a capture of the logs:

====================

MPEG2 is 100.00% VIDEO
Detected as interlaced.
COMMAND EXECUTION: 
"H:\programming\rexx\Videoarkisto\Common\Executables\x264 
builds\x264.1376kMod.core2.x86.exe" "L:\dvd2stream\Temp_Matka elamani 
valtamerelle_1\VideoFile.avs" --pass 1 --stats "L:\dvd2stream\Temp_Matka 
elamani valtamerelle_1\VideoFile.stats" --crf 18 --interlaced --preset 
slower --
level 4 --ref 3 --vbv-bufsize 25000 --vbv-maxrate 25000 --aud --threads 
4 --sar 16:11 --output "L:\dvd2stream\Temp_Matka elamani 
valtamerelle_1\VideoFile.264"

I:\DVD 
interlaced>"H:\programming\rexx\Videoarkisto\Common\Executables\x264 
builds\x264.1376kMod.core2.x86.exe" "L:\dvd2stream\Temp_Matka elamani 
valtamerelle_1\VideoFile.avs" --pass 1 --stats "L:\dvd2stream\Temp_Matka 
elamani valtamerelle_1\VideoFile.stats" --crf 18 --interlaced --preset 
slower --l
evel 4 --ref 3 --vbv-bufsize 25000 --vbv-maxrate 25000 --aud --threads 4 
--sar 16:11 --output "L:\dvd2stream\Temp_Matka elamani 
valtamerelle_1\VideoFile.264"
avs [info]: 704x560 @ 25.00 fps (43438 frames)
x264 [warning]: interlace + direct=temporal is not implemented
x264 [warning]: interlace + weightp is not implemented
x264 [info]: using SAR=16/11
x264 [warning]: VBV bitrate (25000) > level limit (20000)
x264 [info]: using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle 
SSE4.1 Cache64
x264 [info]: cabac=1 ref=1 deblock=1:0:0 analyse=0x1:0 me=dia subme=2 
psy=1 psy_rd=0.0:0.0 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 
8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=4 
sliced_threads=0 nr=0 decimate=1 mbaff=1 constrained_intra=0 bframes=3 
b_pyramid=0 b_adapt=
2 b_bias=0 direct=1 wpredb=1 wpredp=0 keyint=250 keyint_min=25 
scenecut=40 rc_lookahead=60 rc=crf mbtree=1 crf=18.0000 qcomp=0.60 
qpmin=10 qpmax=51 qpstep=4 vbv_maxrate=25000 vbv_bufsize=25000 
ip_ratio=1.40 aq=1:1.00
x264 [info]: profile Main, level 4.0
x264 [info]: frame I:435   Avg QP:14.81  size: 66540
x264 [info]: frame P:17738 Avg QP:17.68  size: 15163
x264 [info]: frame B:25265 Avg QP:20.06  size:  4707
x264 [info]: consecutive B-frames:  8.7% 21.6% 52.1% 17.6%
x264 [info]: mb I  I16..4: 20.0%  0.0% 80.0%
x264 [info]: mb P  I16..4: 18.8%  0.0%  0.0%  P16..4: 61.9%  0.0%  0.0%  
0.0%  0.0%    skip:19.3%
x264 [info]: mb B  I16..4:  4.8%  0.0%  0.0%  B16..8: 20.7%  0.0%  0.0%  
direct:14.6%  skip:59.9%  L0:30.6% L1:44.5% BI:25.0%
x264 [info]: coded y,uvDC,uvAC intra: 73.0% 62.0% 33.3% inter: 26.1% 
16.1% 1.2%
x264 [info]: i16 v,h,dc,p: 25% 26% 33% 16%
x264 [info]: i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 17% 27% 15%  6%  6%  5%  9%  
5% 10%
x264 [info]: kb/s:1919.24

encoded 43438 frames, 65.33 fps, 1919.24 kb/s
1
COMMAND EXECUTION: 
"H:\programming\rexx\Videoarkisto\Common\Executables\tsmuxer.exe" 
"L:\dvd2stream\Temp_Matka elamani valtamerelle_1\VideoFile.meta" 
"D:\Incoming\dvd2stream\Matka elamani valtamerelle_1.m2ts"

I:\DVD 
interlaced>"H:\programming\rexx\Videoarkisto\Common\Executables\tsmuxer.exe" 
"L:\dvd2stream\Temp_Matka elamani valtamerelle_1\VideoFile.meta" 
"D:\Incoming\dvd2stream\Matka elamani valtamerelle_1.m2ts"
SmartLabs tsMuxeR.  Version 1.8.4(b) http://www.smlabs.net
Decoding H264 stream (track 1): Profile: Main at 4.0  Resolution: 704:568i  
Frame rate: 25
H.264 muxing fps not set. Get fps from stream.
Decoding MPEG-Audio stream (track 2): Bitrate: 224Kbps  Sample Rate: 
48KHz  Channels: 2  Layer: 2
Processed 43438 video frames
100.0% complete
Mux successful complete.
Muxing time: 8 sec
Process complete.