How to get rid of blocks when encoding with x264.exe

9th Aug 2021 12:18 #1

Member

Hi,

I'm encoding a jpeg2000 (.mxf) file to a .264 file use x264.exe. When I encode the video, I get very obvious blocks of pixels around the red text. An example of the before and after frames are below, you can see that the crown is encoded pretty well and with detail, but the edges of the text has big blocks around them.

The command line used to encode the video is:

Code:

.\x264_8bit.exe --preset veryslow --crf 14 --level 4.1 --ref 4 -f -3:-3 --merange 32 --qcomp 0.70 --psy-rd 0.85:0.10 --bframes 10 --rc-lookahead 72 --sar 1:1 --colorprim bt709 --transfer bt709 --colormatrix bt709 --vbv-maxrate=62500 --vbv-bufsize=78125 --non-deterministic --no-dct-decimate --input-depth 8 --input-csp i420 --output-csp i420 --input-range tv --range tv --fps 24.000 --vf resize:width=1920,height=1080,fittobox=width -o "output.264" "input.mxf"

I have tried encoding with a lower CRF setting, but no luck yet, those blocks are still there. Is there a way I can get rid of those block (just around the text)? Or is it just something I have to accept when encoding with 264.exe?

JPEG2000 frame:

[Attachment 60251 - Click to enlarge]

.264 frame:

[Attachment 60250 - Click to enlarge]

Mediainfo JPEG2000;

Code:

General
Complete name                            : input.mxf
Format                                   : MXF
Format version                           : 1.2
Format profile                           : OP-Atom
Format settings                          : Closed / Complete
File size                                : 503 MiB
Duration                                 : 1 min 25 s
Overall bit rate                         : 49.5 Mb/s
Package name                             : AS-DCP Material Package / File Package: SMPTE 429-4 frame wrapping of JPEG 2000 codestreams
Encoded date                             : 2020-03-18 13:38:09.000
Writing application                      : Colorfront Transkoder 2017.0.0.37817.2
Writing library                          : win32 2.7.19.27240.1

Video
ID                                       : 2
Format                                   : JPEG 2000
Format profile                           : D-Cinema 2k
Format settings, wrapping mode           : Frame
Codec ID                                 : 0D010301020C0100-0401020203010103
Duration                                 : 1 min 25 s
Bit rate                                 : 49.4 Mb/s
Width                                    : 2 048 pixels
Height                                   : 858 pixels
Display aspect ratio                     : 2.40:1
Frame rate                               : 24.000 FPS
Color space                              : XYZ
Chroma subsampling                       : 4:4:4
Bit depth                                : 12 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 1.173
Stream size                              : 503 MiB (100%)
Title                                    : Picture Track

Other #1
ID                                       : 1-Material
Type                                     : Time code
Format                                   : MXF TC
Time code of first frame                 : 00:00:00:00
Time code settings                       : Material Package
Time code, striped                       : Yes

Other #2
ID                                       : 1-Source
Type                                     : Time code
Format                                   : MXF TC
Time code of first frame                 : 01:00:00:00
Time code settings                       : Source Package
Time code, striped                       : Yes

.264 mediainfo

Code:

General
Complete name                            : output.264
Format                                   : AVC
Format/Info                              : Advanced Video Codec
File size                                : 102 MiB
Writing library                          : x264 core 142 r2431+42 c69a006 tMod [8-bit@all X86_64]
Encoding settings                        : cabac=1 / ref=4 / deblock=1:-3:-3 / analyse=0x3:0x133 / me=umh / subme=10 / psy=1 / fade_compensate=0.00 / psy_rd=0.85:0.10 / mixed_ref=1 / me_range=32 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-3 / threads=12 / lookahead_threads=3 / sliced_threads=0 / nr=0 / decimate=0 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / fgo=0 / bframes=10 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=24 / scenecut=40 / intra_refresh=0 / rc_lookahead=72 / rc=crf / mbtree=1 / crf=14.0000 / qcomp=0.70 / qpmin=0:0:0 / qpmax=69:69:69 / qpstep=4 / vbv_maxrate=62500 / vbv_bufsize=78125 / crf_max=0.0 / nal_hrd=none / filler=0 / ip_ratio=1.40 / aq=1:1.00 / aq-sensitivity=10.00 / aq-factor=1.00:1.00:1.00 / aq2=0 / aq3=0

Video
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L4.1
Format settings                          : CABAC / 4 Ref Frames
Format settings, CABAC                   : Yes
Format settings, RefFrames               : 4 frames
Width                                    : 1 920 pixels
Height                                   : 804 pixels
Display aspect ratio                     : 2.40:1
Frame rate                               : 24.000 FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Writing library                          : x264 core 142 r2431+42 c69a006 tMod [8-bit@all X86_64]
Encoding settings                        : cabac=1 / ref=4 / deblock=1:-3:-3 / analyse=0x3:0x133 / me=umh / subme=10 / psy=1 / fade_compensate=0.00 / psy_rd=0.85:0.10 / mixed_ref=1 / me_range=32 / chroma_me=1 / trellis=2 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-3 / threads=12 / lookahead_threads=3 / sliced_threads=0 / nr=0 / decimate=0 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / fgo=0 / bframes=10 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=24 / scenecut=40 / intra_refresh=0 / rc_lookahead=72 / rc=crf / mbtree=1 / crf=14.0000 / qcomp=0.70 / qpmin=0:0:0 / qpmax=69:69:69 / qpstep=4 / vbv_maxrate=62500 / vbv_bufsize=78125 / crf_max=0.0 / nal_hrd=none / filler=0 / ip_ratio=1.40 / aq=1:1.00 / aq-sensitivity=10.00 / aq-factor=1.00:1.00:1.00 / aq2=0 / aq3=0
Color range                              : Limited
Color primaries                          : BT.709
Transfer characteristics                 : BT.709
Matrix coefficients                      : BT.709

Quote

9th Aug 2021 12:26 #2

Selur

Member

In case you are talking about the banding (https://en.wikipedia.org/wiki/Colour_banding): you could either add dithering or encode to a higher bit depth.

users currently on my ignore list: deadrats, Stears555, marcorocchini

Quote

9th Aug 2021 12:54 #3

poisondeathray

Member

He's probably referring to the chroma subsampling 4:2:0 vs. 4:4:4 since he's referring to the text

You can use a better chroma upscaler for playback, use a softer chroma downsampler, or blur the chroma when preparing 4:2:0,

or use 4:4:4 for encoding (usually not compatible for most end delivery scenarios)