Color change on encoding

[Lipomo]

I just tried last dev, the error is gone.
Output video have all three BT709 info, no more GBR color matrix warning on closing, no visual color difference, 0% difference with diffimg.

How did you managed to find the issue ?

[Selur]

I only fixed the startup problem.
Didn't change anything else, but the dev version can come with different ffmpeg versions, my guess atm. is that your problem was caused by some bug in ffmpeg which they fixed.

Cu Selur

[Lipomo]

I only fixed the startup problem.
Didn't change anything else, but the dev version can come with different ffmpeg versions, my guess atm. is that your problem was caused by some bug in ffmpeg which they fixed.

Cu Selur

That would make sense, I didn't thought about that. Well, problem fixed it's nice 

[Lipomo]

Bad news, the bug is still there, but only when applying any vapoursynth filters. I have investigated and I think you're right, it seems to be ffmpeg, because all codecs encoded by ffmpeg have the issue.

Apparently, the issue is from the last ffmpeg 7.1 which is probably used in Hybrid 2024-11-11

• With ffmpeg 7.1 (manually located on Config > Tools) or internal Hybrid ffmpeg, this is the result :
  

- any codec without vapoursynth filter = OK
- any codec + avisynth filters = OK
- UT Video + vapoursynth filters = colors changed
- FFV1 + vapoursynth filters = colors changed
- FFvhuff + vapoursynth filters = color changed
- x264/x265 lossless + vapoursynth filters = OK

• With ffmpeg 7.0.2 (manually located on Config > Tools) with Hybrid 2024-11-11
  

- any codec without vapoursynth filter = OK
- any codec + avisynth filters = OK
- UT Video + vapoursynth filters = OK
- FFV1 + vapoursynth filters = OK
- FFvhuff + vapoursynth filters = OK
- x264/x265 lossless + vapoursynth filters = OK

• With Hybrid 2024-09-29 (probably using a nightly builf of ffmpeg between 7.0.2 and 7.1)
  

- any codec without vapoursynth filter = OK
- any codec + avisynth filters = OK
- UT Video + vapoursynth filters = colors changed
- FFV1 + vapoursynth filters = OK
- FFvhuff + vapoursynth filters = color changed
- x264/x265 lossless + vapoursynth filters = OK


So if you try the latest Hybrid, with it's internal ffmpeg + enable any vapoursynth filter, you should have the color change issue.

Note :  The Vapoursynth preview with all filters is fine, the issue seems to be on encoding.

[Selur]

1. How do you test the color difference?
2. Did you try another source filter? (BestSource?FFMS2?LWLibavSource?)
3. Did you see any difference in the encoding calls? (seems to be 'just' ffmpeg based encoders)

The Vapoursynth preview with all filters is fine, the issue seems to be on encoding

The problem should then be with ffmpeg or the ffmpeg call.

Cu Selur

[Selur]

Used latest dev (which ffmpeg version N-117721-g000e303de4-g3330b733d3+1) and encoded using UT-Video (+ 'always use Vapoursynth' + LWLibavSource as source filter).
Vapoursynth Preview didn't show any color changes.
Script used:

# Imports
import vapoursynth as vs
# getting Vapoursynth core
import sys
import os
core = vs.core
# Import scripts folder
scriptPath = 'F:/Hybrid/64bit/vsscripts'
sys.path.insert(0, os.path.abspath(scriptPath))
# loading plugins
core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/SourceFilter/LSmashSource/LSMASHSource.dll")
# Import scripts
import validate
# Source: 'G:\099.mkv'
# Current color space: YUV420P8, bit depth: 8, resolution: 1920x1080, frame rate: 23.976fps, scanorder: progressive, yuv luminance scale: limited, matrix: 709, transfer: bt.709, primaries: bt.709, format: FFV1
# Loading G:\099.mkv using LWLibavSource
clip = core.lsmas.LWLibavSource(source="G:/099.mkv", format="YUV420P8", stream_index=0, cache=0, prefer_hw=0)
frame = clip.get_frame(0)
# setting color matrix to 709.
clip = core.std.SetFrameProps(clip, _Matrix=vs.MATRIX_BT709)
# setting color transfer (vs.TRANSFER_BT709), if it is not set.
if validate.transferIsInvalid(clip):
  clip = core.std.SetFrameProps(clip=clip, _Transfer=vs.TRANSFER_BT709)
# setting color primaries info (to vs.PRIMARIES_BT709), if it is not set.
if validate.primariesIsInvalid(clip):
  clip = core.std.SetFrameProps(clip=clip, _Primaries=vs.PRIMARIES_BT709)
# setting color range to TV (limited) range.
clip = core.std.SetFrameProps(clip=clip, _ColorRange=vs.RANGE_LIMITED)
# making sure frame rate is set to 23.976fps
clip = core.std.AssumeFPS(clip=clip, fpsnum=24000, fpsden=1001)
# making sure the detected scan type is set (detected: progressive)
clip = core.std.SetFrameProps(clip=clip, _FieldBased=vs.FIELD_PROGRESSIVE) # progressive
# set output frame rate to 23.976fps (progressive)
clip = core.std.AssumeFPS(clip=clip, fpsnum=24000, fpsden=1001)
# output
clip.set_output()

Encoding call

vspipe "J:\tmp\2024-11-13@14_36_12_1210\encodingTempSynthSkript_2024-11-13@14_36_12_1210_0.vpy" - -c y4m  |  ffmpeg -y -noautorotate -nostdin -threads 8 -f yuv4mpegpipe -i - -an -sn -fps_mode passthrough -vcodec utvideo -pred left -slices 0 -pix_fmt yuv420p -colorspace bt709 -metadata encoding_tool="Hybrid 2024.11.12.1" "J:\tmp\2024-11-13@14_36_12_1210\UT_LWLibavSource_1_2024-11-13@14_36_12_1210_02.mkv"

Compared the outputs using:

# Imports
import vapoursynth as vs
# getting Vapoursynth core
import sys
import os
core = vs.core
# Import scripts folder
scriptPath = 'F:/Hybrid/64bit/vsscripts'
sys.path.insert(0, os.path.abspath(scriptPath))
# loading plugins
core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/Support/libhistogram.dll")
core.std.LoadPlugin(path="F:/Hybrid/64bit/vsfilters/SourceFilter/LSmashSource/LSMASHSource.dll")
# Import scripts
import validate
# Source: 'G:\color_change_099.mkv'
# Current color space: YUV420P8, bit depth: 8, resolution: 1920x1080, frame rate: 23.976fps, scanorder: progressive, yuv luminance scale: limited, matrix: 709, transfer: bt.709, primaries: bt.709, format: FFV1
# Loading G:\color_change_099.mkv using LWLibavSource
clip = core.lsmas.LWLibavSource(source="G:/099.mkv", format="YUV420P8", stream_index=0, cache=0, prefer_hw=0)
clip = core.hist.Color(clip=clip)

reencode = core.lsmas.LWLibavSource(source="G:/Output/UT_LWLibavSource.mkv", format="YUV420P8", stream_index=0, cache=0, prefer_hw=0)
reencode = core.hist.Color(clip=reencode)


clip = core.std.Interleave([clip.text.Text("Org"),reencode.text.Text("Reencode")])

# output
clip.set_output()

=> I can reproduce the problem!
(https://imgsli.com/MzE3OTcy)

Looking into it.

Adding '-loglevel debug' to the ffmpeg call. I see:

Splitting the commandline.
Reading option '-y' ... matched as option 'y' (overwrite output files) with argument '1'.
Reading option '-noautorotate' ... matched as option 'autorotate' (automatically insert correct rotate filters) with argument 0.
Reading option '-nostdin' ... matched as option 'stdin' (enable or disable interaction on standard input) with argument 0.
Reading option '-threads' ... matched as AVOption 'threads' with argument '8'.
Reading option '-f' ... matched as option 'f' (force container format (auto-detected otherwise)) with argument 'yuv4mpegpipe'.
Reading option '-i' ... matched as input url with argument '-'.
Reading option '-an' ... matched as option 'an' (disable audio) with argument '1'.
Reading option '-sn' ... matched as option 'sn' (disable subtitle) with argument '1'.
Reading option '-fps_mode' ... matched as option 'fps_mode' (set framerate mode for matching video streams; overrides vsync) with argument 'passthrough'.
Reading option '-vcodec' ... matched as option 'vcodec' (alias for -c:v (select encoder/decoder for video streams)) with argument 'utvideo'.
Reading option '-pred' ... matched as AVOption 'pred' with argument 'left'.
Reading option '-slices' ... matched as AVOption 'slices' with argument '0'.
Reading option '-pix_fmt' ... matched as option 'pix_fmt' (set pixel format) with argument 'yuv420p'.
Reading option '-colorspace' ... matched as AVOption 'colorspace' with argument 'bt709'.
Reading option '-loglevel' ... matched as option 'loglevel' (set logging level) with argument 'debug'.
Reading option '-metadata' ... matched as option 'metadata' (add metadata) with argument 'encoding_tool=Hybrid 2024.11.12.1'.
Reading option 'G:\Output\UT_LWLibavSource_1_2024-11-13@14_47_27_4010_02.mkv' ... matched as output url.

and

[yuv4mpegpipe @ 000002613b1175c0] After avformat_find_stream_info() pos: 3110466 bytes read:3112960 seeks:0 frames:1
Input #0, yuv4mpegpipe, from 'fd:':
  Duration: N/A, start: 0.000000, bitrate: N/A
  Stream #0:0, 1, 1001/24000: Video: rawvideo, 1 reference frame (I420 / 0x30323449), yuv420p(progressive, center), 1920x1080, 0/1, 23.98 fps, 23.98 tbr, 23.98 tbn
Successfully opened the file.
Parsing a group of options: output url G:\Output\UT_LWLibavSource_1_2024-11-13@14_47_27_4010_02.mkv.
Applying option an (disable audio) with argument 1.
Applying option sn (disable subtitle) with argument 1.
Applying option fps_mode (set framerate mode for matching video streams; overrides vsync) with argument passthrough.
Applying option vcodec (alias for -c:v (select encoder/decoder for video streams)) with argument utvideo.
Applying option pix_fmt (set pixel format) with argument yuv420p.
Applying option metadata (add metadata) with argument encoding_tool=Hybrid 2024.11.12.1.
Successfully parsed a group of options.
Opening an output file: G:\Output\UT_LWLibavSource_1_2024-11-13@14_47_27_4010_02.mkv.
[out#0/matroska @ 000002613b128480] No explicit maps, mapping streams automatically...
[vost#0:0/utvideo @ 000002613949b300] Created video stream from input stream 0:0
[file @ 000002613949d400] Setting default whitelist 'file,crypto,data'
Successfully opened the file.
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> utvideo (native))
[vost#0:0/utvideo @ 000002613949b300] Starting thread...
[vf#0:0 @ 000002613949d5c0] Starting thread...
[vist#0:0/rawvideo @ 000002613949a800] [dec:rawvideo @ 000002613949dc00] Starting thread...
[in#0/yuv4mpegpipe @ 000002613b117200] Starting thread...
[rawvideo @ 000002613b129700] PACKET SIZE: 3110400, STRIDE: 2880
detected 32 logical cores
[rawvideo @ 000002613b129700] PACKET SIZE: 3110400, STRIDE: 2880
[graph -1 input from stream 0:0 @ 000002613b176100] w:1920 h:1080 pixfmt:yuv420p tb:1001/24000 fr:24000/1001 sar:0/1 csp:unknown range:unknown
[format @ 000002613b176600] Setting 'pix_fmts' to value 'yuv420p'
[format @ 000002613b176600] Setting 'color_spaces' to value 'bt709'
[format @ 000002613b176600] Setting 'color_ranges' to value 'tv'
[auto_scale_0 @ 000002613b176ac0] w:iw h:ih flags:'' interl:0
[format @ 000002613b176600] auto-inserting filter 'auto_scale_0' between the filter 'Parsed_null_0' and the filter 'format'
[AVFilterGraph @ 000002613b12a540] query_formats: 4 queried, 6 merged, 3 already done, 0 delayed
[swscaler @ 000002613b18ab40] [swscaler @ 000002613b19ef00] YUV color matrix differs for YUV->YUV, using intermediate RGB to convert
...

[swscaler @ 000002613b18ab40] [swscaler @ 000002613b19ef00] YUV color matrix differs for YUV->YUV, using intermediate RGB to convert

Seems wrong.


Cu Selur

[Lipomo]

Nice ! 

[Selur]

using latest ffmpeg from: https://www.gyan.dev/ffmpeg/builds/ also shows the problem (both with 'master' and 'release')
FFmpegs changelog does not hint to something that should do this.

Think I got, it seems like "-colorspace bt709" now need to be added as input parameters too if pipe input is used.
=> I'll look into it

[Selur]

Uploaded a dev version which now sets vui stuff for input&output when using ffmpeg.
Let me know whether that fixes the problem for you too.

Cu Selur

[Lipomo]

I just tried last build with all FFMPEG codecs + Vapoursynth filters and everything is now fixed