How to use "curves" filter with "hwupload" in FFmpeg?

[elias tsolis]

currently, i use this, however, i am unable to run it specifying points in curves. Is any option to use a gnuplot file directly? or to extract smplayer options on brightness, gamma etc. to use them with ffmpeg somehow?

for vids in *.avi; do ffmpeg -hwaccel vaapi -hwaccel_output_format yuv420p -vaapi_device /dev/dri/renderD128 -i "$vids" -vf 'curves=preset=lighter,setpts=2*PTS,format=nv12,hwupload,scale_vaapi=w=2560:h=1440:format=nv12' -strict experimental -c:v hevc_vaapi -b:v 20M -video_track_timescale 90000 "a_${vids/.*}.mp4"; done;

debian trixie linux,
ffmpeg version 7.0.2-3

[MasterQuestionable]

͏    Interpreted filter-chain:
͏    curves=preset=lighter,
͏    setpts=2*PTS,
͏    format=nv12,
͏    hwupload,
͏    scale_vaapi=w=2560:h=1440:format=nv12

͏    Refer:
͏    https://ffmpeg.org/ffmpeg-filters.html#curves
͏    etc.

[elias tsolis]

i have read, and tried different combinations, nothing worked.
this does not work -->
curves=blue='0/0 0.5/0.58 1/1'
or curves=all='0/0,0.5/0.58,1/1'
or curves=all='0/0:0.5/0.58:1/1'
inside this command:

for vids in *.avi; do ffmpeg -hwaccel vaapi -hwaccel_output_format yuv420p -vaapi_device /dev/dri/renderD128 -i "$vids" -vf 'curves=all='0/0 0.5/0.58 1/1',setpts=2*PTS, format=nv12,hwupload,scale_vaapi=w=2560:h=1440:format=nv12' -strict experimental -c:v hevc_vaapi -b:v 20M -video_track_timescale 90000 "a_${vids/.*}.mp4"; done;

[MasterQuestionable]

͏    Your Unix Shell syntax is invalid: bad quoting.
͏    To embed literal `'` within such quoting: use `'\''`.
͏    E.g. "a'b", as 'a'\''b'.

͏    You may also look at:
͏    ​https://www.shellcheck.net/
͏    ​https://www.gnu.org/software/bash/manual/bash.html#Quoting
͏    ​https://pubs.opengroup.org/onlinepubs/9799919799/utilities/V3_chap02.html
͏    ​https://pubs.opengroup.org/onlinepubs/9799919799/xrat/V4_xcu_chap01.html#tag_23_02_02
͏    ; for reference.

[elias tsolis]

dont work

ffmpeg  -hwaccel vaapi -hwaccel_output_format yuv420p -vaapi_device /dev/dri/renderD128 -i b.mp4 -vf 'curves=all='\"0/0 0.5/0.58 1/1'\",format=nv12,hwupload,format=nv12'             -strict experimental   -c:v hevc_vaapi cp.mp4

'curves=all=‘\’0/0 0.5/0.58 1/1‘\’
'curves=all='\'0/0 0.5/0.58 1/1'\'
'curves=all=\'0/0 0.5/0.58 1/1\'
'curves=all='\"0/0 0.5/0.58 1/1\"'
'curves=all=''0/0 0.5/0.58 1/1\''

[MasterQuestionable]

͏    You typed wrong content.
͏    `''` is not `"` even if they may look the same under some fonts.

͏    Or use `"` as the outer quote to avoid the havoc.
͏    (but caveat its implication on "$" alike)

͏    Hint: Try with `echo` first.

[elias tsolis]

thanks! i search all over the internet and could not find any example for that. Please, add it as an example to ffmpeg curves guide. It does not take too much time from your side, instead for a use to search a whole day how to do it.

Double quotes (") on outer ffmpeg command can make single quoted (') ffmpeg sub-operands to work very fine, inside these double quotes.

For future reference, I place the whole command:

ffmpeg  -hwaccel vaapi -hwaccel_output_format yuv420p -vaapi_device /dev/dri/renderD128 -i vid_original.mp4 -vf "curves=all='0/0 0.8/0.8 1/1',format=nv12, hwupload" -strict experimental   -c:v hevc_vaapi vid_copy.mp4

if I want to update ffmpeg guide, how I can do it?

[MasterQuestionable]

͏    Much yes.
͏    Which guide? You may probably directly edit? (if it's the wiki)

͏    If it's the doc on ͏"ffmpeg.org"... (which is generated from Texinfo)
͏    I don't yet understand its syntax and cannot properly edit.
͏    See also: ​https://trac.ffmpeg.org/ticket/11096#comment:10

͏    The shell command languages is a somewhat convoluted topic:
͏    There are 3 primary shells in use:
͏    |1| Unix Shell (Bash, Dash, Fish, Ksh, Zsh etc.)
͏    |2| Windows CMD
͏    |3| PowerShell
͏    ; each somewhat (or significantly; for CMD) differs in their syntax:
͏    In a much incompatible manner.
͏    .
͏    And cleaning things up may be quite troublesome.
͏    (without having users completely aware of the situation)