== Rotate ==

If the camera was recording in "upside down" mode:

{{{#!highlight sh numbers=off
parallel -u 'echo {}; jpegtran -rotate 180 -perfect -copy all -outfile {}.tran {} && mv {}.tran {}' ::: *.jpg
}}}

== Resize & crop ==

{{{#!highlight sh
# Crop top
find . -name '*JPG' -print0 | xargs -0 -P$(nproc) -n256 gm mogrify -chop 0x486 -resize 1920x1080
# or Crop bottom
find . -name '*JPG' -print0 | xargs -0 -P$(nproc) -n256 gm mogrify -gravity South -chop 0x486 -resize 1920x1080
}}}

For the GoPro HD Hero 2:

{{{#!highlight sh
# Crop top
find . -name '*JPG' -print0 | xargs -0 -P$(nproc) -n256 mogrify -crop 3840x2880+0+720 -resize 1920x1080
}}}

For the Xiaomi Yi:

{{{#!highlight sh
# 16 MP
# Crop top
find . -name '*jpg' -print0 | xargs -0 -P$(nproc) -n256 gm mogrify -chop 0x864 -resize 1920x1080
# Crop top at 4K
find . -name '*jpg' -print0 | xargs -0 -P$(nproc) -n256 gm mogrify -chop 0x864 -resize 3840x2160

# 13 MP
# Crop top
find . -name '*jpg' -print0 | xargs -0 -P$(nproc) -n256 gm mogrify -chop 0x774 -resize 1920x1080
# Crop top at 4K
find . -name '*jpg' -print0 | xargs -0 -P$(nproc) -n256 gm mogrify -chop 0x774 -resize 3840x2160

# Xiaomi Yi 4K
# 8M (native 4K mode)
find . -name '*jpg' -print0 | xargs -0 -P$(nproc) -n256 gm mogrify -resize 1920x1080
}}}

For A6500:

{{{
# Crop bottom, use high-quality resizing
find . -name '*JPG' -print0 | xargs -0 -P$(nproc) -n256 gm mogrify -gravity South -chop 0x625 -resize 3840x2160 -filter Lanczos -unsharp
}}}


== LDR tone mapping ==

{{{#!highlight sh numbers=off
parallel -u 'echo {}; ~/sys/tonemap/tonemapping ~/sys/tonemap/default.tnp {} {}.tonemapped && mv {}.tonemapped {}' ::: *.jpg
}}}

batch:

{{{
for i in $(ls); do (cd $i; parallel -u 'echo {}; ~/sys/tonemap/tonemapping ~/sys/tonemap/default.tnp {} {}.tonemapped && mv {}.tonemapped {}' ::: *.jpg); done;
}}}

== Encode to video (WebM, MP4) ==

{{{#!highlight sh numbers=off
# Old mencoder line
mencoder mf://*.JPG -mf fps=15:type=jpg -ovc lavc -oac lavc -of lavf -lavfopts format=webm -lavcopts threads=4:acodec=vorbis:vcodec=libvpx -ffourcc VP80 -o $(basename $(pwd)).webm

# New MPV line, for VP9
# qmax appears to set video quality… lower number (e.g. qmax=25) is better quality, higher number (default is qmax=63) is less quality
mpv mf://*.jpg -mf-fps=15 -mf-type=jpeg --ovc=libvpx-vp9 -ovcopts qmax=30,threads=$(nproc) -o $(basename $(pwd)).vp9.webm

# MPV for x264
mpv mf://*.jpg -mf-fps=15 -mf-type=jpeg --ovc=libx264 --ovcopts threads=$(nproc) -o $(basename $(pwd)).mp4
# MPV for lossless x264
mpv mf://*.jpg -mf-fps=15 -mf-type=jpeg --ovc=libx264 --ovcopts preset=veryslow,qp=0,threads=$(nproc) -o $(basename $(pwd)).lossless.mp4

}}}

See https://github.com/Argon-/mpv-config/blob/master/encoding-profiles.conf for more mpv encoding profiles.

batch:

{{{
# use one of the commands from above
COMMAND='' # make sure to use single quotes
for i in $(ls); do (echo cd $i; echo $COMMAND; echo cd ../); done
}}}

== Merge files ==

After placing all the WebM files in one directory, merge with:

{{{#!highlight sh numbers=off
f() { args=("$1"); shift; args+=("${@/#/+ }"); echo "${args[@]}"; }; echo mkvmerge $(f $(ls *webm))
}}}

or for MP4:

{{{#!highlight sh numbers=off
echo -n MP4Box ""; for i in $(ls *mp4); do echo -n -cat $i "" ; done; echo -new out.mp4
}}}

== Interesting links ==

Open-source implementation of Microsoft's HyperLapse: [[https://github.com/willcrichton/hyperlapse|willcrichton/hyperlapse: Open-source implementation of MSR Hyperlapse]]