Can we make this script more POSIX?

pfr

Trying to get this nsxiv script to work on NetBSD. However, as the author states in the README :

These are usually met on most modern Linux distributions. If your system is strictly POSIX, this script will fail to work.

So, I figure maybe it's not possible, but no harm in asking if anyone has any ideas.

I managed to circumvent the find error by replacing -printf "%P\0" with -print0, That's a start I guess.

The Script:

#!/usr/bin/env sh

tmpdir="$(mktemp -d)" || {
    printf "%s: %s\n" "${0##*/}" "could not create temporary directory"
    exit 1
}
trap 'rm -rf -- "$tmpdir"' TERM INT EXIT

find '.' -mindepth 1 -maxdepth 1 \( -type f -o -type l \) -print0 \
    | xargs -r0 -n 20 -P 64 file -00 -L --mime-type -- \
    | xargs -r0 -n 2 sh -c '
            case "$2" in
                video/*) printf "%s\0" "$1";;
            esac
        ' -- \
    | sort -z \
    | xargs -r0 -I FILE ffmpegthumbnailer -i FILE -o "$tmpdir/FILE.jpg" -m -t 50% -s 384 -q 10

{ nsxiv -0otp -- "$tmpdir"; rm -rf -- "${tmpdir:?}" > /dev/null; } \
    | sed -z 's|.jpg$||;s|^.*/||' \
    | xargs -r0 -I FILE xdg-open ./FILE

The errors are as expected:

sort: unknown option -- z
xargs: sh terminated by SIGPIPE
xargs: (null) terminated by SIGPIPE
sed: unknown option -- z
nsxiv: No valid image file given, aborting

Edit:

The author has written a slightly more POSIX version that now provides caching of thumbnails

pfr

~~I'll take the discussion over to Codeberg for now.~~

Original post updated with link to new script. Sorry to break any quoted links.

rvp

pfr The author has offered up this POSIX version as a solution.

That won't handle \n in filenames. Here's an almost-fully POSIX-compliant one for feh + mpv which also does caching:

tplay.sh

#!/bin/sh
#
# Play movies by selecting (generated) thumbnails.

set -eu
(set -o pipefail >/dev/null 2>&1) && set -o pipefail
debug=true

# Extract random frame from video file
# (ripped from `cover.sh' in https://github.com/seebye/fmui)
#
extpic() {
	local d h m s nsec rnd width video image

	width="$1" video="$2" image="$3"
	d=$(ffprobe "$video" 2>&1 | fgrep "Duration: ")
	d=$(expr "$d" : '.*\([0-9][0-9]:[0-9][0-9]:[0-9][0-9]\)\..*')
	OIFS="$IFS"
	IFS=:
	set -- $d
	IFS="$OIFS"
	h=${1#0}		# make not octal
	m=${2#0}
	s=${3#0}
	nsec=$((s + m * 60 + h * 60 * 60))
	# < 1 sec: too short--skip
	[ $nsec -eq 0 ] && return

	rnd=$(dd if=/dev/urandom bs=4 count=1 2>/dev/null | od -An -tu4)
	# no random source?--skip
	[ ${rnd:-0} -eq 0 ] && return
	# strip spaces; make not octal
	rnd=$(echo $rnd | sed -Ee 's/^0+//')

	$debug && echo "processing: $video"

	ffmpeg -loglevel quiet -y -ss $(( ((rnd<<15) | rnd) % nsec )) -discard nokey \
	    -noaccurate_seek -i "$video" -frames:V 1 -vf scale=${width}:-1 "$image"
}

CACHEBASE=$HOME/.cache/thumbnail-cache
DIRHASH=$(pwd | md5)
CACHEDIR="$CACHEBASE/$DIRHASH"

# Remove cache dir.
#
[ ${1:-""} = -r ] && { rm -rf "$CACHEDIR"; exit 0; }

[ -d "$CACHEBASE" ] || mkdir -p "$CACHEBASE"
[ -d "$CACHEDIR" ] || mkdir -p "$CACHEDIR"

# Remove stale files from thumbnail cache
#
for f in "$CACHEDIR"/*
do	file=${f##*/}
	file=${file%.jpg}
	if [ ! -f "$file" -o "$f" -ot "$file" ]
	then	rm -f "$f"
	fi
done

# Create thumbnail cache
#
TWID=128	# thumbnail width
for f in *
do	[ -f "$f" -o -L "$f" ] || continue
	[ -s "$CACHEDIR/$f.jpg" ] && continue
	file -b -L --mime-type -- "$f" | grep -q '^video/.*' &&
	    extpic $TWID "$f" "$CACHEDIR/$f.jpg"
done

# Pipe selected filenames to movie player
#
feh -t -A 'qstr.awk %F' -H 768 -W 1366 -y $TWID "$CACHEDIR" |
    xargs -L1 sh -c 'x=${0%.jpg}; qstr.awk "${x##*/}"' |
    xargs mpv

qstr.awk

#!/usr/bin/awk -f
#
# quote strings (typically, filenames) for use with xargs(1)

BEGIN {
	if (ARGC < 2)
		exit 1
	for (i = 1; i < ARGC; i++) {
		for (j = 1; j <= length(ARGV[i]); j++) {
			c = substr(ARGV[i], j, 1)
			s = s ((c ~ /["'\\[:space:]]/) ? "\\"c : c)
		}
		s = s ((i < ARGC) ? " " : "")
	}
	print s
}

JuvenalUrbino

pfr The author has offered up this POSIX version as a solution

Finally something I can understand; the initial script was driving me mad :-P.

rvp Try this one (also does caching):

But I like your scripting better.
EDIT:

@rvp would you consider giving lessons on SDF?
I've been told I'm a good student in the past XD.

pfr

rvp

Edit:

Ok, after fixing some small typos the script seems to run (I dont get any errors).

However, no feh thumbnail window appears to load and while some folder is created inside ~/.cache/thumbnail-cache there are no image files inside.

~/.cache/thumbnail-cache $ ls
drwxr-xr-x - dave 14 Jun 10:47  a351a24d53ac7d8aef743834015889bb
drwxr-xr-x - dave 14 Jun 11:00  e57ac5d89573d3fd83e9bf6145747e3d

I wonder, how do I actually launch mpv on a particular video file from feh?

Also, as it was originally intended to be used with sxiv, is feh in this script interchangeable with sxiv? and if so, is the awk script still needed?

I'm sure the author of the original script would appreciate a PR if his script can be made even more POSIX and if it would be able to handle video titles with /n

rvp

pfr there are no image files inside.

There's a bug in the qstr.awk script. Corrected. And, differences between the multifarious Bourne shell implementations--blech! Fixed.

pfr I wonder, how do I actually launch mpv on a particular video file from feh?

Just click on the images using the mouse (or press Enter), and when the script exits mpv will play the selected vids.

pfr this script interchangeable with sxiv?

You can make it work with very slight modifications.

pfr and if so, is the awk script still needed?

Since nsxiv doesn't shell-quote filenames (à la %Fin feh), the awk script is useless. Just use printf '%s\0' ... and xargs -0. But, urge the nsxiv authors to stick to POSIX (read the Rationale for xargs to see why it doesn't have a -0 flag).

pfr I'm sure the author of the original script would appreciate a PR if his script can be made even more POSIX

It's as POSIX as I can make it--mostly...

JuvenalUrbino @rvp would you consider giving lessons on SDF?

No free time for that, alas.

pfr

rvp
I still get no feh window and the thumbnail cache dir is still empty.. No output in the terminal either?

~/Videos $ /home/dave/./tplay.sh
~/Videos $

rvp Since nsxiv doesn't shell-quote filenames (à la %Fin feh)

What does this mean, exactly?

rvp

pfr Still having problems!? :D I tested on NetBSD too... Copy the scripts again, but, this time use the Copy button the board provides in the code blocks, instead of selecting using the mouse: if one's not careful with mouse-selection, the script may end up with bits missing--like what happened just previously.

pfr What does this mean, exactly?

The "marked" filenames output by nsxiv is not quoted for use in a shell command-line (needed to strip the .jpg extension to get bsck the original video filename).

nsxiv outputs only \n or \0-delimited filenames. \n-delimited filenames won't work if the filenames themselves contain \n. And, \0-delimiting required xargs to have a -0 flag, which is not in POSIX (and POSIX xargs can handle arbitrary chars. in filenames--except \0 and / which are invalid anyway--if you quote them properly as my script shows).

rvp

nsxiv-play.sh

#!/bin/sh
#
# Play movies by selecting (generated) thumbnails.

set -eu
(set -o pipefail >/dev/null 2>&1) && set -o pipefail
debug=true

MPLAYER=mpv	# movie player
CACHEBASE=$HOME/.cache/thumbnail-cache
DIRHASH=$(pwd | md5)
CACHEDIR="$CACHEBASE/$DIRHASH"

# Remove cache dir.
#
[ ${1:-""} = -r ] && { rm -rf "$CACHEDIR"; exit 0; }

[ -d "$CACHEBASE" ] || mkdir -p "$CACHEBASE"
[ -d "$CACHEDIR" ] || mkdir -p "$CACHEDIR"

# Remove stale files from thumbnail cache
#
for f in "$CACHEDIR"/*
do	file=${f##*/}
	file=${file%.jpg}
	[ "${f##*/}" = "*" ] && continue	# literal `*' == no files
	if [ ! -f "$file" -o "$f" -ot "$file" ]
	then	$debug && echo "removing stale: ${f##*/}"
		rm -f "$f"
	fi
done

# Create thumbnail cache
#
TWID=384	# thumbnail width
for f in *
do	[ -f "$f" -o -L "$f" ] || continue
	[ -s "$CACHEDIR/$f.jpg" ] && continue
	file -b -L --mime-type -- "$f" | grep -q '^video/.*' && {
	    $debug && echo "processing: $f"
	    ffmpegthumbnailer -i "$f" -o "$CACHEDIR/$f.jpg" -s $TWID
	}
done

# Pipe selected filenames to movie player
#
nsxiv -0opt "$CACHEDIR" |
    xargs -0 sh -c 'for f; do f=${f%.jpg}; printf "%s\0" "${f##*/}"; done' xxx |
    xargs -0 $MPLAYER

Not POSIX, but should handle arbitrary chars. in filenames. Uses nsxiv, ffmpegthumbnailer and mpv

pfr

rvp Hey RVP, I've only just realised that while this script is much quicker to load the saved thumbnails, I am unable to select multiple thumbnails in order to queue more than one video at a time.

The original script allows the user to select multiple thumbnails to play multiple videos, one after another.

Is this easy enough to replicate in your script?

rvp

pfr Is this easy enough to replicate in your script?

It should already do that (see the for loop passed to sh -c).