From 3e18b2836529d2c5c9b2c9a993b91cf42719ba19 Mon Sep 17 00:00:00 2001
From: nik gaffney <nik@fo.am>
Date: Thu, 27 Feb 2020 16:38:00 +1100
Subject: [PATCH] =?UTF-8?q?=E2=80=9CThe=20odd=20uneven=20time.=E2=80=9C?=
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---
 README.org   | 29 ++++++++++----------
 slitscan.rkt | 77 ++++++++++++++++++++++++++++++----------------------
 2 files changed, 60 insertions(+), 46 deletions(-)

diff --git a/README.org b/README.org
index a264629..848419a 100644
--- a/README.org
+++ b/README.org
@@ -1,51 +1,52 @@
 
 * time, space, stacking, slicing, scanning, etc 
 
-"Slitscan imaging techniques are used to create static images of time-based phenomena. In traditional film photography, slit scan images are created by exposing film as it slides past a slit-shaped aperture. In the digital realm, thin slices are extracted from a sequence of video frames, and concatenated into a new image."
+“Slitscan imaging techniques are used to create static images of time-based phenomena. In traditional film photography, slit scan images are created by exposing film as it slides past a slit-shaped aperture. In the digital realm, thin slices are extracted from a sequence of video frames, and concatenated into a new image.”
 
 [[http://www.flong.com/texts/lists/slit_scan/][An Informal Catalogue of Slit-Scan Video Artworks and Research]] Compiled by Golan Levin.
 
 [[slitscope_0.jpeg]]
 
-This particular slitscan provides some slightly configurable scaffolding around ffmpeg (based on a blogpost from [[http://oioiiooixiii.blogspot.com/2017/11/ffmpeg-temporal-slice-stacking-effect.html][oioiiooixiii]]) and is intended for non-realtime rendering at various resolutions. it's neither first, nor last. it's not especially interesting, educational or efficient. just another cloudform in the endless space of possible implementation... 
+This particular slitscan provides some slightly configurable scaffolding around ffmpeg (based on a blogpost from [[http://oioiiooixiii.blogspot.com/2017/11/ffmpeg-temporal-slice-stacking-effect.html][oioiiooixiii]]) and is intended for non-realtime rendering at various resolutions. it's neither first, nor last. it's not especially interesting, educational or efficient. just another cloudform in the endless space of possible implementation…
 
 * installation, configuration, operation, etc
 
-install (mac)...
+install (macOS)…
 #+BEGIN_SRC text
 brew install ffmpeg drracket
 git clone https://github.com/zzkt/slitscan.git
 #+END_SRC
 
-install (debian/ubuntu)...
+install (debian/ubuntu)…
 #+BEGIN_SRC text
 sudo apt install ffmpeg racket
 git clone https://github.com/zzkt/slitscan.git
 #+END_SRC
 
-simple transform...
+simple transform…
 #+BEGIN_SRC text
-racket slitscan.rkt -v -i <input.mp4> 
+racket slitscan.rkt -v input.mp4
 #+END_SRC
 
-transform at 1080p and delete working files, with minimal command line noise...
+transform at 1080p and delete working files, with minimal command line noise…
 #+BEGIN_SRC text
-racket slitscan.rkt --width 1920 --height 1080 --loglevel quiet --cleanup -i <input.mp4> 
+racket slitscan.rkt --width 1920 --height 1080 --loglevel quiet --cleanup input.mp4
 #+END_SRC
 
-options...
+options…
 #+BEGIN_SRC text
-slitscan [ <option> ... ]
+slitscan [ <option> ... ] <video-file>
  where <option> is one of
   -v, --verbose : various verbose messages
   -l <level>, --loglevel <level> : loglevel for ffmpeg e.g. quiet, error, warning, info, debug
   -c, --cleanup : Clean up temporary/working files
+  -n, --noresize : do not resize the input file
   --horizontal : output a horizontal video only (default: both)
   --vertical : output a vertical video only (default: both)
-  --width <pixels> : width of output output video
-  --height <pixels> : height of output output video
-  -i <video>, --input <video> : input file
-  -f <folder>, --folder <folder> : input folder
+  --width <pixels> : width of transform video
+  --height <pixels> : height of tansform video
+  -f <folder>, --in-folder <folder> : input folder
+  -o <folder>, --out-folder <folder> : output folder
   --help, -h : Show this help
 #+END_SRC
 
diff --git a/slitscan.rkt b/slitscan.rkt
index 00bb32f..e910fd3 100755
--- a/slitscan.rkt
+++ b/slitscan.rkt
@@ -25,7 +25,7 @@
 ;;;
 ;;; Requirements
 ;;;
-;;;  Racket, ffmpeg and zsh or bash (probably)
+;;;  Racket, ffmpeg and zsh or bash (and probably works with other shells)
 ;;;
 ;;; Commentary
 ;;;
@@ -43,10 +43,12 @@
 
 
 ;; cli options
+(define filename (make-parameter ""))
 (define verbose? (make-parameter #f))
 (define cleanup? (make-parameter #f))
-(define filename (make-parameter "untitled"))
-(define input-folder (make-parameter ""))
+(define noresize? (make-parameter #f))
+(define in-folder (make-parameter ""))
+(define out-folder (make-parameter ""))
 (define loglevel (make-parameter "")) ;; leave unset by default
 
 ;; output options horiz/vert/both
@@ -61,17 +63,21 @@
   (command-line
    #:program "slitscan"
    #:once-each
-   (("-v" "--verbose")  "various verbose messages" (verbose? #t))
-   (("-l" "--loglevel") level "loglevel for ffmpeg e.g. quiet, error, warning, info, debug" (loglevel level))
-   (("-c" "--cleanup")  "Clean up temporary/working files" (cleanup? #t))
-   (("--horizontal")    "output a horizontal video only (default: both)" (hout-only? #t))
-   (("--vertical")      "output a vertical video only (default: both)" (vout-only? #t))
-   (("--width")         pixels "width of transform video" (output-width pixels))
-   (("--height")        pixels "height of tansform video"  (output-height pixels))   
-   (("-i" "--input")    video "input file" (filename video))
-   (("-f" "--folder")   folder "input folder"  (input-folder folder))
-   #:args () ; rest of the args? 
-   (printf "slitscanning: ~a\n" (filename))))
+   (("-v" "--verbose")    "various verbose messages" (verbose? #t))
+   (("-l" "--loglevel")   level "loglevel for ffmpeg e.g. quiet, error, warning, info, debug" (loglevel level))
+   (("-c" "--cleanup")    "Clean up temporary/working files" (cleanup? #t))
+   (("-n" "--noresize")   "do not resize the input file" (noresize? #t))   
+   (("--horizontal")      "output a horizontal video only (default: both)" (hout-only? #t))
+   (("--vertical")        "output a vertical video only (default: both)" (vout-only? #t))
+   (("--width")           pixels "width of transform video" (output-width pixels))
+   (("--height")          pixels "height of tansform video"  (output-height pixels))   
+   (("-f" "--in-folder")  folder "input folder"  (in-folder folder))
+   (("-o" "--out-folder") folder "output folder" (out-folder folder))
+   #:args (video-file) ; rest of the args?
+   (filename video-file)
+   (if (file-exists? (filename))
+       (printf "slitscanning: ~a\n" (filename))
+       (raise-user-error 'slitscan "File '~a' does not exist." (filename)))))
 
 ;; emulation of $(...) shell syntax 
 (define-syntax zout 
@@ -87,11 +93,11 @@
       ((and (not (verbose?)) (string=? "" (loglevel))) (loglevel "error")))
 
 ;; variables/various
-(define folder (if (not (string=? "" (input-folder)))
-                   (input-folder) 
+(define folder (if (not (string=? "" (in-folder)))
+                   (in-folder) 
                    (zout "mktemp -d")))
 
-(vecho "using folder: ~a\n" folder)
+(vecho "using folder '~a' for input\n" folder)
 
 ;(define fffeature "ffprobe -v quiet -select_streams v -of default=noprint_wrappers=1:nokey=1 -show_entries stream=")
 
@@ -99,10 +105,10 @@
 
 ;; assume most/all codecs/formats/streams have a duration
 (define duration (let ((f (string->number
-                            (zout (format
-                                   "~aduration \"~a\""
-                                   fffeature (filename))))))
-                    (if f f 0)))
+                           (zout (format
+                                  "~aduration \"~a\""
+                                  fffeature (filename))))))
+                   (if f f 0)))
 
 (vecho "duration: ~a seconds\n" duration)
 
@@ -117,10 +123,10 @@
 
 ;; number of frames. estimate for codecs/formats/streams without nb_frames 
 (define frames (let ((f (string->number
-                           (zout (format
-                                  "~anb_frames \"~a\""
-                                  fffeature (filename))))))
-                   (if f f (ceiling (* duration fps)))))
+                         (zout (format
+                                "~anb_frames \"~a\""
+                                fffeature (filename))))))
+                 (if f f (ceiling (* duration fps)))))
 
 (vecho "frames: ~a\n" frames)
 
@@ -143,10 +149,11 @@
 ;; rezise video
 (define resized-video (string-append folder "/resized.mkv"))
 
+;; resize video, or copy file if 'noresize?' option is set
 (define (resize)
   (define ffmpeg-r1
     (format "ffmpeg -loglevel ~a -i \"~a\" -vf ~a -crf 10 \"~a\" 2>&1 | grep 'frame=' | tr \\n \\r; echo"
-             (loglevel) (filename) scale resized-video)) 
+            (loglevel) (filename) scale resized-video)) 
   (vecho "resizing video: ~a\n" resized-video)
   (system ffmpeg-r1))
 
@@ -199,12 +206,12 @@
   (define ffmpeg-a1 ;; horizontal frame stack 
     (format   
      "ffmpeg -loglevel ~a -r ~a -i ~a/horz_frame%d.png \"~a_horizontal-smear.mkv\""
-      (loglevel) fps folder (filename)))
+     (loglevel) fps folder (filename)))
 
   (define ffmpeg-a2 ;; vertical frame stack 
     (format   
      "ffmpeg -loglevel ~a -r ~a -i ~a/vert_frame%d.png \"~a_vertical-smear.mkv\""
-      (loglevel) fps folder (filename)))
+     (loglevel) fps folder (filename)))
   
   ;; assemble
   (cond  ((hout-only?) (system ffmpeg-a1))  
@@ -234,10 +241,16 @@
       (vecho "leaving working files at ~a\n" folder)))
 
 ;; output in 3 (or 4 (or 5)) steps
+  
+  (define (slitscan)
+    (when (resize)   (printf "resized\n"))
+    (when (slice)    (printf "sliced\n"))
+    (when (assemble) (printf "assembled\n"))
+    (when (cleanup)  (printf "done\n")))
 
-(when (resize)   (printf "resized\n"))
-(when (slice)    (printf "slicwd\n"))
-(when (assemble) (printf "assembled\n"))
-(when (cleanup)  (printf "done\n"))
+  
+  ;; (printf "The file '~a' does not exist.\n" (filename))
+
+(slitscan)
 
 ;;; FIN