From 077ed51e254b9a6af2259b1952e6134ead98afa2 Mon Sep 17 00:00:00 2001
From: Dennis Fink
Date: Sun, 10 May 2026 22:07:29 +0200
Subject: refactor(core): remove awk and bc dependencies

Both tools were used for simple arithmetic that bash handles natively.

awk: fps rounding (num/den) replaced with round-half-up integer
arithmetic: (num + den/2) / den.

bc: savings percentage replaced with bash $(( )) arithmetic. bc was a
conditional dependency (only required with --saving), which made the
dependency story inconsistent. Removing it means the full feature set is
available with only ffmpeg, ffprobe, nice, and optionally tomlq.

Updated README requirements table, man page --saving description, SEE
ALSO section, and exit-code 127 entry accordingly.
---
 README.md      |  1 -
 transcode.sh   | 32 ++++++++++----------------------
 transcode.sh.1 |  8 +-------
 3 files changed, 11 insertions(+), 30 deletions(-)

diff --git a/README.md b/README.md
index 8ce5e12..3c4053f 100644
--- a/README.md
+++ b/README.md
@@ -32,7 +32,6 @@ replaces the original atomically on success.
 | `ffmpeg` | always | encoding |
 | `ffprobe` | always | codec/format detection |
 | `nice` | always | process priority control |
-| `bc` | only with `--saving` | percentage calculation |
 | `tomlq` | only when `config.toml` is present | TOML config parsing |
 
 ## Installation
diff --git a/transcode.sh b/transcode.sh
index f89732c..0501974 100755
--- a/transcode.sh
+++ b/transcode.sh
@@ -675,7 +675,8 @@ list_presets() {
   fi
 
   local -a preset_files=()
-  local f name max_name_len=0
+  local f name max_name_len
+  max_name_len=0
   for f in "$PRESET_DIR"/*.sh; do
     if [[ -f "$f" ]]; then
       preset_files+=("$f")
@@ -702,7 +703,6 @@ list_presets() {
 
     if [[ -L "$f" ]]; then
       target_path=$(resolve_path "$f")
-
       if [[ "$target_path" == "$canonical_preset_dir"/*.sh ]]; then
         target_name="${target_path##*/}"
         target_name="${target_name%.sh}"
@@ -1003,15 +1003,6 @@ command -v nice >/dev/null 2>&1 || {
   exit $EXIT_MISSING_DEPENDENCY
 }
 
-if [[ $SAVING -eq 1 ]]; then
-  # bc is only required when --saving is active; intentionally checked here
-  # rather than in the main dependency block to avoid requiring it universally.
-  command -v bc >/dev/null 2>&1 || {
-    error "bc not found."
-    exit $EXIT_MISSING_DEPENDENCY
-  }
-fi
-
 if [[ $SAVING_FILE_EXPLICIT -eq 1 && $SAVING -eq 0 ]]; then
   warn "--saving-file has no effect without --saving"
 fi
@@ -1140,16 +1131,13 @@ encode_one() {
 
   # Convert ffprobe frame rate fractions like 30000/1001 to rounded integer FPS
   # values for simpler encoder heuristics and logging.
-  input_fps=$(
-    awk -F/ '
-      {
-        if ($2)
-          printf "%.0f\n", $1 / $2
-        else
-          printf "%.0f\n", $1
-      }
-    ' <<<"$input_frame_rate"
-  )
+  local _fps_num _fps_den
+  IFS='/' read -r _fps_num _fps_den <<<"$input_frame_rate"
+  if [[ -n "$_fps_den" && "$_fps_den" -ne 0 ]]; then
+    input_fps=$(((_fps_num + _fps_den / 2) / _fps_den))
+  else
+    input_fps="$_fps_num"
+  fi
   debug "Calculated input fps:" "$input_fps"
 
   # Use a larger GOP for better compression efficiency while keeping seek
@@ -1269,7 +1257,7 @@ encode_one() {
     if [[ $SAVING -eq 1 ]]; then
       local pct
       if [[ $original_filesize -gt 0 ]]; then
-        pct=$(bc <<<"($original_filesize - $new_filesize) * 100 / $original_filesize")
+        pct=$(((original_filesize - new_filesize) * 100 / original_filesize))
       else
         pct=0
       fi
diff --git a/transcode.sh.1 b/transcode.sh.1
index af03bf9..17d9e29 100644
--- a/transcode.sh.1
+++ b/transcode.sh.1
@@ -129,8 +129,7 @@ with the given niceness value. Defaults to
 .BR \-s ", " \-\-saving
 After each successful encode, append a line to the savings log file
 recording the filename, original size in bytes, new size in bytes and the
-percentage saved. Requires
-.BR bc (1).
+percentage saved.
 .TP
 .BR \-\-saving\-file " \fIPATH\fR, " \-\-saving\-file= \fIPATH\fR
 Path to the savings log file written by
@@ -397,10 +396,6 @@ A required dependency
 .RB ( ffmpeg ,
 .BR ffprobe ,
 .BR nice ,
-.B bc
-when
-.B \-\-saving
-is active, or
 .B tomlq
 when
 .B config.toml
@@ -457,7 +452,6 @@ transcode.sh \-\-config\-file ~/profiles/fast.toml input.mp4
 .BR ffmpeg (1),
 .BR ffprobe (1),
 .BR nice (1),
-.BR bc (1),
 .BR tomlq (1)
 .SH AUTHOR
 Dennis Fink <me+coding@dennisfink.me>
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