From 532f335b3c872a2b0d5ad1a1fd201a9d16e1fd82 Mon Sep 17 00:00:00 2001
From: Sridhar Ratnakumar <srid@srid.ca>
Date: Wed, 6 Mar 2024 08:54:01 -0500
Subject: [PATCH] add twitter-convert

---
 home/terminal.nix                       |  1 +
 packages/overlay.nix                    |  1 +
 packages/twitter-convert/default.nix    | 18 ++++++++++++++++++
 packages/twitter-convert/ffmpeg_ar      | 12 ++++++++++++
 packages/twitter-convert/ffmpeg_twitter |  8 ++++++++
 5 files changed, 40 insertions(+)
 create mode 100644 packages/twitter-convert/default.nix
 create mode 100755 packages/twitter-convert/ffmpeg_ar
 create mode 100755 packages/twitter-convert/ffmpeg_twitter

diff --git a/home/terminal.nix b/home/terminal.nix
index ef4439f..44b9cef 100644
--- a/home/terminal.nix
+++ b/home/terminal.nix
@@ -19,6 +19,7 @@
 
     # Publishing
     asciinema
+    twitter-convert
 
     # Dev
     gh
diff --git a/packages/overlay.nix b/packages/overlay.nix
index 35eeeca..e500e79 100644
--- a/packages/overlay.nix
+++ b/packages/overlay.nix
@@ -2,6 +2,7 @@
 
 self: super: {
   fuckport = self.callPackage ./fuckport.nix { };
+  twitter-convert = self.callPackage ./twitter-convert { };
   nixci = flake.inputs.nixci.packages.${system}.default;
   nix-health = flake.inputs.nix-browser.packages.${system}.nix-health;
   actual = flake.inputs.actual.packages.${system}.default;
diff --git a/packages/twitter-convert/default.nix b/packages/twitter-convert/default.nix
new file mode 100644
index 0000000..309095c
--- /dev/null
+++ b/packages/twitter-convert/default.nix
@@ -0,0 +1,18 @@
+{ writeShellApplication, ffmpeg-full, ... }:
+
+# Some useful resources for this undocumented shit:
+# - https://stackoverflow.com/q/59056863/55246
+# - https://gist.github.com/nikhan/26ddd9c4e99bbf209dd7
+writeShellApplication {
+  name = "twitter-convert";
+  runtimeInputs = [ ffmpeg-full ];
+  meta.description = ''
+    Convert a video for uploading to X / Twitter.
+
+    You may need a Basic or Premium tier to upload longer videos.
+  '';
+  text = ''
+    export ARSCRIPT="${./ffmpeg_ar}"
+    ${./ffmpeg_twitter} "$1"
+  '';
+}
diff --git a/packages/twitter-convert/ffmpeg_ar b/packages/twitter-convert/ffmpeg_ar
new file mode 100755
index 0000000..a40aa8d
--- /dev/null
+++ b/packages/twitter-convert/ffmpeg_ar
@@ -0,0 +1,12 @@
+#!/bin/bash
+eval $(ffprobe -v error -show_entries stream=width,height -of default=noprint_wrappers=1 "$1")
+#results in e.g.
+#width=300
+#height=1200
+echo "height=$height"$'\n'"width=$width"
+newenv=$(bc <<< "width=$width; height=$height;"$'\nscale=3; aspect=width / height;\nprint "aspect=", aspect;
+    print "''\n'$'";\n\nif (aspect>3) { r=(height) * (aspect/3); print "height=";}
+    if (aspect<(1/3)) {r=(width) / (aspect/(1/3)); print "width=";}\nscale=0
+    if (r) { print r/1 }')
+[ ! -z "$newenv" ] && echo "$newenv" && export $newenv
+echo "aspect=""$(bc <<< "scale=3; $width/$height")"
diff --git a/packages/twitter-convert/ffmpeg_twitter b/packages/twitter-convert/ffmpeg_twitter
new file mode 100755
index 0000000..6cd45fb
--- /dev/null
+++ b/packages/twitter-convert/ffmpeg_twitter
@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+
+set -xe
+
+export $($ARSCRIPT "$1")
+ffmpeg -i "$1" \
+      -filter_complex 'fps=30,format=yuv420p,pad='"ceil($width/2)*2:ceil($height/2)*2"':(ow-iw)/2:(oh-ih)/2' -c:v h264_videotoolbox -c:a aac -ac 2 -ar 44100 -r 30 \
+      output.mp4
\ No newline at end of file