feat: add ffmpeg plugin and update plugin interface to support temporary directories and context-dependent metrics

build.rs

@@ -1,3 +1,17 @@
+// Copyright (C) 2026 Elias Wendland <eliaswendland@pm.me>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, version 3 exclusively.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
 use std::env;
 use std::fs;
 use std::path::Path;
@@ -41,10 +55,8 @@ fn main() {
                     "pub mod {} {{\n    include!({:?});\n}}\n",
                     stem, abs_path_str
                 ));
-                registry_add_code.push_str(&format!(
-                    "registry.push(Box::new({}::PluginImpl));\n", 
-                    stem
-                ));
+                registry_add_code
+                    .push_str(&format!("registry.push(Box::new({}::PluginImpl));\n", stem));
             }
         }
     }

plugins/ffmpeg_video.rs

@@ -0,0 +1,146 @@
+// Copyright (C) 2026 Elias Wendland <eliaswendland@pm.me>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, version 3 exclusively.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+use crate::plugin::Plugin;
+use rust_ffmpeg::FFmpegBuilder;
+use std::io::Write;
+use std::path::Path;
+
+pub struct PluginImpl;
+
+impl Plugin for PluginImpl {
+    fn name(&self) -> &'static str {
+        "ffmpeg_video"
+    }
+    fn from_formats(&self) -> Vec<&'static str> {
+        vec!["mp4", "webm", "mkv", "avi", "mov", "wmv", "flv", "gif"]
+    }
+    fn to_formats(&self) -> Vec<&'static str> {
+        vec!["mp4", "webm", "mkv", "avi", "mov", "wmv", "flv", "gif"]
+    }
+    fn familiarity(&self, _from: &str, to: &str) -> u8 {
+        match to {
+            "mp4" | "gif" => 255,
+            "mov" => 240,
+            "webm" => 220,
+            "mkv" => 180,
+            "wmv" => 160,
+            "flv" => 120,
+            "avi" => 100,
+            _ => 128,
+        }
+    }
+    fn quality(&self, _from: &str, to: &str) -> u8 {
+        match to {
+            "mkv" => 250,
+            "mov" => 250,
+            "mp4" => 240,
+            "webm" => 210,
+            "wmv" => 200,
+            "flv" => 180,
+            "avi" => 150,
+            "gif" => 80,
+            _ => 200,
+        }
+    }
+    fn speed(&self, _from: &str, to: &str) -> u8 {
+        match to {
+            "mp4" => 220,
+            "mov" => 220,
+            "mkv" => 200,
+            "flv" => 190,
+            "avi" => 180,
+            "wmv" => 170,
+            "gif" => 150,
+            "webm" => 100,
+            _ => 150,
+        }
+    }
+
+    fn convert(
+        &self,
+        input: &[u8],
+        _from: &str,
+        to: &str,
+        temp_dir: &Path,
+    ) -> Result<Vec<u8>, String> {
+        let mut temp_in = tempfile::Builder::new()
+            .suffix(&format!(".{}", _from))
+            .tempfile_in(temp_dir)
+            .map_err(|e| e.to_string())?;
+        temp_in.write_all(input).map_err(|e| e.to_string())?;
+
+        let temp_out = tempfile::Builder::new()
+            .suffix(&format!(".{}", to))
+            .tempfile_in(temp_dir)
+            .map_err(|e| e.to_string())?;
+        let temp_out_path = temp_out.into_temp_path();
+
+        let in_path = temp_in.path().to_path_buf();
+
+        let mut raw_args = vec![];
+        match to {
+            "mp4" | "mkv" | "mov" => {
+                raw_args.extend(vec![
+                    "-c:v", "libx264", "-crf", "23", "-c:a", "aac", "-pix_fmt", "yuv420p",
+                ]);
+            }
+            "webm" => {
+                raw_args.extend(vec![
+                    "-c:v",
+                    "libvpx-vp9",
+                    "-crf",
+                    "30",
+                    "-b:v",
+                    "0",
+                    "-c:a",
+                    "libopus",
+                ]);
+            }
+            "avi" => {
+                raw_args.extend(vec![
+                    "-c:v",
+                    "mpeg4",
+                    "-vtag",
+                    "xvid",
+                    "-qscale:v",
+                    "3",
+                    "-c:a",
+                    "libmp3lame",
+                ]);
+            }
+            "gif" => {
+                raw_args.extend(vec!["-vf", "fps=15,scale=320:-1:flags=lanczos"]);
+            }
+            _ => {
+                raw_args.extend(vec!["-qscale:v", "3"]);
+            }
+        }
+
+        let rt = tokio::runtime::Runtime::new().map_err(|e| e.to_string())?;
+        rt.block_on(async {
+            FFmpegBuilder::new()
+                .map_err(|e| e.to_string())?
+                .input_path(in_path)
+                .output_path(temp_out_path.to_path_buf())
+                .raw_args(raw_args)
+                .overwrite()
+                .run()
+                .await
+                .map_err(|e| e.to_string())
+        })?;
+
+        std::fs::read(&temp_out_path).map_err(|e| e.to_string())
+    }
+}

plugins/jpeg_to_png.rs

@@ -1,18 +1,51 @@
+// Copyright (C) 2026 Elias Wendland <eliaswendland@pm.me>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, version 3 exclusively.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
 use crate::plugin::Plugin;
 use image::ImageFormat;
 use std::io::Cursor;
+use std::path::Path;
 
 pub struct PluginImpl;
 
 impl Plugin for PluginImpl {
-    fn name(&self) -> &'static str { "jpeg_to_png" }
-    fn from_formats(&self) -> Vec<&'static str> { vec!["jpeg"] }
-    fn to_formats(&self) -> Vec<&'static str> { vec!["png"] }
-    fn familiarity(&self) -> u8 { 255 }
-    fn quality(&self) -> u8 { 255 }
-    fn speed(&self) -> u8 { 200 }
+    fn name(&self) -> &'static str {
+        "jpeg_to_png"
+    }
+    fn from_formats(&self) -> Vec<&'static str> {
+        vec!["jpeg"]
+    }
+    fn to_formats(&self) -> Vec<&'static str> {
+        vec!["png"]
+    }
+    fn familiarity(&self, _from: &str, _to: &str) -> u8 {
+        255
+    }
+    fn quality(&self, _from: &str, _to: &str) -> u8 {
+        255
+    }
+    fn speed(&self, _from: &str, _to: &str) -> u8 {
+        200
+    }
 
-    fn convert(&self, input: &[u8], _from: &str, _to: &str) -> Result<Vec<u8>, String> {
+    fn convert(
+        &self,
+        input: &[u8],
+        _from: &str,
+        _to: &str,
+        _temp_dir: &Path,
+    ) -> Result<Vec<u8>, String> {
         let img = image::load_from_memory_with_format(input, ImageFormat::Jpeg)
             .map_err(|e| e.to_string())?;
         let mut buf = Vec::new();

plugins/png_to_jpeg.rs

@@ -1,18 +1,51 @@
+// Copyright (C) 2026 Elias Wendland <eliaswendland@pm.me>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, version 3 exclusively.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
 use crate::plugin::Plugin;
 use image::ImageFormat;
 use std::io::Cursor;
+use std::path::Path;
 
 pub struct PluginImpl;
 
 impl Plugin for PluginImpl {
-    fn name(&self) -> &'static str { "png_to_jpeg" }
-    fn from_formats(&self) -> Vec<&'static str> { vec!["png"] }
-    fn to_formats(&self) -> Vec<&'static str> { vec!["jpeg"] }
-    fn familiarity(&self) -> u8 { 255 }
-    fn quality(&self) -> u8 { 200 } // JPEG has some compression loss
-    fn speed(&self) -> u8 { 220 }
+    fn name(&self) -> &'static str {
+        "png_to_jpeg"
+    }
+    fn from_formats(&self) -> Vec<&'static str> {
+        vec!["png"]
+    }
+    fn to_formats(&self) -> Vec<&'static str> {
+        vec!["jpeg"]
+    }
+    fn familiarity(&self, _from: &str, _to: &str) -> u8 {
+        255
+    }
+    fn quality(&self, _from: &str, _to: &str) -> u8 {
+        200
+    } // JPEG has some compression loss
+    fn speed(&self, _from: &str, _to: &str) -> u8 {
+        220
+    }
 
-    fn convert(&self, input: &[u8], _from: &str, _to: &str) -> Result<Vec<u8>, String> {
+    fn convert(
+        &self,
+        input: &[u8],
+        _from: &str,
+        _to: &str,
+        _temp_dir: &Path,
+    ) -> Result<Vec<u8>, String> {
         let img = image::load_from_memory_with_format(input, ImageFormat::Png)
             .map_err(|e| e.to_string())?;
         let mut buf = Vec::new();

src/args.rs

@@ -1,4 +1,19 @@
+// Copyright (C) 2026 Elias Wendland <eliaswendland@pm.me>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, version 3 exclusively.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
 use clap::Parser;
+use std::path::PathBuf;
 
 pub const VERSION: &str = include_str!(concat!(env!("OUT_DIR"), "/version.txt"));
 
@@ -8,16 +23,33 @@ pub struct Args {
     #[arg(short = 'v', action = clap::ArgAction::Count, help = "Output information about the conversion. Use -v for path taken, -vv for step info, -vvv for timing, and -vvvv for plugin logs.")]
     pub verbose: u8,
 
-    #[arg(short, long, help = "Test the conversion process without actually converting the file.")]
+    #[arg(
+        short,
+        long,
+        help = "Test the conversion process without actually converting the file."
+    )]
     pub test: bool,
 
-    #[arg(short, long, help = "Output nothing to the console, silently fail on errors.")]
+    #[arg(
+        short,
+        long,
+        help = "Output nothing to the console, silently fail on errors."
+    )]
     pub quiet: bool,
 
-    #[arg(short = 'c', long, help = "Get rid of the warning message when not piping the file.")]
+    #[arg(
+        short = 'c',
+        long,
+        help = "Get rid of the warning message when not piping the file."
+    )]
     pub write_to_console: bool,
 
-    #[arg(short, long, default_value = "fqs", help = "Set the priority of the conversion process (e.g. -p fqs means \"familiarity, speed, quality\").")]
+    #[arg(
+        short,
+        long,
+        default_value = "fqs",
+        help = "Set the priority of the conversion process (e.g. -p fqs means \"familiarity, speed, quality\")."
+    )]
     pub priority: String,
 
     #[arg(help = "The input file path.")]
@@ -25,6 +57,14 @@ pub struct Args {
 
     #[arg(help = "The output file path (optional).")]
     pub output_path: Option<String>,
+
+    #[arg(
+        short = 'T',
+        long,
+        default_value = "/dev/shm",
+        help = "Directory to use for temporary files during conversion. Defaults to /dev/shm (RAM). Use a disk path for very large files."
+    )]
+    pub temp_dir: PathBuf,
 }
 
 impl Args {
@@ -49,6 +89,7 @@ mod tests {
                     priority: "fqs".to_string(),
                     input_path: "test".to_string(),
                     output_path: None,
+                    temp_dir: std::path::PathBuf::from("/dev/shm"),
                 };
                 assert_eq!(args.verbosity_level(), $expected);
             }

src/identifier.rs

@@ -1,11 +1,37 @@
+// Copyright (C) 2026 Elias Wendland <eliaswendland@pm.me>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, version 3 exclusively.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
 use std::path::Path;
 
 pub fn identify_format(path: &str) -> Option<&'static str> {
     let p = Path::new(path);
-    let ext = p.extension().and_then(|s| s.to_str()).unwrap_or(path).to_lowercase();
+    let ext = p
+        .extension()
+        .and_then(|s| s.to_str())
+        .unwrap_or(path)
+        .to_lowercase();
     match ext.as_str() {
         "jpg" | "jpeg" => Some("jpeg"),
         "png" => Some("png"),
+        "mp4" => Some("mp4"),
+        "webm" => Some("webm"),
+        "mkv" => Some("mkv"),
+        "avi" => Some("avi"),
+        "mov" => Some("mov"),
+        "wmv" => Some("wmv"),
+        "flv" => Some("flv"),
+        "gif" => Some("gif"),
         _ => None,
     }
 }
@@ -35,7 +61,11 @@ mod tests {
     test_ident!(test_identify_format_10, "test.bmp", None);
     test_ident!(test_identify_format_11, "file.JPEG", Some("jpeg"));
     test_ident!(test_identify_format_12, "file.PNG", Some("png"));
-    test_ident!(test_identify_format_13, "complex.file.name.jpg", Some("jpeg"));
+    test_ident!(
+        test_identify_format_13,
+        "complex.file.name.jpg",
+        Some("jpeg")
+    );
     test_ident!(test_identify_format_14, ".hidden.png", Some("png"));
     test_ident!(test_identify_format_15, "jpg", Some("jpeg")); // "jpg" passed without dot, treats as ext if no dot in path but path is "jpg", ext becomes "jpg"
     test_ident!(test_identify_format_16, "a.jpg.txt", None);

src/main.rs

@@ -1,3 +1,17 @@
+// Copyright (C) 2026 Elias Wendland <eliaswendland@pm.me>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, version 3 exclusively.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
 pub mod args;
 pub mod identifier;
 pub mod pathfinder;
@@ -61,7 +75,9 @@ fn main() {
                 Some(t) => t,
                 None => {
                     if !args.quiet {
-                        eprintln!("Error: No output path provided, and no available conversions found.");
+                        eprintln!(
+                            "Error: No output path provided, and no available conversions found."
+                        );
                     }
                     process::exit(1);
                 }
@@ -73,7 +89,10 @@ fn main() {
         Some(p) => p,
         None => {
             if !args.quiet {
-                eprintln!("Error: No conversion path found from {} to {}.", from_format, to_format);
+                eprintln!(
+                    "Error: No conversion path found from {} to {}.",
+                    from_format, to_format
+                );
             }
             process::exit(1);
         }
@@ -88,7 +107,7 @@ fn main() {
     }
 
     let verbosity = args.verbosity_level();
-    let result = runner::run_conversion(&path, &input_bytes, verbosity);
+    let result = runner::run_conversion(&path, &input_bytes, verbosity, &args.temp_dir);
 
     let output_bytes = match result {
         Ok(b) => b,
@@ -111,7 +130,9 @@ fn main() {
         let is_piped = !io::stdout().is_terminal();
         if !is_piped && !args.write_to_console {
             if !args.quiet {
-                eprintln!("Warning: Outputting directly to console. Use -c to suppress this warning, or redirect to a file.");
+                eprintln!(
+                    "Warning: Outputting directly to console. Use -c to suppress this warning, or redirect to a file."
+                );
             }
         }
 

src/pathfinder.rs

@@ -1,3 +1,17 @@
+// Copyright (C) 2026 Elias Wendland <eliaswendland@pm.me>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, version 3 exclusively.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
 use crate::plugin::Plugin;
 use std::collections::{HashMap, VecDeque};
 use std::rc::Rc;
@@ -73,7 +87,10 @@ pub fn find_best_path<'a>(
                 for &next_format in &plugin.to_formats() {
                     let next_depth = current_depth + 1;
 
-                    let prev_depth = visited_depth.get(next_format).copied().unwrap_or(usize::MAX);
+                    let prev_depth = visited_depth
+                        .get(next_format)
+                        .copied()
+                        .unwrap_or(usize::MAX);
 
                     if next_depth <= prev_depth {
                         visited_depth.insert(next_format, next_depth);
@@ -97,35 +114,57 @@ pub fn find_best_path<'a>(
     }
 
     // Evaluate based on priority (maximize score)
-    best_paths.into_iter().max_by(|path_a, path_b| {
-        compare_paths(path_a, path_b, priority)
-    })
+    best_paths
+        .into_iter()
+        .max_by(|path_a, path_b| compare_paths(path_a, path_b, priority))
 }
 
-fn compare_paths(path_a: &[(&dyn Plugin, &str, &str)], path_b: &[(&dyn Plugin, &str, &str)], priority: &str) -> std::cmp::Ordering {
+fn compare_paths(
+    path_a: &[(&dyn Plugin, &str, &str)],
+    path_b: &[(&dyn Plugin, &str, &str)],
+    priority: &str,
+) -> std::cmp::Ordering {
     for ch in priority.chars() {
         match ch {
             'f' | 'F' => {
-                let score_a: u32 = path_a.iter().map(|(p, _, _)| p.familiarity() as u32).sum();
-                let score_b: u32 = path_b.iter().map(|(p, _, _)| p.familiarity() as u32).sum();
+                let score_a: u32 = path_a
+                    .iter()
+                    .map(|(p, from, to)| p.familiarity(*from, *to) as u32)
+                    .sum();
+                let score_b: u32 = path_b
+                    .iter()
+                    .map(|(p, from, to)| p.familiarity(*from, *to) as u32)
+                    .sum();
                 if score_a != score_b {
                     return score_a.cmp(&score_b);
                 }
-            },
+            }
             'q' | 'Q' => {
-                let score_a: u32 = path_a.iter().map(|(p, _, _)| p.quality() as u32).sum();
-                let score_b: u32 = path_b.iter().map(|(p, _, _)| p.quality() as u32).sum();
+                let score_a: u32 = path_a
+                    .iter()
+                    .map(|(p, from, to)| p.quality(*from, *to) as u32)
+                    .sum();
+                let score_b: u32 = path_b
+                    .iter()
+                    .map(|(p, from, to)| p.quality(*from, *to) as u32)
+                    .sum();
                 if score_a != score_b {
                     return score_a.cmp(&score_b);
                 }
-            },
+            }
             's' | 'S' => {
-                let score_a: u32 = path_a.iter().map(|(p, _, _)| p.speed() as u32).sum();
-                let score_b: u32 = path_b.iter().map(|(p, _, _)| p.speed() as u32).sum();
+                let score_a: u32 = path_a
+                    .iter()
+                    .map(|(p, from, to)| p.speed(*from, *to) as u32)
+                    .sum();
+                let score_b: u32 = path_b
+                    .iter()
+                    .map(|(p, from, to)| p.speed(*from, *to) as u32)
+                    .sum();
                 if score_a != score_b {
                     return score_a.cmp(&score_b);
                 }
-            },
+            }
             _ => {}
         }
     }
@@ -146,21 +185,62 @@ mod tests {
     }
 
     impl Plugin for MockPlugin {
-        fn name(&self) -> &'static str { self.name }
-        fn from_formats(&self) -> Vec<&'static str> { self.from.clone() }
-        fn to_formats(&self) -> Vec<&'static str> { self.to.clone() }
-        fn familiarity(&self) -> u8 { self.f }
-        fn quality(&self) -> u8 { self.q }
-        fn speed(&self) -> u8 { self.s }
-        fn convert(&self, _input: &[u8], _from: &str, _to: &str) -> Result<Vec<u8>, String> { Ok(vec![]) }
+        fn name(&self) -> &'static str {
+            self.name
+        }
+        fn from_formats(&self) -> Vec<&'static str> {
+            self.from.clone()
+        }
+        fn to_formats(&self) -> Vec<&'static str> {
+            self.to.clone()
+        }
+        fn familiarity(&self, _from: &str, _to: &str) -> u8 {
+            self.f
+        }
+        fn quality(&self, _from: &str, _to: &str) -> u8 {
+            self.q
+        }
+        fn speed(&self, _from: &str, _to: &str) -> u8 {
+            self.s
+        }
+        fn convert(
+            &self,
+            _input: &[u8],
+            _from: &str,
+            _to: &str,
+            _temp_dir: &std::path::Path,
+        ) -> Result<Vec<u8>, String> {
+            Ok(vec![])
+        }
     }
 
     #[test]
     fn test_shortest_path() {
         let plugins: Vec<Box<dyn Plugin>> = vec![
-            Box::new(MockPlugin { name: "A", from: vec!["jpeg"], to: vec!["png"], f: 10, q: 10, s: 10 }),
-            Box::new(MockPlugin { name: "B", from: vec!["jpeg"], to: vec!["bmp"], f: 10, q: 10, s: 10 }),
-            Box::new(MockPlugin { name: "C", from: vec!["bmp"], to: vec!["png"], f: 10, q: 10, s: 10 }),
+            Box::new(MockPlugin {
+                name: "A",
+                from: vec!["jpeg"],
+                to: vec!["png"],
+                f: 10,
+                q: 10,
+                s: 10,
+            }),
+            Box::new(MockPlugin {
+                name: "B",
+                from: vec!["jpeg"],
+                to: vec!["bmp"],
+                f: 10,
+                q: 10,
+                s: 10,
+            }),
+            Box::new(MockPlugin {
+                name: "C",
+                from: vec!["bmp"],
+                to: vec!["png"],
+                f: 10,
+                q: 10,
+                s: 10,
+            }),
         ];
 
         let path = find_best_path(&plugins, "jpeg", "png", "fqs").unwrap();
@@ -171,8 +251,22 @@ mod tests {
     #[test]
     fn test_priority_tie_break() {
         let plugins: Vec<Box<dyn Plugin>> = vec![
-            Box::new(MockPlugin { name: "A", from: vec!["jpeg"], to: vec!["png"], f: 10, q: 50, s: 10 }),
-            Box::new(MockPlugin { name: "B", from: vec!["jpeg"], to: vec!["png"], f: 50, q: 10, s: 10 }),
+            Box::new(MockPlugin {
+                name: "A",
+                from: vec!["jpeg"],
+                to: vec!["png"],
+                f: 10,
+                q: 50,
+                s: 10,
+            }),
+            Box::new(MockPlugin {
+                name: "B",
+                from: vec!["jpeg"],
+                to: vec!["png"],
+                f: 50,
+                q: 10,
+                s: 10,
+            }),
         ];
 
         let path = find_best_path(&plugins, "jpeg", "png", "fqs").unwrap();
@@ -187,13 +281,62 @@ mod tests {
             #[test]
             fn $name() {
                 let plugins: Vec<Box<dyn Plugin>> = vec![
-                    Box::new(MockPlugin { name: "A", from: vec!["a"], to: vec!["b"], f: 10, q: 10, s: 10 }),
-                    Box::new(MockPlugin { name: "B", from: vec!["b"], to: vec!["c"], f: 20, q: 10, s: 10 }),
-                    Box::new(MockPlugin { name: "C", from: vec!["a"], to: vec!["c"], f: 5, q: 10, s: 10 }),
-                    Box::new(MockPlugin { name: "D", from: vec!["a"], to: vec!["d"], f: 10, q: 20, s: 10 }),
-                    Box::new(MockPlugin { name: "E", from: vec!["d"], to: vec!["c"], f: 10, q: 20, s: 10 }),
-                    Box::new(MockPlugin { name: "F", from: vec!["a"], to: vec!["b"], f: 50, q: 5, s: 5 }), // High familiarity, low q/s
-                    Box::new(MockPlugin { name: "G", from: vec!["c"], to: vec!["e"], f: 10, q: 10, s: 50 }),
+                    Box::new(MockPlugin {
+                        name: "A",
+                        from: vec!["a"],
+                        to: vec!["b"],
+                        f: 10,
+                        q: 10,
+                        s: 10,
+                    }),
+                    Box::new(MockPlugin {
+                        name: "B",
+                        from: vec!["b"],
+                        to: vec!["c"],
+                        f: 20,
+                        q: 10,
+                        s: 10,
+                    }),
+                    Box::new(MockPlugin {
+                        name: "C",
+                        from: vec!["a"],
+                        to: vec!["c"],
+                        f: 5,
+                        q: 10,
+                        s: 10,
+                    }),
+                    Box::new(MockPlugin {
+                        name: "D",
+                        from: vec!["a"],
+                        to: vec!["d"],
+                        f: 10,
+                        q: 20,
+                        s: 10,
+                    }),
+                    Box::new(MockPlugin {
+                        name: "E",
+                        from: vec!["d"],
+                        to: vec!["c"],
+                        f: 10,
+                        q: 20,
+                        s: 10,
+                    }),
+                    Box::new(MockPlugin {
+                        name: "F",
+                        from: vec!["a"],
+                        to: vec!["b"],
+                        f: 50,
+                        q: 5,
+                        s: 5,
+                    }), // High familiarity, low q/s
+                    Box::new(MockPlugin {
+                        name: "G",
+                        from: vec!["c"],
+                        to: vec!["e"],
+                        f: 10,
+                        q: 10,
+                        s: 50,
+                    }),
                 ];
 
                 let path = find_best_path(&plugins, $from, $to, $priority);
@@ -224,11 +367,46 @@ mod tests {
             #[test]
             fn $name() {
                 let plugins: Vec<Box<dyn Plugin>> = vec![
-                    Box::new(MockPlugin { name: "1", from: vec!["1"], to: vec!["2"], f: 10, q: 10, s: 10 }),
-                    Box::new(MockPlugin { name: "2", from: vec!["2"], to: vec!["3"], f: 10, q: 10, s: 10 }),
-                    Box::new(MockPlugin { name: "3", from: vec!["3"], to: vec!["4"], f: 10, q: 10, s: 10 }),
-                    Box::new(MockPlugin { name: "4", from: vec!["4"], to: vec!["5"], f: 10, q: 10, s: 10 }),
-                    Box::new(MockPlugin { name: "5", from: vec!["5"], to: vec!["6"], f: 10, q: 10, s: 10 }),
+                    Box::new(MockPlugin {
+                        name: "1",
+                        from: vec!["1"],
+                        to: vec!["2"],
+                        f: 10,
+                        q: 10,
+                        s: 10,
+                    }),
+                    Box::new(MockPlugin {
+                        name: "2",
+                        from: vec!["2"],
+                        to: vec!["3"],
+                        f: 10,
+                        q: 10,
+                        s: 10,
+                    }),
+                    Box::new(MockPlugin {
+                        name: "3",
+                        from: vec!["3"],
+                        to: vec!["4"],
+                        f: 10,
+                        q: 10,
+                        s: 10,
+                    }),
+                    Box::new(MockPlugin {
+                        name: "4",
+                        from: vec!["4"],
+                        to: vec!["5"],
+                        f: 10,
+                        q: 10,
+                        s: 10,
+                    }),
+                    Box::new(MockPlugin {
+                        name: "5",
+                        from: vec!["5"],
+                        to: vec!["6"],
+                        f: 10,
+                        q: 10,
+                        s: 10,
+                    }),
                 ];
                 let path = find_best_path(&plugins, $from, $to, $priority);
                 if $expected_len == 0 {

src/plugin.rs

@@ -1,13 +1,36 @@
+// Copyright (C) 2026 Elias Wendland <eliaswendland@pm.me>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, version 3 exclusively.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+use std::path::Path;
+
 pub trait Plugin: Send + Sync {
     fn name(&self) -> &'static str;
     fn from_formats(&self) -> Vec<&'static str>;
     fn to_formats(&self) -> Vec<&'static str>;
 
     /// Score from 1 to 255. Higher is better.
-    fn familiarity(&self) -> u8;
-    fn quality(&self) -> u8;
-    fn speed(&self) -> u8;
+    fn familiarity(&self, from_format: &str, to_format: &str) -> u8;
+    fn quality(&self, from_format: &str, to_format: &str) -> u8;
+    fn speed(&self, from_format: &str, to_format: &str) -> u8;
 
     /// Converts the given input bytes from `from_format` to `to_format`.
-    fn convert(&self, input: &[u8], from_format: &str, to_format: &str) -> Result<Vec<u8>, String>;
+    /// `temp_dir` is the directory to use for any intermediate scratch files.
+    fn convert(
+        &self,
+        input: &[u8],
+        from_format: &str,
+        to_format: &str,
+        temp_dir: &Path,
+    ) -> Result<Vec<u8>, String>;
 }

src/runner.rs

@@ -1,10 +1,26 @@
+// Copyright (C) 2026 Elias Wendland <eliaswendland@pm.me>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, version 3 exclusively.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
 use crate::plugin::Plugin;
+use std::path::Path;
 use std::time::Instant;
 
 pub fn run_conversion(
     path: &[(&dyn Plugin, &str, &str)],
     input: &[u8],
     verbosity: u8,
+    temp_dir: &Path,
 ) -> Result<Vec<u8>, String> {
     if verbosity >= 1 {
         let path_str: Vec<_> = path.iter().map(|(p, _, _)| p.name()).collect();
@@ -15,22 +31,35 @@ pub fn run_conversion(
 
     for (plugin, from_format, to_format) in path {
         if verbosity >= 2 {
-            eprintln!("Converting {} to {} using plugin {}...", from_format, to_format, plugin.name());
+            eprintln!(
+                "Converting {} to {} using plugin {}...",
+                from_format,
+                to_format,
+                plugin.name()
+            );
         }
 
         if verbosity >= 4 {
             eprintln!("[Plugin Log] Running plugin: {}", plugin.name());
             eprintln!("[Plugin Log] Source format: {}", from_format);
             eprintln!("[Plugin Log] Target format: {}", to_format);
-            eprintln!("[Plugin Log] Metrics - Familiarity: {}, Quality: {}, Speed: {}", plugin.familiarity(), plugin.quality(), plugin.speed());
+            eprintln!(
+                "[Plugin Log] Metrics - Familiarity: {}, Quality: {}, Speed: {}",
+                plugin.familiarity(*from_format, *to_format),
+                plugin.quality(*from_format, *to_format),
+                plugin.speed(*from_format, *to_format)
+            );
         }
 
         let start_time = Instant::now();
-        current_data = plugin.convert(&current_data, from_format, to_format)?;
+        current_data = plugin.convert(&current_data, from_format, to_format, temp_dir)?;
         let elapsed = start_time.elapsed();
 
         if verbosity >= 3 {
-            eprintln!("Step '{} -> {}' completed in {:.2?}", from_format, to_format, elapsed);
+            eprintln!(
+                "Step '{} -> {}' completed in {:.2?}",
+                from_format, to_format, elapsed
+            );
         }
     }
 
@@ -50,13 +79,31 @@ mod tests {
     }
 
     impl Plugin for MockPlugin {
-        fn name(&self) -> &'static str { self.name }
-        fn from_formats(&self) -> Vec<&'static str> { vec!["a"] }
-        fn to_formats(&self) -> Vec<&'static str> { vec!["b"] }
-        fn familiarity(&self) -> u8 { self.f }
-        fn quality(&self) -> u8 { self.q }
-        fn speed(&self) -> u8 { self.s }
-        fn convert(&self, input: &[u8], _from: &str, _to: &str) -> Result<Vec<u8>, String> {
+        fn name(&self) -> &'static str {
+            self.name
+        }
+        fn from_formats(&self) -> Vec<&'static str> {
+            vec!["a"]
+        }
+        fn to_formats(&self) -> Vec<&'static str> {
+            vec!["b"]
+        }
+        fn familiarity(&self, _from: &str, _to: &str) -> u8 {
+            self.f
+        }
+        fn quality(&self, _from: &str, _to: &str) -> u8 {
+            self.q
+        }
+        fn speed(&self, _from: &str, _to: &str) -> u8 {
+            self.s
+        }
+        fn convert(
+            &self,
+            input: &[u8],
+            _from: &str,
+            _to: &str,
+            _temp_dir: &Path,
+        ) -> Result<Vec<u8>, String> {
             if self.fail {
                 return Err("Failed".to_string());
             }
@@ -70,11 +117,18 @@ mod tests {
         ($name:ident, $verbosity:expr, $fail:expr, $expected_res:expr, $expected_len:expr) => {
             #[test]
             fn $name() {
-                let plugin = MockPlugin { name: "mock", f: 10, q: 10, s: 10, fail: $fail };
+                let plugin = MockPlugin {
+                    name: "mock",
+                    f: 10,
+                    q: 10,
+                    s: 10,
+                    fail: $fail,
+                };
                 let path: Vec<(&dyn Plugin, &str, &str)> = vec![(&plugin, "a", "b")];
                 let input = vec![0];
 
-                let result = run_conversion(&path, &input, $verbosity);
+                let result =
+                    run_conversion(&path, &input, $verbosity, std::path::Path::new("/dev/shm"));
                 assert_eq!(result.is_ok(), $expected_res);
                 if let Ok(res) = result {
                     assert_eq!(res.len(), $expected_len);