add command line options and temperature calibration

without temperature calibration 0.3%
with ~5%

model name	: Intel(R) Core(TM) i7-3615QM CPU @ 2.30GHz

Cargo.lock

@@ -168,6 +168,54 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "anstream"
+version = "0.6.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "96b09b5178381e0874812a9b157f7fe84982617e48f71f4e3235482775e5b540"
+dependencies = [
+ "anstyle",
+ "anstyle-parse",
+ "anstyle-query",
+ "anstyle-wincon",
+ "colorchoice",
+ "utf8parse",
+]
+
+[[package]]
+name = "anstyle"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8901269c6307e8d93993578286ac0edf7f195079ffff5ebdeea6a59ffb7e36bc"
+
+[[package]]
+name = "anstyle-parse"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c75ac65da39e5fe5ab759307499ddad880d724eed2f6ce5b5e8a26f4f387928c"
+dependencies = [
+ "utf8parse",
+]
+
+[[package]]
+name = "anstyle-query"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e28923312444cdd728e4738b3f9c9cac739500909bb3d3c94b43551b16517648"
+dependencies = [
+ "windows-sys 0.52.0",
+]
+
+[[package]]
+name = "anstyle-wincon"
+version = "3.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1cd54b81ec8d6180e24654d0b371ad22fc3dd083b6ff8ba325b72e00c87660a7"
+dependencies = [
+ "anstyle",
+ "windows-sys 0.52.0",
+]
+
 [[package]]
 name = "anyhow"
 version = "1.0.77"
@@ -715,6 +763,46 @@ dependencies = [
  "libloading 0.8.1",
 ]
 
+[[package]]
+name = "clap"
+version = "4.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c918d541ef2913577a0f9566e9ce27cb35b6df072075769e0b26cb5a554520da"
+dependencies = [
+ "clap_builder",
+ "clap_derive",
+]
+
+[[package]]
+name = "clap_builder"
+version = "4.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9f3e7391dad68afb0c2ede1bf619f579a3dc9c2ec67f089baa397123a2f3d1eb"
+dependencies = [
+ "anstream",
+ "anstyle",
+ "clap_lex",
+ "strsim",
+]
+
+[[package]]
+name = "clap_derive"
+version = "4.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "307bc0538d5f0f83b8248db3087aa92fe504e4691294d0c96c0eabc33f47ba47"
+dependencies = [
+ "heck",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.48",
+]
+
+[[package]]
+name = "clap_lex"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "98cc8fbded0c607b7ba9dd60cd98df59af97e84d24e49c8557331cfc26d301ce"
+
 [[package]]
 name = "clipboard-win"
 version = "5.1.0"
@@ -770,6 +858,12 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3d7b894f5411737b7867f4827955924d7c254fc9f4d91a6aad6b097804b1018b"
 
+[[package]]
+name = "colorchoice"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "acbf1af155f9b9ef647e42cdc158db4b64a1b61f743629225fde6f3e0be2a7c7"
+
 [[package]]
 name = "com"
 version = "0.6.0"
@@ -2925,6 +3019,12 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6637bab7722d379c8b41ba849228d680cc12d0a45ba1fa2b48f2a30577a06731"
 
+[[package]]
+name = "strsim"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5ee073c9e4cd00e28217186dbe12796d692868f432bf2e97ee73bed0c56dfa01"
+
 [[package]]
 name = "syn"
 version = "1.0.109"
@@ -2979,6 +3079,7 @@ name = "thermaldecoder"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "clap",
  "crossbeam",
  "crossbeam-channel",
  "dotenv",
@@ -3227,6 +3328,12 @@ dependencies = [
  "percent-encoding",
 ]
 
+[[package]]
+name = "utf8parse"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "711b9620af191e0cdc7468a8d14e709c3dcdb115b36f838e601583af800a370a"
+
 [[package]]
 name = "v4l"
 version = "0.14.0"

Cargo.toml

@@ -11,6 +11,7 @@ crate-type = ["rlib", "cdylib"]
 
 [dependencies]
 anyhow = "1.0.77"
+clap = { version = "4.5.1", features = ["derive"] }
 crossbeam = "0.8.4"
 crossbeam-channel = "0.5.11"
 dotenv = "0.15.0"

examples/live.rs

@@ -1,9 +1,31 @@
+use clap::Parser;
 use dotenv::dotenv;
 use std::io::Write;
 use thermaldecoder::{Header, HDR_SIZE};
 use v4l::video::Output;
 
+#[derive(Parser, Debug)]
+#[command(version, about, long_about = None)]
+struct Args {
+    #[arg(short, long, default_value_t = false)]
+    temperature: bool,
+    #[arg(short, long, default_value = "/dev/video0")]
+    device: String,
+}
+
+fn pixel_to_celcius(x: u16) -> u16 {
+    let x: f64 = x.into();
+    let x = x / 256.0;
+    let t = (-1.665884e-08) * x.powf(4.)
+        + (1.347094e-05) * x.powf(3.)
+        + (-4.396264e-03) * x.powf(2.)
+        + (9.506939e-01) * x
+        + (-6.353247e+01);
+    (t * 256.0) as u16
+}
+
 fn main() -> anyhow::Result<()> {
+    let args = Args::parse();
     dotenv().ok();
     let device = match std::env::var("THERMALCAM_IFACE=enp1s0f0") {
         Ok(d) => {
@@ -21,9 +43,7 @@ fn main() -> anyhow::Result<()> {
     // get the default Device
 
     println!("Using device {}", device.name);
-    let output = std::env::args()
+    let output = args.device;
-        .nth(1)
-        .expect("required output file argument");
     println!("Using output v4l2loopback device {}", output);
 
     const WIDTH: usize = 288;
@@ -73,8 +93,12 @@ fn main() -> anyhow::Result<()> {
                 // possibly limitation of current v4l2loopback or v4l rust wrapper or libv4l2
                 let mut swapped = [0u8; FRAME_LEN];
                 for i in 0..FRAME_LEN / 2 {
-                    swapped[i * 2] = frame[i * 2 + 1];
+                    let mut pixel = u16::from_be_bytes([frame[i * 2], frame[i * 2 + 1]]);
-                    swapped[i * 2 + 1] = frame[i * 2];
+                    if args.temperature {
+                        pixel = pixel_to_celcius(pixel);
+                    }
+                    let pixel_swapped = pixel.to_le_bytes();
+                    swapped[i * 2..i * 2 + 2].copy_from_slice(&pixel_swapped);
                 }
                 out.write_all(&swapped[..])?;
             }

run_live.sh

@@ -10,4 +10,4 @@ TARGET=./target/release/examples/live
 # setcap does not work yet (EPERM on socket AF_PACKET)
 # sudo setcap cap_net_raw,cap_net_admin=eip $TARGET
 #sudo strace -f -o live.strace $TARGET /dev/video0
-sudo $TARGET /dev/video0
+sudo RUST_BACKTRACE=full $TARGET "$@"

run_live_debug.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+cd $(dirname $0)
+
+set -e
+
+# Python works but stutters
+#sudo ./venv/bin/python ./decode.py --live
+cargo build --example live
+TARGET=./target/debug/examples/live
+# setcap does not work yet (EPERM on socket AF_PACKET)
+# sudo setcap cap_net_raw,cap_net_admin=eip $TARGET
+#sudo strace -f -o live.strace $TARGET /dev/video0
+sudo RUST_BACKTRACE=full $TARGET "$@"