ass to webvtt conversion

2 files changed, 49 insertions, 0 deletions

diff --git a/transcoder/src/lib.rs b/transcoder/src/lib.rs
index 673946b..ef663fb 100644
--- a/transcoder/src/lib.rs
+++ b/transcoder/src/lib.rs
@@ -9,5 +9,6 @@
 use tokio::sync::Semaphore;
 pub mod image;
 pub mod snippet;
+pub mod subtitles;
 
 static LOCAL_TRANSCODING_TASKS: Semaphore = Semaphore::const_new(2);
diff --git a/transcoder/src/subtitles.rs b/transcoder/src/subtitles.rs
new file mode 100644
index 0000000..987405b
--- /dev/null
+++ b/transcoder/src/subtitles.rs
@@ -0,0 +1,48 @@
+use anyhow::anyhow;
+use std::fmt::Write;
+
+pub fn webvtt_from_ass_blocks(
+    title: String,
+    codec_private: Vec<u8>,
+    blocks: Vec<(u64, u64, Vec<u8>)>,
+) -> anyhow::Result<String> {
+    let mut out = String::new();
+
+    writeln!(out, "WEBVTT - {title}")?; // TODO ensure title does not contain "-->"
+    writeln!(out)?;
+
+    for (pts, dur, block) in blocks {
+        let block = String::from_utf8(block)?;
+        let text = convert_block(&block).ok_or(anyhow!("bad ass xD"))?;
+        writeln!(out, "{} --> {}", format_time(pts), format_time(pts + dur))?;
+        writeln!(out, "- {text}")?;
+        writeln!(out)?;
+    }
+
+    Ok(out)
+}
+
+fn format_time(t: u64) -> String {
+    let t = t as f64 / 1_000_000.;
+
+    // let mmm = (t.fract() * 1000.).floor();
+    // let mmm = ((t * 60.).fract() * 60.).floor();
+    // let mmm = ((t / 60).fract() * 60.).floor();
+
+    // format!("{hh:4}:{mm:02}:{ss:02}.{mmm:03}")
+    format!("{t}")
+}
+
+fn convert_block(s: &str) -> Option<&str> {
+    // ReadOrder, Layer, Style, Name, MarginL, MarginR, MarginV, Effect, Text
+    let (_read_order, s) = s.split_once(',')?;
+    let (_layer, s) = s.split_once(',')?;
+    let (_style, s) = s.split_once(',')?;
+    let (_name, s) = s.split_once(',')?;
+    let (_marginl, s) = s.split_once(',')?;
+    let (_marginr, s) = s.split_once(',')?;
+    let (_marginv, s) = s.split_once(',')?;
+    let (_effect, text) = s.split_once(',')?;
+
+    Some(text)
+}