1 files changed, 119 insertions, 0 deletions
diff --git a/remuxer/src/extract.rs b/remuxer/src/extract.rs
new file mode 100644
index 0000000..66c0526
--- /dev/null
+++ b/remuxer/src/extract.rs
@@ -0,0 +1,119 @@
+use crate::seek_index::get_seek_index;
+use anyhow::{anyhow, bail};
+use jellycommon::LocalTrack;
+use jellymatroska::{block::Block, read::EbmlReader, unflatten::IterWithPos, Master, MatroskaTag};
+use log::{debug, info};
+use std::{fs::File, io::BufReader, path::PathBuf};
+
+pub fn extract_track(
+    path_base: PathBuf,
+    track_info: LocalTrack,
+) -> anyhow::Result<Vec<(u64, u64, Vec<u8>)>> {
+    let source_path = path_base.join(track_info.path);
+    let file = File::open(&source_path)?;
+    let mut reader = EbmlReader::new(BufReader::new(file));
+    let index = get_seek_index(&source_path)?;
+    let index = index
+        .get(&(track_info.track as u64))
+        .ok_or(anyhow!("track missing"))?;
+
+    let mut out = Vec::new();
+    for b in &index.blocks {
+        reader.seek(b.source_off, MatroskaTag::Cluster(Master::Start))?;
+        let (duration, block) = read_group(&mut reader)?;
+        out.push((b.pts, duration, block.data))
+    }
+    Ok(out)
+}
+
+pub fn read_group(segment: &mut EbmlReader) -> anyhow::Result<(u64, Block)> {
+    let (mut dur, mut block) = (None, None);
+    loop {
+        let item = segment.next().ok_or(anyhow!("eof"))??;
+        match item {
+            MatroskaTag::Void(_) => (),
+            MatroskaTag::Crc32(_) => (),
+            MatroskaTag::Cluster(_) => (),
+            MatroskaTag::Timestamp(_) => (),
+            MatroskaTag::SimpleBlock(_buf) => {
+                // bail!("unexpected simpleblock, where a group was expected")
+            }
+            MatroskaTag::BlockGroup(Master::Start) => (),
+            MatroskaTag::BlockGroup(Master::End) => return Ok((dur.unwrap(), block.unwrap())),
+            MatroskaTag::BlockDuration(duration) => dur = Some(duration),
+            MatroskaTag::Block(buf) => block = Some(Block::parse(&buf)?),
+            MatroskaTag::Cues(_) => bail!("reached cues, this is the end"),
+            MatroskaTag::Segment(Master::End) => info!("extractor reached segment end"),
+            _ => debug!("(rs) tag ignored: {item:?}"),
+        }
+    }
+}
+
+// fn import_seek_index_segment(
+//     segment: &mut Unflatten,
+//     seek_index: &mut BTreeMap<u64, SeekIndex>,
+// ) -> Result<()> {
+//     while let Some(Ok(Unflat { children, item, .. })) = segment.n() {
+//         match item {
+//             MatroskaTag::SeekHead(_) => {}
+//             MatroskaTag::Info(_) => {}
+//             MatroskaTag::Tags(_) => {}
+//             MatroskaTag::Cues(_) => {}
+//             MatroskaTag::Chapters(_) => {}
+//             MatroskaTag::Tracks(_) => {}
+//             MatroskaTag::Void(_) => {}
+//             MatroskaTag::Cluster(_) => {
+//                 let mut children = children.unwrap();
+//                 let mut pts = 0;
+//                 let mut position = children.position();
+
+//                 loop {
+//                     if let Some(Ok(Unflat { children, item, .. })) = children.n() {
+//                         match item {
+//                             MatroskaTag::Timestamp(ts) => pts = ts,
+//                             MatroskaTag::BlockGroup(_) => {
+//                                 trace!("group");
+//                                 let mut children = children.unwrap();
+//                                 // let position = children.position(); //? TODO where should this point to? cluster or block? // probably block
+//                                 while let Some(Ok(Unflat {
+//                                     children: _,
+//                                     item,
+//                                     position,
+//                                 })) = children.n()
+//                                 {
+//                                     match item {
+//                                         MatroskaTag::Block(ref buf) => {
+//                                             let block = Block::parse(buf)?;
+//                                             debug!(
+//                                                 "block: track={} tso={}",
+//                                                 block.track, block.timestamp_off
+//                                             );
+//                                             seek_index_add(seek_index, &block, position, pts);
+//                                         }
+//                                         _ => trace!("{item:?}"),
+//                                     }
+//                                 }
+//                             }
+//                             MatroskaTag::SimpleBlock(buf) => {
+//                                 let block = Block::parse(&buf)?;
+//                                 trace!(
+//                                     "simple block: track={} tso={}",
+//                                     block.track,
+//                                     block.timestamp_off
+//                                 );
+//                                 trace!("{pts} {}", block.timestamp_off);
+//                                 seek_index_add(seek_index, &block, position, pts);
+//                             }
+//                             _ => trace!("(rsc) tag ignored: {item:?}"),
+//                         }
+//                     } else {
+//                         break;
+//                     }
+//                     position = children.position();
+//                 }
+//             }
+//             _ => debug!("(rs) tag ignored: {item:?}"),
+//         };
+//     }
+//     Ok(())
+// }