v0--v2 replay upgrade, make decoder own file

Cargo.lock

@@ -8,12 +8,55 @@ version = "2.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "320119579fcad9c21884f5c4861d16174d0e06250625266f50fe6898340abefa"
 
+[[package]]
+name = "aho-corasick"
+version = "1.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ddd31a130427c27518df266943a5308ed92d4b226cc639f5a8f1002816174301"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "autocfg"
 version = "1.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c08606f8c3cbf4ce6ec8e28fb0014a2c086708fe954eaa885384a6165172e7e8"
 
+[[package]]
+name = "bindgen"
+version = "0.63.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "36d860121800b2a9a94f9b5604b332d5cffb234ce17609ea479d723dbc9d3885"
+dependencies = [
+ "bitflags 1.3.2",
+ "cexpr",
+ "clang-sys",
+ "lazy_static",
+ "lazycell",
+ "log",
+ "peeking_take_while",
+ "proc-macro2",
+ "quote",
+ "regex",
+ "rustc-hash",
+ "shlex",
+ "syn 1.0.109",
+ "which",
+]
+
+[[package]]
+name = "bitflags"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
+
+[[package]]
+name = "bitflags"
+version = "2.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "812e12b5285cc515a9c72a5c1d3b6d46a19dac5acfef5265968c166106e31dd3"
+
 [[package]]
 name = "bytemuck"
 version = "1.24.0"
@@ -38,12 +81,32 @@ dependencies = [
  "shlex",
 ]
 
+[[package]]
+name = "cexpr"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6fac387a98bb7c37292057cffc56d62ecb629900026402633ae9160df93a8766"
+dependencies = [
+ "nom",
+]
+
 [[package]]
 name = "cfg-if"
 version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
 
+[[package]]
+name = "clang-sys"
+version = "1.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0b023947811758c97c59bf9d1c188fd619ad4718dcaa767947df1cadb14f39f4"
+dependencies = [
+ "glob",
+ "libc",
+ "libloading",
+]
+
 [[package]]
 name = "crc32fast"
 version = "1.5.0"
@@ -53,6 +116,22 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "either"
+version = "1.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "48c757948c5ede0e46177b7add2e67155f70e33c07fea8284df6576da70b3719"
+
+[[package]]
+name = "errno"
+version = "0.3.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "39cab71617ae0d63f51a36d69f866391735b51691dbda63cf6f96d042b63efeb"
+dependencies = [
+ "libc",
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "find-msvc-tools"
 version = "0.1.4"
@@ -82,6 +161,21 @@ dependencies = [
  "wasip2",
 ]
 
+[[package]]
+name = "glob"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0cc23270f6e1808e30a928bdc84dea0b9b4136a8bc82338574f23baf47bbd280"
+
+[[package]]
+name = "home"
+version = "0.5.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cc627f471c528ff0c4a49e1d5e60450c8f6461dd6d10ba9dcd3a61d3dff7728d"
+dependencies = [
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "jobserver"
 version = "0.1.34"
@@ -92,12 +186,34 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "lazy_static"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
+
+[[package]]
+name = "lazycell"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55"
+
 [[package]]
 name = "libc"
 version = "0.2.177"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2874a2af47a2325c2001a6e6fad9b16a53b802102b528163885171cf92b15976"
 
+[[package]]
+name = "libloading"
+version = "0.8.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d7c4b02199fee7c5d21a5ae7d8cfa79a6ef5bb2fc834d6e9058e89c825efdc55"
+dependencies = [
+ "cfg-if",
+ "windows-link",
+]
+
 [[package]]
 name = "libz-rs-sys"
 version = "0.5.2"
@@ -107,6 +223,30 @@ dependencies = [
  "zlib-rs",
 ]
 
+[[package]]
+name = "linux-raw-sys"
+version = "0.4.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d26c52dbd32dccf2d10cac7725f8eae5296885fb5703b261f7d0a0739ec807ab"
+
+[[package]]
+name = "log"
+version = "0.4.28"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "34080505efa8e45a4b816c349525ebe327ceaa8559756f0356cba97ef3bf7432"
+
+[[package]]
+name = "memchr"
+version = "2.7.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f52b00d39961fc5b2736ea853c9cc86238e165017a493d1d5c8eac6bdc4cc273"
+
+[[package]]
+name = "minimal-lexical"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "68354c5c6bd36d73ff3feceb05efa59b6acb7626617f4962be322a825e61f79a"
+
 [[package]]
 name = "miniz_oxide"
 version = "0.8.9"
@@ -123,6 +263,16 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2bf50223579dc7cdcfb3bfcacf7069ff68243f8c363f62ffa99cf000a6b9c451"
 
+[[package]]
+name = "nom"
+version = "7.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d273983c5a657a70a3e8f2a01329822f3b8c8172b73826411a55751e404a0a4a"
+dependencies = [
+ "memchr",
+ "minimal-lexical",
+]
+
 [[package]]
 name = "num-traits"
 version = "0.2.19"
@@ -132,12 +282,24 @@ dependencies = [
  "autocfg",
 ]
 
+[[package]]
+name = "once_cell"
+version = "1.21.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "42f5e15c9953c5e4ccceeb2e7382a716482c34515315f7b03532b8b4e8393d2d"
+
 [[package]]
 name = "paste"
 version = "1.0.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "57c0d7b74b563b49d38dae00a0c37d4d6de9b432382b2892f0574ddcae73fd0a"
 
+[[package]]
+name = "peeking_take_while"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "19b17cddbe7ec3f8bc800887bab5e717348c95ea2ca0b1bf0837fb964dc67099"
+
 [[package]]
 name = "pkg-config"
 version = "0.3.32"
@@ -168,6 +330,46 @@ version = "5.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "69cdb34c158ceb288df11e18b4bd39de994f6657d83847bdffdbd7f346754b0f"
 
+[[package]]
+name = "regex"
+version = "1.12.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "843bc0191f75f3e22651ae5f1e72939ab2f72a4bc30fa80a066bd66edefc24d4"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5276caf25ac86c8d810222b3dbb938e512c55c6831a10f3e6ed1c93b84041f1c"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a2d987857b319362043e95f5353c0535c1f58eec5336fdfcf626430af7def58"
+
+[[package]]
+name = "retro-rs"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "656d99fcb289714d4b7e294187c09fa8d0563414b8b3f1dca2f5d258bd221441"
+dependencies = [
+ "libc",
+ "libloading",
+ "rust-libretro-sys",
+]
+
 [[package]]
 name = "rmp"
 version = "0.8.14"
@@ -187,6 +389,7 @@ dependencies = [
  "byteorder",
  "flate2",
  "nohash-hasher",
+ "retro-rs",
  "rmp",
  "smallvec",
  "thiserror",
@@ -194,6 +397,47 @@ dependencies = [
  "zstd",
 ]
 
+[[package]]
+name = "rust-libretro-sys"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1cbdb106ca97d195be38097412623e1e89926fa3de9f3af995145f6fa0c958c6"
+dependencies = [
+ "bindgen",
+ "libc",
+ "rust-libretro-sys-proc",
+]
+
+[[package]]
+name = "rust-libretro-sys-proc"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dad70ae46523827ed74c292727aa40021db22397e570a31dd86240c87fc2d929"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 1.0.109",
+]
+
+[[package]]
+name = "rustc-hash"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "08d43f7aa6b08d49f382cde6a7982047c3426db949b1424bc4b7ec9ae12c6ce2"
+
+[[package]]
+name = "rustix"
+version = "0.38.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fdb5bc1ae2baa591800df16c9ca78619bf65c0488b41b96ccec5d11220d8c154"
+dependencies = [
+ "bitflags 2.10.0",
+ "errno",
+ "libc",
+ "linux-raw-sys",
+ "windows-sys 0.59.0",
+]
+
 [[package]]
 name = "shlex"
 version = "1.3.0"
@@ -212,6 +456,17 @@ version = "1.15.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "67b1b7a3b5fe4f1376887184045fcf45c69e92af734b7aaddc05fb777b6fbd03"
 
+[[package]]
+name = "syn"
+version = "1.0.109"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "72b64191b275b66ffe2469e8af2c1cfe3bafa67b529ead792a6d0160888b4237"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
 [[package]]
 name = "syn"
 version = "2.0.108"
@@ -240,14 +495,14 @@ checksum = "3ff15c8ecd7de3849db632e14d18d2571fa09dfc5ed93479bc4485c7a517c913"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn",
+ "syn 2.0.108",
 ]
 
 [[package]]
 name = "unicode-ident"
-version = "1.0.20"
+version = "1.0.22"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "462eeb75aeb73aea900253ce739c8e18a67423fadf006037cd3ff27e82748a06"
+checksum = "9312f7c4f6ff9069b165498234ce8be658059c6728633667c526e27dc2cf1df5"
 
 [[package]]
 name = "wasip2"
@@ -258,6 +513,106 @@ dependencies = [
  "wit-bindgen",
 ]
 
+[[package]]
+name = "which"
+version = "4.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "87ba24419a2078cd2b0f2ede2691b6c66d8e47836da3b6db8265ebad47afbfc7"
+dependencies = [
+ "either",
+ "home",
+ "once_cell",
+ "rustix",
+]
+
+[[package]]
+name = "windows-link"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f0805222e57f7521d6a62e36fa9163bc891acd422f971defe97d64e70d0a4fe5"
+
+[[package]]
+name = "windows-sys"
+version = "0.59.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e38bc4d79ed67fd075bcc251a1c39b32a1776bbe92e5bef1f0bf1f8c531853b"
+dependencies = [
+ "windows-targets",
+]
+
+[[package]]
+name = "windows-sys"
+version = "0.61.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ae137229bcbd6cdf0f7b80a31df61766145077ddf49416a728b02cb3921ff3fc"
+dependencies = [
+ "windows-link",
+]
+
+[[package]]
+name = "windows-targets"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9b724f72796e036ab90c1021d4780d4d3d648aca59e491e6b98e725b84e99973"
+dependencies = [
+ "windows_aarch64_gnullvm",
+ "windows_aarch64_msvc",
+ "windows_i686_gnu",
+ "windows_i686_gnullvm",
+ "windows_i686_msvc",
+ "windows_x86_64_gnu",
+ "windows_x86_64_gnullvm",
+ "windows_x86_64_msvc",
+]
+
+[[package]]
+name = "windows_aarch64_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "32a4622180e7a0ec044bb555404c800bc9fd9ec262ec147edd5989ccd0c02cd3"
+
+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09ec2a7bb152e2252b53fa7803150007879548bc709c039df7627cabbd05d469"
+
+[[package]]
+name = "windows_i686_gnu"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e9b5ad5ab802e97eb8e295ac6720e509ee4c243f69d781394014ebfe8bbfa0b"
+
+[[package]]
+name = "windows_i686_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0eee52d38c090b3caa76c563b86c3a4bd71ef1a819287c19d586d7334ae8ed66"
+
+[[package]]
+name = "windows_i686_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "240948bc05c5e7c6dabba28bf89d89ffce3e303022809e73deaefe4f6ec56c66"
+
+[[package]]
+name = "windows_x86_64_gnu"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "147a5c80aabfbf0c7d901cb5895d1de30ef2907eb21fbbab29ca94c5b08b1a78"
+
+[[package]]
+name = "windows_x86_64_gnullvm"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "24d5b23dc417412679681396f2b49f3de8c1473deb516bd34410872eff51ed0d"
+
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.52.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "589f6da84c646204747d1270a2a5661ea66ed1cced2631d546fdfb155959f9ec"
+
 [[package]]
 name = "wit-bindgen"
 version = "0.46.0"

Cargo.toml

@@ -13,3 +13,4 @@ smallvec = "1.15.1"
 thiserror = "2.0.17"
 xxhash-rust = { version = "0.8.15", features = ["xxh3"] }
 zstd = "0.13.3"
+retro-rs = { version = "0.5.2", default-features=false }

src/bin/dump.rs

@@ -4,8 +4,8 @@ fn main() {
     let args: Vec<_> = std::env::args().collect();
     let file =
         std::fs::File::open(args.get(1).unwrap_or(&"examples/bobl.replay".to_string())).unwrap();
-    let mut file = std::io::BufReader::new(file);
+    let file = std::io::BufReader::new(file);
-    let mut rply = decode(&mut file).unwrap();
+    let mut rply = decode(file).unwrap();
     let header = &rply.header;
     println!("{header:?}");
     let mut frame = Frame::default();

src/bin/reencode.rs

@@ -9,13 +9,13 @@ fn main() {
             .unwrap_or(&"examples/bobl_smallblocks.replay".to_string()),
     )
     .unwrap();
-    let mut file = std::io::BufReader::new(file);
+    let file = std::io::BufReader::new(file);
     let mut outfile = std::io::BufWriter::new(outfile);
-    let mut rply = decode(&mut file).unwrap();
+    let mut rply = decode(file).unwrap();
     let header = &rply.header;
     println!("{header:?}");
     if header.version() == 0 {
-        println!("Can't upgrade v0 replays without a core");
+        println!("Can't upgrade v0 replays with reencode, upgrade to v1 first using upgrade0");
         std::process::exit(-1);
     }
     let mut header_out = header.clone();
@@ -38,6 +38,10 @@ fn main() {
             rply.frame_number,
             frame.inputs(),
         );
+
+        // TODO run libretro core here, maybe serialize into frame.checkpoint_bytes
+        // TODO maybe get screenshot or add to video
+
         //frame.drop_checkpoint();
         out.write_frame(&frame).unwrap();
         if Some(rply.frame_number) == rply.header.frame_count() {

src/bin/upgrade0.rs

@@ -0,0 +1,73 @@
+use retro_rs::Emulator;
+use rply_codec::{Frame, InputData, ReplayError, decode, encode};
+use std::cell::RefCell;
+use std::path::Path;
+use std::rc::Rc;
+
+fn main() {
+    let args: Vec<_> = std::env::args().collect();
+    let file =
+        std::fs::File::open(args.get(1).unwrap_or(&"examples/v0.replay".to_string())).unwrap();
+    let outfile =
+        std::fs::File::create(args.get(2).unwrap_or(&"examples/v2.replay".to_string())).unwrap();
+    let corefile = args
+        .get(3)
+        .unwrap_or(&"cores/fceumm_libretro".to_string())
+        .clone();
+    let romfile = args.get(4).unwrap_or(&"roms/demo.nes".to_string()).clone();
+    let mut emu = Emulator::create(Path::new(&corefile), Path::new(&romfile));
+    let file = std::io::BufReader::new(file);
+    let mut outfile = std::io::BufWriter::new(outfile);
+    let mut rply = decode(file).unwrap();
+    let header = &rply.header;
+    println!("Header in: {header:?}");
+    if header.version() != 0 {
+        println!("Only use this program for v0 replays!");
+        std::process::exit(-1);
+    }
+    assert!(emu.load(&rply.initial_state));
+    let mut header_out = header.clone();
+    header_out.upgrade();
+    let mut encoder = encode(header_out, &rply.initial_state, &mut outfile).unwrap();
+    let mut frame = Frame::default();
+    rply.read_key_events(&mut frame).unwrap();
+    rply.read_end_of_frame(&mut frame).unwrap();
+    let frame = Rc::new(RefCell::new(frame));
+    let rply = Rc::new(RefCell::new(rply));
+    let cb = {
+        let frame = Rc::clone(&frame);
+        let rply = Rc::clone(&rply);
+        Box::new(move |port, device, idx, id| {
+            let val = rply.borrow_mut().read_v0_button().unwrap();
+            //println!("{port}-{device}-{idx}-{id}: 0x{val:x}");
+            frame.borrow_mut().input_events.push(InputData {
+                port: u8::try_from(port).unwrap(),
+                device: u8::try_from(device).unwrap(),
+                idx: u8::try_from(idx).unwrap(),
+                id: u16::try_from(id).unwrap(),
+                val,
+            });
+            val
+        })
+    };
+    loop {
+        frame.borrow_mut().clear();
+        emu.run_with_button_callback(cb.clone());
+        match rply.borrow_mut().read_key_events(&mut frame.borrow_mut()) {
+            Ok(()) => {}
+            Err(ReplayError::IO(e)) => {
+                if e.kind() == std::io::ErrorKind::UnexpectedEof {
+                    break;
+                }
+                panic!("{e}");
+            }
+            Err(e) => panic!("{e}"),
+        }
+        rply.borrow_mut()
+            .read_end_of_frame(&mut frame.borrow_mut())
+            .unwrap();
+        encoder.write_frame(&frame.borrow()).unwrap();
+    }
+    encoder.finish().unwrap();
+    println!("Header out: {:?}", encoder.header);
+}

src/rply.rs

@@ -176,15 +176,15 @@ pub enum ReplayError {
 
 type Result<T> = std::result::Result<T, ReplayError>;
 
-pub struct ReplayDecoder<'a, R: std::io::BufRead> {
+pub struct ReplayDecoder<R: std::io::BufRead> {
-    rply: &'a mut R,
+    rply: R,
     pub header: Header,
     pub initial_state: Vec<u8>,
     pub frame_number: u64,
     ss_state: statestream::Ctx,
 }
 
-impl<R: std::io::BufRead> ReplayDecoder<'_, R> {
+impl<R: std::io::BufRead> ReplayDecoder<R> {
     /// Creates a [`ReplayDecoder`] for the given buffered readable stream.
     ///
     /// # Errors
@@ -192,7 +192,7 @@ impl<R: std::io::BufRead> ReplayDecoder<'_, R> {
     /// [`ReplayError::Magic`]: Invalid magic number at beginning of file
     /// [`ReplayError::Version`]: Version identifier not recognized by parser
     /// [`ReplayError::Compression`]: Unsupported compression scheme for checkpoints
-    pub fn new(rply: &mut R) -> Result<ReplayDecoder<'_, R>> {
+    pub fn new(mut rply: R) -> Result<ReplayDecoder<R>> {
         use byteorder::{LittleEndian, ReadBytesExt};
         let magic = rply.read_u32::<LittleEndian>()?;
         if magic != MAGIC {
@@ -245,35 +245,20 @@ impl<R: std::io::BufRead> ReplayDecoder<'_, R> {
             frame_number: 0,
             ss_state: statestream::Ctx::new(block_size, superblock_size),
         };
-        if replay.header.version() == 1 {
-            replay.rply.read_exact(&mut replay.initial_state)?;
-        } else {
         replay.decode_initial_checkpoint()?;
-        }
         Ok(replay)
     }
 
-    /// Reads a single frame at the current decoder position.
+    pub fn inner(&mut self) -> &mut R {
+        &mut self.rply
+    }
+
+    /// Reads keyboard event records at the current input position.  Only really appropriate to explicitly call for v0 replays.
     /// # Errors
     /// [`ReplayError::IO`]: Unexpected end of stream or other I/O error
-    /// [`ReplayError::Compression`]: Unsupported compression scheme
+    pub fn read_key_events(&mut self, frame: &mut Frame) -> Result<()> {
-    /// [`ReplayError::Encoding`]: Unsupported encoding scheme
-    /// [`ReplayError::BadFrameToken`]: Frame token not recognized or misaligned
-    /// [`ReplayError::NoCoreRead`]: Tried to read a frame on a version 0 replay without a loaded core
-    /// [`ReplayError::CheckpointTooBig`]: Tried to read a checkpoint bigger than the address space
-    #[allow(clippy::too_many_lines)]
-    pub fn read_frame(&mut self, frame: &mut Frame) -> Result<()> {
         use byteorder::{LittleEndian, ReadBytesExt};
-        let stopwatch = clock::time(Timer::DecodeFrame);
+        let rply = &mut self.rply;
-        let vsn = self.header.version();
-        let rply = &mut *self.rply;
-        if vsn == 0 {
-            return Err(ReplayError::NoCoreRead());
-        }
-        if vsn > 1 {
-            /* skip over the backref */
-            let _ = rply.read_u32::<LittleEndian>()?;
-        }
         let key_count = rply.read_u8()? as usize;
         frame.key_events.resize_with(key_count, Default::default);
         for ki in 0..key_count {
@@ -294,6 +279,74 @@ impl<R: std::io::BufRead> ReplayDecoder<'_, R> {
             };
             frame.key_events[ki] = key_data;
         }
+        Ok(())
+    }
+
+    /// Reads an end of frame marker at the current input position.  Only really appropriate to explicitly call for v0 replays.
+    /// # Errors
+    /// [`ReplayError::IO`]: Unexpected end of stream or other I/O error
+    /// [`ReplayError::Compression`]: Unsupported compression scheme
+    /// [`ReplayError::Encoding`]: Unsupported encoding scheme
+    /// [`ReplayError::BadFrameToken`]: Frame token not recognized or misaligned
+    /// [`ReplayError::CheckpointTooBig`]: Tried to read a checkpoint bigger than the address space
+    pub fn read_end_of_frame(&mut self, frame: &mut Frame) -> Result<()> {
+        use byteorder::{LittleEndian, ReadBytesExt};
+        let rply = &mut self.rply;
+        let tok = rply.read_u8()?;
+        match FrameToken::from(tok) {
+            FrameToken::Regular => {
+                frame.checkpoint_compression = Compression::None;
+                frame.checkpoint_encoding = Encoding::Raw;
+                frame.checkpoint_bytes.clear();
+            }
+            FrameToken::Checkpoint => {
+                frame.checkpoint_compression = Compression::None;
+                frame.checkpoint_encoding = Encoding::Raw;
+                let cp_size = usize::try_from(rply.read_u64::<LittleEndian>()?)
+                    .map_err(ReplayError::CheckpointTooBig)?;
+                frame.checkpoint_bytes.resize(cp_size, 0);
+                rply.read_exact(frame.checkpoint_bytes.as_mut_slice())?;
+            }
+            FrameToken::Checkpoint2 => {
+                self.decode_checkpoint(&mut frame.checkpoint_bytes)?;
+            }
+            _ => return Err(ReplayError::BadFrameToken(tok)),
+        }
+        Ok(())
+    }
+
+    /// Reads a single button value at the current input position.  Only appropriate for v0 replays and only if you are implementing an input callback for a core.
+    /// # Errors
+    /// [`ReplayError::IO`]: Unexpected end of stream or other I/O error
+    pub fn read_v0_button(&mut self) -> Result<i16> {
+        use byteorder::{LittleEndian, ReadBytesExt};
+        self.rply
+            .read_i16::<LittleEndian>()
+            .map_err(ReplayError::IO)
+    }
+
+    /// Reads a single frame at the current decoder position.
+    /// # Errors
+    /// [`ReplayError::IO`]: Unexpected end of stream or other I/O error
+    /// [`ReplayError::Compression`]: Unsupported compression scheme
+    /// [`ReplayError::Encoding`]: Unsupported encoding scheme
+    /// [`ReplayError::BadFrameToken`]: Frame token not recognized or misaligned
+    /// [`ReplayError::NoCoreRead`]: Tried to read a frame on a version 0 replay without a loaded core
+    /// [`ReplayError::CheckpointTooBig`]: Tried to read a checkpoint bigger than the address space
+    #[allow(clippy::too_many_lines)]
+    pub fn read_frame(&mut self, frame: &mut Frame) -> Result<()> {
+        use byteorder::{LittleEndian, ReadBytesExt};
+        let stopwatch = clock::time(Timer::DecodeFrame);
+        let vsn = self.header.version();
+        if vsn == 0 {
+            return Err(ReplayError::NoCoreRead());
+        }
+        if vsn > 1 {
+            /* skip over the backref */
+            let _ = self.rply.read_u32::<LittleEndian>()?;
+        }
+        self.read_key_events(frame)?;
+        let rply = &mut self.rply;
         let input_count = rply.read_u16::<LittleEndian>()? as usize;
         frame
             .input_events
@@ -315,26 +368,7 @@ impl<R: std::io::BufRead> ReplayDecoder<'_, R> {
             };
             frame.input_events[ii] = inp_data;
         }
-        let tok = rply.read_u8()?;
+        self.read_end_of_frame(frame)?;
-        match FrameToken::from(tok) {
-            FrameToken::Invalid => return Err(ReplayError::BadFrameToken(tok)),
-            FrameToken::Regular => {
-                frame.checkpoint_compression = Compression::None;
-                frame.checkpoint_encoding = Encoding::Raw;
-                frame.checkpoint_bytes.clear();
-            }
-            FrameToken::Checkpoint => {
-                frame.checkpoint_compression = Compression::None;
-                frame.checkpoint_encoding = Encoding::Raw;
-                let cp_size = usize::try_from(rply.read_u64::<LittleEndian>()?)
-                    .map_err(ReplayError::CheckpointTooBig)?;
-                frame.checkpoint_bytes.resize(cp_size, 0);
-                rply.read_exact(frame.checkpoint_bytes.as_mut_slice())?;
-            }
-            FrameToken::Checkpoint2 => {
-                self.decode_checkpoint(&mut frame.checkpoint_bytes)?;
-            }
-        }
         self.frame_number += 1;
         drop(stopwatch);
         Ok(())
@@ -350,7 +384,7 @@ impl<R: std::io::BufRead> ReplayDecoder<'_, R> {
     fn decode_checkpoint(&mut self, checkpoint_bytes: &mut Vec<u8>) -> Result<()> {
         use byteorder::{LittleEndian, ReadBytesExt};
         let stopwatch = clock::time(Timer::DecodeCheckpoint);
-        let rply = &mut *self.rply;
+        let rply = &mut self.rply;
         // read a 1 byte compression code
         let compression =
             Compression::try_from(rply.read_u8()?).map_err(ReplayError::Compression)?;
@@ -424,7 +458,7 @@ impl<R: std::io::BufRead> ReplayDecoder<'_, R> {
 ///
 /// # Errors
 /// See [`ReplayDecoder::new`].
-pub fn decode<R: std::io::BufRead>(rply: &mut R) -> Result<ReplayDecoder<'_, R>> {
+pub fn decode<R: std::io::BufRead>(rply: R) -> Result<ReplayDecoder<R>> {
     ReplayDecoder::new(rply)
 }
 
@@ -723,14 +757,15 @@ impl Header {
             *self = Header::V2(HeaderV2 {
                 base: base.clone(),
                 frame_count: 0,
-                block_size: 0,
+                block_size: 256,
-                superblock_size: 0,
+                superblock_size: 256,
-                checkpoint_commit_interval: 0,
+                checkpoint_commit_interval: 8,
-                checkpoint_commit_threshold: 0,
+                checkpoint_commit_threshold: 4,
                 checkpoint_compression: Compression::None,
             });
         }
         let Header::V2(v2) = self else { unreachable!() };
+        v2.base.version = 2;
         v2
     }
     #[must_use]
@@ -830,6 +865,11 @@ impl Frame {
         self.checkpoint_compression = Compression::None;
         self.checkpoint_encoding = Encoding::Raw;
     }
+    pub fn clear(&mut self) {
+        self.key_events.clear();
+        self.input_events.clear();
+        self.drop_checkpoint();
+    }
 }
 
 impl Default for Frame {