diff --git a/examples/main.rs b/examples/main.rs
index 9fe77cc..c8f45a4 100644
--- a/examples/main.rs
+++ b/examples/main.rs
@@ -30,8 +30,23 @@ fn main() {
         std::process::exit(1);
     };
 
+    let cd = read_as_custom_io(path.clone());
+    scan_input(cd);
+
+    let fd = read_as_file(path.clone());
+    scan_input(fd);
+}
+
+fn read_as_custom_io(path: PathBuf) -> Demuxer {
     let file = File::open(path).unwrap();
-    let mut demuxer = Demuxer::new_custom_io(DropTest { inner: file });
+    Demuxer::new_custom_io(DropTest { inner: file })
+}
+
+fn read_as_file(path_buf: PathBuf) -> Demuxer {
+    Demuxer::new(path_buf.to_str().unwrap())
+}
+
+fn scan_input(mut demuxer: Demuxer) {
     unsafe {
         let info = demuxer.probe_input().expect("demuxer failed");
         println!("{}", info);
@@ -43,7 +58,7 @@ fn main() {
                 break; // EOF
             }
             if let Ok(frames) = decoder.decode_pkt(pkt, stream) {
-                for (mut frame, stream) in frames {
+                for (mut frame, _stream) in frames {
                     // do nothing but decode entire stream
                     av_frame_free(&mut frame);
                 }
diff --git a/src/decode.rs b/src/decode.rs
index e652fd7..3cc22ce 100644
--- a/src/decode.rs
+++ b/src/decode.rs
@@ -29,7 +29,6 @@ impl Drop for CodecContext {
 
 pub struct Decoder {
     codecs: HashMap<i32, CodecContext>,
-    pts: i64,
 }
 
 unsafe impl Send for Decoder {}
@@ -40,7 +39,6 @@ impl Decoder {
     pub fn new() -> Self {
         Self {
             codecs: HashMap::new(),
-            pts: 0,
         }
     }
 
diff --git a/src/demux.rs b/src/demux.rs
index dbeb02e..c2731c8 100644
--- a/src/demux.rs
+++ b/src/demux.rs
@@ -1,14 +1,13 @@
 use anyhow::Error;
 use ffmpeg_sys_the_third::*;
 use std::ffi::CStr;
-use std::time::Instant;
 use std::{ptr, slice};
 
 use crate::get_ffmpeg_error_msg;
 use crate::return_ffmpeg_error;
 use slimbox::{slimbox_unsize, SlimBox, SlimMut};
 use std::fmt::{Display, Formatter};
-use std::io::{Read, Write};
+use std::io::Read;
 use std::mem::transmute;
 
 #[no_mangle]
@@ -150,11 +149,14 @@ impl Display for StreamInfoChannel {
     }
 }
 
+pub enum DemuxerInput {
+    Url(String),
+    Reader(Option<SlimBox<dyn Read + 'static>>),
+}
+
 pub struct Demuxer {
     ctx: *mut AVFormatContext,
-    input: String,
-    started: Instant,
-    buffer: Option<SlimBox<dyn Read + 'static>>,
+    input: DemuxerInput,
 }
 
 impl Demuxer {
@@ -163,9 +165,7 @@ impl Demuxer {
             let ps = avformat_alloc_context();
             Self {
                 ctx: ps,
-                input: input.to_string(),
-                started: Instant::now(),
-                buffer: None,
+                input: DemuxerInput::Url(input.to_string()),
             }
         }
     }
@@ -177,40 +177,40 @@ impl Demuxer {
 
             Self {
                 ctx: ps,
-                input: String::new(),
-                started: Instant::now(),
-                buffer: Some(slimbox_unsize!(reader)),
+                input: DemuxerInput::Reader(Some(slimbox_unsize!(reader))),
             }
         }
     }
 
     unsafe fn open_input(&mut self) -> libc::c_int {
-        if let Some(buffer) = self.buffer.take() {
-            const BUFFER_SIZE: usize = 4096;
-            let pb = avio_alloc_context(
-                av_mallocz(BUFFER_SIZE) as *mut libc::c_uchar,
-                BUFFER_SIZE as libc::c_int,
-                0,
-                buffer.into_raw(),
-                Some(read_data),
-                None,
-                None,
-            );
+        match &mut self.input {
+            DemuxerInput::Url(input) => avformat_open_input(
+                &mut self.ctx,
+                format!("{}\0", input).as_ptr() as *const libc::c_char,
+                ptr::null_mut(),
+                ptr::null_mut(),
+            ),
+            DemuxerInput::Reader(input) => {
+                let input = input.take().expect("input stream already taken");
+                const BUFFER_SIZE: usize = 4096;
+                let pb = avio_alloc_context(
+                    av_mallocz(BUFFER_SIZE) as *mut libc::c_uchar,
+                    BUFFER_SIZE as libc::c_int,
+                    0,
+                    input.into_raw(),
+                    Some(read_data),
+                    None,
+                    None,
+                );
 
-            (*self.ctx).pb = pb;
-            avformat_open_input(
-                &mut self.ctx,
-                ptr::null_mut(),
-                ptr::null_mut(),
-                ptr::null_mut(),
-            )
-        } else {
-            avformat_open_input(
-                &mut self.ctx,
-                format!("{}\0", self.input).as_ptr() as *const libc::c_char,
-                ptr::null_mut(),
-                ptr::null_mut(),
-            )
+                (*self.ctx).pb = pb;
+                avformat_open_input(
+                    &mut self.ctx,
+                    ptr::null_mut(),
+                    ptr::null_mut(),
+                    ptr::null_mut(),
+                )
+            }
         }
     }
 
@@ -297,9 +297,8 @@ impl Demuxer {
 impl Drop for Demuxer {
     fn drop(&mut self) {
         unsafe {
-            if !(*(*self.ctx).pb).opaque.is_null() {
-                let ptr: SlimBox<dyn Read> = SlimBox::from_raw((*(*self.ctx).pb).opaque);
-                drop(ptr)
+            if let DemuxerInput::Reader(_) = self.input {
+                drop(SlimBox::<dyn Read>::from_raw((*(*self.ctx).pb).opaque));
             }
             avformat_free_context(self.ctx);
             self.ctx = ptr::null_mut();
diff --git a/src/lib.rs b/src/lib.rs
index 0f717a3..41cb5a2 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -6,7 +6,7 @@ mod demux;
 mod resample;
 mod scale;
 
-#[macro_export(crate)]
+#[macro_export]
 macro_rules! return_ffmpeg_error {
     ($x:expr) => {
         if $x < 0 {