diff --git a/examples/transcode-audio.rs b/examples/transcode-audio.rs
index eff780c4..d3190ca6 100644
--- a/examples/transcode-audio.rs
+++ b/examples/transcode-audio.rs
@@ -62,7 +62,7 @@ struct Transcoder {
     out_time_base: ffmpeg::Rational,
 }
 
-fn transcoder<P: AsRef<Path>>(
+fn transcoder<P: AsRef<Path> + ?Sized>(
     ictx: &mut format::context::Input,
     octx: &mut format::context::Output,
     path: &P,
diff --git a/src/codec/codec.rs b/src/codec/codec.rs
index 2e6c8cd0..0a1e1f45 100644
--- a/src/codec/codec.rs
+++ b/src/codec/codec.rs
@@ -7,24 +7,20 @@ use {media, Error};
 
 #[derive(PartialEq, Eq, Copy, Clone)]
 pub struct Codec {
-    ptr: *mut AVCodec,
+    ptr: *const AVCodec,
 }
 
 unsafe impl Send for Codec {}
 unsafe impl Sync for Codec {}
 
 impl Codec {
-    pub unsafe fn wrap(ptr: *mut AVCodec) -> Self {
+    pub unsafe fn wrap(ptr: *const AVCodec) -> Self {
         Codec { ptr }
     }
 
     pub unsafe fn as_ptr(&self) -> *const AVCodec {
         self.ptr as *const _
     }
-
-    pub unsafe fn as_mut_ptr(&mut self) -> *mut AVCodec {
-        self.ptr
-    }
 }
 
 impl Codec {
diff --git a/src/codec/context.rs b/src/codec/context.rs
index 07b17c34..50d2e2e3 100644
--- a/src/codec/context.rs
+++ b/src/codec/context.rs
@@ -8,7 +8,7 @@ use super::{threading, Compliance, Debug, Flags, Id, Parameters};
 use ffi::*;
 use libc::c_int;
 use media;
-use {Codec, Error};
+use {Codec, Error, Rational};
 
 pub struct Context {
     ptr: *mut AVCodecContext,
@@ -41,6 +41,15 @@ impl Context {
         }
     }
 
+    pub fn new_with_codec(codec: Codec) -> Self {
+        unsafe {
+            Context {
+                ptr: avcodec_alloc_context3(codec.as_ptr()),
+                owner: None,
+            }
+        }
+    }
+
     pub fn from_parameters<P: Into<Parameters>>(parameters: P) -> Result<Self, Error> {
         let parameters = parameters.into();
         let mut context = Self::new();
@@ -129,6 +138,31 @@ impl Context {
             }
         }
     }
+
+    pub fn time_base(&self) -> Rational {
+        unsafe { Rational::from((*self.as_ptr()).time_base) }
+    }
+
+    pub fn set_time_base<R: Into<Rational>>(&mut self, value: R) {
+        unsafe {
+            (*self.as_mut_ptr()).time_base = value.into().into();
+        }
+    }
+
+    pub fn frame_rate(&self) -> Rational {
+        unsafe { Rational::from((*self.as_ptr()).framerate) }
+    }
+
+    pub fn set_frame_rate<R: Into<Rational>>(&mut self, value: Option<R>) {
+        unsafe {
+            if let Some(value) = value {
+                (*self.as_mut_ptr()).framerate = value.into().into();
+            } else {
+                (*self.as_mut_ptr()).framerate.num = 0;
+                (*self.as_mut_ptr()).framerate.den = 1;
+            }
+        }
+    }
 }
 
 impl Default for Context {
diff --git a/src/codec/decoder/decoder.rs b/src/codec/decoder/decoder.rs
index 6990ab71..c7f69239 100644
--- a/src/codec/decoder/decoder.rs
+++ b/src/codec/decoder/decoder.rs
@@ -107,8 +107,14 @@ impl Decoder {
         }
     }
 
-    pub fn time_base(&self) -> Rational {
-        unsafe { Rational::from((*self.as_ptr()).time_base) }
+    pub fn packet_time_base(&self) -> Rational {
+        unsafe { Rational::from((*self.as_ptr()).pkt_timebase) }
+    }
+
+    pub fn set_packet_time_base<R: Into<Rational>>(&mut self, value: R) {
+        unsafe {
+            (*self.as_mut_ptr()).pkt_timebase = value.into().into();
+        }
     }
 }
 
diff --git a/src/codec/encoder/encoder.rs b/src/codec/encoder/encoder.rs
index 3dd507b4..2cd3723b 100644
--- a/src/codec/encoder/encoder.rs
+++ b/src/codec/encoder/encoder.rs
@@ -6,7 +6,7 @@ use libc::c_int;
 
 use super::{audio, subtitle, video};
 use codec::Context;
-use {media, packet, Error, Frame, Rational};
+use {media, packet, Error, Frame};
 
 pub struct Encoder(pub Context);
 
@@ -116,23 +116,6 @@ impl Encoder {
             }
         }
     }
-
-    pub fn set_time_base<R: Into<Rational>>(&mut self, value: R) {
-        unsafe {
-            (*self.as_mut_ptr()).time_base = value.into().into();
-        }
-    }
-
-    pub fn set_frame_rate<R: Into<Rational>>(&mut self, value: Option<R>) {
-        unsafe {
-            if let Some(value) = value {
-                (*self.as_mut_ptr()).framerate = value.into().into();
-            } else {
-                (*self.as_mut_ptr()).framerate.num = 0;
-                (*self.as_mut_ptr()).framerate.den = 1;
-            }
-        }
-    }
 }
 
 impl Deref for Encoder {
diff --git a/src/codec/packet/packet.rs b/src/codec/packet/packet.rs
index 72a38ea7..dc0039d5 100644
--- a/src/codec/packet/packet.rs
+++ b/src/codec/packet/packet.rs
@@ -143,6 +143,18 @@ impl Packet {
         self.0.dts = value.unwrap_or(AV_NOPTS_VALUE);
     }
 
+    #[inline]
+    #[cfg(feature = "ffmpeg_5_0")]
+    pub fn time_base(&self) -> Rational {
+        self.0.time_base.into()
+    }
+
+    #[inline]
+    #[cfg(feature = "ffmpeg_5_0")]
+    pub fn set_time_base(&mut self, value: Rational) {
+        self.0.time_base = value.into();
+    }
+
     #[inline]
     pub fn size(&self) -> usize {
         self.0.size as usize
diff --git a/src/filter/context/sink.rs b/src/filter/context/sink.rs
index 0c744e46..71801339 100644
--- a/src/filter/context/sink.rs
+++ b/src/filter/context/sink.rs
@@ -1,7 +1,7 @@
 use super::Context;
 use ffi::*;
 use libc::c_int;
-use {Error, Frame};
+use {Error, Frame, Rational};
 
 pub struct Sink<'a> {
     ctx: &'a mut Context<'a>,
@@ -41,4 +41,8 @@ impl<'a> Sink<'a> {
             av_buffersink_set_frame_size(self.ctx.as_mut_ptr(), value);
         }
     }
+
+    pub fn time_base(&self) -> Rational {
+        unsafe { av_buffersink_get_time_base(self.ctx.as_ptr()) }.into()
+    }
 }
diff --git a/src/format/context/output.rs b/src/format/context/output.rs
index 7df5b0eb..3ab52c9e 100644
--- a/src/format/context/output.rs
+++ b/src/format/context/output.rs
@@ -9,7 +9,7 @@ use super::common::Context;
 use super::destructor;
 use codec::traits;
 use ffi::*;
-use {format, ChapterMut, Dictionary, Error, Rational, StreamMut};
+use {codec, format, ChapterMut, Dictionary, Error, Rational, StreamMut};
 
 pub struct Output {
     ptr: *mut AVFormatContext,
@@ -90,6 +90,25 @@ impl Output {
         }
     }
 
+    pub fn add_stream_with(&mut self, context: &codec::Context) -> Result<StreamMut, Error> {
+        unsafe {
+            let ptr = avformat_new_stream(self.as_mut_ptr(), ptr::null());
+
+            if ptr.is_null() {
+                return Err(Error::Unknown);
+            }
+
+            match avcodec_parameters_from_context((*ptr).codecpar, context.as_ptr()) {
+                0 => (),
+                e => return Err(Error::from(e)),
+            }
+
+            let index = (*self.ctx.as_ptr()).nb_streams - 1;
+
+            Ok(StreamMut::wrap(&mut self.ctx, index as usize))
+        }
+    }
+
     pub fn add_chapter<R: Into<Rational>, S: AsRef<str>>(
         &mut self,
         id: i64,
diff --git a/src/format/format/output.rs b/src/format/format/output.rs
index fdad3502..4cfd2d53 100644
--- a/src/format/format/output.rs
+++ b/src/format/format/output.rs
@@ -63,7 +63,7 @@ impl Output {
         }
     }
 
-    pub fn codec<P: AsRef<Path>>(&self, path: &P, kind: media::Type) -> codec::Id {
+    pub fn codec<P: AsRef<Path> + ?Sized>(&self, path: &P, kind: media::Type) -> codec::Id {
         // XXX: use to_cstring when stable
         let path = CString::new(path.as_ref().as_os_str().to_str().unwrap()).unwrap();
 
diff --git a/src/format/mod.rs b/src/format/mod.rs
index 30ded96c..df389827 100644
--- a/src/format/mod.rs
+++ b/src/format/mod.rs
@@ -58,12 +58,12 @@ pub fn license() -> &'static str {
 }
 
 // XXX: use to_cstring when stable
-fn from_path<P: AsRef<Path>>(path: &P) -> CString {
+fn from_path<P: AsRef<Path> + ?Sized>(path: &P) -> CString {
     CString::new(path.as_ref().as_os_str().to_str().unwrap()).unwrap()
 }
 
 // NOTE: this will be better with specialization or anonymous return types
-pub fn open<P: AsRef<Path>>(path: &P, format: &Format) -> Result<Context, Error> {
+pub fn open<P: AsRef<Path> + ?Sized>(path: &P, format: &Format) -> Result<Context, Error> {
     unsafe {
         let mut ps = ptr::null_mut();
         let path = from_path(path);
@@ -100,7 +100,7 @@ pub fn open<P: AsRef<Path>>(path: &P, format: &Format) -> Result<Context, Error>
     }
 }
 
-pub fn open_with<P: AsRef<Path>>(
+pub fn open_with<P: AsRef<Path> + ?Sized>(
     path: &P,
     format: &Format,
     options: Dictionary,
@@ -148,7 +148,7 @@ pub fn open_with<P: AsRef<Path>>(
     }
 }
 
-pub fn input<P: AsRef<Path>>(path: &P) -> Result<context::Input, Error> {
+pub fn input<P: AsRef<Path> + ?Sized>(path: &P) -> Result<context::Input, Error> {
     unsafe {
         let mut ps = ptr::null_mut();
         let path = from_path(path);
@@ -167,7 +167,7 @@ pub fn input<P: AsRef<Path>>(path: &P) -> Result<context::Input, Error> {
     }
 }
 
-pub fn input_with_dictionary<P: AsRef<Path>>(
+pub fn input_with_dictionary<P: AsRef<Path> + ?Sized>(
     path: &P,
     options: Dictionary,
 ) -> Result<context::Input, Error> {
@@ -193,7 +193,7 @@ pub fn input_with_dictionary<P: AsRef<Path>>(
     }
 }
 
-pub fn input_with_interrupt<P: AsRef<Path>, F>(
+pub fn input_with_interrupt<P: AsRef<Path> + ?Sized, F>(
     path: &P,
     closure: F,
 ) -> Result<context::Input, Error>
@@ -219,7 +219,7 @@ where
     }
 }
 
-pub fn output<P: AsRef<Path>>(path: &P) -> Result<context::Output, Error> {
+pub fn output<P: AsRef<Path> + ?Sized>(path: &P) -> Result<context::Output, Error> {
     unsafe {
         let mut ps = ptr::null_mut();
         let path = from_path(path);
@@ -235,7 +235,7 @@ pub fn output<P: AsRef<Path>>(path: &P) -> Result<context::Output, Error> {
     }
 }
 
-pub fn output_with<P: AsRef<Path>>(
+pub fn output_with<P: AsRef<Path> + ?Sized>(
     path: &P,
     options: Dictionary,
 ) -> Result<context::Output, Error> {
@@ -267,7 +267,10 @@ pub fn output_with<P: AsRef<Path>>(
     }
 }
 
-pub fn output_as<P: AsRef<Path>>(path: &P, format: &str) -> Result<context::Output, Error> {
+pub fn output_as<P: AsRef<Path> + ?Sized>(
+    path: &P,
+    format: &str,
+) -> Result<context::Output, Error> {
     unsafe {
         let mut ps = ptr::null_mut();
         let path = from_path(path);
@@ -289,7 +292,7 @@ pub fn output_as<P: AsRef<Path>>(path: &P, format: &str) -> Result<context::Outp
     }
 }
 
-pub fn output_as_with<P: AsRef<Path>>(
+pub fn output_as_with<P: AsRef<Path> + ?Sized>(
     path: &P,
     format: &str,
     options: Dictionary,