codec/parameters: make api more flexible and consistent

examples/transcode-audio.rs

@@ -51,7 +51,7 @@ fn transcoder<P: AsRef<Path>>(ictx: &mut format::context::Input, octx: &mut form
 	let codec   = try!(ffmpeg::encoder::find(octx.format().codec(path, media::Type::Audio)).expect("failed to find encoder").audio());
 	let global  = octx.format().flags().contains(ffmpeg::format::flag::GLOBAL_HEADER);
 
-	try!(decoder.set_parameters(input.codec_parameters()));
+	try!(decoder.set_parameters(input.parameters()));
 
 	let mut output  = try!(octx.add_stream(codec));
 	let mut encoder = try!(output.codec().encoder().audio());
@@ -75,7 +75,7 @@ fn transcoder<P: AsRef<Path>>(ictx: &mut format::context::Input, octx: &mut form
 	output.set_time_base((1, decoder.rate() as i32));
 
 	let encoder = try!(encoder.open_as(codec));
-	try!(output.set_codec_parameters_from(&encoder));
+	output.set_parameters(&***encoder);
 
 	let filter  = try!(filter(filter_spec, &decoder, &encoder));
 

src/codec/parameters.rs

@@ -2,7 +2,7 @@ use std::rc::Rc;
 
 use ffi::*;
 use media;
-use super::Id;
+use super::{Id, Context};
 
 pub struct Parameters {
 	ptr:   *mut AVCodecParameters,
@@ -69,3 +69,13 @@ impl Clone for Parameters {
 		}
 	}
 }
+
+impl<'a> From<&'a Context> for Parameters {
+	fn from(context: &'a Context) -> Parameters {
+		let mut parameters = Parameters::new();
+		unsafe {
+			avcodec_parameters_from_context(parameters.as_mut_ptr(), context.as_ptr());
+		}
+		parameters
+	}
+}

src/format/stream/stream.rs

@@ -27,7 +27,7 @@ impl<'a> Stream<'a> {
 		}
 	}
 
-	pub fn codec_parameters(&self) -> codec::Parameters {
+	pub fn parameters(&self) -> codec::Parameters {
 		unsafe {
 			codec::Parameters::wrap((*self.as_ptr()).codecpar, Some(self.context.destructor()))
 		}

src/format/stream/stream_mut.rs

@@ -2,7 +2,7 @@ use std::ops::Deref;
 use std::mem;
 
 use ffi::*;
-use ::{Rational, Error};
+use ::{Rational, codec};
 use super::Stream;
 use format::context::common::Context;
 
@@ -41,12 +41,11 @@ impl<'a> StreamMut<'a> {
 		}
 	}
 
-	pub fn set_codec_parameters_from(&mut self, context: &::codec::Context) -> Result<(), Error> {
+	pub fn set_parameters<P: Into<codec::Parameters>>(&mut self, parameters: P) {
+		let parameters = parameters.into();
+
 		unsafe {
-			match avcodec_parameters_from_context((*self.as_mut_ptr()).codecpar, context.as_ptr()) {
-				e if e < 0 => Err(Error::from(e)),
-				_          => Ok(()),
-			}
+			avcodec_parameters_copy((*self.as_mut_ptr()).codecpar, parameters.as_ptr());
 		}
 	}
 }