Support FFmpeg 7.0 (#48)

* sys: Run cargo fmt

* sys: Add new channel layout consts

* sys: Update build script for 7.0

- Add new FF_API flags
- Update version_check_info range
- Add ffmpeg_7_0 feature entry

* sys: Update non-exhaustive match statement

* Update enums

* Mark old APIs as removed with 7.0

* Make Audio frame work with 7.0

The .unwrap() in clone() is a bit wonky

* Add API for swr_alloc_set_opts2

* Use AVFrame::duration field in 7.0+

* Include 7.0 in CI runs

* Add fn ChanneLayoutIter::best

* Update examples for new API

* Add/update Context setter for ch layout

src/filter/context/context.rs

@@ -2,9 +2,15 @@ use std::marker::PhantomData;
 
 use super::{Sink, Source};
 use crate::ffi::*;
-use crate::{format, option, ChannelLayoutMask};
+use crate::{format, option};
 use libc::c_void;
 
+#[cfg(feature = "ffmpeg_5_1")]
+use crate::ChannelLayout;
+
+#[cfg(not(feature = "ffmpeg_7_0"))]
+use crate::ChannelLayoutMask;
+
 pub struct Context<'a> {
     ptr: *mut AVFilterContext,
 
@@ -49,9 +55,15 @@ impl<'a> Context<'a> {
         let _ = option::Settable::set(self, "sample_rates", &i64::from(value));
     }
 
+    #[cfg(not(feature = "ffmpeg_7_0"))]
     pub fn set_channel_layout(&mut self, value: ChannelLayoutMask) {
         let _ = option::Settable::set(self, "channel_layouts", &value.bits());
     }
+
+    #[cfg(feature = "ffmpeg_5_1")]
+    pub fn set_ch_layout(&mut self, value: ChannelLayout) {
+        let _ = option::Settable::set_str(self, "channel_layouts", &value.description());
+    }
 }
 
 unsafe impl<'a> option::Target for Context<'a> {