decoder/h264: make CurrentPicType take the picture type as generic pa…

…rameter

Since handles are not used in the reference pictures lists and this is
now the only type we need from the backend, let's take it directly.

src/decoder/stateless/h264.rs

@@ -231,13 +231,13 @@ enum CurrentMacroblockTracking {
 /// State of the picture being currently decoded.
 ///
 /// Stored between calls to [`StatelessDecoder::handle_slice`] that belong to the same picture.
-struct CurrentPicState<B: StatelessDecoderBackend<H264>> {
+struct CurrentPicState<P> {
     /// Data for the current picture as extracted from the stream.
     pic: PictureData,
     /// PPS at the time of the current picture.
     pps: Rc<Pps>,
     /// Backend-specific data for that picture.
-    backend_pic: B::Picture,
+    backend_pic: P,
     /// List of reference pictures, used once per slice.
     ref_pic_lists: ReferencePicLists,
     /// The current macroblock we are processing
@@ -274,7 +274,7 @@ pub struct H264DecoderState<B: StatelessDecoderBackend<H264>> {
 
     /// The picture currently being decoded. We need to preserve it between calls to `decode`
     /// because multiple slices will be processed in different calls to `decode`.
-    current_pic: Option<CurrentPicState<B>>,
+    current_pic: Option<CurrentPicState<B::Picture>>,
 }
 
 impl<B> Default for H264DecoderState<B>
@@ -997,7 +997,7 @@ where
         }
     }
 
-    fn finish_picture(&mut self, pic: CurrentPicState<B>) -> anyhow::Result<()> {
+    fn finish_picture(&mut self, pic: CurrentPicState<B::Picture>) -> anyhow::Result<()> {
         debug!("Finishing picture POC {:?}", pic.pic.pic_order_cnt);
 
         // Submit the picture to the backend.
@@ -1189,7 +1189,7 @@ where
         &mut self,
         timestamp: u64,
         slice: &Slice,
-    ) -> Result<CurrentPicState<B>, DecodeError> {
+    ) -> Result<CurrentPicState<B::Picture>, DecodeError> {
         let nalu_hdr = &slice.nalu.header;
 
         if nalu_hdr.idr_pic_flag {
@@ -1269,7 +1269,11 @@ where
 
     // Check whether first_mb_in_slice increases monotonically for the current
     // picture as required by the specification.
-    fn check_first_mb_in_slice(&mut self, cur_pic: &mut CurrentPicState<B>, slice: &Slice) {
+    fn check_first_mb_in_slice(
+        &mut self,
+        cur_pic: &mut CurrentPicState<B::Picture>,
+        slice: &Slice,
+    ) {
         match &mut cur_pic.current_macroblock {
             CurrentMacroblockTracking::SeparateColorPlane(current_macroblock) => {
                 match current_macroblock.entry(slice.header.colour_plane_id) {
@@ -1299,7 +1303,7 @@ where
     /// Handle a slice. Called once per slice NALU.
     fn handle_slice(
         &mut self,
-        cur_pic: &mut CurrentPicState<B>,
+        cur_pic: &mut CurrentPicState<B::Picture>,
         slice: &Slice,
     ) -> anyhow::Result<()> {
         self.check_first_mb_in_slice(cur_pic, slice);