filters: lavfi: allow hwdec_interop selection for filters

Today, lavfi filters are provided a hw_device from the first
hwdec_interop that was loaded, regardless of whether it's the right one
or not. In most situations where a hardware based filter is used, we
need more control over the device.

In this change, a `hwdec_interop` option is added to the lavfi wrapper
filter configuration and this is used to pick the correct hw_device to
inject into the filter or graph (in the case of a graph, all filters
get the same device).

Note that this requires the use of the explicit lavfi syntax to allow
for the extra configuration.

eg:

```
mpv --vf=hwupload
```

becomes

```
mpv --vf=lavfi=[hwupload]:hwdec_interop=cuda-nvdec
```

or

```
mpv --vf=lavfi-bridge=[hwupload]:hwdec_interop=cuda-nvdec
```

1 files changed, 2 insertions, 2 deletions

diff --git a/filters/filter.c b/filters/filter.c
index 2522209b49..eb757f5753 100644
--- a/filters/filter.c
+++ b/filters/filter.c
@@ -685,7 +685,7 @@ struct mp_stream_info *mp_filter_find_stream_info(struct mp_filter *f)
     return NULL;
 }
 
-struct AVBufferRef *mp_filter_load_hwdec_device(struct mp_filter *f, int imgfmt)
+struct mp_hwdec_ctx *mp_filter_load_hwdec_device(struct mp_filter *f, int imgfmt)
 {
     struct mp_stream_info *info = mp_filter_find_stream_info(f);
     if (!info || !info->hwdec_devs)
@@ -697,7 +697,7 @@ struct AVBufferRef *mp_filter_load_hwdec_device(struct mp_filter *f, int imgfmt)
     };
     hwdec_devices_request_for_img_fmt(info->hwdec_devs, &params);
 
-    return hwdec_devices_get_imgfmt(info->hwdec_devs, imgfmt);
+    return hwdec_devices_get_by_imgfmt(info->hwdec_devs, imgfmt);
 }
 
 static void filter_wakeup(struct mp_filter *f, bool mark_only)