[PATCH] winegstreamer: Check whether transforms are supported at creation time.

[Zebediah Figura]

On 4/27/22 12:50, Rémi Bernon wrote:
> diff --git a/dlls/winegstreamer/h264_decoder.c b/dlls/winegstreamer/h264_decoder.c
> index 8bfa15529db..778729f576c 100644
> --- a/dlls/winegstreamer/h264_decoder.c
> +++ b/dlls/winegstreamer/h264_decoder.c
> @@ -585,10 +585,20 @@ static const IMFTransformVtbl transform_vtbl =
>   
>   HRESULT h264_decoder_create(REFIID riid, void **ret)
>   {
> +    struct wg_format output_format = {.major_type = WG_MAJOR_TYPE_UNKNOWN};
> +    struct wg_format input_format = {.major_type = WG_MAJOR_TYPE_H264};

This feels a bit awkward. input_format is somewhat ill-formed [not that 
struct wg_format is highly formalized, but wg_format_to_caps_h264() at 
least expects the profile and level to be set], but output_format has a 
major type of UNKNOWN, presumably to avoid passing an ill-formed type.

> @@ -210,9 +209,13 @@ NTSTATUS wg_transform_create(void *args)
>        * based on the actual output caps now. Matching decoders with the
>        * raw output media type should be enough.
>        */
> -    media_type = gst_structure_get_name(gst_caps_get_structure(sink_caps, 0));
> -    if (!(raw_caps = gst_caps_new_empty_simple(media_type)))
> +    if (!(raw_caps = gst_caps_new_any()))
>           goto out;
> +    if (gst_caps_get_size(sink_caps))
> +    {
> +        const gchar *media_type = gst_structure_get_name(gst_caps_get_structure(sink_caps, 0));
> +        gst_caps_append_structure(raw_caps, gst_structure_new_empty(media_type));
> +    }

And this will end up checking whether H.264 or WMA can decode to 
*anything*, which, while probably sufficient in practice, is less useful 
in theory than checking whether it can decode to, say, NV12 or PCM 
respectively.

I don't think that wg_format structs need to be fully specified (e.g. 
just enough to calculate the GstStructure name seems sufficient), 
although it'd be nice to avoid generating GStreamer FIXMEs under normal 
operation.