jpegdecoder: fail early if no input caps have been provided

The jpegdecoder class does not implement the ->parse() virtual function,
and we always need to add the jpegparse element before it. So we should
set_needs_format of the decoder to TRUE, then if no parse before it, it
can fail with a "not-negotiated" error early, rather than go on and
generate unexpected error.

Fixes: https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/1829
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/4066>

diff --git a/subprojects/gst-plugins-bad/sys/va/gstjpegdecoder.c b/subprojects/gst-plugins-bad/sys/va/gstjpegdecoder.c
index 9771f5c..ce2c67d 100644 (file)
--- a/subprojects/gst-plugins-bad/sys/va/gstjpegdecoder.c
+++ b/subprojects/gst-plugins-bad/sys/va/gstjpegdecoder.c
@@ -90,6 +90,8 @@ static void
 gst_jpeg_decoder_init (GstJpegDecoder * self)
 {
   gst_video_decoder_set_packetized (GST_VIDEO_DECODER (self), TRUE);
+  gst_video_decoder_set_needs_format (GST_VIDEO_DECODER (self), TRUE);
+
   self->priv = gst_jpeg_decoder_get_instance_private (self);
 }