switch to gortsplib v2 (#1301)

Fixes #1103

gortsplib/v2 supports multiple formats inside a single track (media). This allows to apply the resizing algorithm to single formats inside medias.

For instance, if a media contains a a proprietary format and an H264 format, and the latter has oversized packets, they can now be resized.

internal/core/formatprocessor.go

@@ -0,0 +1,22 @@
+package core
+
+import (
+	"github.com/aler9/gortsplib/v2/pkg/format"
+)
+
+type formatProcessor interface {
+	process(data, bool) error
+}
+
+func newFormatProcessor(forma format.Format, generateRTPPackets bool) (formatProcessor, error) {
+	switch forma := forma.(type) {
+	case *format.H264:
+		return newFormatProcessorH264(forma, generateRTPPackets)
+
+	case *format.MPEG4Audio:
+		return newFormatProcessorMPEG4Audio(forma, generateRTPPackets)
+
+	default:
+		return newFormatProcessorGeneric(forma, generateRTPPackets)
+	}
+}