if (second_field_offset == 4) {
/*
* Overlapping first and second fields is used to signal
- * encoding only a single field (the second field then comes
- * as a separate, later frame).
+ * encoding only a single field. In this case, "height"
+ * is ambiguous; it could mean either the height of the
+ * frame as a whole, or of the field. The former would make
+ * more sense for compatibility with legacy decoders,
+ * but this matches the convention used in NDI, which is
+ * the primary user of this trick.
*/
- frame->height >>= 1;
if ((ret = decode_speedhq_field(s, buf, buf_size, frame, 0, 4, buf_size, 1)) < 0)
return ret;
} else {