util/libav: do not bail on MEL-only RPUs w/EL

[intelfx]

We can still map DV metadata that indicates enhancement layer usage (!disable_residual_flag, Profile 7 and 4) for MEL-only bitstreams, which is indicated by trivial NLQ parameters.

[kasper93]

pl_map_avframe_ex() should also be fixed in similar fashion to use pl_can_map_avdovi_metadata(). And for parity with libdovi code path max_pq and avg_pq should be mapped also when dovi meta is not used. Also needs API version bump.

diff --git a/src/include/libplacebo/utils/libav_internal.h b/src/include/libplacebo/utils/libav_internal.h
index a754e98b..928d37f6 100644
--- a/src/include/libplacebo/utils/libav_internal.h
+++ b/src/include/libplacebo/utils/libav_internal.h
@@ -925,14 +925,14 @@ PL_LIBAV_API void pl_map_avdovi_metadata(struct pl_color_space *color,
             pl_hdr_rescale(PL_HDR_PQ, PL_HDR_NITS, dovi_color->source_min_pq / 4095.0f);
         color->hdr.max_luma =
             pl_hdr_rescale(PL_HDR_PQ, PL_HDR_NITS, dovi_color->source_max_pq / 4095.0f);
+    }

 #if LIBAVUTIL_VERSION_INT >= AV_VERSION_INT(59, 12, 100)
-        if ((dovi_ext = av_dovi_find_level(metadata, 1))) {
-            color->hdr.max_pq_y = dovi_ext->l1.max_pq / 4095.0f;
-            color->hdr.avg_pq_y = dovi_ext->l1.avg_pq / 4095.0f;
-        }
-#endif
+    if ((dovi_ext = av_dovi_find_level(metadata, 1))) {
+        color->hdr.max_pq_y = dovi_ext->l1.max_pq / 4095.0f;
+        color->hdr.avg_pq_y = dovi_ext->l1.avg_pq / 4095.0f;
     }
+#endif
 }

 PL_LIBAV_API void pl_frame_map_avdovi_metadata(struct pl_frame *out_frame,

which makes it awkward with dovi allocation part, but since the API is changed already it can be done while at it. See how pl_map_avframe_ex() maps RPU info always, regardless of header->disable_residual_flag.

[kasper93]

pl_map_avdovi_metadata could map more metadata, but without pl_dovi_metadata use. This could be pl_is_dovi_metadata_needed or something and pl_map_avdovi_metadata could take NULL if the former function returns false. This would allow to still make RPU values.

[intelfx]

pl_map_avdovi_metadata could take NULL if the former function returns false. This would allow to still make RPU values.

Sorry, I don't follow — how? If we're talking about that av_dovi_find_level() block from your diff above, it still needs the AVDOVIMetadata *, no? Or are we talking about some hypothetical yet-unwritten code?

[kasper93]

pl_map_avdovi_metadata(&color, &repr, NULL, &metadata); I'm talking about output parameter, when we decide not to use pl_dovi_metadata, but still populate max_pq and avg_pq. This is how pl_map_avframe_ex() works.