[FFmpeg-devel] [PATCH] avcodec/dovi_rpudec - correctly read el_bit_depth_minus8 when ext_mapping_idc is non-zero

[Cosmin Stejerean]

From: Cosmin Stejerean <cosmin at cosmin.at>

It looks like the el_bitdepth_minus8 value in the header can also encode
ext_mapping_idc in the upper 8 bits.

Samples having a non-zero ext_mapping_idc fail validation currently because the
value returned is out of range. This bypasses this by currently ignoring the
ext_mapping_idc and using only the lower 8 bits for el_bitdepth_minus8.

---
 libavcodec/dovi_rpudec.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libavcodec/dovi_rpudec.c b/libavcodec/dovi_rpudec.c
index 7c7eda9d09..1b11ad3640 100644
--- a/libavcodec/dovi_rpudec.c
+++ b/libavcodec/dovi_rpudec.c
@@ -411,7 +411,9 @@ int ff_dovi_rpu_parse(DOVIContext *s, const uint8_t *rpu, size_t rpu_size,
 
         if ((hdr->rpu_format & 0x700) == 0) {
             int bl_bit_depth_minus8 = get_ue_golomb_31(gb);
-            int el_bit_depth_minus8 = get_ue_golomb_31(gb);
+            // this can encode a two byte value, with higher byte being ext_mapping_idc
+            // use only the lower byte for el_bit_depth_minus8
+            uint8_t el_bit_depth_minus8 = get_ue_golomb_long(gb) & 0xFF;
             int vdr_bit_depth_minus8 = get_ue_golomb_31(gb);
             VALIDATE(bl_bit_depth_minus8, 0, 8);
             VALIDATE(el_bit_depth_minus8, 0, 8);
-- 
2.42.1