avcodec/dynamic_hdr10_plus: don't take a GetBitContext as input argument

Create a local one instead from a byte buffer input argument.
This prevents skipping bytes that may belong to another SEI message.
Signed-off-by: James Almer <jamrial@gmail.com>

libavcodec/dynamic_hdr10_plus.c

@@ -17,6 +17,7 @@
  */
 
 #include "dynamic_hdr10_plus.h"
+#include "get_bits.h"
 
 static const uint8_t usa_country_code = 0xB5;
 static const uint16_t smpte_provider_code = 0x003C;
@@ -30,11 +31,19 @@ static const int32_t knee_point_den = 4095;
 static const int32_t bezier_anchor_den = 1023;
 static const int32_t saturation_weight_den = 8;
 
-int ff_parse_itu_t_t35_to_dynamic_hdr10_plus(GetBitContext *gb, AVDynamicHDRPlus *s)
+int ff_parse_itu_t_t35_to_dynamic_hdr10_plus(AVDynamicHDRPlus *s, const uint8_t *data,
+                                             int size)
 {
+    GetBitContext gbc, *gb = &gbc;
+    int ret;
+
     if (!s)
         return AVERROR(ENOMEM);
 
+    ret = init_get_bits8(gb, data, size);
+    if (ret < 0)
+        return ret;
+
     s->application_version = get_bits(gb, 8);
 
     if (get_bits_left(gb) < 2)
@@ -189,7 +198,5 @@ int ff_parse_itu_t_t35_to_dynamic_hdr10_plus(GetBitContext *gb, AVDynamicHDRPlus
         }
     }
 
-    skip_bits(gb, get_bits_left(gb));
-
     return 0;
 }

libavcodec/dynamic_hdr10_plus.h

@@ -20,15 +20,16 @@
 #define AVCODEC_DYNAMIC_HDR10_PLUS_H
 
 #include "libavutil/hdr_dynamic_metadata.h"
-#include "get_bits.h"
 
 /**
  * Parse the user data registered ITU-T T.35 to AVbuffer (AVDynamicHDRPlus).
- * @param gb The bit content to be decoded.
  * @param s A pointer containing the decoded AVDynamicHDRPlus structure.
+ * @param data The byte array containing the raw ITU-T T.35 data.
+ * @param size Size of the data array in bytes.
  *
  * @return 0 if succeed. Otherwise, returns the appropriate AVERROR.
  */
-int ff_parse_itu_t_t35_to_dynamic_hdr10_plus(GetBitContext *gb, AVDynamicHDRPlus *s);
+int ff_parse_itu_t_t35_to_dynamic_hdr10_plus(AVDynamicHDRPlus *s, const uint8_t *data,
+                                             int size);
 
 #endif /* AVCODEC_DYNAMIC_HDR10_PLUS_H */

libavcodec/hevc_sei.c

@@ -216,7 +216,8 @@ static int decode_registered_user_data_dynamic_hdr_plus(HEVCSEIDynamicHDRPlus *s
     if (!metadata)
         return AVERROR(ENOMEM);
 
-    err = ff_parse_itu_t_t35_to_dynamic_hdr10_plus(gb, metadata);
+    err = ff_parse_itu_t_t35_to_dynamic_hdr10_plus(metadata,
+                                                   gb->buffer + get_bits_count(gb) / 8, size);
     if (err < 0) {
         av_free(metadata);
         return err;
@@ -229,6 +230,8 @@ static int decode_registered_user_data_dynamic_hdr_plus(HEVCSEIDynamicHDRPlus *s
         return AVERROR(ENOMEM);
     }
 
+    skip_bits_long(gb, size * 8);
+
     return 0;
 }