State explicitly when this field will be removed and how to access it in
a forward compatible way.
*
* @deprecated the custom get_buffer2() callback should always be
* thread-safe. Thread-unsafe get_buffer2() implementations will be
- * invalid once this field is removed.
+ * invalid starting with LIBAVCODEC_VERSION_MAJOR=60; in other words,
+ * libavcodec will behave as if this field was always set to 1.
+ * Callers that want to be forward compatible with future libavcodec
+ * versions should wrap access to this field in
+ * #if LIBAVCODEC_VERSION_MAJOR < 60
*/
attribute_deprecated
int thread_safe_callbacks;