+/**
+ * Allocate the stream private data and initialize the codec, but do not write the header.
+ * May optionally be used before avformat_write_header to initialize stream parameters
+ * before actually writing the header.
+ * If using this function, do not pass the same options to avformat_write_header.
+ *
+ * @param s Media file handle, must be allocated with avformat_alloc_context().
+ * Its oformat field must be set to the desired output format;
+ * Its pb field must be set to an already opened AVIOContext.
+ * @param options An AVDictionary filled with AVFormatContext and muxer-private options.
+ * On return this parameter will be destroyed and replaced with a dict containing
+ * options that were not found. May be NULL.
+ *
+ * @return AVSTREAM_INIT_IN_WRITE_HEADER on success if the codec requires avformat_write_header to fully initialize,
+ * AVSTREAM_INIT_IN_INIT_OUTPUT on success if the codec has been fully initialized,
+ * negative AVERROR on failure.
+ *
+ * @see av_opt_find, av_dict_set, avio_open, av_oformat_next, avformat_write_header.
+ */
+av_warn_unused_result
+int avformat_init_output(AVFormatContext *s, AVDictionary **options);
+