+static int bprint_to_extradata(AVCodecContext *avctx, struct AVBPrint *buf)
+{
+ int ret;
+ char *str;
+
+ ret = av_bprint_finalize(buf, &str);
+ if (ret < 0)
+ return ret;
+ if (!av_bprint_is_complete(buf)) {
+ av_free(str);
+ return AVERROR(ENOMEM);
+ }
+
+ avctx->extradata = str;
+ /* Note: the string is NUL terminated (so extradata can be read as a
+ * string), but the ending character is not accounted in the size (in
+ * binary formats you are likely not supposed to mux that character). When
+ * extradata is copied, it is also padded with AV_INPUT_BUFFER_PADDING_SIZE
+ * zeros. */
+ avctx->extradata_size = buf->len;
+ return 0;
+}
+