attachment_value_size  683 libavformat/wtvenc.c         write_metadata_header(pb, 2, "WM/Picture", attachment_value_size(&wctx->thumbnail, tag));
attachment_value_size  712 libavformat/wtvenc.c         pos += metadata_header_size("WM/Picture") + attachment_value_size(&wctx->thumbnail, av_dict_get(st->metadata, "title", NULL, 0));