I added support for automatically building the filename from the info_dict (for example see this [brightcove test](https://github.com/rg3/youtube-dl/blob/17ab4d3b5e3075d32a0a93422e40f61ef4919d7d/youtube_dl/extractor/brightcove.py#L51-L58)), on new extractors I create I tend to use this new style. I personally prefer using the info_dict, it's more clear.