Like: -f " bestvideo+bestaudio/ best "
For iframe URLs
@dstftw explained in https://github.com/rg3/youtube-dl/pull/9918#issuecomment-228625878 that extractor names are supposed to be unique. @dstftw has fixed the two offending extractors, and here I add a test to ensure this does not happen in the future.
Use the HTML5 API. Only low-resolution formats available Related: #9839 Thanks @zhangn1985 for the overall algorithm (soimort/you-get#1224)