This is an old enough thread. Some things have changed. For one, the Metropolitan Opera
is no longer offering their free nightly streams, more's the pity, because they are
supposed to be getting back to live performances in their theater next month, which is
good news. For another, VDH now has a feature for merging 2 separately downloaded files,
one being video without audio & the other being audio without video. You still have to
guess which file will be which on the VDH menu, but once you've guessed right & done the
2 downloads, you can use VDH to merge them. Personally, I'm happy to leave them separate
& play them using the VLC synchronous playback feature, as I describe here:
https://groups.google.com/g/video-downloadhelper-q-and-a/c/YwvzcYm-fP0
Sadly, there is still no support in VDH for subtitles (captions).
Many of the manifests I've looked at show multiple audio-only streams with associated
video-only streams. These relationships are explicitly identified in the manifests. VDH
should, but still does not, structure its menu in such a way that you can easily
associate the multiple -- I emphasize -- multiple audio streams with certain video
streams. Some given audio streams are associated with multiple video streams of varying
resolutions & bitrates. VDH really could very easily reflect these relationships in its
menu but it does not. We are left to either guess, or try them all to find out, or
interpret the manifest ourselves. But some sites don't use manifests so you can't always
get what you want. (Who knew Mick Jagger uses VDH?) As for captions, when they exist
they also might appear in the manifest. VDH does not pay any attention to them at all.
When captions are not in the manifest, I'm not sure how VDH would detect them. Players
that support captions that can be turned on & off do something to support that so I
should think there is something VDH could do about captions even in these cases.
I have suggested that VDH use ffprobe to determine properties of streams for display on
the VDH menu. In general, this would allow VDH to properly identify streams that have
only video, only audio, or both. ffprobe also identifies stream duration, an attribute
that sometimes is & sometimes is not displayed in the VDH menu. ffprobe also identifies
video resolution, an attribute that sometimes is & sometimes is not displayed in the VDH
menu. ffprobe also identifies associations between audio-only & video-only streams,
something VDH today gives us no help whatsoever in identifying.
I have seen sites on which VDH displays the size of the variant before you download it.
I'm not sure where this information comes from. It doesn't seem to be consistent but it
would be nice if we could get a file size for every variant all the time. I suspect this
is one of those things that VDH must rely on the web site to get & since there's no
international standard for these things, maybe VDH can't always get the information. But
I am just speculating.
Things are possible. We can only hope they are in the works.