[youtube] --dump-json "subtitles" key = null for video with subtitles

[Vdragon]

I'm writing a program to parse youtube video supported format and subtitles, however the subtitles key of JSON output of youtube-dl --dump-json https://www.youtube.com/watch?v=iAy0tG56ZYg is null while youtube-dl --list-subs https://www.youtube.com/watch?v=iAy0tG56ZYg declares that the video has zh-TW,en,ja subtitles:

[youtube] iAy0tG56ZYg: Downloading webpage
[youtube] iAy0tG56ZYg: Extracting video information
[youtube] iAy0tG56ZYg: Looking for automatic captions
[youtube] iAy0tG56ZYg: Downloading XML
WARNING: Video doesn't have automatic captions
[youtube] iAy0tG56ZYg: Available subtitles for video: zh-TW,en,ja
[youtube] iAy0tG56ZYg: Available automatic captions for video:

I wonder that if it's youtube-dl's bug for not listing the available subtitles in subtitles key, or if it isn't, how should I parse a video's available subtitles?

Tested using 2014.12.16.2 version of youtube-dl

[jaimeMF]

Subtitles info is not extracted unless you request it, you'll need to use --all-subs:

$ youtube-dl 'iAy0tG56ZYg' --all-subs --dump-json | jq '.subtitles | keys'
[
  "en",
  "ja",
  "zh-TW"
]

[Vdragon]

@jaimeMF
Thanks for replying, what I really need is a list of available subtitle languages(for a later youtube-dl call to actually download them, like --list-subs), however --all-subs includes entire subtitle content into the json which is far more than I expected.

Is there any better way to accomplish the same goal?

BTW: I've tried youtube-dl 'iAy0tG56ZYg' --list-formats --dump-single-json but it output null instead.

[jaimeMF]

In the next version, youtube-dl 'iAy0tG56ZYg' --all-subs --dump-json will just return the subtitles urls and it won't download the contents with the --dump-json option (for reference: the changes are in PR #4964), therefore I'm closing the issue. Thanks for the report.

[phihag]

I believe this issue to be fixed in youtube-dl version 2015.02.24 and newer. See our FAQ if you need help updating.