Oui j’ai essayé, mais parmi la ribambelle de sous-titres récupérés (66) ceux en anglais auto-générés n’y sont pas. (vérifié avec mpv)
Par acquis de conscience, je suis passé par le site DownSub et j’ai bien récupéré mes sous-titres anglais auto-générés ! 
C’est donc bien au niveau de youtube-dl que le pb se pose.
Et c’est là que ta dernière suggestion est intéressante car si on fait un :
$ youtube-dl -v --list-subs https://www.youtube.com/watch?v=uzbquKCqEQY
[debug] System config: []
[debug] User config: ['-o', '%(title)s.%(ext)s', '--user-agent', 'Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:67.0) Gecko/20100101 Firefox/67.0']
[debug] Custom config: []
[debug] Command-line args: ['-v', '--list-subs', 'https://www.youtube.com/watch?v=uzbquKCqEQY']
[debug] Encodings: locale UTF-8, fs utf-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2019.07.16
[debug] Python version 3.5.3 (CPython) - Linux-4.9.0-9-amd64-x86_64-with-debian-9.9
[debug] exe versions: ffmpeg 3.2.14-1, ffprobe 3.2.14-1, rtmpdump 2.4
[debug] Proxy map: {}
[youtube] uzbquKCqEQY: Downloading webpage
[youtube] uzbquKCqEQY: Downloading video info webpage
[youtube] uzbquKCqEQY: Looking for automatic captions
Available automatic captions for uzbquKCqEQY:
Language formats
lt vtt, ttml, srv3, srv2, srv1
fy vtt, ttml, srv3, srv2, srv1
cs vtt, ttml, srv3, srv2, srv1
mi vtt, ttml, srv3, srv2, srv1
tr vtt, ttml, srv3, srv2, srv1
lo vtt, ttml, srv3, srv2, srv1
km vtt, ttml, srv3, srv2, srv1
sm vtt, ttml, srv3, srv2, srv1
gl vtt, ttml, srv3, srv2, srv1
cy vtt, ttml, srv3, srv2, srv1
sw vtt, ttml, srv3, srv2, srv1
be vtt, ttml, srv3, srv2, srv1
iw vtt, ttml, srv3, srv2, srv1
af vtt, ttml, srv3, srv2, srv1
hu vtt, ttml, srv3, srv2, srv1
ga vtt, ttml, srv3, srv2, srv1
th vtt, ttml, srv3, srv2, srv1
ro vtt, ttml, srv3, srv2, srv1
ca vtt, ttml, srv3, srv2, srv1
la vtt, ttml, srv3, srv2, srv1
ku vtt, ttml, srv3, srv2, srv1
jv vtt, ttml, srv3, srv2, srv1
tg vtt, ttml, srv3, srv2, srv1
sl vtt, ttml, srv3, srv2, srv1
fi vtt, ttml, srv3, srv2, srv1
sv vtt, ttml, srv3, srv2, srv1
mn vtt, ttml, srv3, srv2, srv1
et vtt, ttml, srv3, srv2, srv1
id vtt, ttml, srv3, srv2, srv1
hy vtt, ttml, srv3, srv2, srv1
bs vtt, ttml, srv3, srv2, srv1
vi vtt, ttml, srv3, srv2, srv1
yi vtt, ttml, srv3, srv2, srv1
ig vtt, ttml, srv3, srv2, srv1
haw vtt, ttml, srv3, srv2, srv1
it vtt, ttml, srv3, srv2, srv1
yo vtt, ttml, srv3, srv2, srv1
pl vtt, ttml, srv3, srv2, srv1
eu vtt, ttml, srv3, srv2, srv1
fa vtt, ttml, srv3, srv2, srv1
zu vtt, ttml, srv3, srv2, srv1
co vtt, ttml, srv3, srv2, srv1
mt vtt, ttml, srv3, srv2, srv1
sk vtt, ttml, srv3, srv2, srv1
ur vtt, ttml, srv3, srv2, srv1
am vtt, ttml, srv3, srv2, srv1
ps vtt, ttml, srv3, srv2, srv1
ar vtt, ttml, srv3, srv2, srv1
kn vtt, ttml, srv3, srv2, srv1
kk vtt, ttml, srv3, srv2, srv1
pt vtt, ttml, srv3, srv2, srv1
mr vtt, ttml, srv3, srv2, srv1
te vtt, ttml, srv3, srv2, srv1
ka vtt, ttml, srv3, srv2, srv1
eo vtt, ttml, srv3, srv2, srv1
da vtt, ttml, srv3, srv2, srv1
hmn vtt, ttml, srv3, srv2, srv1
ne vtt, ttml, srv3, srv2, srv1
ha vtt, ttml, srv3, srv2, srv1
el vtt, ttml, srv3, srv2, srv1
hi vtt, ttml, srv3, srv2, srv1
fil vtt, ttml, srv3, srv2, srv1
ta vtt, ttml, srv3, srv2, srv1
lb vtt, ttml, srv3, srv2, srv1
bn vtt, ttml, srv3, srv2, srv1
ht vtt, ttml, srv3, srv2, srv1
su vtt, ttml, srv3, srv2, srv1
sd vtt, ttml, srv3, srv2, srv1
so vtt, ttml, srv3, srv2, srv1
ny vtt, ttml, srv3, srv2, srv1
ru vtt, ttml, srv3, srv2, srv1
ml vtt, ttml, srv3, srv2, srv1
gu vtt, ttml, srv3, srv2, srv1
mg vtt, ttml, srv3, srv2, srv1
xh vtt, ttml, srv3, srv2, srv1
zh-Hans vtt, ttml, srv3, srv2, srv1
zh-Hant vtt, ttml, srv3, srv2, srv1
mk vtt, ttml, srv3, srv2, srv1
ms vtt, ttml, srv3, srv2, srv1
si vtt, ttml, srv3, srv2, srv1
sn vtt, ttml, srv3, srv2, srv1
uz vtt, ttml, srv3, srv2, srv1
fr vtt, ttml, srv3, srv2, srv1
ky vtt, ttml, srv3, srv2, srv1
sq vtt, ttml, srv3, srv2, srv1
ja vtt, ttml, srv3, srv2, srv1
st vtt, ttml, srv3, srv2, srv1
no vtt, ttml, srv3, srv2, srv1
es vtt, ttml, srv3, srv2, srv1
gd vtt, ttml, srv3, srv2, srv1
uk vtt, ttml, srv3, srv2, srv1
bg vtt, ttml, srv3, srv2, srv1
sr vtt, ttml, srv3, srv2, srv1
pa vtt, ttml, srv3, srv2, srv1
is vtt, ttml, srv3, srv2, srv1
ceb vtt, ttml, srv3, srv2, srv1
lv vtt, ttml, srv3, srv2, srv1
hr vtt, ttml, srv3, srv2, srv1
de vtt, ttml, srv3, srv2, srv1
az vtt, ttml, srv3, srv2, srv1
en vtt, ttml, srv3, srv2, srv1
my vtt, ttml, srv3, srv2, srv1
nl vtt, ttml, srv3, srv2, srv1
ko vtt, ttml, srv3, srv2, srv1
Available subtitles for uzbquKCqEQY:
Language formats
lt vtt, ttml, srv3, srv2, srv1
cs vtt, ttml, srv3, srv2, srv1
ur vtt, ttml, srv3, srv2, srv1
mr vtt, ttml, srv3, srv2, srv1
da vtt, ttml, srv3, srv2, srv1
sl vtt, ttml, srv3, srv2, srv1
tr vtt, ttml, srv3, srv2, srv1
ne vtt, ttml, srv3, srv2, srv1
km vtt, ttml, srv3, srv2, srv1
gl vtt, ttml, srv3, srv2, srv1
hi vtt, ttml, srv3, srv2, srv1
fil vtt, ttml, srv3, srv2, srv1
pt-PT vtt, ttml, srv3, srv2, srv1
sw vtt, ttml, srv3, srv2, srv1
be vtt, ttml, srv3, srv2, srv1
iw vtt, ttml, srv3, srv2, srv1
af vtt, ttml, srv3, srv2, srv1
hu vtt, ttml, srv3, srv2, srv1
de vtt, ttml, srv3, srv2, srv1
ro vtt, ttml, srv3, srv2, srv1
id vtt, ttml, srv3, srv2, srv1
gu vtt, ttml, srv3, srv2, srv1
ja vtt, ttml, srv3, srv2, srv1
ca vtt, ttml, srv3, srv2, srv1
zh-TW vtt, ttml, srv3, srv2, srv1
ta vtt, ttml, srv3, srv2, srv1
zh-Hans vtt, ttml, srv3, srv2, srv1
pl vtt, ttml, srv3, srv2, srv1
mk vtt, ttml, srv3, srv2, srv1
my vtt, ttml, srv3, srv2, srv1
ms vtt, ttml, srv3, srv2, srv1
sv vtt, ttml, srv3, srv2, srv1
mn vtt, ttml, srv3, srv2, srv1
et vtt, ttml, srv3, srv2, srv1
te vtt, ttml, srv3, srv2, srv1
hy vtt, ttml, srv3, srv2, srv1
uz vtt, ttml, srv3, srv2, srv1
fr vtt, ttml, srv3, srv2, srv1
bs vtt, ttml, srv3, srv2, srv1
vi vtt, ttml, srv3, srv2, srv1
sq vtt, ttml, srv3, srv2, srv1
no vtt, ttml, srv3, srv2, srv1
es-419 vtt, ttml, srv3, srv2, srv1
it vtt, ttml, srv3, srv2, srv1
pt-BR vtt, ttml, srv3, srv2, srv1
zh-HK vtt, ttml, srv3, srv2, srv1
eu vtt, ttml, srv3, srv2, srv1
uk vtt, ttml, srv3, srv2, srv1
bg vtt, ttml, srv3, srv2, srv1
ru vtt, ttml, srv3, srv2, srv1
th vtt, ttml, srv3, srv2, srv1
zu vtt, ttml, srv3, srv2, srv1
es-ES vtt, ttml, srv3, srv2, srv1
sr vtt, ttml, srv3, srv2, srv1
pa vtt, ttml, srv3, srv2, srv1
is vtt, ttml, srv3, srv2, srv1
sk vtt, ttml, srv3, srv2, srv1
lv vtt, ttml, srv3, srv2, srv1
hr vtt, ttml, srv3, srv2, srv1
am vtt, ttml, srv3, srv2, srv1
ar vtt, ttml, srv3, srv2, srv1
kn vtt, ttml, srv3, srv2, srv1
el vtt, ttml, srv3, srv2, srv1
nl vtt, ttml, srv3, srv2, srv1
az vtt, ttml, srv3, srv2, srv1
ko vtt, ttml, srv3, srv2, srv1
on remarque que, sur cette vidéo, beaucoup de sous-titres sont en doubles : 105 pour la trad auto et 66 pour la version rédigée.
Tiens, tiens, comme par hasard on retrouve nos 66 sous-titres téléchargés avec l’option “–all-subs”. (–write-all-subs n’existe pas ou plus apparemment)
Alors maintenant, comment dire à youtube-dl de télécharger ce “fr” (par exemple) plutôt que cet autre “fr”, puisqu’ils ont la même dénomination ?
=> sachant ça, je pourrais agir de même avec les sous-titres “en”…