Fix 403 "Access Denied" for encrypted videos

[Camelva]

Description

Turns out, request without playbackContext and, in particular, signatureTimestamp always lead to 403 "Access Denied" after decrypting signature. This value seems like doesn't change too often, so temporarily hard-coding it just to fix problem as soon as possible. But later need to fetch it from youtube.

I don't know how often this signatureTimestamp changes, but i tried few different videos from different browsers and it was 18795 every time. Probably should work at least until tomorrow.

Its possible to get this value from player js (same as decipher options). Need to look for sts or signatureTimestamp (its stored several times). Though, this require a bit more changes in code (and possibly rearrangements), so i decided to make this small temporary fix for now.

Also browser metadata isn't mandatory for request, instead its better to specify language so server responses always be same instead of server changing response language based on your ip.

Issues to fix

Please link issues this PR will fix:
#198 (comment)

if no relevant issue, but this will fix something important for reference
, please free to open an issue.

Reminding

Something you can do before PR to reduce time to merge

• run "make build" to build the code
• run "make format" to reformat the code
• run "make lint" if you are using unix system
• run "make test-integration" to pass all tests

[Camelva]

@corny if i have additional thoughts about all this stuff, should i write it here or open new issue?

[corny]

I don't mind - what you prefer :-)

[Camelva]

I don't mind - what you prefer :-)

Alright, this pr is already closed, so new issue it is :)