YT 403

[InfinityLoop1308]

@Priveetee seems 403 also happens sometimes with SABR enabled? Have you encountered that before?

[Priveetee]

Yeah, seen it before. I wrote it down in my notes: the 403 on web-like clients (empty UMP at probe time), and the "SABR segment stalled" we count as an error in the codec matrix. It's the same family as #2557 (SABR Error on load) and #2490 (Source error / stalled mid-playback). The probe or a per-segment SABR fetch gets back a response YouTube won't honour, and it surfaces differently depending on where in the pipeline it hits.

I also have a draft fix for the "0 formats" symptom of #2557 sitting on a local wip/2557-sabr-fallback branch (turn the throw into a log + fall back to the audio stream), but I haven't shipped it because I couldn't repro the crash either, and it's the wrong fix for the 403 family anyway.

If you want me to dig into a specific call site (the segment-fetch 403 in SabrSegmentDataSource, or the SABR cookie lifecycle), let me know which one and I'll get on it.

[InfinityLoop1308]

There are generally 3 kinds of 403s:

• 403 at a specific timestamp (e.g. ~1 min mark): Player client being deprecated by YT (like android_vr). Safari path is not affected btw.
• Non-deterministic 403 (randomly mid-stream): Usually due to network changes (IP switching).
• 403 from the very first request: A construction error in the request itself.

Since we only have one isolated report of SABR + 403 so far, it doesn't look like a systematic construction error (Category 3). It's more likely 2, and have a small chance to be 1 (if YT returns random 403 for all anon sessions). I think you don't need to dig into this for now. Let's wait and see if we get more reports first, so you don't waste your time :)

[InfinityLoop1308]

Actually when I checked InfinityLoop1308/PipePipe#2490 (comment) again, I found the log shows Caused by: androidx.media3.datasource.HttpDataSource$InvalidResponseCodeException: Response code: 403 at org.schabi.newpipe.player.datasource.YoutubeHttpDataSource.open(r8-map 🤔

do sabr use YoutubeHttpDataSource? It's possible he mixed things up.

[Priveetee]

Yeah, SABR doesn't go through YoutubeHttpDataSource :p SABR has its own DataSource (SabrSegmentDataSource implements DataSource directly) that talks SABR/UMP over a POST. YoutubeHttpDataSource is the fork of DefaultHttpDataSource used for the legacy progressive / DASH URL fetches.

So a 403 surfacing on YoutubeHttpDataSource.open in the same stack is on a legacy stream, not on the SABR fetch itself. Could be the player falling back to a legacy URL for that specific segment, or it could be a mixed log with non-SABR calls in the same session. Hard to tell without the full log :)

Agreed on waiting for more reports before digging deeper. If we get a clean SABR-only 403 repro I'll instrument SabrSegmentDataSource then.

[PsykoRider]

@Priveetee seems 403 also happens sometimes with SABR enabled? Have you encountered that before?

Yes and yes.