Opus streams are being ignored for seeking, and in at least one place (SeekBisection) it was looking for the (usually NULL) mVorbisState pointer instead of checking for either kind of stream. This could made random seeks in a large file stall eating 100% of the CPU.
Created attachment 628096 [details] [diff] [review]
Use Opus streams when seeking in Ogg, if present
Greenish on try: https://tbpl.mozilla.org/?tree=Try&rev=33c12ea9f51f