Atrac3 no longer hardcodes 384 bytes per frame. The context only carries the
joint-stereo flag for Atrac3 - libatrac3plus.prx writes nothing else there, and
AtracCtx2 already mirrors that - but exactly one of the five supported frame
sizes is joint stereo (66kbps stereo, 0xC0 bytes), so that flag identifies it
on its own. Everything else keeps the old 132kbps assumption, now via the
existing at3HeaderMap rather than a magic number.
MP3 was passing srcBytesRead as the input length, which is an output field
holding what the *previous* call consumed - zero on the first frame. Use the
bound at 0x28 instead, which is what the hardware uses and which the caller
guarantees is readable at inBuf, since it does a cache writeback over exactly
that range. Channels and sample rate now come from the context's channel
configuration and its version/sample-rate index pair, using the same table
avcodec.prx indexes, rather than being assumed stereo 44100.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
