AnyPS5/docs/dev/debt/libSceVorbisDec.md

libSceVorbisDec technical debt

Unknown function info

• sceVorbisDecOpenCallbacks, sceVorbisDecRead and the other libvorbisfile exports (libSceVorbisDec) - the 31 exports named after libvorbisfile functions are taken to be the libvorbisfile API with a sceVorbisDec prefix (Read is ov_read, CrossLap is ov_crosslap, HalfrateP is ov_halfrate_p). ReadFilter, ReadFloat and Halfrate exist in libvorbis (ov_read_filter since 1.2.2, with the same vorbisfile.h signatures through 1.3.7 apart from const) but not in Tremor, so times are double and ov_read takes bigendianp, word and sgned. Guest long arguments and results are 64-bit. They run the bundled libvorbis 1.3.7 and libogg 1.3.6; the console's libvorbis version, any Sony changes to its behaviour or error codes, and the signatures themselves are unverified on a PS5.
• sceVorbisDecGetDecodePriority (libSceVorbisDec) - declared without parameters, signature unknown; name from the NID database
• sceVorbisDecGetLastDecodeError (libSceVorbisDec) - declared without parameters, signature unknown; name from the NID database
• sceVorbisDecSetDecodePriority (libSceVorbisDec) - declared without parameters, signature unknown; name from the NID database

Functional

• libSceVorbisDec (libSceVorbisDec) - the guest OggVorbis_File is never written: the decoder state lives on the host, keyed by the struct's address, so fields a title reads directly keep what it stored, and a struct never opened, cleared or failed to open behaves as libvorbisfile's zeroed struct. sceVorbisDecInfo returns a copy of each link's vorbis_info with 64-bit long fields, refreshed after every call on the struct and valid until sceVorbisDecClear. Reopening a struct that is still open frees its old state without calling its close callback; libvorbisfile leaks it.
• sceVorbisDecClear and sceVorbisDecCrossLap (libSceVorbisDec) - a null vf throws, as libvorbisfile dereferences it, except that sceVorbisDecClear and sceVorbisDecCrossLap with the same pointer twice return 0, and sceVorbisDecCrossLap with a null second pointer after a first that is not open returns OV_EINVAL, as libvorbisfile does. sceVorbisDecClear frees the state before it calls the close callback, as ov_clear does, so when that callback throws the struct is already cleared, where libvorbisfile leaves it freed but not zeroed.
• sceVorbisDecOpenCallbacks and sceVorbisDecBitrate (libSceVorbisDec) - on Windows the host long is 32-bit: a tell result outside it, or an initial byte count outside it with a non-null initial, throws; a sample rate of 2^31 Hz or more is rejected as a bad header; and sceVorbisDecBitrate rounds halves up instead of to even.