Merge pull request #6672 from xXPBSXx/docs/debt-ajm-codec-23

docs(debt): list the unimplemented AJM codec 23 of PPSA21480

docs/dev/debt/libSceAjm.native.md

@@ -7,6 +7,7 @@
 - [sceAjmDecMp3ParseFrame](../../../core/libs/prx/libSceAjm.native/src/Ajm.cpp) (libSceAjm.native) - signature, result layout and rate tables taken from the [shadPS4](https://github.com/shadps4-emu/shadPS4) reimplementation of the PS4 library, not confirmed on a PS5 title: the layer field is not checked and MPEG-2.5 stops at 64 kbps; the original file length (`parse_ofl`) layout (Xing/Info + LAME tag, VBRI, Fraunhofer `0xB4` block with its CRC, encoder delay = samples per frame + LAME delay + 529) also comes from shadPS4 only, and the Fraunhofer block has no other public description
 - [sceAjmBatchJobGetCodecInfo, sceAjmBatchJobGetGaplessDecode](../../../core/libs/prx/libSceAjm.native/src/Ajm.cpp) (libSceAjm.native) - the `RUN_GET_CODEC_INFO` flag (0x800), the ATRAC9 codec info layout and its next frame size are taken from the [shadPS4](https://github.com/shadps4-emu/shadPS4) and [RPCSX](https://github.com/RPCSX/rpcsx) reimplementations, not confirmed on a PS5 title; a run job without buffers returns result 0, as in shadPS4. The gapless sideband reports the total and skip counts the title set and does not count them down: RPCSX does the same, shadPS4 counts them down and BryKytyPS5 returns its current counts
 - [AJM Opus decoder](../../../core/libs/prx/libSceAjm.native/src/Ajm.cpp) (libSceAjm.native, codec 24) - the initialize parameter layout and little-endian `u16` packet byte count come from The Smurfs Dreams (`2, 48000, 0`) and Lost Soul Aside (`4, 48000, 1`). The third word is interpreted as the mapping family, as in [KytyPS5's initialize structure](https://github.com/KytyPS5/KytyPS5/blob/984cfcebd141b211aa9e0a8cde63b0ebe652d07a/src/libs/ajm/opus_decoder.h#L11-L15). Family 1 uses the conventional stream counts, coupled counts and channel map from [libopus 1.5.2's surround layout](https://github.com/xiph/opus/blob/v1.5.2/src/opus_multistream_encoder.c#L47-L55), passed to FFmpeg through an [RFC 7845 section 5.1](https://datatracker.ietf.org/doc/html/rfc7845#section-5.1) header with zero pre-skip and gain; gapless skipping remains controlled by AJM sideband parameters. FFmpeg returns PCM in its native speaker order. The implicit stream layout, PCM channel order and invalid family-0 channel count result are not verified on a console. NHL 27 (PPSA34063) passes `1, 48000, 255`. Family 255 with one channel is decoded as one mono stream, the same as family 0; this is assumed, since the stream count, coupled stream count and channel mapping that a family-255 Opus header carries ([RFC 7845 section 5.1.1](https://datatracker.ietf.org/doc/html/rfc7845#section-5.1.1)) are not passed. Only 48000 Hz, mapping families 0 and 1, and family 255 with one channel are implemented; other rates and families, and family 255 with more channels, throw
+- [AJM decoders other than MP3, ATRAC9, M4AAC and Opus](../../../core/libs/prx/libSceAjm.native/src/Ajm.cpp) (libSceAjm.native) - decoding throws for every other codec id. Broken Sword - Shadow of the Templars: Reforged (PPSA21480) stops at codec 23 (`AJM: decoding codec 23 is not implemented`). The ids known here are MP3 0, ATRAC9 1, M4AAC 2 and Opus 24; id 23 is not among them and which codec it is, is unknown.
 - [sceAjmBatchJobSetResampleParametersEx](../../../core/libs/prx/libSceAjm.native/src/Ajm.cpp) (libSceAjm.native) - the `(info, instance, float ratio_start, float ratio_change_per_sample, flags, result)` signature is inferred from the name and from `sceAjmBatchJobSetResampleParameters`; with a zero change per sample it sets the ratio as `sceAjmBatchJobSetResampleParameters` does (Watch Dogs: Legion, PPSA01500, calls it so). How a non-zero change ramps the ratio is not confirmed on a console (no source: KytyPS5 ignores it, prosper stubs it, the PS5 firmware does not export the batch builders to a payload): it is assumed to be added to the ratio after each emitted output frame, clamped at zero, and kept across batches. RIDE 4 (PPSA01599) passes one call with a change of 4.6e-7, so the exact rule matters little there.
 - [sceAjmBatchJobControl](../../../core/libs/prx/libSceAjm.native/src/Ajm.cpp) (libSceAjm.native) - RESET (bit 13), INITIALIZE (bit 14) and the sideband input order (gapless decode, then initialize parameters) come from [shadPS4](https://github.com/shadps4-emu/shadPS4) (PS4); other flags throw
 - [sceAjmBatchJobControl](../../../core/libs/prx/libSceAjm.native/src/Ajm.cpp) (libSceAjm.native) - RESET is assumed to clear the context as sceAjmBatchJobClearContext does