Add flash0:/kd/mpeg.prx to the sceUtility module swap, hung off av_mpegbase,
so it loads when DisableHLEFlags::sceMpeg is set. Games that ship their own
sceMpeg_library on the disc never get here and just use theirs.
The piece that was missing to make it work: the access unit address mpeg.prx
passes to sceVideocodecDecode is in Media Engine space, which we can't read.
On hardware sceMpegBasePESpacketCopy DMA'd the payload there first. That copy
is ours, so it now gathers the blocks and sceVideocodec decodes from those,
falling back to main memory for any caller that points at it directly. The
gather is keyed by destination, because that call carries the audio payload
too - video to an ME address, audio to main memory - and handing an ATRAC
packet to the H.264 decoder gets you nothing.
With that, video/mpeg/basic gets a 144x80 frame out of real Sony code driving
our sceVideocodec through ffmpeg. The test still fails overall, as it did
before this branch - it is in tests_next.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
mpeg.prx copies only the four luma buffers into the descriptor it passes to
sceMpegBaseCscAvc, at +0x20, and keeps a stride where the chroma ones would
be - so the conversion had nothing to read. Both ends of this are ours, so the
full set is recovered from the allocation sceVideocodec handed out.
Death Jr. now runs the whole chain: 504 frames decoded by real mpeg.prx through
sceVideocodec, and 505 colour conversions into the game's display buffers at
480x272, no exceptions.
The picture is still black, and the cause is now upstream of all of this: the
decoder itself returns blank frames, so what we feed it isn't the video
elementary stream. The first access unit being 162 bytes was the early sign.
sceMpegBasePESpacketCopy gathers the LLI blocks it is given, and that is
evidently not the whole story - PES headers, or blocks it isn't counting.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
The last piece mpeg.prx needs from us. It decodes through AvcDecoder and writes
the result where sceMpegbase expects to read it: for type 0, the eight-buffer
tiled layout, produced here as the exact inverse of the reader added with the
colour conversion. Type 1 hands back plain planar YUV instead.
The descriptor mpeg.prx passes in is empty - on hardware the Media Engine owns
the frame buffers and reports back where it put them - so they are allocated
here and their addresses filled in, and sceMpegbase can recover the full set
from that allocation afterwards. The list is only read as addresses once it
holds addresses: a caller that leaves small integers there used to take us
straight into a memory exception.
Both those buffers and the block sceVideocodecGetEDRAM hands out live in a
model of the ME's own 2MB of embedded DRAM rather than in either PSP partition,
with a BlockAllocator carving it up. The CPU can't reach ME memory on hardware:
mpeg.prx keeps the EDRAM value and hands it back without ever dereferencing it,
and it has no way to say where the frame buffers should go - sceVideocodecSetMemory
is given a frame size and a buffer count, 480, 272 and 2 for a full-screen movie.
Taking either from the game would push its own allocations around or spend memory
a real PSP never spends, so sceMpegbase reads the frame through a host pointer
into that block instead of through Memory::.
A game can hold several contexts at once - Silent Hill Origins runs two, one
that owns the EDRAM and one that does every decode - so the decoder, the frame
buffers and the EDRAM address are per context, keyed by context address the way
sceAudiocodec keys its decoders. The EDRAM itself the firmware tracks in the
caller's context struct and nowhere else, including refusing a second request
rather than replacing the first, as videocodec_260.prx shows, so we do the same.
Registered at the end of RegisterAllModules, since a savestate stores the
syscall opcode encoding that order.
GetSEI, ScanHeader, GetFrameCrop and the two unnamed NIDs return 0 and log -
mpeg.prx calls them but nothing yet shows what they need to return, and
guessing seemed worse than being loud about it.
Untested: nothing calls this until mpeg.prx is loaded, which is the next step.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Five of the six functions in this module were registered as nullptr, so any
caller reaching them got nothing. mpeg.prx needs all of them, and this is the
first of the pieces required before the real module can run in place of our
sceMpeg HLE.
The module gets its own file at the same time. It was a tail of sceMpeg.cpp,
which is long enough already, and everything below is new code for it.
sceMpegBaseCscAvc and sceMpegBaseCscAvcRange convert the ME's decoded output to
RGB. The 48-byte descriptor holds the frame size in macroblocks at 0x10 and
0x14 - it appears at 0x00/0x04 too, but scaled differently depending on which
path built it, so the second pair is the one every caller agrees on - and the
four luma buffers at 0x20. What they point at is not planar: luma arrives as
16-pixel-wide vertical strips alternating between buffers on every other line,
and chroma as Cb/Cr pairs interleaved across four more. All eight are untangled
into planes once per frame before converting, which keeps the pixel loop
readable.
sceMpegBaseCscInit carries the default buffer width for callers that pass zero.
sceMpegBaseCscSetPixelMode (0x0530BE4E - the official name isn't known) carries
the output format, in mpegbase's own numbering rather than the GE's: mpeg.prx
gets it by indexing a table of {1, 2, 3, 0} with the pixel mode the game gave
sceMpegAvcDecodeMode, making 0 ABGR8888 and 2 ABGR5551. Read as a GE mode it
turned Thrillville's black into blue.
sceMpegBaseYCrCbCopy copies the descriptor but not the buffers it points at,
and says so in its log - nothing seen so far needs more, and inventing the
buffer copy without something to test it against seemed worse than a note.
Behaviour is cross-checked against JPCSP, which implements all of these.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
