Files
ppsspp/android
Henrik RydgårdandClaude Opus 5 7c6f9d18b8 sceMpegbase: implement the colour conversion functions
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) <[email protected]>
2026-09-12 11:52:09 -06:00
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2026-08-31 11:02:32 +02:00
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2026-08-03 18:55:33 +02:00
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2026-06-15 09:17:13 +02:00
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================================================================

NOTE: These are legacy instructions for building using ndk-build.

We mostly only use this on CI because it's faster than gradle.
There might also be some holdouts around still using eclipse.

================================================================

First, build the C++ static library:

> cd android
> ./ab.sh
Or
> ./ab.cmd

as appropriate.

Start Eclipse, import the android directory as an existing project
You need to also load the "native" project into your eclipse workspace
Build and run. 

If you modify the C++ code, you need to rebuild the static library, of
course. To get Eclipse to understand that you have in fact changed something
if you haven't also changed any Java code, just add a space character to 
PPSSPPActivity.java, or right click the project and choose Refresh, and then
relaunch the app on the device.

A real Android device is strongly recommended for testing. Don't trust
the emulator.