Fix FF decode by miniMax AI

[sum2012]

by https://agent.minimax.io/share/334835562430541?chat_type=1
fix #15203

original bad log (v1.19.3-1105-g636e5b33b6)
v1.19.3-1105-g636e5b33b6-bad-ppsspplog.txt.zip
Modify good log:
fixed-ppsspplog.zip

The data at offset 2048 shows:
008800 00 00 01 ba 44 00 05 86 d5 c3 01 86 a3 f8 00 00
The pattern 00 00 01 ba is the MPEG-2 transport stream sync marker! This means the video data after the 2048-byte PSMF header is in MPEG-TS format.

[anr2me]

Hmm.. I saw that the AI is mentioning "sync marker bytes 00 00 01 ba" at the end.

But according to this (page 7) https://ossrs.net/lts/zh-cn/assets/files/hls-mpeg-ts-VB_WhitePaper_TransportStreamVSProgramStream_rd2-54391b430dd4df50a827467e80854828.pdf

The first byte (Sync Byte) in MPEG-TS header supposed to be 0x47 🤔 which matched the answer at https://stackoverflow.com/questions/35974281/mpeg2-ts-sync-byte-and-continuity-error

[sum2012]

Hmm.. I saw that the AI is mentioning "sync marker bytes" at the end.

But according to this (page 7) https://ossrs.net/lts/zh-cn/assets/files/hls-mpeg-ts-VB_WhitePaper_TransportStreamVSProgramStream_rd2-54391b430dd4df50a827467e80854828.pdf

The first byte (Sync Byte) in MPEG-TS header supposed to be 0x47 🤔 which matched the answer at https://stackoverflow.com/questions/35974281/mpeg2-ts-sync-byte-and-continuity-error

MPEG-TS header check is in here
https://github.com/hrydgard/ppsspp/pull/21012/files#diff-72f58d004beb4c29fe682970ebc40289bfd08d1ddbbf8cdd450a8338ac925d07R493

[hrydgard]

Interesting, will look at this soon.

[sum2012]

@hrydgard do you plan merge this patch after v1.20 ?

[hrydgard]

Possibly. My problem is that I don't really understand if all the new logic is actually correct, or just a bunch of AI-invented stuff that happens to work in this case (and could easily break other things).

The latter part is why we can't merge before 1.20.

[sum2012]

@hrydgard JPCSP has identical logic for "Need to read additional data to reach stream offset" in https://github.com/jpcsp/jpcsp/blob/cd20cf312b358b4260f26f6754f9c62926c70ba6/src/jpcsp/HLE/modules/scePsmfPlayer.java#L482