I got the mpegplayer patch partially working. Some memory problem causes mpeg_malloc_internal to return null, due to the:
if (*mem_ptr + size > bufsize)
{
DEBUGF("OUT OF MEMORY\n");
return NULL;
}
line (rather easy to see it's because it's out of memory..). Of the video I tried, it plays roughly 35 seconds of it before "missing packet start code prefix". In the sim, I get:
end diff: 8564430,8564430,8565430,8366C30,A02F00C,8FC8430
end diff: 8566C30,0,8566C30,8366C30,A02F00C,8FC8430
before it crashes.

I've got to go to bed, but here's some debug info:

mem_ptr: 0, size: 2097152, bufsize: 32935600
mem_ptr: 0, size: 30246876, bufsize: 2097152
OUT OF MEMORY
mem_ptr: 2097152, size: 67284, bufsize: 32935600
mem_ptr: 2164436, size: 524288, bufsize: 32935600
mem_ptr: 30246876, size: 17984, bufsize: 2097152
OUT OF MEMORY
mem_ptr: 30264860, size: 1222660, bufsize: 2097152
OUT OF MEMORY
mem_ptr: 31487520, size: 9856, bufsize: 2097152
OUT OF MEMORY
mem_ptr: 31497376, size: 2464, bufsize: 2097152
OUT OF MEMORY
mem_ptr: 31499840, size: 2464, bufsize: 2097152
OUT OF MEMORY
mem_ptr: 31502304, size: 39424, bufsize: 2097152
OUT OF MEMORY
mem_ptr: 31541728, size: 9856, bufsize: 2097152
OUT OF MEMORY
mem_ptr: 31551584, size: 9856, bufsize: 2097152
OUT OF MEMORY
mem_ptr: 31561440, size: 39424, bufsize: 2097152
OUT OF MEMORY
mem_ptr: 31600864, size: 9856, bufsize: 2097152
OUT OF MEMORY
mem_ptr: 31610720, size: 9856, bufsize: 2097152
OUT OF MEMORY
mem_ptr: 31620576, size: 39424, bufsize: 2097152
OUT OF MEMORY
mem_ptr: 31660000, size: 9856, bufsize: 2097152
OUT OF MEMORY
mem_ptr: 31669856, size: 9856, bufsize: 2097152
OUT OF MEMORY

bufsize comes from mpeg2_bufsize, which is "mpeg2_bufsize = libmpeg2size;"