Bizarre MP3 Bug

Fidodadog · Post by **Fidodadog** » Mon Apr 25, 2005 2:42 am

I'm not sure if this may be of usefulness to development or finding holes into the PSP but I'll say it anyway. I'll list the music I was listening to so people may be able to replicate this effect.

I am using the Japanese PSP with firmware version 1.5

My PSP has been "corrupting" my MP3 files

Let me explain.

I have a Queens of the Stonage Album

Every song the PSP sees it happily plays. It is when it reaches the last track that something strange happens

When the last track (Everyon's Happy) finishes, the PSP moves on to the next album

Closing the song and then going back to Queens of the Stonage song list, some of the Songs the PSP sees have now been seen as corrupt! And THESE ARE THE SAME SONGS THAT PREVIOUSLY PLAYED FINE.

Strange enough

Putting the PSP into Sleep and back or removing the memory card and ptting it back in again.

The PSP reads the song as normal again!

I don't know why it does this but I decided to post it here as it could be an exploit of some sort.

I apoligise if this problem has been previously posted about and if this isn't of any use then I would happily let the mods/admins close this topic.

PS: If you need a video to explain this clearly Then just ask.

MelGibson · Post by **MelGibson** » Mon Apr 25, 2005 3:34 am

I have read about this somewhere else before .... Indeed kind of strange... and most definitly a bug...

But i don't think this could be exploitet... still thanks for the detailed info...

Btw... have you tried to delete and copy the mp3 onto the MS again... ?

Thanhda · Post by **Thanhda** » Mon Apr 25, 2005 3:54 am

ha, my teacher works at electronic playground, and he has the japanese model as well. its really buggy, and a lot of original jap models were sent back to recall. because of all the bugs that was going on with the system. when they finally fix all the bugs they decided to launch the US version. unless you still have your original receipt your just screwed. i suggest you go sell that somewhere on ebay(sure they will give you a lot for it), and buy a US model. hope that helps.

Neila · Post by **Neila** » Mon Apr 25, 2005 4:00 am

If everything is "ok" after restart this problem points again to memory management problems. You should report this problem to Sony. I don't think we can use it, so at least they may fix it in an update later. =)

Fidodadog · Post by **Fidodadog** » Mon Apr 25, 2005 4:12 am

The thing is that it only happens ON THAT ONE SONG

None of my other songs have this bizarre effect.

I would post the song but unfortunately That would be Illegal but the song was ripped from the CD using Itunes

Thanhda · Post by **Thanhda** » Mon Apr 25, 2005 4:14 am

Neila wrote:If everything is "ok" after restart this problem points again to memory management problems. You should report this problem to Sony. I don't think we can use it, so at least they may fix it in an update later. =)

i dont think they can fix it, or even worth fixing. depending where your from, you may not even be eligible for repair, plus it will be gone for a month or two. also where did you buy it from? from a sony store, or a legit sony retailer, or just some shop down the street.

Thanhda · Post by **Thanhda** » Mon Apr 25, 2005 4:15 am

Fidodadog wrote:The thing is that it only happens ON THAT ONE SONG

None of my other songs have this bizarre effect.

I would post the song but unfortunately That would be Illegal but the song was ripped from the CD using Itunes

if thats the case, then its just your mp3 song then. just re-encode it. or just let it be and move on.

Fidodadog · Post by **Fidodadog** » Mon Apr 25, 2005 4:18 am

I'm fine with it, it doesn't bother me.

I just posted as I thought it may be of some use.

But if it isn't then

oh well ..... :)

I'll try to make a sound clip that incorporates this bug to post here so as to keep it legal and see if it's just my PSP doing this

PS: If you badly want to test this on your PSP then send me a PM or get me on AIM: FidoforLife and I'll "lend" you the song

pdc · Post by **pdc** » Mon Apr 25, 2005 9:10 am

My 1.5 JPN PSP sometimes doesn't detect corrupted mp3s until I play them.

Perhaps it is an anomaly in the encoding.

I have had no problems with any mp3s encoded using LAME.

fwaggle · Post by **fwaggle** » Tue Apr 26, 2005 2:26 am

uh. my us psp does this too. after playing through my playlist, at least 10 songs are corrupt. i attributed it to shitty encoding. :/

fireether · Post by **fireether** » Tue Apr 26, 2005 2:52 am

It could be a possible exploit..

Theres no hardware decoder in the PSP that I know of, so it must be done via software.. In that case, if the PSP is showing gibberish or so, then theres something wrong with their decoder.. I.e. its not checking something right and reading back data from somewhere else than its supposed to.

I would follow up on this bug to see if it can be used as an exploit to insert something in.. I.e. have a MP3 file that uses this exploit to insert a JMP to the address of the next MP3 file, which is actually executable code.

Just an idea. It'll only work if a buffer-overrun exploit can be done.

wulf · Post by **wulf** » Fri Apr 29, 2005 1:48 pm

My us psp does the same thing.. but not if you put it on shuffle... weird

cheriff · Post by **cheriff** » Fri Apr 29, 2005 2:12 pm

fireether wrote:Theres no hardware decoder in the PSP that I know of, so it must be done via software..

From watching (a video of) the psp seminar from bp05, it seems to me that decoding isn't really hardware and not really software.
It uses the Virtual Mobile Engine (VME) which is basically some sort of FPGA-like reconfigurable chip. So when you're playing mp3 the kernel configures it to be a mp3decoding chip. if you're listening to ATRAC3plus then the VME has an atrac decoder instansiated(sic?) in/on it. I imagine it also helps out somehow when playing videos.
So they get very nearly the performance of a HW only decoder for every supported codec with just one chip. And by updating the bitstream used to configure the VME, they can update/add new decoders, etc.
But it would react similarly to HW only decoders in the face of bad data, so i'm not sure how useful this would be as a vector to homebrew...

Fidodadog · Post by **Fidodadog** » Sun May 01, 2005 2:09 am

I've uploaded a snippet of the MP3 file that has this behaviour

It's a 10 sec snippet of part of the song.

Strange enough, when this is played, it straight away moves to the next song and becomes corrupted.

anyway, try this and poke around this strange behaviour

http://fidodadog.freewebspace.com/