Need Open Source Player for Testing

[medha]

HI All,
We are developing a player engine which parses Mpeg-TS and does AvSync Calculations and push the data to decoders. But to test the code, we dont have hardware support as of now..
So i want to know any open soure player -- Where
(1) Replace the AvSync logic of player with our AvSync logic
(2) Should be able to decode H.264 and AAC data
(3) Need GUI -- Displaying the decoded data

Please let me know your suggestions on this..

Thanks and Regards,
Medha

[Adub]

Media Player Classic?
Mplayer?

I don't know if they are exactly what you are looking for (haven't looked at the code) but they are the to best open source players available, so the should be a good place to start.