We've noticed a graphics card mempory leak on ffdshow for H264 Videos.
This is how we've tested:
We have a program that uses directshow under Windows 7 64 bit. The frames are delivered to an opengl texture and displayed inside a opengl program. After looping a 15 seconds Videos on a intel i5/HD4600 machine with the latest drivers OpenGL returs a out of memory error. We've recoded the video into a divx mp4 and still using ffdshow to decode, no problem after 48 hours loop. The problems occurs after around 8 hours playing a Quad-HD Video of 15 seconds coded using After Effects H264.
We've also tried a xvid video in avi container and it plays fine as well.
It looks for me - although I don't know the internals of libav - that it's using graphics memory and GPU to decode and either libav or intel did a mistake and memory is not freed up.
Please feel free to contact me for further information.