I found out and see it with my software, that the IPP can decode MPEG4 H263 und MPEG4 H264.
I created test videos in MPEG4 XVID and MPEG4 MPEG4 format, but my software does not manage it to decode this video types.
Now, I ask myself, if it is possible to decode them with the IPP lib after changing my source code.
The software analyses the video stream and selected the video decoder then. At the moment I am not sure if this is set-up in the right way. Maybe there is a fault and due to this the decoding does not start to run.
How can I check if the UMC video decoder is set-up correctly?
Even if your problem is linked with the bug inside UMC, this bug will never be fixed, because UMC is deprecated by Intel.
So, you have two ways to solve this problem.
1. To read UMC samples documentation and white papers.
2. To use Intel Media SDK instead of UMC/IPP. In that case you'll get full support from Intel.
One of parts from Media SDK tutorial is encoding<->decoding mp4 file with H.264 video track which is very similar to your problem.