HW accelerated video in chromium-browser required some firmware changes. Unfortunately these changes have also introduced new bugs.
I discovered it in my transcoding software and it always happens, when I transcode an original 720x576 video (576i, MPEG2 or H264) to a H264 stream of 384x288 pixels (half size). If I transcode to another (working) output size it doesn't happen. The second image below shows the corruption at the left side.
Epiphany (or kweb3) are also affected and show a similar bug, when a HTML5 web video of a certain size is displayed, as shown in the first image.
In both cases "sudo vcdbg reloc" reports "heap corruption detected", usually some entries like the following:
0x3c85bf00: corrupt trailer (space 165952 != 165953)
I have created a test package for the developers which will reproduce the bugs without needing any other software (or live TV streams). Link available via PM.