Millisecond Forums

Videos slow and freezing

By AnjaK - 3/10/2016

I have a problem showing videos with Inquisit 4. The script works, but the videos (.avi; 2.21 MB) are always preceded by a gray placeholder (appearing shortly before the video, for a different time in each trial) and the videos are very slow and keep freezing. I have downloaded the necessary codecs (for a Windows 7 32-bit system; also directshow codecs) and updated the driver of the graphic card. On a different (newer) computer, everything works fine. Is this likely related to the graphic card being too old (although it's not so old; NVIDIA GeForce8400) or could it also be something else?
By Dave - 3/10/2016

All of the things you mention (codec, graphics driver, insufficient processing power) are potential causes. The specific symptom "slow & freezing" would point to either a remaining codec issue or insufficient performance *given* the way the AVIs are encoded. (AVI is a container format, i.e., the file extension alone says little about the actual video codec used). Trying to play back a HD-resolution video encoded with some modern codec (for which older graphics cards / drivers may not provide direct hardware support), can easily overwhelm an older system in terms of processing demands and lead to stuttering and/or apparent freezing.

I would try re-encoding the videos in question, possibly at a lower resolution and using a different codec, to see if this affects the play back performance on the system in question.
By AnjaK - 3/10/2016

Thank you! I lowered the resolution of the video and tried a number of different codecs and finally found one with which it worked (H.264(x264)).