Frequently Asked Questions
Any PC with a MIDI input device and running Windows 7 (or later) should be ok to run VidPlayMTC. Note that rendering video is a CPU intensive operation so, on a slower machine, you should close all other applications to minimize CPU load.
If MIDI is being received but the video is not playing, then there may be contention with another application that has opened the same audio output device that VidPlayMTC is using.
The PC may be running at 90% or more CPU usage. VidPlayMTC will lose synchronisation if there is not enough CPU time available. Check the CPU load in Task Manager/Resource Monitor. Refer to the next question for a solution.
The best way to optimise the required resources (CPU time and memory) is to reduce the video frame size. If you halve the width and height then each frame will decode and render four times faster, thus reducing CPU load.
There are tools available online to re-encode a video down to a smaller frame size. 426*240 is the default size of the VidPlayMTC window, so that would be a good minimum size to choose.
Close down all other applications (including your internet browser) and disconnect from the internet.
If you are using a software MIDI interface such as loopBe, loopMIDI or rtpMIDI, you should check the CPU usage of that service in Resource Monitor. A hardware interface connected with a physical cable will be a much more CPU efficient setup.
The cache files are created in the same folder as the video. They are named with "_acache.vdp" and "_vcache.vdp" appended to the video path name. The 'OPTIMIZE: Cache File Analysis' option must remain set, otherwise the cache files are ignored. You may delete the cache files at any time, and VidPlayMTC will simply re-create them next time the video is opened.
The video probably has very long key frame intervals. Click on the application logo to open the About window. Video statistics are displayed here, including 'Average key frame interval'. If this exceeds 5000 msecs then seek time will be noticeable as a delay in synchronization when playback is started.
A video may have been encoded with long key frame intervals in order to get maximum compression. For a video to be quickly 'seekable' it needs to have key frame intervals of 1000 msecs or less. The fix for this problem is to re-encode the video.
The video has probably been encoded without any key frames. Click on the application logo to open the About window. Video statistics are displayed here, including 'Final key frame'. If this is zero it indicates that VidPlayMTC was not able to find any key frames in the file.
As an example, the GIF format encodes video without key frames, and also without a video length parameter in the file header. VidPlayMTC takes a long time to start playback because the application has to decode all the frames from zero to the sync position. The fix for this problem is to make the video 'seekable' by re-encoding with key frames, preferably at an interval of 1000 msecs or less.