Sunday, December 4, 2016
Vlog #3: Audio/Video Synchronization Issues
Episode #3 of the ITS Gaming vlog! Audio drift has improved, making audio/video synchronization easier. This means more gaming videos coming up soon!
The Don't Starve Together session had an audio/video drift of at least 8 seconds and as high as 17 seconds. In our latest test, we reduced this drift to only 1 second. The drift was being caused by straining limited resources, in particular RAM. Increasing system memory from 4GB to 8GB seems to have improved the situation. We are also recording in shorter sessions, to mitigate the effects of any drift.
But, an audio/video drift of 1 second is still noticeable. If you place a block in Minecraft, you won't hear the sound effect for an entire second. So we will still need to correct the drift.
The gameplay footage also recorded the computer's clock. Using this as a somewhat stable reference point, Mike discovered that the video is not drifting. But, the audio is shorter than the video by 1 second. This means that we will need to stretch the audio to fit the video.
Unfortunately, Blackmagic Design's DaVinci Resolve does not support stretching audio clips. So, we will need to synchronize the audio/video in REAPER. This isn't bad though: REAPER has excellent time stretching tools.
One thing REAPER is not good at is video. This isn't much of a surprise, considering REAPER is a DAW (digital audio workstation). Emphasis on the "audio" part. We can't import our gameplay or facecam footage into REAPER. To see what is happening along with the audio, we will need to transcode the video files into a format that REAPER can digest.
The video files play back sluggishly, especially when viewing all three at once. To make video editing easier, we will be reducing the quality of the videos. These low-quality video files are called "proxies". Proxy workflows for video editing aren't new, and the tools we have support it. Once editing is finished, the original high quality video files can be swapped back in. The end result has no hint that a low quality video was used in the editing process.
We are currently synchronizing and editing a test session of Minecraft. Once the editing is finished, there should be a new video published. Stay tuned!