I am merging around 12 clips of videos into a single one. I had added a caption as part 1, part 2, etc. on the front. Now this videos are based on a video tutorial. I had used a online screen recording software. All recorded videos are saved in MP4 format with HD resolution. I imported them in Movie Maker that took really long time. But the audio quality is very bad. I am not able to figure out why Movie Maker is just spoiling the audio quality. While the video is fine. It is not having any problem.
Bookmarks