Maybe you'd like to realize such a scenario on the same computer: use the PC speaker to play music while playing games wearing a headphone. At the same time, let the TV play movie via HDMI connection to your computer.... In this case, CheVolume can perfectly meet your needs. It provides complete control to all audio devices (including sound card and headset).
SolveigMM Video Splitter is an outstanding and very fast (no encoding/decoding process required) lossless video editing software. Its intuitive interface enables users to split (remove the unwanted parts) / merge (join any format of video clips into a single big one) pretty much all common video formats accurately, correctly without quality loss.
WebM is an open, high-quality video format defined by Google, specially designed for the web to save disk space and speed up the video file transfer. Its essence is a kind of new container format based on MKV that contains video streams compressed with the VP8/VP9 video codecs and audio streams compressed with Vorbis/Opus audio codecs.
People who like to watch movies probably have encountered such a situation: the cineframe or sound track is not synchronized with the subtitles. Watching films like this is wasting the film itself and our time, and that's really a mental torture at the same time! While don't worry, we can use some software to easily adjust/correct the movie subtitles.
Aegisub (successor of the original SubStation Alpha and Sabbu) is a free, open-source and cross-platform advanced subtitles creating & modifying tool. Recognized as an industry standard of all subtitle editors, it is widely used by numerous subtitle groups and subtitling fans for the subtitling and translation of concert, OP, PV, TV, animation and some other aspects like video post-production.