dsh-mp4
Play MP4 / M4V / MOV videos inside the DeepSeek Harness right sidebar — the browser's own video player replaces the "this file type cannot be previewed" placeholder.
Why this exists
When the pane says "this file type cannot be previewed / download to view", the file is fine. No renderer claims mp4, and which preview system opens a file depends on what you have installed:
| Your right column | What opens the file | Before |
|---|
dsh-better-sidebar installed | its editor tab, picking a viewer through matchFileViewer(path) | ships markdown / html / jsonl / code only, so mp4 falls through to the catch-all code viewer, reads as binary → "cannot be previewed" plus a download link |
| Native DSH sidebar | @deepseek-ai/dsh-client-ui-sidebar-documentpreview | mp4 sits in UNVIEWABLE_BINARY_EXTENSIONS, matches no renderer → empty state, and not a single byte is read |
This plugin registers with both, so one package works on Desktop, plain dsh web, and any other profile. The two halves are independent: whichever system is missing simply stays idle instead of failing the plugin.
Install
Search dsh-mp4 in the plugin market, or:
# Desktop users: prefer Settings → Plugins (Desktop runs its own profile)
dsh plugin --profile web add dsh-mp4
dsh plugin --profile <your-profile> add dsh-mp4
