FastPlay

FastPlay is a keyboard-first Windows video player for fast local playback, smooth scrubbing, and ergonomic control across monitors.

It is intentionally focused on local playback. No media library. No plugin maze. No feature sprawl. Just fast open, clean playback, responsive controls, and a tighter Windows-native experience.

Download FastPlay v0.4.1 for Windows x64 • All releases • Report an issue

Current status: early release, actively improving playback speed, seek feel, and UI polish on Windows x64.

Why FastPlay exists

Most of the time you open a video player, you are not managing a library or transcoding a stream. You are opening one local file and watching it. FastPlay is built around that single moment: how fast the file opens, how quickly the first frame appears, whether it resumes where you left off, and how cleanly it scrubs and gets out of the way.

The mainstream players are excellent and do far more than this. FastPlay deliberately does less, so the path from double-click to watching stays short and the controls stay responsive. It is a focused tool for local playback on Windows, not a replacement for a full-featured media suite.

Compared to VLC and MPC-HC

VLC and MPC-HC are mature, capable, and the right choice for most people when they need broad format support, streaming, playlists, deep configuration, and years of hardening. FastPlay is not trying to compete on breadth.

Where FastPlay differs is scope and intent:

	FastPlay	VLC	MPC-HC
Primary focus	Fast local playback on Windows	Everything, everywhere	Lightweight local playback (Windows)
Platforms	Windows x64 only	Cross-platform	Windows
Format/codec breadth	Common formats via FFmpeg	Very broad	Broad
Streaming / network	No	Yes	Limited
Playlists / library	No	Yes	Basic
Per-file resume	Built in	Plugin/config	Limited
Render path	D3D11-first, GPU-resident	Multiple backends	DirectShow / madVR etc.

Use VLC or MPC-HC when you need format coverage, streaming, or platform reach. Reach for FastPlay when you want a snappy, no-friction window for the local file in front of you.

Controls

Key	Action
Space	Pause / resume / replay at end
Left	Seek backward 5s, hold for 15s steps
Right	Seek forward 5s, hold for 15s steps
Ctrl+F	Move one frame forward
Ctrl+B	Move one frame backward
Ctrl+O	Open media file
Ctrl+Shift+O	Recent files overlay (↑↓ select · Enter open · Del remove · Esc close)
PageUp / PageDown	Previous / next file in the play queue
Ctrl+S	Save screenshot
S	Toggle subtitles
I	Set in-point at current position
Shift+I	Clear in-point
O	Set out-point at current position
Shift+O	Clear out-point
R	Toggle loop range (if in/out set) · toggle auto-replay (if no range)
MouseWheel	Adjust volume
Esc	Exit borderless fullscreen
Ctrl+H	Toggle borderless fullscreen
Ctrl+W	Fill screen height with no black padding
Ctrl+Q	Snap window to half the video's native resolution
Ctrl+R	Rotate clockwise 90 degrees
Ctrl+E	Rotate counter-clockwise 90 degrees
Ctrl+MouseWheel	Zoom at cursor
Ctrl+Drag	Pan when zoomed in
Ctrl+0	Reset zoom, pan, and rotation
H (hold)	Show controls overlay
[ / ]	Decrease / increase playback speed
\	Reset playback speed to 1×
Backspace	Cancel scrub and return to original position
`	Toggle HW/SW decode mode in title bar

Timeline scrubbing is available by hovering near the bottom of the window and clicking or dragging.

In / Out range

Press I to mark where playback starts and O to mark where it ends. The range adapts to however many points are set:

In	Out	Plays	Space at end goes to
—	—	start → end	start
✓	—	in-point → end	in-point
—	✓	start → out-point	start
✓	✓	in-point → out-point	in-point

Press R while a range is active to loop it continuously. Use Shift+I / Shift+O to clear individual points. In/out points reset when a new file is opened.

Features

Playback

• Ctrl+O file open dialog and drag-and-drop file open
• lightweight play queue: drop multiple files or a folder, step through with PageUp / PageDown, and auto-advance to the next file at the natural end of each one
• recent-files overlay with automatic per-file resume playback
• quick open and first-frame path
• responsive keyboard seek with accelerated hold behavior
• timeline scrubbing overlay with playback position
• in/out point range with loop and auto-replay
• replay at end of playback
• playback metrics such as open-to-frame latency, seek latency, and dropped frames

Video and audio

• FFmpeg-based demux and decode
• hardware video decode on the preferred D3D11 path
• software video decode fallback with D3D11 upload and present
• WASAPI shared-mode audio playback
• audio-master playback timing when audio exists
• generation-safe seek and reopen behavior
• device-loss and resize recovery paths

Viewing controls

• borderless fullscreen
• cursor-centered zoom and drag-to-pan
• 90-degree view rotation with auto-rotate from stream display matrix metadata
• fit-to-screen window sizing with no black padding
• half native resolution window sizing
• volume control with on-screen overlay
• hold-to-show keybind reference overlay

Subtitles

• external .srt subtitle overlay
• runtime subtitle toggle
• accepts both comma and period millisecond separators in SRT timestamps
• UTF-8 with BOM support and Windows-1252 fallback encoding
• strips common formatting tags (<b>, <i>, <u>, <font>)

Platform

• per-monitor DPI awareness (Per-Monitor V2 with system-aware fallback)
• minimum window size enforcement (640×360)

Goals

FastPlay prioritizes:

• low open-to-first-frame latency
• responsive seek behavior
• GPU-resident presentation on the normal hardware path
• bounded queues and explicit ownership
• narrow, maintainable architecture
• Windows-specific performance rather than broad platform support

Non-goals

FastPlay does not currently aim to provide:

• media library management, scraping, or collection organization
• streaming support
• plugin support
• browser or web UI
• advanced subtitle styling or embedded subtitle track selection
• HDR or tone mapping
• extra hardware backends beyond the current D3D11-first design

Lightweight queue/folder playback is implemented (see Features); full playlists, persistent playlist files, and media-library behavior remain non-goals.

Known limitations

These are current real-world caveats, separate from the deliberate non-goals above:

• Windows x64 only. No macOS, Linux, or ARM builds.
• Common formats, not exhaustive. Decoding depends on the FFmpeg build in use; uncommon or exotic codecs may not play. Software decode is the fallback when hardware decode is unavailable.
• External .srt subtitles only. Embedded subtitle tracks and other subtitle formats are not loaded, and styling is intentionally minimal.
• Queue is in-memory and session-only. Dropping multiple files or a folder builds a play queue you can step through (PageUp / PageDown) with auto-advance at end of file, but the queue is not saved between runs, there are no persistent playlist files, folder scanning is non-recursive, and there is no shuffle, repeat, or in-window queue list.
• No streaming or network sources. Local files only.
• Audio is WASAPI shared-mode. No exclusive mode, no multi-track/audio-track switching.
• HDR is not tone-mapped. HDR content plays but is not color-managed.
• Early release. Behavior, shortcuts, and metrics are still changing between versions.

Requirements

• Windows 10 or later
• Rust toolchain
• FFmpeg development headers and libraries available locally
• D3D11 / DXGI / WASAPI-capable system

FFmpeg setup

build.rs supports these FFmpeg discovery patterns.

Preferred

Set FFMPEG_DIR.

Or set explicitly

• FFMPEG_INCLUDE_DIR
• FFMPEG_LIB_DIR
• optional: FFMPEG_BIN_DIR

Fallback search locations

• %VCPKG_ROOT%/installed/x64-windows
• %USERPROFILE%/vcpkg/installed/x64-windows
• C:\tools\vcpkg\installed\x64-windows

The build expects the usual FFmpeg development layout with include/ and lib/. Runtime DLL staging works when a bin/ directory is available.

Build

cargo build --release

Run

Normal playback:

cargo run --release -- <path-to-media>

Or drag and drop a media file onto the FastPlay window.

Force software decode fallback:

cargo run --release -- --force-sw <path-to-media>

External subtitles

FastPlay supports external sidecar .srt files only. Place a subtitle file next to the media file with the same basename:

movie.mp4
movie.srt

The subtitle sidecar will be auto-loaded if present.

Architecture

Preferred path

FFmpeg -> AV_PIX_FMT_D3D11 -> D3D11 video processor -> DXGI present

Software fallback path

FFmpeg demux -> software decode -> D3D11 upload -> D3D11 video processor -> DXGI present

Audio path

FFmpeg decode -> WASAPI shared-mode sink

Subtitle path

• external .srt sidecar only
• CPU parsing and layout
• GPU alpha composition during present

For the full implementation charter, see ARCHITECTURE.md.

Project structure

src/
  app/        # session coordinator, commands, events, state
  audio/      # audio sink abstractions
  ffi/        # FFmpeg / D3D11 / DXGI / WASAPI interop
  media/      # source, video, audio, seek, subtitle
  platform/   # Win32 window/input
  playback/   # clock, metrics, queue policy, generations
  render/     # presenter, swapchain, surface registry, timeline overlay

License

MIT