MetalMPV

A fast video player for Windows built on libmpv

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MetalMPV is a video player for Windows with a classic layout: the picture fills the window, the seek bar and the buttons sit under it with Play in the middle, and the playlist opens on the right. Playback is done by libmpv, the library of the mpv player, so practically every video and audio format plays, with hardware decoding where the graphics card supports it. The program is built for opening files quickly and for instant seeking on keyframes.

Screenshot of version 0.1.0.

Features

• Fast start: the playback engine starts while the window is being created; on a warm start the first frame of a 1080p file appears about 0.4 s after the program is launched.
• Instant seeking on keyframes with the arrow keys, exact seeking and frame stepping on other keys (see Keyboard shortcuts); every seek is reported on the screen.
• Every common format: MP4, MKV, AVI, MOV, WebM, TS, WMV and more, audio files included; subtitles next to the video are loaded automatically.
• Hardware decoding (NVDEC, D3D11VA and others, chosen by libmpv), which can be turned off in the settings.
• Audio tracks and subtitles in one window by the volume (T); subtitles from a file of their own (see Audio and subtitles).
• Video, sound and subtitles panel (U): the picture's colour, zoom and pan, sharpness, noise reduction, aspect ratio, deinterlacing, HDR tone mapping and rotation; the output device, channels, volume boost up to 200 %, normalization, clearer speech, stereo to 5.1, the subwoofer, a ten-band equalizer and Dolby and DTS sent to a receiver undecoded; the look of the subtitles (see Video, sound and subtitles panel).
• File information (I): the cover, the tags and the details of every track in a window over the player; the cover of an audio file fills the picture (see File information).
• Window for the picture: 50–200 % of the video's size, the largest window without black bars, fullscreen without black bars, four layouts of the interface, a mini player over the other windows (see Window size and layouts).
• Chapters, A-B repeat, bookmarks, going to a time: see Chapters, A-B repeat (also saved as a file of its own), Bookmarks and Go to time.
• Resume: a film opened again goes on from where it was stopped, with the audio track and subtitles chosen in it (see Settings).
• Playlist: files opened together or dropped onto the window, optionally the folder's files or an album's tracks; a search, M3U and IPTV lists with groups and channel logos, lines of how far each file was watched (see Playlist).
• One window: a file opened from Explorer while the player runs is played in the window already open.
• File types: the player can be registered with Windows for its formats, each with an icon of its own (see File types).
• English or Russian interface: it follows the language of Windows and can be changed in the settings (F5).
• Portable: the portable archive keeps its settings next to the program.
• Privacy: no network access beyond the addresses opened, the optional update check and the logos of IPTV channels, which can be turned off (see Update check and privacy).

Installation

The installer and the portable archive are on the Releases page. Both contain libmpv-2.dll (about 115 MB unpacked), the playback engine, which must stay next to metalmpv.exe. The executables are not code-signed, so Windows SmartScreen may warn about an unknown publisher on first launch.

• Installer, MetalMPV_<version>_Setup.exe: needs no administrator rights; the program is placed in %LOCALAPPDATA%\Programs\MetalMPV and keeps its settings in %APPDATA%\MetalMPV. Its File types task, on by default, registers the player for its formats (see File types); on the last page it offers to open Windows Settings to choose the player as the default. Uninstalling removes the registration; the settings (with the remembered positions and the channel logos) are kept.
• Portable archive, MetalMPV_<version>_portable.zip: the program in a MetalMPV folder, run without installation; the settings are kept next to it, so it can be carried on a removable drive.

Where the portable program keeps its settings

The archive holds an empty metalmpv.ron. While that file is next to metalmpv.exe and the folder is writable, the settings are kept in it. Without the file, the program keeps them in %APPDATA%\MetalMPV, as the installed program does. The About window shows where the settings are kept.

Beside the settings file lies a copy of it made at each start (app.ron.bak or metalmpv.ron.bak); a settings file found damaged, for instance by a power cut while it was being written, is replaced by that copy.

Usage

Opening files

A file is opened with the Open button (the eject symbol, Ctrl+O), by dropping it onto the window, from Explorer (Open with), or from the command line: metalmpv.exe file.mkv [more files]. Several files make a playlist; at the end of a file the next one starts. Ctrl+U or Open an address… in the context menu plays a direct link to a video or a stream. While nothing plays, the start screen lists the files played last.

Dropped files, M3U and IPTV lists, addresses, recent files, the taskbar

• Dropped files are added to the end of the playlist, and play at once only when the playlist was empty or nothing plays (a file the playlist has already plays then from its place; added out of sight, the on-screen message says how many). A subtitle file dropped with a video while nothing plays goes with that video.
• M3U and M3U8 playlists opened, dropped or given on the command line are replaced by their entries: relative paths are from the playlist's folder, file:/// addresses are taken as paths, and an .m3u file not in UTF-8 is read in the system's code page, as older players wrote it. An HLS stream's playlist, with #EXT-X- tags, is played as one stream instead. A playlist at an address (http://…/list.m3u) and one listed inside another are replaced too, once mpv has read them. Of a list's addresses, only streams play (http, https, rtsp, rtmp, udp and the like); a list from an address names no files on the computer.
• IPTV lists: the #EXTINF lines name the entries. The playlist, the window title and saved frames show the channel's name instead of the stream's file name, the tooltip of an entry shows its group, and the channel's logo (tvg-logo) is shown beside the name (see Channel logos in the settings); Save the list writes the names, logos and groups back.
• Addresses: a direct link to a video or a stream (http, https, rtsp, rtmp, udp and others; an address on the command line works too). Pages of YouTube and other sites are not supported, since the player does not use yt-dlp.
• Recent files: the start screen lists the files played last under the RECENT heading, centred under the hint (up to eight, as many as the window's height allows; the rest of the thirty kept scroll in their place). A click plays one, and Clear the list empties it, as does Forget all under Resume in the settings. With Remember the recent files off, no files are kept.
• Taskbar: the program's button shows the position as its progress (yellow while paused), and its thumbnail has the buttons Previous file, Play/Pause and Next file.
• Sleep: while a video plays, the display does not turn off and the computer does not sleep; while only sound plays, the computer does not sleep, and when playback pauses or ends, Windows' power settings apply again.

Window and fullscreen

The window has its own title row: it is moved by dragging the title, the picture or the free space of the control bar, resized by its edges, and maximised by a double click on the title. A double click on the picture or Enter switches to fullscreen, where only the picture is left; the control bar at the bottom and the file's name at the top appear over it independently, each while the pointer is near its edge, and the pointer itself hides after half a second of rest away from them. The strip with the name can be turned off, and the transparency of both is set in the settings. L or a middle click shows the playlist over the right side of the screen, as tall as it and resized by its left edge; Esc or the same key hides it, and leaving fullscreen does so too.

The control bar holds the seek bar (a click or a drag moves there; the time under the pointer is shown), the time (a click on it switches between the position with the duration, the position alone and the time remaining; the choice is kept), the buttons Open, Stop, Previous file, Play/Pause, Next file, Settings and Playlist, the Video, sound and subtitles panel and the tracks buttons, the sound on/off button with the volume, and the fullscreen button. A right click on the picture opens a menu with the same commands.

Window size and layouts

1–4 size the window for 50 %, 100 %, 150 % or 200 % of the video, 5 makes the largest window without black bars, ` (the key left of 1) fits the window to the picture, and 6 switches to fullscreen with the picture cropped to fill the screen. 8 switches between four layouts of the interface, 7 leaves only the picture, and 0 makes the window a mini player. The same commands are in the Zoom and Interface submenus of the picture's context menu.

More on the window's size and the layouts

• Window for the picture: at 100 % a pixel of the video falls on a pixel of the screen. 5 makes the largest window the screen holds with the picture's shape, and ` fits the window to the picture shown, removing the black bars. A maximised window is restored first and fullscreen is left; a window that would not fit the screen is made smaller, the picture keeping its shape, and keeps its centre where possible.
• Fullscreen without black bars: 6 enlarges the picture to fill the screen, its edges cropped; 6 again shows the picture whole with the black bars, still in fullscreen, and leaving fullscreen does so too.
• Layouts: Full (the title row and the control bar of two rows), Without the title row, Compact (no title row, the control bar in one row: Play, previous and next, the time and the seek bar from the left, the volume and the other buttons on the right; Open and Stop remain in the context menu and on the keys, and in a narrow window the less needed buttons are left out so that the seek bar keeps its room) and Only the picture. Without the title row, the title row with the window's buttons appears over the top of the picture while the pointer is there. The layout is kept between starts (also chosen on the General page of the settings); in fullscreen the control bar is compact in the compact layout. On a change of layout the window grows or shrinks by the difference, so the picture keeps its place and size; a maximised window or one in fullscreen keeps its size and is fitted once restored.
• Only the picture (7) hides the title row, the control bar and the playlist. The title row appears over the picture's top and the control bar of the layout chosen over its bottom while the pointer is near the edge, and the window is still moved by dragging the picture and resized by its edges. 7 again, Esc or Show the interface at the top of the context menu brings back the layout shown before (the full one after a start with only the picture); so does asking for the playlist (L, the middle click, the context menu), which then shows it.
• Mini player (0, the button left of Minimize in the title row, or Mini player in the context menu): the window becomes small and stays over the other windows, showing only the picture; the first time it is 384 points wide in the bottom right corner of the screen, later where it was left and of the size it had. Its shape follows the picture's, also while its edges are dragged and when another file is opened, and while it is moved it is drawn to the edges and corners of the screen. While the pointer moves over the picture, or nothing plays, Play, the sound and the volume and the seek bar appear at the bottom, and the button back to the player's window in the top right corner. The picture moves the window, the wheel sets the volume and the keys work as usual. 0 again, a double click on the picture, the button or The player's window at the top of the context menu bring back what was before it: the window as it was, maximised if it was, or fullscreen; Esc brings the window back; so do the playlist, fullscreen, the window sizes, the layouts, the tracks window, the panel and the file information.

Playlist

The playlist (L) lists the files with the current one highlighted. A double click plays an entry, the selected entries are moved by dragging them, and the right button opens an entry's menu. The icon buttons above the list add, remove, sort, clear, save and shuffle the entries and switch the repeat mode; their names are shown in the tooltips. The magnifier or Ctrl+F searches the list.

Selection, menus, progress lines, groups, search, buttons, repeat

• Selection: a click selects an entry, Ctrl+click adds one to the selection or takes it out, Shift+click selects a range of the entries shown (a search or a folded group leaves the others out of the selection, as does Select all). The list scrolls to the current entry when it changes.
• Moving: the selected entries are moved by dragging them; a line shows where they go (not while searching or in groups).
• Entry's menu: Play, Show in its folder, Copy the path (the paths of all the selected entries), Select all and Remove from the list.
• How far files were watched: under an entry a thin line shows how far it was watched, and a tick at the right marks a file watched to its end (for files of five minutes or more, while Go on from where it stopped is on). Show how far files went in an entry's menu turns the lines off and on (the ticks stay), and the choice is kept.
• IPTV groups: the entries of an IPTV list with groups (group-title) are shown under their groups, which fold by a click on their headers; a group's menu folds or unfolds them all, and Show the groups in the menu of an entry or of a group turns them off and on, and the choice is kept.
• Search: the magnifier at the right of the buttons, or Ctrl+F, shows a search field. The list then shows the entries whose names contain the text typed, Enter plays the first one, and Esc in the field closes it; outside the field Esc does what it always does.
• Buttons: add files (+), remove the selected entries (−, Delete), sort the list by name, numbers by value (the bars with an arrow), clear it (the bin), save it as an M3U8 playlist (the arrow into a tray), and after a line, shuffle it (crossing arrows; the current file plays on, first in the list).
• Repeat: the loop button, R or the Repeat submenu of the context menu switches the repeat mode, which is kept: off, the file (played again without a gap) or the list (the first file after the last; Next and Previous go round).

The playlist in a window of its own

The button at the right end of the playlist's buttons (a window with an arrow), or Playlist in a window of its own in the picture's context menu, moves the list into a window of its own and back. That window is frameless as the player's, with a title row of its own (dragged to move the window, a close button on the right) and edges that resize it; it has no taskbar button, stays above the player and is minimised with it; the first time it stands at the player's right edge, as tall as the player.

Moved near an edge of the player, it is drawn to it and lined up with the player's top, bottom or side; once it touches an edge, it goes along when the player is moved or resized (not while the player is maximised or in fullscreen). In fullscreen it is hidden while it would cover the player's screen. The player's keys work in it, except Esc, which closes it. Its place and size are remembered.

Video, sound and subtitles panel

U (also F7), the sliders button left of the tracks button in the control bar, or Video, sound and subtitles… in the picture's context menu opens a panel over that button with the tabs Video, Sound and Subtitles. Playback and the keys go on while it is open; a click outside it, the button again, U, F7 or Esc closes it. The camera in its head, Save the frame (Ctrl+E), saves the frame on screen.

How the panel works

• Place: over its button, as the tracks window is (at the bottom right corner when only the picture is shown), as tall as its tallest tab, whichever is shown; in a window too low for it, it takes the height there is above the button and its tabs scroll under the head.
• Sections: in the tabs, a click on a section's title folds the section or unfolds it, and the panel keeps that between runs.
• Values are set by sliders whose rail is lit from the starting point to the knob, so that a change shows at once; the arrows at the slider's ends move the value a step back or forward, again and again while held; the value beside each can also be dragged or typed and is shown in the accent colour while it differs from the default, which a double click on the slider or the round arrow beside it brings back. On and off are switches.
• Tooltips: each setting's tooltip says how it applies: to which subtitles, on the processor or the graphics card, whether it is kept between runs.
• Save the frame saves the frame as decoded, without subtitles, as a PNG or a JPG (see Video in the settings) named after the file and the position into Pictures\MetalMPV or the folder chosen; a right click on the camera offers Open the folder.

Video tab

• Colour: the brightness, the contrast, the saturation, the hue and the gamma, from −100 to 100.
• Zoom, from 50 to 400 %, and under it the navigator: the picture in small with the part on screen framed. The frame is dragged, or put where a click lands, to pan the picture (up to ±50 % of it either way); the figures beside Pan take it typed, and a double click on the navigator centres it. Navigator on the picture shows the same in the picture's bottom right corner while it is zoomed in past the window (above where the control bar comes over the picture).
• Sharpness (AMD's contrast adaptive sharpening) and noise reduction (from 0, off, to 100 %; 40 % is FFmpeg's usual strength, more blurs). Gradient smoothing removes the steps in skies and dark scenes.
• Aspect ratio: the file's or one forced on it: 4:3, 16:9, 16:10, 1.85:1, 2.35:1 or 2.39:1 (also in the Aspect ratio submenu of the picture's context menu).
• Deinterlacing weaves interlaced pictures, as in TV recordings, into whole frames: automatically for frames marked interlaced (the default), always or never.
• HDR on SDR chooses how an HDR picture is brought down to an ordinary screen: automatically, BT.2390 (the standard's), Hable (filmic), Möbius (bright), Reinhard (soft) or clipped.
• Rotation and flips: Rotation chooses the angle, 0°, 90°, 180° or 270° clockwise (Ctrl+R turns it on by 90°), and Flip turns the picture upside down or mirrors it, each lit while on.

The sharpness, the noise reduction and the flips are FFmpeg filters run by the processor (while any of them is on, hardware decoding copies each frame back to memory for them); the rest is done by the graphics card. The adjustments apply to every file until the program is closed, and between runs with Remember on; Reset all puts them back.

Sound tab

The tab (also opened by the Equalizer action, which has no default key) starts with what is playing: the track's channels drawn as speakers round the listener (and, when the sound is mixed to other channels for the device, an arrow to the device's), its format as the decoder names it (E-AC3 Atmos, DTS-HD MA and the like; the codec's full name in the tooltip), its channels, sampling rate and bitrate of the moment, and what the device receives (the rate, the channels and the sample format, or the bitstream passed to a receiver). Then it holds:

• Output device: while the chosen one is unplugged, the sound goes to Windows' default.
• Channels: Auto follows the device's setup in Windows; mono, stereo, 5.1 or 7.1 mixes the sound to that layout.
• Receiver: Dolby and DTS sound sent out compressed for a receiver to decode (over S/PDIF AC3 and DTS, over HDMI also E-AC3, DTS-HD and TrueHD). The player's volume, normalization, equalizer and channels do not apply to it, Windows gives the device to the player alone, and a format the device does not take is decoded as usual.
• Volume boost: up to 130, 150 or 200 %; loud passages may then distort.
• Delay of the sound against the picture: a slider of ±5 s; the keys go further, and it is not kept between runs.
• Normalization (FFmpeg's dynaudnorm): quiet dialogue louder, loud scenes quieter; its Strength soft, medium or strong raises quiet passages up to 3, 5 or 10 times, the strong following the quickest.
• Clearer speech raises the voice over the music: in a stereo track through FFmpeg's dialogue enhancer, in a 5.1 or larger one by raising the centre channel, a mono one as it is. Its Strength, +1 to +20 dB (+4 by default), is how much louder the voice is than the rest: the centre is raised up to 12 dB, past that the other channels are lowered instead, so that a loud voice does not distort; in stereo the enhancer works as strongly first (up to its limit at 12 dB).
• Stereo to 5.1 spreads a stereo track over 5.1 for speakers that take it (FFmpeg's surround: what both sides share, mostly the voice, goes to the centre, what differs to the surrounds, the low end to the subwoofer; Clearer speech then raises that centre); not while Channels makes the sound mono or stereo. Under it, Subwoofer up to sets where the subwoofer's sound ends (40–200 Hz, 80 by default, the cinemas' crossover; it fades out up to twice that), and Bass to the subwoofer only takes the low end out of the other speakers instead of only copying it to the subwoofer, for small front speakers.
• Subwoofer: its Level in dB (−20 to +10), for a 5.1 or 7.1 track against the track's own level, for Stereo to 5.1 against a 5.1's standard, 10 dB under the other channels, as receivers play that channel 10 dB louder; and Cut the infrasound, which takes out what lies under the frequency set (15–40 Hz, 25 by default; 24 dB an octave) in all channels: a subwoofer hardly plays it, but its cone is driven to the limit and the bass bubbles, and films with deep bass hold much of it.
• Equalizer: ten bands, 31 Hz to 16 kHz, ±12 dB a band (a double click or the round arrow under a band puts it back to 0), with a scale of ±12 dB, the 0 dB line and a curve through the bands. Its switch turns it on, and the list beside it holds the presets Flat, Rock, Pop, Jazz, Classical, Bass, Voice and Treble. The plus beside the list saves the gains under a name typed in the row that appears (Enter saves, Esc gives up; a name already there is replaced); such gains follow the presets in the list under "Mine", at most twenty, and the bin deletes the ones chosen.

A function's settings show only while it is on. Reset all puts the rest back, the delay included; the output device, the receiver and one's own equalizer gains stay. All but the delay are kept between runs; the equalizer, the normalization and clearer speech do not apply to sound sent to a receiver undecoded.

Subtitles tab

• Looks: ready-made ones first: soft with a shadow (the default), classic as in mpv, thin outline, bold with a thick outline, shadow only, cream, pale mint, on a dark box, and dark on a light box. Each sets the colours, the outline, the shadow, boldness and the box, and leaves the font, the size and the height as they are (the list says "Custom" once anything of it is changed).
• One's own looks: the plus beside the list saves the whole look, the font, the size and the height included, under a name typed in the row that appears; such looks follow the ready-made ones under "Mine", at most twenty, and the bin deletes the one chosen. They are kept between runs, and Reset in the settings keeps them.
• Sample: under the list, large sample text shows the look roughly, in the interface's font and at a fixed size, on a ground from dark to light.
• Settings: the font and the size (of all subtitles, ASS included), bold letters, the colour of the letters and of their outline, the outline's thickness, the shadow, a slightly see-through box behind each line in place of the outline (of the outline's colour, the thickness becoming its margin), and the height of the subtitles on the picture.
• In the black bars (on by default): where the picture has black bars, subtitles, ASS ones too, go in them; off, over the picture.
• Style for ASS too: the font, the colours and the outline replace those of ASS subtitles as well, whose signs and effects then lose their look.
• Delay: a slider of ±5 s, not kept between runs. Under it a timeline shows a stretch of time round the position, the vertical line in the middle, with the lines of a subtitle file of its own (SRT, WebVTT, ASS) as blocks moved by the delay. Dragging the blocks sets the delay, and a line's start stops for a moment on the position line; so a pause where a line is spoken and its block put on the line match the subtitles to the speech. The arrow buttons at its ends put the line before or after the one on screen at the position (Ctrl+Shift+← and Ctrl+Shift+→, for any subtitles), and − and + widen or narrow the stretch, from 10 s to 5 min 20 s.

Reset all puts the look back. Without Style for ASS too, the size and the height apply to all subtitles, the font and the colours to text subtitles (SRT and the like). All but the delay are kept between runs.

Audio and subtitles

The button with a speech bubble left of the volume (T) opens a window with the audio tracks and the subtitles of the file. Each entry names the language first and the track's title after a dash ("Russian — Superbit"), with badges for the format, the channels and whether the track is external, forced or the file's default. A choice applies at once and the window stays open. Load from a file… under the subtitles adds subtitles from a file of their own (SRT, ASS, SSA, VobSub, PGS, WebVTT); a subtitle file dropped onto the playing video is added the same way, and subtitles named like the video next to it are loaded by themselves.

More on the tracks window

The two lists are shown as tabs; the button at the right of the tabs shows them side by side in two columns instead, and the same button in that view turns back to tabs (the choice is kept between runs). A long list scrolls. As with the Video, sound and subtitles panel, which it replaces at that place, playback and the keys go on while it is open, and a click outside, the button again, T or Esc closes it. The same lists are in the picture's context menu, and every change is reported on the screen.

Chapters

When the file has chapters, the seek bar is cut at the start of each, and the tooltip over the bar names the chapter under the pointer. The marks are turned off and on in the Chapters submenu of the picture's context menu or in the settings (Playback). Under the playlist, the Chapters section lists them with their starts, the playing one highlighted; a click goes to a chapter, and a click on the header folds the section. The same list is in the Chapters submenu. The move is reported on the screen with the chapter's number and title.

Go to time

Ctrl+G or Go to time… in the picture's context menu opens a window with the position playing in its field, selected, so that a time typed replaces it. The field takes 1:23:45, 83:20, a number of seconds (5000), a fraction after a point or a comma (1:23,5), a share of the file (50%), or a move from the position playing (+30, -1:00, +10%); under the field the window shows the time this names, with its share of the file, or says that the text is not a time in this file. Enter or Go moves there to the exact frame; a time past the end goes to the end.

Bookmarks

Ctrl+B or Bookmarks → Add a bookmark here in the picture's context menu keeps the file playing and the position. The Bookmarks submenu lists them, the latest first, each by the file's name and the time with a thin line under it showing where in the file it is, those of the file playing marked: a click goes there, in the file playing at once, else playing its file from that place (its playlist entry, or the file opened); the cross beside one deletes it, and Delete all bookmarks deletes them all. Up to 30 are kept between runs, the oldest giving way; Reset in the settings keeps them.

A-B repeat

[ marks the start of a stretch at the position playing and ] its end; from then on, playback goes back to the start each time it reaches the end, until \ turns the repeat off. An end marked without a start repeats from the beginning of the file, and an end before the start swaps the two. The points appear as yellow ticks on the seek bar with the stretch between them highlighted, the on-screen message gives them to a tenth of a second, and the A-B repeat submenu of the picture's context menu does the same. The points belong to the file: another file starts without them.

Ctrl+Shift+S or Save the stretch… in the same submenu saves the stretch between the points as a file of its own, while playback goes on.

Saving the stretch as a file

• File: an MP4 next to the source, or in the folder of saved frames for an address, with the times in its name; … chooses another. A name typed without a folder goes to that folder, and one without .mp4, .mkv or .mov gets .mp4. The file playing and a file already there are not written over, except one the … dialog was told to replace; that one is replaced only once the new file is complete.
• Encoding: H.264 or HEVC, on the processor (x264, x265) or an NVIDIA card (NVENC), the quality (22 at first; lower is better and larger), and, if wanted, the subtitles shown burnt into the picture in their look. The sound is the audio track playing, in AAC; the audio and subtitle delays and the deinterlacing are those of the player. The stretch is cut exactly at the points.
• Progress: a progress bar, Cancel and Hide follow. Hidden, the window lets the player be used while the saving goes on, and Ctrl+Shift+S shows it again; the on-screen message names the file saved, or says why it was not (NVENC needs an NVIDIA card). The choices are kept.

File information

I, the i button in the title row or File information in the picture's context menu opens a window over the player; playback and the keys go on while it is open, and I or Esc closes it. At the top it shows the cover with the title, the artist and the album, and under them the main facts in rows of chips: the file, the picture and the sound, a chip per audio track (a click on one plays that track), and the subtitles. Below come sections with every detail of the file, the playback and the tracks.

Ctrl+I or Information over the picture in the context menu shows the same chips alone, see-through, in the picture's top right corner, until Ctrl+I hides them; they make way for the window while it is open. They stay on between runs; the Video page of the settings turns them on and off, sets how transparent their ground is and, with Briefly, leaves one row of what plays: the format, the picture's codec, size and HDR, the audio track and the subtitles.

What the window shows

• Cover: a click on it shows it as big as the window allows. A channel of an IPTV list is shown by the list's name and group, with its logo in place of the cover once fetched.
• Chips: the file (format, size, duration, overall bitrate), the picture (codec, size, aspect ratio, frame rate, bit depth, HDR, bitrate) and the sound, a chip per audio track (codec, channels, language) with the playing one outlined; with more than four, the others are folded into one chip that lists them in its tooltip and shows them all when clicked (the chip − after them folds them again, as does another file). The subtitles' chip, on a row of its own, gives their language and count; with more than one track a click shows a chip per track instead, a click on one shows those subtitles, and − folds them again. Each chip's tooltip says more: the container's name, the codec's full name and profile, the track's name and details. The chips are coloured: the format in the colours of its file icon, the picture, the sound and the subtitles each in a hue of their own.
• Sections fold with a click on their heading and are copied as text from its context menu:
  • File: name, folder, size, container, duration, overall bitrate, number of chapters, the program that wrote a Matroska file and when, and the file's dates; a click on the folder shows the file in Explorer.
  • Playback, refreshed every second: the bitrates of the moment with a line of the last minute's, the frame rate shown against the screen's, the dropped frames, what the sound device receives (the format passed through, if any) and, for a stream, the data read ahead.
  • Tags: the common ones first, named in the interface's language, then the others as the file names them; a long one is cut short, with more to show it all.
  • Tracks, grouped as video, audio and subtitles, the playing one marked with a dot, each with a line of its format, size, frame rate, bit depth, HDR, channels, sampling rate and bitrate; a sound track's format is named precisely once the decoder reports it (DTS-HD MA, DTS:X, E-AC3 Atmos, TrueHD Atmos, HE-AAC). A click on a track unfolds its details, and the video on screen is unfolded from the start: the codec's profile and level, the aspect ratio, the channel layout, the bitrate and the stream's size (from the statistics mkvmerge writes into a Matroska file, else estimated), the number of frames, the track's flags and tags, and for the video on screen also the chroma subsampling, the scan, the colour range, primaries, transfer and matrix, the HDR format and light levels with the mastering display, and whether it is decoded in hardware.
• Copying: every value can be selected, and its context menu copies it or its row. Two icon buttons at the right end of the title's line, named in their tooltips, act on it: Copy all (two sheets) puts the whole of it on the clipboard as text, the values in a column, and shows a tick for a moment, and Save the cover… (an arrow into a tray) saves the picture as it is stored.
• Place: the window stays at the player's top right corner, also when the player's window is resized. Its bottom edge can be dragged to make it taller or shorter.

The cover is taken from the file's tags (MP3, FLAC, OGG, Opus, M4A, MP4, WAV, APE and others) or from its attachments (MKV, MKA, WebM); for an audio file without one, a picture named cover, folder or front next to it is used. While an audio file plays, its cover fills the picture with the title, the artist and the album under it.

File types

The File types page of the settings (F5) registers the player for its formats, opens Windows' choice of the default program and removes the registration. The registration is per user and needs no administrator rights; the installer registers the formats too. Each format gets a type of its own with an icon (one hue per family of formats, Play on video, a note on audio, a list on playlists).

The page, the registration and the formats

• The page shows whether the player is registered, a row per action with its button on the right — Register (Update once registered), Choose… for the default program and Unregister — and the formats the player registers with their extensions and whether the player opens each by default: the extensions it opens are bright, and a format it opens only some extensions of shows how many. Choose… is available once the player is registered.
• The registration gives each format a name in Explorer's Type column; the player appears in Open with for these files and in Settings → Apps → Default apps. Windows lets only the user choose the default program: Choose… opens that page of Settings, and Windows also offers the player the next time such a file is opened. A format no program opens yet gets the player as its default at once. Unregister removes everything the registration wrote; the choice of another program stays as it is.
• Registered formats: video MP4 (.mp4, .m4v), MKV, WebM, AVI (.avi, .divx), MOV (.mov, .qt), WMV (.wmv, .asf), FLV (.flv, .f4v), MPEG (.mpg, .mpeg, .m2v, .vob), TS (.ts, .m2ts, .mts), 3GP (.3gp, .3g2), OGV and RM (.rm, .rmvb); audio MP3, FLAC, AAC (.m4a, .aac), Ogg (.ogg, .oga), Opus, WAV, WMA, APE, WavPack (.wv), MKA, AC3 and DTS; playlists M3U (.m3u, .m3u8).
• Command line: the installer and other scripts can do the same with metalmpv.exe --register and metalmpv.exe --unregister.

Settings

The settings window (F5 or the gear button) lists the categories on the left and shows the settings of the chosen one on the right in groups: each row names a setting, explains it underneath and holds its control on the right; the round arrow at the right of a slider puts its value back to the default. Reset under the list puts the settings of the window back to their defaults (those of the Video, sound and subtitles panel are reset on the panel); the remembered positions, the recent files, the repeat mode and the playlist's place are kept.

The sound and the look of the subtitles are set on the Video, sound and subtitles panel and kept between runs. The Keyboard shortcuts category lists every action with its keys, which can be changed (see Keyboard shortcuts). The volume, the window and the playlist's visibility and width are remembered between runs.

General

Setting	Default	Meaning
Language	as in Windows	"As in Windows" follows the language of Windows
Accent colour	blue	Blue, teal, green, orange, red, pink, purple, graphite, or a colour of one's own (the last swatch, a colour wheel: a picker with a field for the code, shown as #RRGGBB, RGB(r, g, b) or HSL(h, s%, l%) by a click on its name and taking any of them, and fields for red, green and blue, 0–255): the Play button, the seek bar and the volume, the switches, the playing file of the playlist and the selection, and the screen of the icon in the window, on the taskbar button of the running player and on the start screen (the icon of the program's file and of its shortcuts stays blue)
Layout	full	Full, without the title row, compact or only the picture; 8 switches the layouts, 7 leaves only the picture and brings the layout back
Over the other windows	never	Never, always, or while a file plays (not paused); Ctrl+T switches it
Window when a file opens	keeps its size	Keeps its size, fitted to the picture (the black bars taken off, the width kept, as ` does) or 100 % of the video (a pixel of the video on a pixel of the screen, made smaller if the screen is, as 2 does); not while maximised or in fullscreen, nor for sound alone
Snap to the screen's centre	on	While the window is moved, its centre is drawn to the screen's centre, across or up and down, when it comes within 8 pixels of it; moved on, it comes away
Add the folder's files	off	One opened file brings the media files of its folder into the playlist
Only for audio	off	Shown while the previous setting is on: only an audio file brings its folder's files, and only the audio ones (an album's tracks); a video opens alone
Channel logos	on	The pictures an IPTV list gives its channels are fetched from their sites for the visible rows of the playlist, only over HTTPS and never from the local network, at most 512 KB each, PNG or JPEG only, and kept for 30 days in the logos folder next to the settings
On-screen messages: show messages	on	The line in the top left corner after a seek, a volume change and the like; off, only errors, files saved and the line saying where the data of an incomplete file ends are shown
On-screen messages: font	default	A font installed in Windows, for the line in the top left corner; the list of fonts has a search field at its top
On-screen messages: size	100 %	50–200 % of the usual size, which follows the height of the picture
On-screen messages: shown for	2 s	How long a message stays on the screen (0.5–10 s); it fades out in its last 0.4 s
On-screen messages: look	yellow letters, thin black outline, shadow	As for the subtitles: the colour of the letters and of the outline, the outline's thickness (0–4), the shadow (0–4), bold letters, and a slightly see-through box of the outline's colour in place of the outline, the thickness then being its margin; Default brings the yellow line back; a sample line under them shows the font, the size and the look

Playback

Setting	Default	Meaning
Go on from where it stopped	on	A file of 5 minutes or more opened again starts where it was left, with a message on the screen; Home goes to the beginning. A file watched to its last 30 seconds, or stopped in its first 10 seconds, starts from the beginning. The last 500 files are remembered; Forget all clears the list
Remember the recent files	on	The start screen lists the last thirty files played, those that do not fit scrolling in the list; when off, none are kept and the list is cleared
Left / Right	10 s	The step of ← and →, on keyframes
Ctrl+Left / Right	60 s	The step of Ctrl+← and Ctrl+→, on keyframes
Marks on the seek bar	on	Cuts in the seek bar where the chapters start; also in the context menu
Stay in the file	on	A file whose download has not finished shows its whole length, but its data ends earlier. Where the data ends, whether reached by playing or by a seek past it, playback stops, paused, with a message on the screen that stays until playback goes on; Play then goes on from where there was data (the place before the seek, or the end of the data, which may have grown meanwhile). When off, the file ends there and the next one in the playlist plays. An end within the last 15 seconds is taken as the end of the file. In a format whose duration may be an estimate (MP3, AAC and the like, unlike MKV and MP4), an early end counts as missing data only where the file shows it: zeros where data is to come, as a download keeps the room for it, or fewer bytes than its header declares; elsewhere it is the end of the file
Media keys	always	Always (also while another window is active, through Windows' media controls), while the player is active, or off: the player takes none and they go on to Windows and the other programs

Tracks

Setting	Default	Meaning
Sound: languages	none	Up to three languages in order: a file opened for the first time plays the first of them it has; none of them, or none chosen, the track the file marks
Subtitles: shown	as the file marks them	As the file marks them (a default or forced track), off, forced only (the signs and the lines in other languages), or in the languages below
Subtitles: languages	none	Up to three, for "In the languages below": the first of them the file has; none of them, only forced subtitles in the sound's language
Load from the folder	the same name	Subtitle files loaded with a video, from its folder and its Subs, Subtitles or Sub folder: the same name (Film.srt), names with the video's in them (Film.rus.srt, Film.Forced.ass), all in the folder, or none
Remember the tracks	on	A file opened again plays the audio track and the subtitles (or no subtitles) chosen in it last time, whatever its length (subtitles from a file of their own by that file, loaded again if needed); kept for files with more than one audio track or with subtitles
Like tracks in new files	on	A file opened for the first time plays the audio track and the subtitles most like those last chosen by hand: the same title first, else the same language, never a track in another language, and among equals forced subtitles or a commentary as the last one was or was not; subtitles turned off by hand stay off, and no subtitles are chosen while Subtitles: shown is off. Meant for series: the voice-over chosen in one episode plays in the next. Nothing alike leaves the usual choice

Video and Updates

Category	Setting	Default	Meaning
Video	Hardware decoding (GPU)	on	Decoding on the graphics card where possible; the decoder in use is shown below
Video	File name at the top	on	A strip with the file's name across the top in fullscreen, shown while the pointer is near the top edge
Video	Panel transparency	12 %	Transparency of the control bar and the file's name over the picture in fullscreen, 0–80 %
Video	Saving a frame: folder	Pictures\MetalMPV	Where Save the frame writes; Choose… picks another folder, Default goes back
Video	Saving a frame: format	PNG	PNG keeps every pixel; a JPG file is several times smaller, at a little loss
Updates	Check at start-up	off	See Update check and privacy; Check now asks at once, and the date of the last check is shown

Keyboard shortcuts

The keys below are the defaults; they can be changed in the settings (Keyboard shortcuts). A seek on keyframes is instant, since nothing has to be decoded before the frame shown; it lands on the keyframe nearest to the target, and the on-screen line reports where. An exact seek decodes from the previous keyframe up to the target frame.

Playback and seeking

Key	Action
Space	Play / pause
← / →, the mouse's back / forward buttons	Back / forward by the short step (10 s), on keyframes; the mouse's buttons with Ctrl or Shift as the arrows
Ctrl+← / Ctrl+→	Back / forward by the long step (60 s), on keyframes
Shift+← / Shift+→	Back / forward by 1 s to the exact frame
, / . (or D / F)	Previous / next frame
Home / End	Start / end of the file
Ctrl+Page Up / Ctrl+Page Down	Previous / next chapter (more than 5 s into a chapter, back to its start; before the first, the file's start; past the last, a message says so)
Page Up / Page Down	Previous / next file of the playlist
C / X / Z	Faster / slower / normal speed (0.25× to 4×, the voice keeps its pitch; also the Speed submenu of the context menu)
Tab	Shows the position, the duration and the chapter playing on the screen, going on while it is shown
Ctrl+G	Go to time: a window for a time in the file
Ctrl+B	Add a bookmark at the position playing (the Bookmarks submenu of the context menu)
[ / ]	A-B repeat: start / end at the position playing
\	A-B repeat off
Ctrl+Shift+S	Save the A-B stretch as a file
R	Repeat: off, the file, the list
Media keys	Play/Pause, Stop, Previous and Next of a keyboard, a headset or a remote, also while another window is active (through Windows' media controls, whose flyout over the volume's shows the title playing); see the Media keys setting

Sound and subtitles

Key	Action
↑ / ↓, mouse wheel	Volume up / down
M	Mute
T	The audio and subtitles window
U, F7	The Video, sound and subtitles panel
A	Next audio track
S, J	Next subtitles; after the last, none
V	Subtitles off, and on again
Ctrl+= / Ctrl+-	Sound later / earlier by 100 ms against the picture
Ctrl+0	Sound back in sync
Shift+. / Shift+,	Subtitles later / earlier by 100 ms (> and <)
Shift+0	Subtitles back in sync
Ctrl+Shift+← / Ctrl+Shift+→	The subtitle line before / after the one on screen shown now (the delay set for it)
E / N / B	Equalizer / normalization / clearer speech on or off
Shift+B	Stereo to 5.1 on or off

Picture and window

Key	Action
Enter, Alt+Enter, F11, double click	Fullscreen
1 / 2 / 3 / 4	Window for the picture at 50 % / 100 % / 150 % / 200 % of the video's size
5	The largest window the screen holds, without black bars
`	Window fitted to the picture, without black bars
6	Fullscreen without black bars (the picture cropped); again, with them
7	Only the picture, without the title row, the control bar and the playlist; again, the interface returns
8	Interface: full, without the title row, compact, only the picture, in turn (also in the context menu)
0	Mini player over the other windows; again, the player's window returns
Ctrl+T	Over the other windows: never, always, while playing (also in the settings and the context menu)
Ctrl+E	Save the frame (into Pictures\MetalMPV unless another folder is chosen)
Q	Reset the picture's settings: colour, zoom, filters, turns (as Reset all on the panel's Video tab)
Ctrl+R	Turn the picture 90° clockwise
Ctrl+A	Aspect ratio in turn: as in the file, 4:3, 16:9, 16:10, 1.85:1, 2.35:1, 2.39:1
Ctrl+D	Deinterlacing: auto, on, off
Ctrl+1 / Ctrl+2	Brightness down / up; Ctrl+3/Ctrl+4 contrast, Ctrl+5/Ctrl+6 gamma, Ctrl+7/Ctrl+8 saturation
Alt+= / Alt+-	Zoom the picture in / out
Alt+arrows	Move the picture
Alt+Backspace	The picture's zoom and position as they were

Files, playlist and program

Key	Action
Ctrl+O	Open files
Ctrl+U	Open an address: a direct link to a video or a stream
L, middle click on the picture	Show or hide the playlist; in fullscreen, over the right side of the picture
Delete	Remove the selected playlist entries
Ctrl+F	Search the playlist
Insert	Add files to the playlist
Ctrl+S	Save the playlist as M3U8
I	The file information window
Ctrl+I	The information's chips over the picture
F5, Ctrl+,	Settings
F1	About
Esc	Closes the file information window, else the tracks window, else the Video, sound and subtitles panel, else the playlist shown in fullscreen, else leaves fullscreen, else leaves the mini player, else brings the interface back after 7, else closes the program

Changing the keys

In the settings, the Keyboard shortcuts category lists the actions in groups, each with its keys:

• A click on a key waits for the key combination (or the mouse's back or forward button, with Ctrl, Alt or Shift if wanted) that takes its place, + adds one more, the cross removes it, and Esc gives up.
• A combination another action had is taken from that action, and the page says so, with Undo beside.
• A search field above the groups leaves the actions whose name or keys contain the text typed.
• The round arrow at the right of an action puts its own keys back (taken from the action that had them, with Undo), and Reset the keys puts them all back. The menus and tooltips show the keys as they are set.
• A few actions without a default key can be given one: Stop, A-B repeat: start, end, off (one key for the three in turn), Load subtitles, Equalizer, Reset the equalizer (flat, off), Reset the subtitles' look, Chapter marks on the seek bar, Time: both, elapsed, remaining, Shuffle, Sort and Clear the playlist, Show the file in its folder, Open the folder of saved frames, Save the cover…, Playlist in a window of its own / in the player, IPTV groups in the playlist, How far files were watched in the playlist, Minimize, Maximize and Close the program.
• The mouse wheel, the double and middle clicks and the media keys stay as described; Ctrl+V and Shift+Insert cannot be chosen, and Ctrl+Insert is taken as Ctrl+C.

Update check and privacy

The update check is optional and off by default. With Check at start-up enabled on the Updates page of the settings, the program asks the GitHub Releases API (api.github.com) for the latest release at most once a day; Check now on the same page asks at once. The request carries nothing but the program version in its User-Agent header, and nothing is downloaded or installed: when a newer release exists, a button with its version appears in the title row and opens the release page in the browser.

Otherwise the program accesses the network only for what is opened: an address or a playlist with addresses is played from its server, and with Channel logos on, the logos named by an IPTV list are fetched from their sites (over HTTPS only, never from the local network; see the settings). The streams of an IPTV list come from whoever runs its servers, which see the address of the computer and what it plays. youtube-dl/yt-dlp is not used.

Building

Requirements: Windows 10 or later, a stable Rust toolchain (MSVC target, 2024 edition), the Visual Studio 2022 Build Tools with the C++ workload and Python 3. For build.py, uv.

uv run build.py          # target\release\metalmpv.exe with libmpv-2.dll next to it
cargo test

How the build works

build.py closes a metalmpv.exe running from the project's target folder, because it would lock the file, fetches libmpv when it is missing (tools/get_libmpv.py) and runs cargo build --release. tools/get_libmpv.py downloads a pinned build of libmpv from shinchiro/mpv-winbuild-cmake and the standalone 7zr.exe of 7-Zip to unpack it, checks both against their SHA-256 and puts them into vendor (not in the repository); build.rs copies the DLL next to the executable. The executable links the C runtime statically (.cargo/config.toml) and loads libmpv at run time, so it needs nothing beyond Windows and libmpv-2.dll.

Setting up the environment and the source layout

The tools can be installed with winget:

winget install Rustlang.Rustup Microsoft.VisualStudio.2022.BuildTools Python.Python.3.12 astral-sh.uv JRSoftware.InnoSetup

The C++ workload of the Build Tools ("Desktop development with C++") is selected in the Visual Studio Installer.

Path	Contents
src/main.rs	Command line, start of the engine, window options
src/app.rs	The window: layout, commands, events
src/mpv/	libmpv's C API and its safe wrapper
src/player.rs, src/video.rs	Playback state and commands; rendering into the window
src/playlist.rs, src/input.rs, src/keymap.rs, src/format.rs	Playlist, commands and keys, texts of times and of the on-screen line
src/ui/	Title row, control bar, playlist, on-screen line, dialogs
tools/	libmpv download, release script, installer script, icon export

Installer and release

The release script builds the executable, the installer and the portable archive. It needs Inno Setup 6.

python tools/make_release.py              # libmpv, tests, release build, installer, archive
python tools/make_release.py --no-tests   # the same without cargo test
python tools/make_release.py --install    # then a silent installation over the installed copy

The release procedure

The script writes the files to dist and takes the version from Cargo.toml. The installer script is tools/setup.iss; metalmpv.exe --export-icon <file.ico> writes the installer icon.

Releases on GitHub are built by the Release workflow (.github/workflows/release.yml). Between releases the version in Cargo.toml carries -dev. A release drops the suffix (after python tools/notices.py if Cargo.lock has changed: a test checks the notices), is committed as Version X.Y.Z, and pushing a matching tag publishes it with the installer and the portable archive; the next version with -dev follows:

git tag v0.1.0
git push origin v0.1.0

The workflow stops if the tag does not match the version in Cargo.toml or the version still carries a suffix such as -dev. Running the workflow manually (Actions → Release → Run workflow) builds the files and attaches them to the run, without making a release.

Built with

• mpv / libmpv: decoding, playback and rendering of every file;
• mpv-winbuild-cmake: the Windows build of libmpv that is shipped;
• egui / eframe: the user interface and the window;
• Lofty: the covers stored in tags;
• image: decoding the covers;
• fontdb: the list of the system's fonts;
• 7-Zip: unpacking libmpv during the build;
• Inno Setup: the installer.

License

MIT, see LICENSE. The included libmpv-2.dll is licensed under the GNU GPL version 3, so the program as distributed with it is subject to the terms of that license; the sources and details are listed in THIRD_PARTY_LICENSES.md. The licences and copyright notices of the Rust libraries and fonts compiled into the program are in licenses/THIRD_PARTY_NOTICES.txt. The program shows all of these texts in its About window (Licenses…), and the installer and the portable archive include them as files.