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What is Video Converter?

Video Converter converts video files in batches. You add files or whole folders, choose how the video is to be encoded, and press Convert; ffmpeg, the well-known free converter, does the work, and you never type a command.

What sets it apart is that the choices are kept separate. The preset decides how the video is encoded; the size, the audio, the colour LUT, the effects and the trim are each chosen on their own. One preset therefore serves every combination: you do not need a new preset for "the same, but smaller", "the same, but with a watermark" or "the same, but with the sound kept".

The rest of this page goes through what you can do: convert a batch, let the app look after ffmpeg, choose a preset, limit the size, decide what happens to the sound, add effects, apply a colour LUT and keep only part of each file.

Convert a batch

Add files with Add files, or a whole folder with Add folder — every video file inside it is found, sub-folders included. You can also drag files and folders onto the window. Each file is a row in the list, with its name, its path and, once it is queued, a status. Clear the list empties the list except for what is running right now.

Press Convert and every file that is not already queued or running is converted, each with its own settings (see below). That includes files that were already converted, or failed, or were skipped: pressing it again converts them again, with the settings each row now holds. While a file is converting its row shows the percentage; hover over the status of a finished row to read where the result went, or, for a failure, the reason ffmpeg gave. The line at the bottom says how many files are ready, how far a run is, and how it ended — for example "3 converted · 1 skipped · 2 failed".

Every file carries its own settings — its preset, size, audio, colour LUT, effects, cut, destination and what to do if the file exists. A file you add takes the choices the options panel shows at that moment, and only the newly added files are selected afterwards. The panel is a brush: it never shows the choices of a row, and selecting rows never changes it. To give other files different choices, select them, set the panel, and press Apply: it writes all of the panel's choices onto the selected rows that are not queued or running. It is off while nothing is selected, and while the panel's cut cannot be read. Select with a click, Ctrl (or Cmd) and click to add or remove a row, Shift and click for a range from the last click, or Ctrl+A for every row; a click on the empty part of the list clears the selection. The line at the bottom also says how many rows are selected.

Each row shows one small chip per choice — the preset, size, audio, colour LUT, effects, destination and if-exists policy. A choice that leaves everything as it is (original size, original audio, no LUT, no effects) is left out, so a plain row shows only its preset.

Apply — applies the panel's choices to the selected files.
Stop — appears while files are converting and cancels all of them. A cancelled file leaves no half-written output behind.
Cancel and Remove from the list — the cross at the end of a row cancels that file while it is running and removes it from the list once it is not.
Preset — how the video is encoded; see Presets. The button beside it opens the preset editor.
Files converted at the same time — how many files are converted at the same time, from one up to the number of physical cores in your computer, with a ceiling of four. The default is one, because a video encoder already uses every core by itself; more files at once only make them compete.
Open the output folder — opens the folder of the file that finished last, or the output folder you chose.

Where the converted files go

The destination drop-down of the options panel (Where the converted files are written) chooses where the converted files are written. Its first choice, Source Folder, writes each converted file beside its source and is built in; the other choices are destinations you made on the Destinations tab of the settings, which the button beside the drop-down (Edit the destinations) opens. There, as with presets, you add (New), copy (Duplicate) and delete (Delete) destinations and drag them into order; each has a name and a folder.

Folder — where the files are written. Leave it empty to write beside each file. The button beside it (Browse) picks a folder, and you can also type or paste a path.

A path that is complete (D:\Converted) is one place for everything. When you add a folder, its own name and its sub-folders are kept inside it, so two folders with files of the same name never land on top of each other.

A path that is relative — convert, .\convert or ..\convert — is counted from the folder of each file instead. .\convert is a convert folder beside the file; ..\convert is one beside the folder the file is in. This lets one setting serve files that sit in many different folders. The folder is created when it does not exist, and no structure is added to it: the folders the files already sit in are the structure.

The converted file is named after its source with the extension of the preset's container. It never replaces its source: if the name and the place would be the same, (converted) is added to the name.

What to do when the output file already exists — what to do when the output file already exists. Skip it (the default) leaves it alone and reports the file as skipped; Overwrite it writes over it; Keep both writes a second file, name (2), name (3) and so on.

ffmpeg, looked after

ffmpeg is the program that does the conversion. Video Converter looks for it beside itself, then in its own folder, then on your computer's PATH, so an ffmpeg you already have is used as it is.

When none is found, the window says so and offers a button.

Download ffmpeg — fetches the current release build from gyan.dev, about 30 MB, and checks it against the checksum published with it before it is unpacked into the app's own folder. A download that does not match is thrown away. You are told how far it has got, and why, if it fails.

Why it is downloaded, not included

The ffmpeg builds that contain the best H.264 and H.265 encoders (x264 and x265) are licensed under the GPL. If Video Converter came with one inside it, the whole application would have to be GPL too. So the app does not carry ffmpeg: you fetch it, once, and it stays a separate program of its own.

If you use your own ffmpeg, check that it has what your presets need. A preset that names an encoder your ffmpeg does not have fails with ffmpeg's own message ("Unknown encoder"); nothing is checked beforehand. The one the app downloads has x264 and x265.

Presets: how the video is encoded

A preset says how the picture is written: the container, the video codec, how good it is to be, and how long the encoder may take over it. It says nothing about the picture's size, the sound, the colour or the effects — those are chosen next to it, see the sections that follow.

The preset editor is a page of the settings, opened by the button beside the preset drop-down. On the left is the list of presets: New, Duplicate and Delete work on it, and dragging a preset changes its place — the same order is used in the window's drop-down. On the right are the options of the selected preset; every change is saved at once, and there is no save button. A fresh installation comes with presets for the common cases: H.264 and H.265, the same two on a graphics card, AV1, ProRes, uncompressed RGB and a straight copy.

Container and codec

The container is the file's outer form (.mkv, .mp4, .webm, .mov, .avi); the codec is how the picture inside is compressed. They are separate choices, and not every pair is possible: a container only offers the codecs it can hold. Choose the container first, and the list of codecs follows it. If you change the container to one that cannot hold the codec you had, the preset moves to one that it can.

As a rule: MKV holds almost everything and keeps subtitles; MP4 is the one every device plays; WebM is for the web and takes only VP9 or AV1; MOV is the editing and Apple world; AVI is old, and in practice here only for H.264 or uncompressed pictures.

Name — the name the preset has in the lists.
Container — MKV, MP4, WebM, MOV or AVI.
Video — the codec. H.264 and H.265 are the usual ones: widely played, small. AV1 and VP9 compress still further, but take longer. ProRes is an editing format: large files that are easy to edit. Uncompressed RGB writes the picture with no compression at all, which is lossless but enormous — about 9 GB a minute for full-HD video. Keep the original (no re-encoding) is described under copy and re-encode.

Quality or bitrate

An encoder is steered either by a quality number or by a target bitrate. With a quality number (CRF) you say how good the picture must be and the file gets the size it needs; lower is better and larger. The scale is 0 to 51 for H.264 and H.265, and 0 to 63 for AV1 and VP9. For H.264 around 18 to 23 is the usual range, and 20 is the default. With a target bitrate you say how large the file may be — so many kilobits for each second of video — and the quality is what that allows. It is done in one pass, so the result is less exact than a two-pass encode, which Video Converter does not have.

Use the quality number when the picture matters; use a bitrate when a file must fit a limit.

Encoding mode — Quality (CRF) or Target bitrate. Offered for H.264, H.265, AV1 and VP9.
Quality (CRF) — the quality number. For the encoders of a graphics card it is the constant quantizer (named Quality (QP) for AMD).
Bitrate — the target, in kilobits a second, when the mode is a bitrate.
Encoding speed — how long the encoder may take. Ultrafast (largest files) (only for H.264 and H.265), Fast, Balanced and Slow (smaller files): a slower setting makes a smaller file for the same quality. The AMD encoders have no speed setting.
Bit depth — 8 or 10 bits for each colour. Ten bits avoid visible bands in smooth gradients; it is offered for H.265 and AV1, and only plays on devices that support it.
Tune — tells H.264 or H.265 what the pictures are like: film, animation, grain, a still image, fast decoding or zero latency. Leave it at none unless one of these is exactly your material; H.265 has no film or still-image tune.
Extra x265 parameters — extra settings for the H.265 encoder, as key=value pairs joined by colons, passed to x265 as they are. For experts only.
ProRes profile — for ProRes only: 422 Proxy, 422 LT, 422, 422 HQ or 4444, from the lightest to the heaviest. ProRes has no quality number and no speed.

Copy, or encode again

Keep the original (no re-encoding) does not touch the picture: it is lifted out of the old container and put in the new one. That is very fast and loses nothing, so it is the right choice to change the container alone — an MKV into an MP4, say. Because the picture is not decoded, nothing that changes the picture can apply: the size, the colour LUT and all the effects but one are ignored. The exception is Remove the metadata, which only concerns the file's tags. The sound, and the trim, work as usual.

Any other codec encodes the picture again, which takes time and, with a lossy codec, costs a little quality.

Encoders on a graphics card

Most graphics cards can encode video themselves, much faster than the processor. Video Converter offers them for H.264 and H.265, one set for each maker: AMD, NVIDIA and Intel (Quick Sync). They need the card and its driver; on a computer without them the file fails with ffmpeg's own message. Not every Intel chip can do H.265.

The price of the speed is the file size: at the same quality a card's encoder makes a larger file than x264 or x265. Use them when time matters more than size. Their quality number is a different scale from CRF, and they have no extra settings but the speed (for NVIDIA and Intel).

Size

The size limits how large the picture of the converted file may be. It is chosen in the window, apart from the preset, and edited under Sizes in the settings, with the same list tools as the presets. A fresh installation has the usual heights, from 4K down to 360p.

The picture is shrunk to fit inside the box you give, keeping its shape, and it is never enlarged: a 480p video converted with a 1080p size stays 480p. Leave a side empty — No limit — for no limit on that side. The remaining width or height is made even, which video encoders require.

Original size — the first choice in the window; leaves the size alone.
Maximum width and Maximum height — the box, in pixels.

A size does not apply to a copied picture.

Audio

What happens to the sound is chosen in the window, apart from the preset, from a list of audio entries that you edit under Audio in the settings. The list in the window offers only the entries that the chosen preset's container can hold: MKV takes AAC, Opus, AC-3, PCM or no sound; MP4 takes AAC and AC-3; MOV takes AAC, PCM and AC-3; WebM takes Opus; AVI takes AC-3, PCM and AAC. If you change to a preset that cannot hold the entry you had, the window shows Original audio.

Original audio

Original audio is not an entry of the settings but a rule, worked out for each file. It keeps the sound exactly as it is — not even decoded — when the container can hold that kind of sound. When it cannot, the sound is converted to what the container normally takes: AAC at 192 kbit/s, Opus at 128 for WebM, AC-3 for AVI. A ProRes picture always gets uncompressed PCM sound, which is what editing programs expect. A file with no sound is left without any.

This is the right choice most of the time. Choose a real entry when you want the sound changed.

An audio entry has these controls:

Audio — AAC, Opus, AC-3, PCM (uncompressed) or No audio.
Audio bitrate — for AAC, Opus and AC-3, in kilobits a second.
Channels — Keep the source, Mono or Stereo; a surround sound is mixed down to what you choose.
Level change — louder or quieter, in decibels, from −30 to 30.
Bring to a standard loudness (-16 LUFS) — brings the sound to one standard loudness whatever its source level, so files from different places play at the same volume.

The channels, the level and the loudness are only asked of a sound that is converted; they work even when the picture is only copied. A fresh installation has entries for AAC at three bitrates, AAC stereo, Opus, AC-3 stereo, PCM and no sound.

Effects

An effects entry is a named list of things to do to the picture: turn it, cut a border off it, put a watermark or a line of text over it, and more. It is chosen in the window, apart from the preset; the entries are edited under Effects in the settings. No effects is the first choice in the window and does nothing. A fresh installation has one entry for each way of turning or flipping the picture.

In the editor, each effect is a card with its settings and a button (Remove this effect) that removes it. The Add an effect menu offers the kinds the entry does not have yet: an entry holds each kind at most once.

The order the effects run in

The order is fixed, and you cannot get it wrong. First come the colour LUT and the effects that must see the picture as it is: deinterlace, crop, frame rate, turn or flip, the blurred background, and burned-in subtitles. Then the size is applied. After it come the effects that work on the finished picture: stereoscopic, playing backwards, the watermark and the text.

The reason is practical. A size limit then applies to the picture as it is delivered, and a margin is counted in the delivered picture's own pixels. A reversed video holds smaller pictures in memory. And a countdown in the text is not played backwards.

Only Remove the metadata works on a copied picture; every other effect is ignored by it. A watermark whose picture file is missing makes that file fail with a clear message, before any work is done.

Turn or flip — Turn: a quarter turn clockwise or counter-clockwise, either of them with a vertical flip, a half turn, or a flip from left to right or top to bottom. For a video shot with the phone on its side.
Crop — Cut from the left, Cut from the right, Cut from the top and Cut from the bottom, in pixels. What remains is made even in both directions. Use it to take off black bars.
Frame rate — Frames per second: 15, 23.976, 24, 25, 29.97, 30, 50, 59.94 or 60. Frames are dropped or repeated to reach it.
Deinterlace — for interlaced video, such as old television recordings and DV tapes, where each picture is made of two half-pictures: each pair becomes one whole picture.
Fit in 16:9 on a blurred background — a vertical video is set in the middle of a 16:9 picture, on an enlarged, blurred copy of itself, instead of between black bars. Picture height is the height of that picture, Blur strength how strongly the background is blurred.
Burn in the subtitles — the first subtitle stream of the file is drawn into the picture, so every player shows it; the converted file then has no subtitle track of its own. Only text subtitles can be burned in; picture-based ones from DVDs and Blu-rays cannot.
Watermark — lays a picture, usually a PNG with transparent parts, over the video. Picture file is the file (a Browse button picks it), Corner where it sits, Margin its distance from the edges in pixels, Width its width in pixels (empty keeps its own), and Opacity how much of the video shows through, in percent.
Text — a line of text over the video. In it, {name} is the file's name, {elapsed} the time so far and {remaining} the time left, both as minutes:seconds, counted for the part that is kept after a trim. Corner and Margin place it, Letter height (percent of the picture) sets the height of the letters, and Dark box behind the text puts a dark box behind it so it can be read on any picture.
Remove the metadata — leaves out the file's tags (title, date, camera and so on) and its chapters. It works on a copied picture too.
Stereoscopic, side by side and Play backwards — see the questions at the end.

Colour LUTs

A LUT is a table, in a .cube file, that changes the colours of a picture — to give a log recording its proper colours, or a look to a clip. It is chosen in the window, apart from the preset, and the list is edited under Colour LUTs in the settings. It starts empty, since the file is yours.

The table is applied to the picture before it is resized, so the colour is worked out on the picture as it was shot. It is not applied to a picture that is only copied. A LUT file that cannot be found makes that file fail, and the editor warns you.

No LUT — the first choice in the window; no LUT.
LUT file (.cube) — the path of the .cube file; Browse picks it.

Trim

The two fields Start and End under the options keep only part of each file. Type a time as seconds (90), minutes and seconds (1:30) or hours, minutes and seconds (1:02:03); a field left empty cuts nothing on that side. The same times apply to every file of the run.

The cut is not saved. It is forgotten when you close the app, so one left over from yesterday can never quietly shorten the files you convert tomorrow. If the end is not after the start, Convert is switched off and the line at the bottom tells you why.

When the picture is encoded again, the cut is exact. When it is only copied, a cut can only start at a keyframe — a picture the video can be started from — so it begins at the one just before your start time. The progress and the countdown of a text effect follow the part that is kept.

Other settings

The settings page, opened with Open settings, holds the lists described above and a few general settings. Help opens this help.

Language — the language of the app.
Theme — Light or Dark.
Show news from yaiol — whether Video Converter may show news from yaiol when it starts. It is one switch for every yaiol app on the computer; when it is off, nothing is requested at all.

When a newer version of Video Converter is out, a small news dialog opens on launch with a card that says New version available and the version, lists what is new since the one you run and offers Download. It only tells you: nothing is installed by itself, and a failed check is silent. Don't show again on a card keeps it from coming back; for the new-version card, until an even newer version ships. The new-version card does not depend on the news switch above.

Questions

A file fails with "Unknown encoder". Why?

The preset names an encoder that your ffmpeg does not have. This happens with an ffmpeg that was built without x264 or x265, or with a preset for a graphics card that your computer does not have. Download the ffmpeg the app offers, which has the two software encoders, or choose another preset.

What do "Play backwards" and "Stereoscopic" do?

Play backwards plays the video and its sound backwards. ffmpeg has to hold the whole clip in memory to do it, so use it on short clips only. The sound is always converted, even when the original audio could have been kept, because a copy cannot be reversed.

Stereoscopic, side by side is for a video whose frames alternate between the left eye and the right: it becomes one picture with both eyes side by side. It is of use only for such material.

Is there two-pass encoding?

Not yet. A target bitrate is done in a single pass, which is less exact than two. For a file of a given size, the best choice at present is a quality number, then checking the size.