Remux vs Encode vs Transcode: A Simple Guide for AMV Editors
If you have spent any time around video editing, you have probably seen words like remux, encode, transcode, codec, container, and bitrate thrown around like everyone is supposed to already know them. They sound technical, but the ideas behind them are simple once someone explains them in plain language. This guide does exactly that. No film-school jargon, just clear explanations so you understand what is actually happening to your video when you import it, edit it, and export your final AMV.
Quick answer Remux means repackaging video without touching the quality (fast, lossless). Encode means turning raw or edited video into a compressed file (this is what your editor does on export). Transcode means converting an already-compressed file into a different format (which loses a little quality each time). Understanding the difference helps you keep your AMVs sharp and avoid wasting time on slow exports or quality loss.
First, the building blocks: container vs codec
Before the three big words make sense, you need two smaller ones: container and codec. Almost all the confusion around video comes from people mixing these two up.
The box-and-contents analogy. Think of a video file as a shipping box. The container is the box itself (the file extension you see: .mp4, .mkv, .mov, .avi). The codec is the actual stuff packed inside the box (the compressed video and audio, like H.264, HEVC, ProRes, AAC). The box tells you how things are organized. The contents are the thing you actually watch.
The container (.mp4) is the box. The codecs (H.264, AAC) are what is packed inside. Change the box without touching the contents and you have a remux.
A container (also called a wrapper) holds everything together: the video stream, one or more audio streams, subtitles, and chapter info. Common containers:
- .mp4: the universal box. Plays everywhere, uploads everywhere. This is what we use for every clip on animeclips.online.
- .mkv (Matroska): a flexible box that can hold multiple audio tracks, subtitles, and almost any codec. Common for anime releases (raws).
- .mov: Apple's box, the standard home for ProRes.
- .avi: an old Windows box, still used in the AMV world for lossless editing workflows (more on that later).
A codec (short for "coder-decoder") is the method used to squeeze the video down to a reasonable file size and then play it back. H.264 is a codec. HEVC (H.265) is a codec. ProRes is a codec. The codec decides how much the video is compressed and how much computer power it takes to play.
Key point that clears up most confusion: the same codec can live in different containers. An H.264 video can be inside a .mp4, a .mkv, or a .mov. The box and the contents are separate choices. This is exactly why remuxing is possible.
What is remuxing?
Remuxing means moving the video and audio from one container into another without re-compressing anything. You are taking the contents out of one box and putting them into a different box. The actual video data is untouched, so there is zero quality loss and it happens almost instantly.
Moving day. Remuxing is like moving your stuff from a cardboard box into a plastic bin. The stuff inside (your clothes, books) is exactly the same. You just changed the box. Nothing got damaged, and it took two minutes.
A classic example: you download an anime episode as an .mkv, but your editor does not like .mkv files. You remux it to .mp4. The H.264 video inside stays bit-for-bit identical, you just changed the wrapper. We cover this exact process in our guide on converting MKV to MP4 without re-encoding, which is really a remux, not a conversion.
- Speed: very fast (seconds to a minute, even for a full episode)
- Quality: perfect, zero loss, the video data is copied as-is
- When to use it: when you need a different container but the codec inside is already fine
What is encoding?
Encoding means taking video and compressing it into a codec. This is the step that actually does the heavy lifting of shrinking video down. When your editing software renders out your finished AMV, it is encoding: it takes your timeline (which the program holds as uncompressed frames while you work) and writes it out as a compressed H.264 .mp4, for example.
Vacuum-sealing. Encoding is like vacuum-sealing a bag of clothes for storage. You squeeze all the air out so it takes way less space. Done well, the clothes come out fine. Done badly (too aggressive), they come out wrinkled. The "how aggressive" setting is your bitrate, which we get to soon.
Every time you export from After Effects, Premiere, Vegas, DaVinci Resolve, or CapCut, you are encoding. The settings you pick (codec, bitrate, resolution, framerate) decide how good the final file looks and how big it is. This is the single most important step for AMV quality, because a beautiful edit can be ruined by a bad export. Our AMV scripting and encoding guide walks through the exact settings.
- Speed: slow (this is the part that makes your computer work hard and take time)
- Quality: depends entirely on your settings, can be near-perfect or visibly bad
- When it happens: every export, every render
What is transcoding?
Transcoding means converting an already-compressed file into a different codec or settings. It is decode-then-encode in one step: the software unpacks the existing compressed video, then re-compresses it into the new format you asked for.
The photocopy of a photocopy. Transcoding is like photocopying a page that is already a photocopy. It works, and at first you barely notice, but each generation loses a little sharpness. Do it enough times and the text gets fuzzy. With video, every transcode of a lossy codec throws away a little more quality, forever. You cannot get it back.
Example: you have an H.264 .mp4 and you convert it to HEVC (H.265) to save space. That is a transcode. The file gets smaller, but because both are lossy codecs, you lose a tiny bit of quality in the process. This is the key danger for editors: avoid unnecessary transcodes. Every extra round-trip through a lossy codec compounds the damage.
- Speed: slow (it is a full decode plus a full encode)
- Quality: always loses a little, because you are re-compressing already-compressed video
- When to avoid it: any time you do not absolutely need the new format. Edit from the highest-quality source you have, and only encode once at the very end.
The three side by side
| Operation | What it does | Quality loss | Speed | Everyday example |
|---|---|---|---|---|
| Remux | Changes the container only | None (lossless) | Very fast | .mkv to .mp4, same video inside |
| Encode | Compresses video into a codec | Depends on settings | Slow | Exporting your finished AMV |
| Transcode | Re-compresses into a different codec | Always some loss | Slow | H.264 to HEVC to save space |
Remux lossless
Encode compresses
Transcode re-compresses
Remux copies the data untouched. Encode compresses once. Transcode decodes then re-compresses, losing a little quality every time.
The one-line memory trick: remux changes the box, encode fills the box, transcode swaps the contents for a smaller copy.
Bitrate, the quality dial
Bitrate is the amount of data used per second of video, usually measured in megabits per second (Mbps). It is the single biggest factor in how good your encoded video looks. Higher bitrate = more detail kept = bigger file. Lower bitrate = more detail thrown away = smaller file, more blocky artifacts.
Water through a pipe. Bitrate is how wide the pipe is. A wide pipe lets all the detail flow through cleanly. A narrow pipe forces the video to drop detail to fit, which is where blocky, smeary "compression artifacts" come from, especially in fast motion and dark scenes (both extremely common in anime).
There are two main ways encoders handle bitrate:
- CBR (Constant Bitrate): the same data rate the whole way through. Predictable file size, but wastes data on simple scenes and starves complex ones. Mostly used for live streaming.
- VBR (Variable Bitrate): the encoder spends more data on busy scenes and less on calm ones. Smarter, better quality per file size. This is what you want for AMV exports.
For AMV work there is also CRF (Constant Rate Factor), used by the x264 and x265 encoders. Instead of picking a bitrate, you pick a quality level (a number, lower means higher quality) and the encoder figures out the bitrate needed to hit it. CRF 16 to 18 is a common sweet spot for high-quality anime exports. It keeps quality consistent across the whole video, which is exactly what you want.
Intra-frame vs long-GOP (why ProRes feels nicer to edit)
This is the concept that explains why some codecs feel smooth to scrub through in your editor and others feel laggy. It comes down to how the codec stores frames.
Long-GOP codecs (like H.264 and HEVC, the codecs used for delivery and downloads) only store a full picture every so often. The frames in between are saved as "differences" from the nearby full frames. This is brilliant for small file sizes, but bad for editing, because to show you any single frame, the computer has to rebuild it from the surrounding frames. That is the lag you feel when scrubbing a heavily compressed file.
Full photos vs sticky notes. A long-GOP codec stores one full photo, then a stack of sticky notes saying "same as the photo but this part moved." Tiny to store, but to see frame 47 the computer has to read the photo plus 46 sticky notes first. An intra-frame codec stores every frame as its own full photo. Huge to store, but any frame is instantly ready.
Long-GOP (H.264, HEVC) — small files, laggy to scrub
Intra-frame (ProRes, DNxHR, MagicYUV) — big files, instant to scrub
Long-GOP stores one full frame then a run of difference frames. To show frame 4, the computer rebuilds it from the full frame plus everything between. Intra-frame stores every frame whole, so any frame is instantly ready, which is why ProRes feels smooth on the timeline.
Intra-frame codecs (also called all-intra or I-frame-only, like ProRes, DNxHD, and most lossless codecs) store every single frame as a complete picture. Files are much bigger, but every frame is instantly available, so scrubbing, trimming, and playback in your editor are buttery smooth. This is the main reason editors transcode laggy source footage to ProRes before editing: not for quality, but for editing smoothness.
So the benefit of ProRes (and intra-frame codecs in general) is responsiveness on the timeline and clean frame-accurate cuts, at the cost of large file sizes. You would never upload ProRes to YouTube (the file would be enormous); you use it as a working format, then encode to H.264 for the final upload.
Codec cheat sheet for editors
| Codec | Type | Best for | Notes |
|---|---|---|---|
| H.264 (AVC) | Lossy, long-GOP | Final delivery, uploads | The universal standard. Plays everywhere, great quality per size. Use this for your final AMV export. |
| HEVC (H.265) | Lossy, long-GOP | Smaller files at same quality | About 40% smaller than H.264 for the same quality, but slower to encode and not supported everywhere. |
| ProRes | Intra-frame, light compression | Editing intermediate | Industry standard working format. Smooth to edit. Now exports natively on Windows in Premiere and DaVinci Resolve. |
| DNxHD / DNxHR | Intra-frame, light compression | Editing intermediate | Avid's equivalent to ProRes. Works great as a cross-platform editing format. |
| MagicYUV | Lossless, intra-frame | Modern AMV lossless workflow | Ultra-fast GPU and SSE optimized lossless codec. More than double the speed of UTVideo with instant seeking. Has a free version. The current go-to for high-resolution lossless editing. |
| UTVideo | Lossless, intra-frame | AMV lossless workflow | Free, fast lossless codec long popular in the AMV scene. Common in VirtualDub and AviSynth pipelines. |
| Lagarith / HuffYUV | Lossless, intra-frame | AMV lossless workflow | Older free lossless codecs. UTVideo and MagicYUV are preferred now for faster decoding. |
| AV1 | Lossy, long-GOP | Future-proof streaming | Newer royalty-free codec, very efficient, but slow to encode and still gaining editor support. |
The codecs you actually download and install are the lossless intermediates: MagicYUV (free version), UTVideo, Lagarith, and Avid DNxHR/DNxHD. On Windows these install as VFW codecs, so editors like VirtualDub, After Effects, and Vegas can see them as export options. H.264, HEVC, ProRes, and AV1 are not separate downloads, they are already built into modern editors and your operating system.
What about K-Lite Codec Pack? K-Lite is a popular Windows codec pack, but it is built for media playback (helping players open various file types), not for editing or exporting. For an AMV workflow you do not need it. Install the specific lossless codec you want to edit with (MagicYUV, UTVideo, or Lagarith from the links above) and your editor will pick it up directly. Installing K-Lite on top of an editing setup can sometimes even cause codec conflicts, so most editors skip it.
Intermediate and lossless codecs (UTVideo, Lagarith, ProRes)
An intermediate codec is a working format you use during editing, not for final delivery. The idea: you do not want to edit directly from a heavily compressed download (laggy and fragile), and you do not want to re-compress your work multiple times (quality loss). So you convert once to a high-quality intermediate, do all your editing, and encode to H.264 only at the very end.
There are two flavors:
- Visually lossless intermediates like ProRes and DNxHR. Lightly compressed, so files are large but manageable, and the quality loss is invisible to the eye. Great balance for most editors.
- Truly lossless codecs like MagicYUV, UTVideo, Lagarith, and HuffYUV. Zero quality loss, every pixel preserved exactly. Files are huge (a few minutes can be tens of gigabytes), but this is the gold standard in the AMV community for keeping anime line-art razor sharp through the whole edit. MagicYUV is the modern favorite (very fast, instant seeking, free version available), with UTVideo a close second. These usually live inside an .avi container on Windows.
Why bother? Editing from a lossless or visually-lossless intermediate is like working on the original painting instead of a printout. When you finally export, you are compressing once, from the cleanest possible source, so the final AMV looks as good as it possibly can.
Quick reality check: you do not always need a lossless workflow. If your clips are already high quality (like the pre-cut clips on animeclips.online, which keep the original framerate and source quality), you can often edit directly and just export once cleanly. The lossless intermediate route matters most when you are doing heavy effects work, lots of layered compositing, or when you want absolute maximum quality for a contest entry.
What about the audio?
Everything so far has been about video, but the audio is its own separate stream sitting in the same container (remember the box analogy: the box holds a video stream AND one or more audio streams). That separation is powerful, because it means the audio can be left untouched, swapped, or re-encoded completely independently of the video. When you remux an .mkv to .mp4, the audio usually rides along bit-for-bit just like the video does.
Audio codecs you will run into
Just like video has H.264, HEVC, and so on, audio has its own set of codecs. The ones that show up in anime and editing:
| Audio codec | Type | Where you see it |
|---|---|---|
| AAC | Lossy | The universal standard. What you export your final AMV in, and what most streaming/web anime uses. Plays everywhere. |
| FLAC | Lossless | Common in high-quality Blu-ray anime rips. Zero quality loss, bigger files. Great as a source, overkill for a final upload. |
| Opus | Lossy | Newer, very efficient. Increasingly common in modern anime releases. Better quality than AAC at low bitrates, but less universally supported. |
| AC3 (Dolby Digital) | Lossy | Older codec, often the English dub track and the home of 5.1 surround in dual-audio releases. |
For an AMV the rule is simple: edit from whatever the source gives you, and export the final mix as AAC. It is the safe, universal choice that every platform accepts.
Channels: stereo vs surround
Audio also has channels, which is just how many separate speakers the sound is split across:
- Mono: one channel. Rare for anime, sometimes used for old shows.
- Stereo (2.0): two channels (left and right). This is what you want for almost every AMV, since YouTube, TikTok, Instagram, and most viewers play back in stereo.
- 5.1 surround: six channels for home-theater setups. Some anime ships with a 5.1 dub track. For an AMV you almost always want to ignore or downmix this to stereo, because surround does not translate to social media playback and can cause missing-audio issues if a platform only reads the first two channels.
If your source has a 5.1 track and your edit comes out with weird or missing audio, downmixing to stereo fixes it. A handy shortcut: AMVtool (a free, AMV-focused GUI tool) can losslessly remux a file AND downmix its audio to stereo at the same time. So if you grab an .mkv with a 6-channel (5.1) track, you remux and downmix it to clean stereo in one step instead of dealing with it later in your editor. The video stays untouched and you get the stereo track you actually want.
Dual audio (the anime-specific one)
A lot of anime releases are dual audio, meaning the file carries both the original Japanese track and the English dub as two separate audio streams inside the same container (usually .mkv). This is where the container-holds-multiple-streams idea really pays off.
Two soundtracks, one box. A dual-audio .mkv is like a box with one video stream and two audio streams sitting side by side. Nothing is mixed together. Your editor sees them as separate selectable tracks, so you pick the one you want (or keep both) without ever touching the video.
Practical notes for editors:
- When you remux a dual-audio file, both audio tracks are preserved by default. Nothing is lost or re-encoded.
- Most editors let you choose which audio track to use when you import, or show both so you can mute one. If your editor only shows one, it is usually defaulting to the first track (often Japanese).
- Some lossless intermediate workflows (the .avi + UTVideo/MagicYUV route) only carry one audio track, so if you convert to an intermediate you may need to pick your language first or handle the audio separately.
- If a file ships with a 6-channel (5.1) track and you just want clean stereo, AMVtool can downmix to stereo during the remux, so you fix the audio and change the container in a single step.
- The on-site player at animeclips.online plays a single language for in-browser preview (a player limitation), but downloaded clips with dual audio keep both tracks, so you choose in your editor.
What settings should I actually export my AMV in?
Here is the practical, no-overthinking answer for a final AMV you are uploading to YouTube, Instagram, or TikTok:
- Container: .mp4
- Codec: H.264 (universal) or HEVC if your platform and audience support it and you want smaller files
- Bitrate: VBR, 2-pass, around 15 to 25 Mbps for 1080p. Or CRF 16 to 18 if your encoder offers it.
- Resolution: match your source (usually 1920x1080)
- Framerate: match your source exactly, never change it. If your anime is 23.976fps, export at 23.976fps. We explain why in our guide on anime frame rates and why you should never edit AMVs in 60fps.
- Audio: AAC, 320 kbps
The golden rule that ties this whole article together: edit from the highest-quality source you can get, avoid extra transcodes along the way, and encode to H.264 once at the very end. Do that and your AMV will look as sharp on screen as it did on your timeline.
FAQ
Is remuxing the same as converting?
No. Remuxing only changes the container (the file wrapper) and keeps the compressed video untouched, so it is lossless and fast. Converting usually means transcoding, which re-compresses the video into a new codec and loses a little quality. Many tools labeled "converters" actually remux when the codec stays the same, which is why MKV-to-MP4 can be instant and lossless.
Does converting MKV to MP4 lose quality?
Not if it is done as a remux. If the video codec inside the MKV (usually H.264) is simply copied into the MP4 container, there is zero quality loss. It only loses quality if the tool re-encodes the video, which you can usually avoid by choosing "copy" or "remux" instead of "convert" in your tool.
Why does my downloaded anime lag when I scrub through it in my editor?
Because it is encoded in a long-GOP codec like H.264, which only stores full frames occasionally and rebuilds the rest from differences. Your editor has to reconstruct each frame on the fly, which causes lag. Converting to an intra-frame intermediate like ProRes or DNxHR (where every frame is a full picture) makes scrubbing smooth. This is editing convenience, not a quality upgrade.
What is the difference between a codec and a container?
A container is the file format you see, like .mp4, .mkv, or .mov. It is the box that holds everything. A codec is the actual compression method used on the video inside, like H.264, HEVC, or ProRes. The same codec can live in different containers, which is exactly why remuxing (changing the box without touching the contents) is possible.
Can I export ProRes on Windows?
Yes, as of recent versions. Adobe Premiere Pro, After Effects, and Media Encoder can read and write ProRes natively on Windows, and DaVinci Resolve added native ProRes encoding on Windows in version 19.1.4 (both free and Studio). For years this was Mac-only, so older guides may say otherwise.
What bitrate should I export my AMV at?
For 1080p, around 15 to 25 Mbps using 2-pass VBR is a safe, high-quality range for upload. If your encoder supports CRF (the x264 encoder does), CRF 16 to 18 gives consistent high quality without you having to guess a bitrate. Higher than that mostly just makes the file bigger without a visible improvement after the platform re-compresses it.
Should I use H.264 or HEVC for my AMV?
Use H.264 for maximum compatibility, it plays and uploads everywhere with no issues. Use HEVC (H.265) if you want roughly 40% smaller files at the same quality and you know your platform and viewers support it. For most AMV editors uploading to YouTube, Instagram, or TikTok, H.264 is the safe default since the platform re-encodes your upload anyway.
What is an intermediate codec and do I need one?
An intermediate codec (like ProRes, DNxHR, or lossless UTVideo) is a high-quality working format you edit from instead of editing directly from a compressed download. You need one mainly for heavy effects work, lots of compositing, or maximum-quality contest entries. For simple edits from already-high-quality clips, you can often skip it and just export once cleanly.
Why does transcoding lose quality but remuxing does not?
Remuxing copies the already-compressed video data exactly as it is into a new container, so nothing is recalculated and nothing is lost. Transcoding decodes the compressed video back to pixels and then re-compresses it with a lossy codec, and that re-compression always throws away a little detail. Every transcode of a lossy file compounds the loss, which is why you should minimize them.
How do I handle dual audio (Japanese and English) in an anime file?
Dual-audio releases hold both the Japanese track and the English dub as two separate audio streams in the same container, usually an .mkv. When you remux the file both tracks are kept untouched. In your editor you pick which track to use on import, or keep both and mute one. Converting to a single-track intermediate like .avi with UTVideo or MagicYUV may only carry one language, so choose your audio before that step.
What audio codec and channels should I export my AMV in?
Export audio as AAC at around 320 kbps in stereo (2.0). AAC is universally supported, and stereo is what YouTube, TikTok, Instagram, and most viewers play back. If your source has a 5.1 surround track, downmix it to stereo, because surround does not translate to social platforms and can cause missing-audio problems if a platform only reads the first two channels. If you grab a file with a 6-channel track, amvtool can downmix it to stereo during the remux in one step.