Audio Merge Review: Add Your Audio Track to a Video Online

Audio Merge is a WebTerra AI tool that puts a ready-made audio track onto a ready-made video. There is no generation involved: you upload a video and an audio file and get back a single file with picture and sound together. In this Audio Merge review we explain why a tool like this belongs in an AI model platform, how to use it online, what it costs, and how to prepare your files for a clean result.

The task sounds trivial, yet it is exactly where many AI content creators get stuck. Plenty of video models produce clips without sound, while music, voiceover and effects come from separate audio models. You end up with two files, and combining them means installing a video editor, learning a timeline and waiting for an export. Audio Merge handles that step right in the dashboard.

Under the hood the tool uses FFmpeg, the well-known open-source toolkit for processing video and audio that powers a large share of media services. The key benefits for you: no loss of video quality and a fixed price — the length of the clip does not affect the cost.

What Audio Merge can do

• Puts your track on your video. Music, voice, sound effects or a finished mix — any audio track you have prepared.
• No generation. The tool does not invent anything or change the content: it simply combines your two files.
• No quality loss. The video stays exactly as you uploaded it.
• Fixed price. One credit per merge, whether the clip lasts a few seconds or longer.
• Online in the browser. No video editor to install and no editing skills required.

The tool is especially handy alongside other WebTerra AI models: generate a video with one model, the sound with another, and merge them in a minute.

Audio Merge specs

How to use Audio Merge in WebTerra AI

1. Sign up for WebTerra AI — you get 60 free credits.
2. Prepare a video (generated in the service or your own footage) and an audio track.
3. Open Audio Merge in the dashboard.
4. Upload the video file and the audio file.
5. Start the merge and wait for the result.
6. Watch the clip with sound and download the finished file.

The whole process takes minutes; most of your time goes into preparing the files themselves — more on that below.

Audio Merge pricing

The price is fixed and the same on every plan:

Clip length does not change the price. The 60 free credits you get on sign-up cover dozens of merges — or, more realistically, a merge plus generating the sound itself, such as a few sound effects and one merge. Credit packs are listed on the pricing page.

Typical use cases

There is no prompt here, so instead of prompt examples, here are the scenarios where the tool saves the most time.

AI video + music

You generated an atmospheric clip in a video model and a music bed in a music model. Merge them and you have a ready clip for Reels or Stories.

AI video + sound effects

A silent clip feels plastic. Generate a few effects — rain, footsteps, city hum — combine them into one track and put it on the video. Even a short clip comes alive.

Video + voiceover

For an explainer, a product presentation or a training video: visuals from one model, narration from a speech synthesis model.

Your own footage + a new track

The tool is not limited to AI content. Take a video shot on your phone and give it a new soundtrack — for example, put music under travel footage.

Several versions of one clip

Pair the same footage with different tracks: English and Spanish voiceovers, upbeat and calm music. At a fixed 1 credit, that is a cheap way to A/B test creatives.

Example: a short clip from idea to file with sound

To show how the tool fits into real work, here is a full cycle for a short clip in WebTerra AI.

1. Video. Generate a clip in a video model — say, an anime scene in PixVerse V6. The shortest 720p clip costs about 25 credits on the Starter plan.
2. Sound. In ElevenLabs SFX, create two or three effects for the scene: wind, footsteps on a rooftop, distant city hum. Each effect is 2 credits.
3. Mix. In any free audio editor, place the effects at the right seconds, balance the levels and export a single track of the right length.
4. Merge. Upload the video and the mix to Audio Merge — one more credit.
5. Publish. Check the result on your phone and post it.

All in, the clip with sound comes to roughly 30–35 credits, and the merge itself is the cheapest link in the chain. If you need music or a voice instead of effects, the pipeline is the same — only the model you use for audio changes.

Tips for preparing your files

Match the length in advance

It works best when the audio track is the same length as the video. If the track is longer, trim it in any audio editor and add a fade-out at the end; if it is shorter, pick a different section or loop it. That keeps the result predictable.

Mix down to one track

The tool lays down one finished audio track. If you have music, voice and effects separately, combine them in an audio editor first: voice louder, music lower, effects at the right moments.

Watch your levels

Listen to the whole track before merging. Sudden jumps in volume, clipping or a recording that is too quiet will be just as noticeable on the video. Normalize the level so the clip sounds even.

Check the sync

If sounds are tied to on-screen events — a hit, a step, a door opening — make sure those sounds sit at the right seconds in the audio file. The tool combines files; it does not align individual events.

Do a final check

Watch the result from start to finish, ideally on headphones and on a phone — the way your audience will see it.

Pre-merge checklist

• The video is final: framing, length and quality are what you want.
• The audio is mixed into a single track: voice, music and effects already blended.
• The track length matches the video, with a smooth fade-out at the end.
• Levels are even, with no clipping or sudden jumps.
• Key sounds land on the seconds where the matching events happen on screen.
• You have the rights to use the music and voice — especially if the clip will run as an ad.

Where to get sound in WebTerra AI

If you do not have a track yet, you can create one right here with the service’s audio models:

• Sound effects — ElevenLabs SFX: clicks, whooshes, vehicles, animals, ambience, magic.
• Voiceover — ElevenLabs Multilingual for a narrator in 29 languages; ElevenLabs Turbo as a budget option; ElevenLabs v3 for the most lifelike delivery.
• Loops and beds — Stable Audio and Stable Audio 2.5 for background musical textures.
• Music — ElevenLabs Music for studio-quality tracks, MiniMax Music 2.6 for songs with vocals, Lyria 3 Pro for instrumentals.

All of them are on the voice and sound page.

Who Audio Merge is for

• Social media managers and creators. Add music or voiceover to Reels and Stories without editing software.
• Marketers. Ad creatives from AI video plus a separate voice or jingle; several versions for testing.
• Online store owners. Product videos with background music for marketplace listings.
• Course creators. Visuals and narration in a single file.
• Editing beginners. Anyone who would rather not install and learn a video editor for one operation.

More video tools are on the video generation page.

Audio Merge vs. other approaches

Some video models generate sound themselves — see our Veo 3.1 review, for example. But often you need your own audio: specific music, a brand jingle or a particular voiceover. That is where merging helps. A typical pairing: video from Hailuo 02 or PixVerse V6 plus effects from ElevenLabs SFX.

Audio Merge limitations

• No generation. The tool does not create sound or change the video — you need both files ready.
• One track. Music, voice and effects must be mixed into a single audio file beforehand.
• Not an editor. There is no timeline, no cuts, no titles and no manual event alignment.
• Preparation is on you. Check length, levels and sync before merging.

FAQ

How much does a merge cost?

1 credit — about one cent — on any plan. Clip length does not change the price.

Does the video lose quality?

No, the tool combines the files without any loss of video quality.

Can I use my own video rather than a generated one?

Yes, any video and any audio track of yours will work.

Does the tool generate music or voice?

No. WebTerra AI has separate audio models for music, voiceover and sound effects. Audio Merge only combines finished files.

What if the audio is longer than the video?

The safest option is to trim the track to length beforehand and add a fade-out, so the result is predictable.

Can I add several tracks at once?

The tool works with one audio track. Mix multiple sound sources into a single file first.

Do I need to install anything?

Not for the merge itself — it runs in the browser. You only need an audio editor if you want to mix several sounds into one track or trim a track to the length of the video.

Is the merge useful if my video model already makes sound?

It can be, when you need something specific rather than whatever the model produced: your brand jingle, licensed music or a voiceover in another language. Generate the footage, prepare the track you need, merge them, and always watch the result through once to confirm it sounds exactly the way you expect before you publish.

Try Audio Merge online

If you have a finished video and finished sound, there is no need to install an editor and wrestle with exports. Upload both files, spend one credit and get your clip with sound in the WebTerra AI dashboard.