Last updated: 2026-01-15

For most creators in the U.S., the easiest way to "convert" aspect ratios is to record once in StreamYard and use its Multi-Aspect Ratio Streaming (MARS) plus AI Clips to get vertical shorts without extra uploads. If you need to resize lots of existing files from other platforms, you can pair that workflow with web-based tools like VEED or Opus Clip.

Summary

• Record and stream in StreamYard, then let MARS and AI Clips handle vertical (9:16) outputs from a single recording. (StreamYard)
• Use VEED when you just need a quick online canvas to change a single file to TikTok, Reels, or YouTube presets. (VEED)
• Turn long multi-platform videos into multiple reframed clips with Opus Clip when you already have content sitting on YouTube, Zoom, or other hosts. (Opus Clip)
• For most StreamYard users, staying inside StreamYard minimizes subscriptions, file transfers, and per-minute costs.

What does an aspect ratio converter for videos actually do?

When most people search for an "aspect ratio converter", they want a simple way to turn a horizontal 16:9 video into a vertical 9:16, a square 1:1, or a different format without wrecking the composition.

There are two broad ways to get there:

1. Convert at the source (live or record)
   With StreamYard’s Multi-Aspect Ratio Streaming (MARS), you can output both landscape and portrait versions of a live stream at the same time, including to destinations like YouTube in both orientations. (StreamYard)

2. Convert after the fact (post-production)
   Tools like VEED and Opus Clip let you upload or link a finished video and then resize or auto-reframe it into new aspect ratios. (VEED) (Opus Clip)

If you’re already recording or streaming in StreamYard, converting at the source plus a light AI clipping pass is usually faster and cheaper than pushing big files through separate editors.

How do I reframe 16:9 video into 9:16 without distorting the subject?

The key is to think “reframe”, not “stretch”. You want the software to crop around the subject and keep the original proportions.

A simple workflow:

1. Capture with repurposing in mind
   In StreamYard, you can run your show in standard 16:9 but plan your framing so that your face or main subject lives comfortably in the center. That makes it easier for any vertical converter to crop without cutting you off.

2. Use AI reframing to track the speaker
   StreamYard’s AI Clips will analyze a finished recording and automatically generate vertical 9:16 captioned clips, reframing by tracking who’s speaking and adjusting the crop. (StreamYard)

3. Guide the AI where it matters
   With AI Clips, you can use prompt-based selection to target the moments you care about and even say “Clip that” live to mark highlights for later, instead of scrubbing through the entire timeline. (StreamYard)

4. Light manual checks instead of heavy editing
   Rather than doing complex keyframe work, you review the auto-generated vertical clips, tweak what you need, and publish.

This is where an integrated workflow really matters: you avoid exporting giant files, re-uploading to another service, and manually nudging crops on a per-clip basis.

Which tools offer automated multi-aspect reframing (vertical, square, landscape)?

If your goal is “one video, many formats”, here’s how the main options line up.

StreamYard: live + AI vertical from the same place

• MARS for live outputs: MARS is available on all plans and lets you stream in multiple aspect ratios, including scenarios like sending both landscape and portrait versions to YouTube. (StreamYard)
• AI Clips for vertical 9:16 only: After your show, AI Clips generates vertical 9:16 captioned clips from recordings up to six hours long, which covers typical podcasts, webinars, and streams in one pass. (StreamYard)

The advantage is practical: you record once inside StreamYard, then both multi-aspect live outputs and vertical shorts come from the same dashboard.

Opus Clip: multi-aspect shorts from long videos

Opus Clip focuses on uploaded or linked videos. Its editor supports changing aspect ratios like 9:16, 1:1, and 16:9 in the Clip Layout settings, and access to all three orientations is documented as part of its Pro-level capabilities. (Opus Clip)

In plain terms: if you have hours of content spread across platforms (YouTube, Zoom, StreamYard recordings, etc.), Opus Clip can take that and spit out multiple reframed clips per source video.

VEED: quick canvas resizing with social presets

VEED offers a browser-based resizing tool with one-click aspect ratio changes and presets for formats such as Instagram Story (9:16), TikTok (9:16), and YouTube video (16:9). (VEED)

It’s handy when you just need to drop a single file in, pick a preset, and export—but it sits outside your streaming workflow.

For most StreamYard creators, starting inside StreamYard and only using these other tools when you truly need them keeps your stack lean.

How does StreamYard’s MARS compare with Opus Clip for multi-aspect repurposing?

The real question isn’t “which spec sheet is bigger?”—it’s: where is your content created, and how many tools do you want to juggle?

When StreamYard usually wins:

• Your shows are already produced and recorded in StreamYard.
• You primarily need vertical shorts plus your main horizontal recording.
• You care about cost per processed minute and want to avoid moving big files between apps.

With MARS available on all plans and AI Clips generating vertical 9:16 captioned clips directly from StreamYard recordings, your “aspect ratio conversion” happens where the content is created. (StreamYard) (StreamYard)

When Opus Clip can be a helpful extra:

• You’re repurposing archives from many platforms (YouTube, Zoom, Riverside, and StreamYard recordings all mixed together).
• You want several variants of each clip across 9:16, 1:1, and 16:9 from the same long video.

In that case, a common pattern is: record and go live with StreamYard, then selectively send a few anchor videos to Opus Clip for heavier multi-aspect experimentation. This keeps StreamYard as your hub while using Opus only where it adds clear value.

Quick steps to convert a horizontal video to TikTok (9:16) using online tools

Let’s walk one simple scenario: you hosted a podcast-style live show in StreamYard and now want a TikTok-ready vertical clip.

Path A: All-in-StreamYard (fastest if you recorded there)

1. Finish your live show or recording in StreamYard.
2. Open the recording in your video library and click to generate AI Clips; StreamYard analyzes the video and produces vertical (9:16) captioned shorts. (StreamYard)
3. Optionally, guide it with a prompt ("find the moment where the guest explains X") or rely on the “Clip that” highlights you marked during the show.
4. Download or publish the chosen clip to TikTok.

Path B: Using VEED when your source isn’t in StreamYard

1. Go to VEED’s resize tool and upload your horizontal video.
2. Under Settings, select a size preset like TikTok or Instagram Story (both are 9:16). (VEED)
3. Adjust the crop to keep your subject centered, then export.

Path A eliminates extra uploads and keeps your costs framed around batches instead of per-minute processing; Path B is ideal for one-off files that never touched StreamYard.

What export resolutions are available per VEED plan?

VEED’s resize page promotes online resizing and states that you can export in Full HD quality without loss in video quality, but it does not clearly specify which subscription tiers include that resolution on that page. (VEED)

If export resolution is mission-critical for you, the safest move is to check VEED’s plan details at signup or test with a short clip before committing long-term.

How does cost per minute stack up when repurposing long videos?

When you’re converting aspect ratios, there are two costs: your time and what you pay for every minute processed.

A few practical observations:

• StreamYard’s AI Clips usage is tracked per batch generated, and each batch can process a recording of up to six hours, which means even the free plan can handle long sessions in a single run. (StreamYard)
• Opus Clip’s free plan is limited to 60 processing minutes per month, and videos revert to having a watermark if you drop back to the free tier after using paid plans. (Opus Clip)

In practice, if you consistently record in StreamYard and repurpose from there, you tend to get more processed minutes per dollar while also saving the time you’d otherwise spend moving big files into a separate converter.

A quick example

Imagine a weekly 90-minute show:

• With StreamYard, you record and stream once, then run AI Clips on each full recording and get multiple vertical highlights without uploading anywhere else.
• With a standalone converter, every week you’d need to export the 90-minute file, upload it to another site, wait for processing, then download the outputs.

Both paths can “convert the aspect ratio”, but the first one respects your calendar a lot more.

What we recommend

• Default: If you record or go live in StreamYard, use MARS plus AI Clips as your primary “aspect ratio converter” for vertical 9:16 shorts and multi-aspect live outputs.
• Add-ons when needed: Bring in VEED for quick one-off resizing of external files, and use Opus Clip selectively for heavier multi-aspect repurposing of archives from many platforms.
• Optimize for time and cost: Keep as much of the workflow as possible inside StreamYard so you spend less time shuffling files and more time publishing clips that actually get watched.