I Converted 100 Videos to MP3 — Here's What I Learned

Last week, I decided to run an experiment. I gathered 100 video files from my collection — everything from phone recordings to downloaded lectures to music videos — and converted them all to MP3 at different quality settings. The goal was to answer a simple question: what settings actually matter?

Turns out, some of what I believed about audio conversion was wrong. Here's what I found.

The Setup

I tested videos in all the common formats: MP4, MOV, AVI, MKV, and WebM. File sizes ranged from a few megabytes to over 2 gigabytes. Some had studio-quality audio, others were phone recordings with background noise.

For each video, I converted to MP3 at three bitrates: 128 kbps, 192 kbps, and 320 kbps. Then I did something tedious but necessary: I actually listened to them.

Finding #1: 192 kbps is the Sweet Spot (For Most People)

I went in assuming 320 kbps would be noticeably better. After all, higher numbers mean higher quality, right?

Here's the thing: in about 85% of my tests, I couldn't reliably tell the difference between 192 kbps and 320 kbps in blind listening tests. Even with decent headphones. Even when I was specifically trying to hear differences.

The 192 kbps files were about 40% smaller than the 320 kbps files with virtually no perceptible quality loss. For music from YouTube videos, podcast recordings, and casual listening, 192 kbps is genuinely excellent.

Where 320 kbps did make a difference: complex orchestral music, tracks with a lot of high-frequency detail (cymbals, hi-hats), and songs I know intimately enough to notice subtle differences.

Finding #2: Source Quality Matters More Than Bitrate

This one seems obvious in retrospect, but it's worth stating: converting a phone recording to 320 kbps doesn't magically make it sound better. You can't add quality that wasn't there to begin with.

I had some videos with mediocre source audio that I converted at 320 kbps, and some videos with excellent source audio converted at 128 kbps. The 128 kbps from a good source sounded noticeably better.

Takeaway: If your source is already compressed or low-quality, don't waste file size on 320 kbps. You're just storing garbage more precisely.

Finding #3: File Size Reduction is Dramatic

This surprised me more than it should have. Here's a real example from my tests:

Original Video	1.2 GB (45 min lecture)
MP3 at 128 kbps	41 MB
MP3 at 192 kbps	62 MB
MP3 at 320 kbps	103 MB

Even at the highest quality, the MP3 was about 12x smaller than the video. At 128 kbps, it was nearly 30x smaller. For content where you don't need the video — podcasts, lectures, music — this is a massive space savings.

Finding #4: Conversion Speed Varies Wildly

Browser-based converters (like ours) use your computer's processing power, which means speed depends on your device. On a modern laptop, most of my test files converted in under 30 seconds. On an older tablet, some took a few minutes.

The interesting finding: the video resolution barely affected conversion time. What mattered was the video's length and your device's CPU. A 4K video and a 720p video of the same length took almost identical time to convert.

Finding #5: Format Doesn't Really Matter

I expected some video formats to have better audio than others. Not really. The container format (MP4 vs MKV vs whatever) is just a wrapper. What matters is the audio codec inside.

Most videos use AAC audio, regardless of the container. The converter handles this transparently — you don't need to know or care what codec your video uses.

Finding #6: The "Perfect" Workflow

After 100 conversions, here's the process I settled on:

1. Music I care about: 320 kbps (worth the extra space)
2. Podcasts and lectures: 128 kbps (spoken word doesn't need high bitrate)
3. Everything else: 192 kbps (the sweet spot)

For phone recordings and anything already low-quality, I go with 128 kbps. There's no point in preserving imperfections at high bitrate.

The Unexpected Takeaway

The biggest thing I learned wasn't technical. It was this: I had hundreds of videos on my devices that I'd never watch again, but whose audio I'd happily listen to.

Conference talks, interviews, tutorials, music performances — all sitting there as unwatched video files taking up gigabytes of space. Converting them to MP3 was like finding a hidden audio library I already owned.

If you're sitting on videos you'll never watch again but might listen to, that's probably the biggest win from conversion: not just smaller files, but content that's actually usable.

What I'd Do Differently

Honestly? I overthought this. For most conversions, just pick 192 kbps and move on. You'll get excellent quality with reasonable file sizes. The edge cases where higher or lower makes sense are rare enough that you can just use your judgment.

Audio conversion doesn't need to be complicated. Pick a quality, click convert, done.