WebM is an open, royalty-free container format designed for web video. It holds VP8, VP9, or AV1 video with Vorbis or Opus audio. All major browsers (Chrome, Firefox, Edge, Safari 14.1+) support WebM playback.

Which WebM codec should I choose?

VP8 is the fastest to encode and has the broadest compatibility. VP9 offers roughly 50% better compression than VP8 at the same quality. AV1 gives the smallest files but encodes 5–20× slower than VP9 — best for archival or when encode time is not a concern.

What does the CRF value control?

CRF (Constant Rate Factor) sets the quality/size trade-off. For VP9, 0 is lossless and 63 is worst; 31–33 is a good default. For VP8, 4–63 range applies; 10 is high quality. Lower numbers produce better quality and larger files.

Does FFmpeg support MPEG-1 and MPEG-2 input?

Yes. FFmpeg reads MPEG-1 (.mpg), MPEG-2 (.mpeg, .mpg, .vob), and MPEG-4 natively. No extra codec packs are needed on any platform.

How long does MPEG to WebM conversion take?

VP8 encodes in roughly 1–3 minutes per gigabyte on a modern CPU. VP9 is 2–4× slower than VP8. AV1 (libaom-av1) can take 10–30× longer than VP9, though the SVT-AV1 encoder (libsvtav1) is much faster for AV1.

How do I install FFmpeg?

Windows: download a build from ffmpeg.org/download.html and add the bin/ folder to your PATH. macOS: run "brew install ffmpeg". Linux (Debian/Ubuntu): run "sudo apt install ffmpeg". Linux (Fedora): run "sudo dnf install ffmpeg".

MPEG to WebM Converter

Name: MPEG to WebM Converter
Availability: InStock
Author: Nham Vu

Build an FFmpeg command to convert any MPEG/MPG file to WebM with VP8, VP9, or AV1, then copy and run it locally.

Choose a WebM Codec

All three codecs produce WebM output. Pick based on your speed and compression needs.

Install FFmpeg

Windows: Download from ffmpeg.org/download.html, extract, and add the bin/ folder to your PATH.
macOS: Run brew install ffmpeg in Terminal.
Linux: Run sudo apt install ffmpeg (Debian/Ubuntu) or sudo dnf install ffmpeg (Fedora).

Run the VP9 conversion command

Open a terminal in the folder containing your MPEG file and run one of these commands:

Good quality (CRF 31, recommended)

ffmpeg -i input.mpeg -c:v libvpx-vp9 -crf 31 -b:v 0 -c:a libopus output.webm

High quality (CRF 20)

ffmpeg -i input.mpeg -c:v libvpx-vp9 -crf 20 -b:v 0 -c:a libopus output.webm

Batch convert all .mpg files

for f in *.mpg; do ffmpeg -i "$f" -c:v libvpx-vp9 -crf 31 -b:v 0 -c:a libopus "${f%.mpg}.webm"; done macOS / Linux / Git Bash on Windows

Verify the output

Open output.webm in Chrome, Firefox, or VLC. VP9/WebM plays natively in all modern browsers without a plugin.

VP9 CRF Reference (0 = lossless, 63 = worst)

Near-lossless
Very large

High quality
Large

Default
Balanced

Smaller file
Visible loss

VP9 constrained quality mode requires -b:v 0 alongside -crf.

Install FFmpeg (same as VP9)

See the VP9 tab for platform-specific install instructions. VP8 is part of the same libvpx library bundled with FFmpeg.

Run the VP8 conversion command

Good quality (qmin 4, qmax 20)

ffmpeg -i input.mpeg -c:v libvpx -qmin 4 -qmax 20 -b:v 0 -c:a libvorbis output.webm

Target bitrate (2 Mbps video)

ffmpeg -i input.mpeg -c:v libvpx -b:v 2M -c:a libvorbis output.webm

Verify the output

VP8 has the broadest WebM support, including older Chrome and Firefox versions. Open output.webm in any modern browser to confirm playback.

VP8 vs VP9 at a glance

VP8

Fastest encode speed
Widest browser support
Larger files than VP9

VP9

~50% better compression
Supported in all modern browsers
2–4× slower to encode

FFmpeg Command Builder

Fill in the fields to generate a ready-to-run FFmpeg command for MPEG to WebM conversion.

Input filename

Output filename

Video codec

Quality (CRF)

Audio codec

Generated command

ffmpeg -i video.mpeg -c:v libvpx-vp9 -crf 31 -b:v 0 -c:a libopus video.webm

WebM Codec Comparison

Property	VP8	VP9	AV1
FFmpeg encoder	libvpx	libvpx-vp9	libsvtav1 / libaom-av1
Compression vs H.264	Similar	~30–50% smaller	~50–60% smaller
Encode speed	Fast	Moderate (2–4× slower than VP8)	Slow (libaom) / Fast (SVT)
Browser support	Chrome 6+, Firefox 4+, Edge	Chrome 29+, Firefox 28+, Edge 18+, Safari 14.1+	Chrome 70+, Firefox 67+, Safari 17+
Recommended audio	Vorbis	Opus	Opus
Best use case	Legacy browser support	Modern web video delivery	Archival, streaming with SVT-AV1

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Summary