FFmpeg - Encode MPEG-4 Part 2
FFmpeg provides two primary ways to encode MPEG‑4 Part 2 video: the external libxvid library and FFmpeg’s native mpeg4 encoder. Both generate broadly compatible MPEG‑4 Part 2 output suitable for AVI‑based and legacy workflows. This article explains the differences, when to use each option, how to control FourCC behaviour, and practical examples.
Context
MPEG‑4 Part 2 (sometimes simply “MPEG‑4 Visual”) is an older but still widely supported video compression standard. It remains relevant for:
- Legacy systems and appliances
- AVI‑based delivery pipelines
- Devices that pre‑date widespread H.264 adoption
- Archival scenarios where compatibility is more important than efficiency
FFmpeg offers two encoders:
- libxvid — external Xvid library, quality‑focused
- mpeg4 — FFmpeg’s native MPEG‑4 Part 2 encoder
Encoding Options
Using libxvid (Xvid Encoder)
ffmpeg -i input.avi -c:v libxvid output.avi
Using the Native FFmpeg mpeg4 Encoder
ffmpeg -i input.avi -c:v mpeg4 -vtag xvid output.avi
FourCC
Use -vtag to override the default FMP4 FourCC. Example:
-vtag xvid
Quality Notes
libxvid generally produces higher quality at low bitrates (~1000 kbit/s for 720p). The native encoder is faster and dependency‑free.
Practical Examples
High‑Quality Xvid Encoding
ffmpeg -i input.mp4 -c:v libxvid -qscale:v 3 -c:a libmp3lame -qscale:a 3 output.avi
Native MPEG‑4 with Xvid FourCC
ffmpeg -i input.mp4 -c:v mpeg4 -vtag xvid -b:v 1500k -c:a mp2 output.avi
