AVI
AVI video containerUsed for recorded motion video with an accompanying soundtrack.
- Family
- Video
- MIME
- video/x-msvideo
Convert AVI to MP4 online
To convert AVI to MP4, upload the AVI file, start the conversion and download the result: Converter.now writes an MP4 with H.264 video (CRF 23) and AAC audio at 192 kbps, set up for fast web start. The first video and audio tracks are re-encoded; extra audio tracks and embedded subtitles are not copied. Both formats are lossy, so this adds a second round of compression; convert from the best original you have rather than an earlier export.
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AVI to MP4 at a glance
- Converts
- AVI video container → MPEG-4 video
- Output
- An MP4 with H.264 video (CRF 23) and AAC audio at 192 kbps, set up for fast web start
- Compression
- AVI: lossy → MP4: lossy
- Engine
- FFmpeg
- Privacy
- Private download link; files are deleted after 6 hours. No account needed.
How AVI turns into MP4: Timed-stream transcoding
Decoding AVI recovers the picture, sound, and timing streams it carries; writing MP4 means re-expressing that under a different codec and container profile. Duration commonly survives untouched even while compression, channel mapping, cadence, metadata, or auxiliary streams do not. AVI is reconstructed from RIFF indexes and interleaved chunks; codec tags, frame timing, keyframes, and audio alignment determine whether seeking remains stable. MP4 output organizes tracks around web-friendly sample timing and fast-start playback; captions, chapters, rotation, and any auxiliary streams remain separate preservation decisions.
Decoded from an older Microsoft media container commonly paired here with Xvid video and MP3 audio. Encoded to a broadly supported MPEG-4 container written here with H.264 video and AAC audio when those streams exist.
Not quite the pair you need? Browse more ways to convert AVI files or the MP4 converter hub for every route into and out of MP4.
If you want the reasoning behind this AVI to MP4 route, containers vs. codecs explains why a familiar extension can still fail to play.
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MP4
MPEG-4 videoDesigned for widely compatible web and device video.
- Family
- Video
- MIME
- video/mp4
Reading AVI correctly and satisfying what MP4 expects
What can fail when AVI video container is interpreted
AVI has limited support for modern metadata, captions, variable frame rates, and some web players.
What MPEG-4 video cannot safely promise
An audio-only source does not gain pictures, and ancillary streams such as captions may not carry over.
How the MP4 writer handles this route
The MP4 profile that has been verified writes H.264 video at CRF 23 alongside AAC audio at 192 kbit/s, with fast-start metadata for web playback.
How to confirm the converted MP4 actually works
Record the AVI evidence before conversion
Test seeking and audio sync in the target player, not only the opening frame.
Test the MP4 file in its receiving workflow
Test playback, seeking, audio sync, dimensions, and whether the expected video stream actually exists.
The delivery decision for this AVI to MP4 route
Choose MP4 only after the player, editor, or publishing service confirms its container and codecs; keep AVI if extra tracks or source encoding must survive.
What changes between the AVI model and the MP4 deliverable
- The first video and audio tracks are re-encoded; extra audio tracks and embedded subtitles are not copied.
- Both formats are lossy, so this adds a second round of compression; convert from the best original you have rather than an earlier export.
- AVI and MP4 use different metadata conventions, so application-specific fields should be treated as optional until verified.