AVI to FLV Converter

How to Convert AVI to FLV Online

1. Upload Your AVI File: Drag and drop or click "Add Files" to select AVI files. Old camcorder dumps, DivX/Xvid rips from the early 2000s, recorded TV captures, and Windows Movie Maker exports all work. Batch is supported.
2. Pick a Video Codec: Default is FLV1 (Sorenson H.263) — the classic Flash codec used by every Flash Video player. Choose H.264 for FLV containers that need to play in legacy Flash 9.0.115+ pipelines (Adobe added H.264-in-FLV support in 2007), VP6 (FLASHSV) for screen-recording style content, or H.263 for maximum compatibility with very old Flash 6/7 players. Set the Video Quality Preset (Highest → Lowest), target a percentage of original size, target an exact size in MB, or fine-tune with CRF (H.264: 18 = visually lossless, 23 = default, 28 = small).
3. Set Resolution and Audio Codec (Optional): Pick a Resolution Preset (1080p / 720p / 480p / 360p / 240p), enter custom width × height, or scale by percentage — most legacy FLV pipelines expect 480p or 360p. Switch the Audio Codec to MP3 (default for FLV — universally accepted) or AAC for newer Flash 9.0.115+ environments. Trim using Video Trim with start time + duration in HH:MM:SS.sss format.
4. Convert and Download: Click Convert. Files process in your browser session — no sign-up, no watermark.

Why Convert AVI to FLV?

AVI (Audio Video Interleave) is Microsoft's 1992 container — common for DivX/Xvid rips, old camcorder output, and Windows-era video editing. FLV (Flash Video) is Adobe's 2003 container that powered web video from YouTube's launch through about 2015. Adobe officially discontinued Flash Player on December 31, 2020, so FLV is now an archival/legacy format. Most users converting AVI → FLV are feeding a pipeline that still expects FLV input. Common reasons:

• Legacy e-learning platforms still on Flash — A surprising number of corporate LMS and academic course platforms built between 2008-2015 still expect FLV uploads. Migration to HTML5 is ongoing but slow at large institutions, so you may need to convert a new AVI lecture recording into FLV to fit the existing player.
• Adobe Animate / Adobe Captivate workflows — Adobe Animate (the renamed Flash Professional) still imports FLV natively for use in HTML5 Canvas and AIR projects. Captivate's older project files often embed FLV. Converting an AVI source to FLV lets it slot into existing .fla / .cptx projects.
• Flash game and SWF preservation — Projects archiving Flash games via Ruffle or standalone Flash projector apps need FLV-encoded video for cutscenes and intros. Converting AVI source assets to FLV is the standard preservation workflow.
• Old streaming server pipelines (RTMP / Wowza / Red5) — Some on-premise streaming servers from the late 2000s still ingest FLV. Re-encoding AVI to FLV with H.264 + AAC keeps these systems functional without replacing the whole stack.
• Smaller files than raw AVI — DivX/Xvid AVIs are often 700 MB - 1.5 GB per hour. The same content as FLV with H.264 typically lands at 200-400 MB per hour with similar visual quality, making it easier to host on legacy CMS systems with file-size limits.
• Repackaging without re-encoding when possible — If your AVI is already H.264 + MP3/AAC, converting to FLV mostly just re-muxes the container, which is fast and quality-lossless. The output is essentially the same video in a Flash-compatible wrapper.

If you're not feeding a Flash-era pipeline, convert AVI to MP4 instead — MP4 is the modern web standard.

AVI vs FLV — Format Comparison

Codec Choice for the FLV Output

Frequently Asked Questions

Should I pick FLV1 (Sorenson) or H.264 inside the FLV container?

H.264 if your target environment is Flash Player 9.0.115 (December 2007) or newer — that's almost every Flash-era system. H.264 is roughly 2× more efficient than Sorenson H.263, so files are about half the size at the same visual quality. Use FLV1 / Sorenson H.263 only if you're targeting Flash 6/7 players or a very old SWF runtime that pre-dates H.264-in-FLV support.

Can FLV files even play anywhere in 2026?

Not in any modern browser — Chrome, Firefox, Edge, and Safari all dropped Flash support in early 2021. FLV files still play in VLC, MPC-HC, Adobe Animate, the standalone Flash Projector (preserved by archive.org), and Ruffle (an open-source Flash emulator). Almost everyone using FLV in 2026 is feeding a specific legacy pipeline rather than expecting end-user playback.

What audio codec should I pick for FLV?

MP3 is the safest default — supported in every Flash Player version since FLV existed. AAC is supported from Flash Player 9.0.115+ and gives noticeably better quality at the same bitrate. Avoid Nellymoser (speech-only, low quality) and ADPCM (large files). Match the audio codec to whatever your downstream Flash player expects.

Why is my FLV smaller than the AVI even at the same quality?

AVI containers from the DivX/Xvid era often shipped with uncompressed PCM audio and inefficient video bitrates. FLV with H.264 video + AAC audio at moderate bitrates (1500-2500 kbps video, 128 kbps audio) gives similar visible quality at roughly half the file size. Compression efficiency is real — FLV doesn't degrade the video, it just stores it more efficiently.

Will my AVI's subtitles transfer to the FLV?

No. AVI subtitle tracks (typically SRT or hard-coded XSUB) are dropped — FLV's container has no standard subtitle stream. If you need captions in a Flash pipeline, you'd typically pair the FLV with an external XML cue points file or burn subtitles directly into the video frames before conversion. Most legacy FLV systems handled captions via Flash-side overlays, not embedded streams.

Can I batch convert a folder of old AVI camcorder tapes?

Yes — drop in the whole folder. Each AVI converts in your browser session in parallel and downloads individually or as a single ZIP. Useful for digitized VHS-to-AVI archives that you're feeding into a Flash-era preservation pipeline (museums, university media archives, corporate training reruns).

My AVI uses Xvid / DivX — does that matter?

No. Xvid and DivX are MPEG-4 ASP video codecs — they're decoded transparently and re-encoded into the FLV's chosen codec. Quality is preserved as long as you pick a high-enough quality preset or a low CRF. Old Xvid AVIs at ~1 Mbps re-encode cleanly to H.264-in-FLV at similar bitrate with better perceived quality because H.264 is more efficient.

Should I just convert to MP4 instead?

Almost always, yes. MP4 with H.264 + AAC plays everywhere in 2026 — every browser, every device, every modern player. Use AVI to MP4 unless you have a specific Flash-era system that requires FLV input. The only reason to pick FLV in 2026 is feeding a legacy pipeline that hasn't been migrated yet. For modern web embedding consider AVI to WebM instead.

Can I trim out commercials or dead air while converting?

Yes. Use the trim section to enter a start time and duration. Both accept seconds (12.5) or HH:MM:SS.sss format (00:01:30.500). Useful for trimming TV-capture AVIs down to the program content before feeding the FLV to a streaming server, or cutting old VHS-digitization tape leader/trailer.