Step 1: Provide your AVI files using the button above or by toss and let go.
Step 2: Click the 'Convert' button to start the conversion.
Step 3: Fetch your converted FLV files.
AVI to FLV Conversion FAQ
How do I convert AVI to FLV without re-encoding the video stream?
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When the AVI and FLV containers can both carry the same codec (H.264, H.265, VP9, AV1), the converter falls back to a remux: the elementary streams are copied byte-for-byte into the FLV container and only the wrapper changes. A remux of a 1 GB AVI into FLV typically finishes in 5-15 seconds with zero quality loss. AVI files predate modern codecs: expect MPEG-4 Part 2 (DivX/Xvid), Motion JPEG or raw uncompressed frames rather than H.264. FLV typically holds Sorenson Spark or H.264 video with MP3 or AAC audio, wrapped in a stream format designed for RTMP delivery.
My AVI footage shows comb lines on movement — will that carry into the FLV?
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It will unless you deinterlace, and AVI content very often is interlaced because the format comes from the broadcast and DVD era. Interlaced frames store two half-height fields captured a fiftieth of a second apart; on a progressive-scan phone or monitor that reads as horizontal combing on anything that moves. Turn on the deinterlace option and the encoder weaves the fields into whole progressive frames before writing the FLV. AVI is Microsoft’s Audio Video Interleave, introduced in 1992 on top of the RIFF chunk format — one of the oldest containers still in circulation.
My AVI recordings are split into numbered parts — does FLV have the same limit?
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No, and that is one of the better reasons to move. The AVI container has a practical single-file ceiling that long or high-bitrate recordings run straight into, which is exactly why old captures arrive as part1, part2, part3. FLV has no equivalent limit, so the pieces can be rejoined into one continuous file. AVI has no native support for modern codecs, variable frame rate, soft subtitles or files over 4 GB without hacks, and its per-chunk overhead bloats the file.
My AVI has several audio tracks — do they all survive into the FLV?
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Not dependably. AVI stores multiple audio streams as first-class tracks, but FLV playback support past the first track is inconsistent, so most players will only ever expose one. Choose the track you actually want before converting; the others are better extracted to their own files than left in a container that hides them. AVI is trivially simple, which is exactly why ancient camcorders, capture cards, DVD ripping tools and Windows-era software all still emit it. No current browser, phone or TV can play FLV — anything still in this container has to be moved out of it to remain watchable.
Is there any point converting between two legacy formats like AVI and FLV?
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Only if a specific piece of equipment demands the target. Both formats come from the same pre-H.264 era, so neither conversion buys efficiency, quality or future-proofing — it buys compatibility with one particular device. If the goal is to keep the footage usable long-term, convert to a current container instead of sideways.
Will multi-track audio survive AVI to FLV conversion?
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Yes — every audio track in the AVI (director commentary, alternate languages, descriptive audio) is preserved in the FLV when the target container supports multi-stream audio. MKV and MOV handle unlimited audio tracks; MP4 supports many but some hardware players only see track 1; WebM is capped at one Opus / Vorbis track. FLV is the Flash Video container that carried essentially all web video from roughly 2003 until Flash was switched off at the end of 2020.
Are subtitle tracks preserved when converting AVI to FLV?
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Soft subtitles (selectable tracks) survive when FLV can carry them: MKV holds SRT, ASS, SSA, PGS, VobSub natively; MP4 only holds mov_text (a stripped-down format). Converting an MKV with ASS styled subs to MP4 will typically downgrade them to mov_text or burn them in. Hardsubs (burned into the video) carry over regardless.
Does AVI to FLV keep chapter markers / DVD-style navigation?
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Chapter metadata transfers between AVI and FLV whenever both containers support a chapter atom (MKV, MP4, MOV). WebM stores chapters in a Matroska-compatible block, so MKV <-> WebM chapters round-trip cleanly. AVI has no chapter spec at all, so an AVI source arrives with no chapters to carry across and an AVI target cannot store the ones it was handed; add markers manually afterwards if you need them.
What about MKV attachments (fonts, cover art) when going AVI to FLV?
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MKV is the only mainstream container that stores arbitrary attached files (TTF fonts for ASS subs, JPG cover art, fan-translated PDF inserts). Going from AVI to FLV drops these attachments when FLV is not MKV — the elementary streams convert, but the attached payload stays in the source. Keep AVI as a backup if you depend on attached fonts.
Which codec does the FLV output use by default?
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The default codec is chosen to match the FLV container conservatively: MKV defaults to H.265 (HEVC) for better compression; MP4 defaults to H.264 for the widest device support; WebM defaults to VP9; AVI uses MPEG-4 ASP (DivX/Xvid lineage). Override via the advanced codec dropdown — AV1 is available for MKV / WebM where you want maximum compression and can wait through the encode. FLV’s low per-packet overhead made it excellent at streaming over the unreliable connections of its era, and huge archives of it still exist.
How does HDR (HDR10, Dolby Vision) survive AVI to FLV?
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HDR static metadata (HDR10 mastering display values, max content light level) carries through to FLV when both containers and the chosen codec support it (HEVC, AV1 in MKV / MP4). Dolby Vision is more fragile — DV profile 5 / 7 / 8.1 in AVI commonly survives only into MKV with HEVC; converting to an FLV container that does not carry the DV layer flattens to HDR10.
Will the AVI to FLV converter keep variable framerate (VFR)?
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MKV and WebM record real per-frame timestamps and handle VFR natively, so AVI VFR survives into an FLV of those formats with no resampling. MP4 nominally stores timestamps too but some players assume CFR; the converter exposes a "force CFR" toggle that resamples VFR AVI to 24 / 30 / 60 fps FLV for problematic targets.
