FLV vs MTS
A detailed comparison of Flash Video and AVCHD Video — file size, quality, compatibility, and which format to choose for your workflow.
Flash Video
Video FilesFLV was the dominant web video format during the Flash era. While Flash is now deprecated, many legacy video files still exist in FLV format and need conversion to modern formats.
About FLV filesAVCHD Video
Video FilesMTS (AVCHD) is a high-definition video format from Sony and Panasonic camcorders.
About MTS filesStrengths Comparison
FLV Strengths
- Low overhead — the container is extremely compact.
- Designed for streaming — progressive download and seeking work well.
- Decoded natively by Flash Player on every OS for 20 years.
MTS Strengths
- Native format for every AVCHD camcorder since 2006.
- H.264 compression — small files for high-def quality.
- Direct compatibility with iMovie, Premiere, Resolve, Final Cut.
- Carries Dolby Digital 5.1 audio on flagship camcorders.
Limitations
FLV Limitations
- Flash Player is dead — no modern browser can play FLV without conversion.
- Legacy codecs (Sorenson, VP6) are poorly supported in modern tooling.
- Hardware video decoders never added FLV support.
- Metadata format is primitive compared to MP4 or MKV.
- Actively harmful to use today — every major security agency has warned against Flash since 2015.
MTS Limitations
- Slow to decode — editors typically transcode for editing.
- Proprietary folder-structure conventions complicate direct import.
- Largely legacy as smartphones replaced dedicated camcorders.
- 192-byte packet format adds overhead vs plain TS.
Technical Specifications
| Specification | FLV | MTS |
|---|---|---|
| MIME type | video/x-flv | video/mp2t |
| Extensions | .flv, .f4v | — |
| Video codecs | Sorenson Spark, VP6, H.264 (F4V) | H.264 (AVCHD Main/High Profile) |
| Audio codecs | MP3, Nellymoser, AAC | AC-3 (Dolby Digital), LPCM |
| Status | Deprecated since December 31, 2020 | — |
| Extension | — | .mts |
| Container | — | BDAV MPEG-2 Transport Stream (192-byte packets) |
Typical File Sizes
FLV
- 10-min YouTube 2008-era video 40-80 MB
- 45-min TV show (FLV H.264) 200-500 MB
MTS
- 1 min HD AVCHD (17 Mbps) ~130 MB
- 1 hour AVCHD Full HD ~8 GB
Ready to convert?
Convert between FLV and MTS online, free, and without installing anything. Encrypted upload, automatic deletion after 60 minutes.
Frequently Asked Questions
FLV (Flash Video) is a video container format that bundles one or more video streams, audio tracks, and optional subtitles into a single file. The container format determines how metadata is organised and which codecs can live inside; the visual quality itself depends on the codec (H.264, H.265, VP9, AV1) rather than the FLV wrapper. It is part of the video files family.
FLV (Flash Video) is a video container formato that bundles one ou more video streams, audio tracks, e optional subtitles em a single file. The container formato determines how metadata is organised e which codecs can live inside; the visual quality itself depende de the codec (H.264, H.265, VP9, AV1) em vez de the FLV wrapper. It is part of the video arquivos family.
VLC, MPV and PotPlayer play nearly every FLV file on desktop. Browser support varies: modern Chromium, Firefox and Safari play common containers via the HTML5 <video> tag, but niche FLV variants may fail. If a device refuses your FLV, convert to MP4 with our FLV to MP4 converter for universal playback.
VLC, MPV e PotPlayer reproduzir nearly every FLV arquivo on desktop. Browser support varies: moderno Chromium, Firefox e Safari reproduzir common containers via the HTML5 <video> tag, mas niche FLV variants may fail. If a device refuses your FLV, converter to MP4 com our FLV to MP4 converter para universal playback.
Upload your FLV to KaijuConverter and pick MP4, MOV, MKV, WebM, or any other target. Our pipeline uses FFmpeg under the hood and stream-copies when codecs are compatible (no quality loss) or transcodes at high-quality defaults otherwise. Conversion runs server-side; both files delete within two hours.
Only when the target requires re-encoding. If the codecs inside FLV match what the target container supports, FFmpeg stream-copies the streams and the output is bit-identical to the source. Transcoding uses transparent quality defaults (CRF 20–23 H.264) and produces output indistinguishable from the original at normal viewing distance.