The Legacy Format Graveyard
The history of digital video is littered with abandoned formats. Three stand out for their once-dominant positions:
- AVI (Audio Video Interleave) — Microsoft, 1992. The first mainstream PC video format.
- WMV (Windows Media Video) — Microsoft, 1999. Microsoft's proprietary streaming format.
- FLV (Flash Video) — Macromedia/Adobe, 2002. The format that powered YouTube's first five years.
All three represent abandoned technology ecosystems. AVI lost to more efficient containers, WMV lost to cross-platform standards, and FLV died with Flash Player. Today, MP4 with H.264 has replaced all three as the universal video format.
| Format | Creator | Year | Peak Era | Status |
|---|---|---|---|---|
| AVI | Microsoft | 1992 | 2000–2010 (DivX era) | Obsolete |
| WMV | Microsoft | 1999 | 2003–2008 | Obsolete |
| FLV | Macromedia/Adobe | 2002 | 2005–2015 | Dead (Flash EOL Dec 2020) |
Why AVI Is Obsolete
AVI (Audio Video Interleave) was Microsoft's first video container, introduced with Video for Windows in 1992. It dominated desktop video through the DivX/Xvid era (2000-2010), when nearly every downloaded video and DVD rip was an AVI file.
AVI is obsolete for several critical reasons:
- Enormous file sizes: AVI's container does not support B-frames, preventing the most effective compression technique in modern video codecs. Xvid/DivX AVI files are typically 40-60% larger than H.264 MP4 at equivalent quality.
- No streaming support: AVI has no progressive download capability. The entire file must download before playback can begin. This makes AVI unusable for web embedding.
- No modern browser plays AVI natively: Chrome, Firefox, Safari, and Edge all refuse AVI files. Zero web browser support.
- Declining codec support: Windows 11 has less Xvid/DivX support than Windows 7. Each OS update removes more legacy codecs.
Common sources of AVI files today: old camcorder recordings (DV/MiniDV), DVD rips from the 2000s, legacy surveillance camera systems, and old screen recording software like early Fraps.
Why WMV Died
WMV (Windows Media Video) was Microsoft's attempt to dominate online video streaming in the early 2000s. It used Microsoft's proprietary VC-1 codec inside an ASF (Advanced Systems Format) container, requiring Windows Media Player or the WMV ActiveX plugin for playback.
WMV failed for fundamental reasons:
- Windows-only: Mac and Linux users could not play WMV files without installing third-party software. In an increasingly multi-platform world, this was fatal.
- No mobile support: iOS never supported WMV. Android support was limited and inconsistent.
- DRM lock-in: WMV was heavily used for DRM-protected content (Windows Media DRM). This DRM system was eventually abandoned, leaving many purchased videos unplayable.
- No web browser support: WMV playback in browsers required the Windows Media Player plugin, which was only available for Internet Explorer. When Chrome and Firefox removed plugin support, WMV became completely unplayable in browsers.
- VC-1 codec obsolescence: Microsoft's VC-1 codec (used in WMV) was competitive with H.264 in 2006 but never gained industry adoption. H.264 won the codec war decisively.
Common sources of WMV files today: old Windows Movie Maker exports, purchased videos with Windows Media DRM (now unplayable), corporate training videos from the 2000s, and early webcam recordings.
Why FLV Is Gone
FLV (Flash Video) was the format that made online video possible in the 2000s. YouTube, Vimeo, Dailymotion, and virtually every video-sharing site used FLV inside Flash Player embeds. At its peak, Flash Player was installed on 99% of desktop computers.
FLV died because Flash Player died:
- Flash Player end of life: Adobe officially killed Flash Player on December 31, 2020. All major browsers removed Flash support. Without Flash Player, FLV files cannot play in any browser.
- Steve Jobs' 2010 letter: Apple's refusal to support Flash on iPhone (2007) and Steve Jobs' "Thoughts on Flash" letter (2010) were the beginning of the end. Mobile web without Flash proved that HTML5 video was the future.
- Security vulnerabilities: Flash Player was a constant source of zero-day exploits. Its removal improved web security dramatically.
- HTML5
<video>replacement: HTML5's native<video>element (with MP4/H.264) replaced everything Flash Video did, without requiring a plugin.
Common sources of FLV files today: old web video downloads, legacy content management systems, archived web pages, and old yt-dlp/youtube-dl downloads from the pre-MP4 era.
What You Gain by Converting to MP4
Converting any legacy format (AVI, WMV, or FLV) to MP4 with H.264 produces immediate benefits:
50-80% file size reduction
H.264 is dramatically more efficient than legacy codecs. Re-encoding an Xvid AVI, a VC-1 WMV, or a Sorenson/VP6 FLV to H.264 MP4 typically produces files that are 50-80% smaller at equivalent visual quality. The savings come from H.264's advanced motion compensation, B-frame prediction, and CABAC entropy coding.
Universal compatibility
H.264 MP4 plays on every device manufactured in the last 15 years. Every phone, tablet, computer, smart TV, gaming console, and web browser supports H.264 MP4 natively. No codec packs, no plugins, no third-party software needed.
Streaming support
MP4 with the faststart flag enables instant progressive playback. Web browsers can start playing the video before the entire file downloads. This is impossible with AVI, WMV, or FLV (without Flash Player).
Future-proofing
H.264 is an ISO/IEC standard with hardware decoder support in every CPU and GPU. It will remain playable for decades. Legacy codec support (Xvid, VC-1, Sorenson) is actively being removed from modern operating systems.
Quality Preservation Tips
When converting legacy video to MP4, quality settings matter:
- CRF 20 for irreplaceable content: For home videos, family recordings, and content that cannot be re-obtained, use CRF 20 (or lower). This preserves maximum quality at a modest increase in file size compared to CRF 23.
- CRF 23 for general content: Our default setting. Produces quality indistinguishable from the source for most content, with excellent file size reduction. VMAF scores of 93-96.
- Do not exceed source quality: Legacy AVI/WMV/FLV files are already compressed with lossy codecs. Using a very low CRF (e.g., CRF 15) wastes space without improving quality — you cannot recover detail that the original codec already discarded.
Our pipeline: ffmpeg -i input -c:v libx264 -crf 23 -preset medium -c:a aac -b:a 192k -movflags +faststart output.mp4. For legacy content, CRF 20 with the slow preset maximizes quality at the cost of longer encoding time.
Handling Interlaced Content
Old camcorder recordings and TV captures are often interlaced — each frame consists of two interleaved half-images (fields) that were designed for CRT televisions. On modern progressive displays (LCD, OLED), interlaced video shows characteristic horizontal lines during motion, called "combing artifacts."
If your AVI file comes from a DV camcorder, VHS capture, or DVB recording, it is almost certainly interlaced. Our converter detects and deinterlaces such content using the yadif filter, producing clean progressive video suitable for modern screens.
The FFmpeg command for deinterlacing legacy content:
ffmpeg -i input.avi -vf yadif -c:v libx264 -crf 20 -c:a aac -b:a 192k output.mp4
This applies the yadif (Yet Another DeInterlacing Filter) to convert interlaced fields into progressive frames before encoding to H.264.