FLV Compressor
Initializing... drag & drop files here
Supports: FLV
Advanced Options - Our defaults are optimized for the best results. We recommend you keeping the defaults unless you have a specific need.
Reset to defaults
Need help?How to Compress FLV Videos
- Upload your FLV — Click "+ Add Files" or drag and drop your FLV video files. Batch upload is supported.
- Choose compression method — Under "File Compression," select "Quality Preset" (Highest to Lowest), "Target file size (%)" to reduce by a percentage, "Specific file size" to target exact MB/KB, "Constant Bitrate" or "Variable Bitrate" for manual control, "Constant Quality" (CRF slider), or "Constraint Quality" (CRF + max bitrate cap).
- Adjust resolution — Under "Video resolution," keep original, scale by percentage, pick a preset (1080p, 720p, 480p, 360p, etc.), or enter exact width/height in pixels.
- Trim if needed — Under "Trim," set a start time and duration to extract a specific clip, further reducing file size.
- Compress and download — Click "Compress" and download your smaller FLV files.
Why Compress FLV Files?
FLV (Flash Video) was the dominant web video format during the Flash era (2005–2015), used by early YouTube, Dailymotion, and countless streaming sites. While Flash Player is discontinued, millions of FLV files still exist in video archives, screen recordings, and legacy content management systems. These files are often larger than necessary because they were encoded with older, less efficient codecs.
Compressing FLV files reduces storage requirements and makes them easier to share or upload to modern platforms. XConvert offers multiple compression strategies — from simple quality presets for quick results to advanced CRF-based encoding for precise quality-to-size control. For archival purposes, you can also trim unnecessary footage to cut file size without re-encoding the entire video.
If you no longer need the FLV container, consider converting to MP4 for universal compatibility or WebM for web-optimized playback.
FLV Compression Methods Compared
| Method | Best For | How It Works |
|---|---|---|
| Quality Preset | Quick compression | Predefined quality levels from Highest to Lowest |
| Target file size (%) | Predictable output size | Set 50% to halve the file size; Smart Scaling adjusts resolution automatically |
| Specific file size | Email/upload limits | Target exact MB — e.g., compress a 100 MB FLV to 25 MB |
| Constant Quality (CRF) | Best quality-to-size ratio | Lower CRF = higher quality; 18 = visually lossless, 23 = default, 28 = smaller |
| Variable Bitrate | Streaming optimization | Allocates more bits to complex scenes, fewer to simple ones |
| Trim | Remove unwanted footage | Set start time + duration to extract a clip |
FLV vs Modern Formats
| Feature | FLV | MP4 (H.264) | WebM (VP9) |
|---|---|---|---|
| Era | 2005–2015 | 2003–present | 2010–present |
| Typical codec | Sorenson Spark, VP6 | H.264, H.265 | VP9, AV1 |
| Compression efficiency | Low | High | Very high |
| Browser support (2026) | None (Flash dead) | Universal | All modern browsers |
| Mobile support | Poor | Universal | Good |
| Streaming support | RTMP only | HLS, DASH | DASH |
Frequently Asked Questions
Is FLV still used?
FLV is a legacy format — Flash Player was discontinued in December 2020 and no modern browser plays FLV natively. However, FLV files remain common in video archives, old screen recordings, and legacy systems. Compressing them reduces storage costs; converting to MP4 makes them playable everywhere.
What's the best compression method for FLV?
"Target file size (%)" is the easiest — set 50% to roughly halve the file. For best quality-to-size ratio, use "Constant Quality (CRF)" with a value of 23 (default balance) or 28 (smaller files, slight quality reduction). The "Quality Preset" option is fastest if you don't want to fine-tune settings.
Can I trim and compress at the same time?
Yes. Under "Trim," set a start time and duration to extract a specific portion of the video. This is combined with your compression settings in a single processing step — trimming a 10-minute video to 2 minutes alone can reduce file size by 80%.
Will compressing FLV reduce video quality?
Any lossy compression involves a quality trade-off. At "Quality Preset: High" or CRF 18–23, the quality loss is minimal and often imperceptible. More aggressive settings (CRF 28+, "Low" preset) produce noticeably smaller files but with visible quality reduction, especially in fast-motion scenes.
Should I convert FLV to MP4 instead of compressing?
If you don't specifically need the FLV container, converting to MP4 is recommended. MP4 with H.264 offers better compression efficiency than FLV's older codecs, universal device/browser support, and compatibility with every modern video player and platform.
Can I compress multiple FLV files at once?
Yes. Upload multiple FLV files and compress them all with the same settings in one batch. No file count limits or sign-up required.