Download like
someone who knows what they're doing

Step by step:

1. Open Download SIU and paste the URL of the video, or of the page it's playing on.

2. Switch to PRO mode to expose the advanced options.

3. Pick your resolution — 4K, 2K, 1080p, whatever the source actually has.

4. Set FPS to Original so the frame rate matches the source exactly.

5. Choose MKV as the container to preserve everything.

6. Hit download and let the queue do the rest.

Pro tip: always use MKV for 4K. It carries higher bitrates and multiple audio tracks without forcing a re-encode, which is where quality quietly disappears.

FLAC — lossless compression, bit-for-bit identical to the source. Roughly 30 MB per track. Use it for archives and anything you might re-encode later.

MP3 320 kbps — high quality, plays literally everywhere. About 8 MB per track. The safe default for day-to-day listening.

MP3 128 kbps — noticeably compressed but tiny, around 3 MB per track. Fine for spoken word, podcasts or a phone that's nearly full.

How to extract: switch to the AUDIO EXTRACT tab, choose format and bitrate, paste the URL and download.

Method 1 — playlist URL. Paste the full playlist address and SIU detects every video in it automatically.

Method 2 — the queue. Add as many individual URLs as you like; they're processed in order without you touching anything.

Method 3 — full season. For series, enable season download and SIU walks from episode to episode on its own.

Getting the most out of it: raise the CPU-thread slider in PRO mode, download to an SSD rather than a mechanical drive, and keep the connection stable — interrupted segments are what actually slows a batch down.

MKV (Matroska)

Carries multiple audio tracks and multiple subtitle tracks in one file, tolerates higher bitrates, and rarely forces a re-encode. Right choice for films, series and anything you're keeping.

MP4 (MPEG-4)

Plays on essentially every device and platform ever made, and the files come out smaller. Right choice for phones, social uploads and sending things to other people.

Rule of thumb: archive in MKV, share in MP4.

30 FPS — the standard for film and television. Smooth enough for almost everything that isn't fast motion.

60 FPS — gaming footage, sports, anything with quick camera movement. The jump from 30 is genuinely visible.

120 FPS — professional gaming capture and usable slow motion. Demands real hardware to play back properly.

240 FPS — extreme slow motion and sports analysis. The files are enormous; only reach for it if you're going to slow the footage down.

Setting it: in PRO mode, choose the FPS from the dropdown. Leave it on Original unless you have a reason not to — forcing a different rate triggers a re-encode.

128 kbps — fine on a phone with earbuds on a noisy commute. ~3 MB per track.

256 kbps — high quality, and the point past which most people genuinely can't hear a difference. ~6 MB per track.

320 kbps — the ceiling for MP3. ~8 MB per track.

Quick reference:

• Phone with earbuds → 128–256 kbps
• Car audio → 256 kbps
• Home stereo → 320 kbps
• Archive or mastering → FLAC, lossless

In PRO mode the AUDIO and SUBS selectors let you decide exactly which streams survive the download.

AUDIO → All keeps every language the source publishes. Main keeps only the primary track and produces a much smaller file.

SUBS → All embeds every subtitle track as a selectable stream. None discards them entirely.

Important: multiple audio and subtitle tracks require the MKV container. MP4 will silently drop most of them.

Use ECO when you're happy with whatever quality the source has. There's no re-encode, so the download finishes in a fraction of the time and your CPU stays idle. The file is identical to the original, just rewrapped.

Use PRO when you need a specific resolution or frame rate, want to drop audio tracks or subtitles, or are targeting a device with strict format requirements. That means re-encoding, which is slower and works your CPU hard.

Rule of thumb: start in ECO. Move to PRO only when the file it produced isn't what you needed.