PNG to MKV Converter

How to Convert PNG to MKV Online

1. Upload Your PNG Files: Drag and drop or click "Add Files" to select one or many PNG images. Batch upload is supported — drop a whole timelapse sequence or a folder of slideshow stills.
2. Pick Merge Strategy and Duration: Choose Merge images to combine every PNG into a single MKV, or Video per image to render one MKV per file. Set Duration per frame from 1/60 second (single frame at 60 fps) up to 10 seconds. Timelapses typically use 1/24 or 1/30 second per frame; slideshows look natural at 3–5 seconds.
3. Set Quality, Resolution, and Background (Optional): Pick a Quality Preset (Highest, Very High, High, Medium, Low, Very Low, or Lowest), choose a Fixed Resolution preset (720p, 1080p, 1440p, 4K UHD) or enter a custom width × height with aspect-ratio lock, and choose a Background Color (Black by default) to fill any letterbox area when your PNG aspect ratio differs from the output.
4. Convert and Download: Click Convert. Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically after a few hours — no sign-up, no watermark, never shared.

The default MKV uses H.264 video and AAC audio. Under Advanced settings you can switch the Video Codec to H.265, VP9, AV1, MPEG-4, MJPEG, Theora, or copy (no re-encode), and the Audio Codec to AAC, MP3, FLAC, Opus, or Vorbis.

Why Convert PNG to MKV?

PNG (ISO/IEC 15948) is a lossless raster format — perfect for keeping every pixel of a render, screenshot, or photograph intact. But once you have a sequence of stills, PNG can't carry timing, audio, subtitles, or chapter markers. MKV (Matroska, announced 6 December 2002 by Steve Lhomme) is a royalty-free open container that can hold virtually any modern codec along with multiple audio tracks, embedded subtitles, and chapters. Converting a PNG sequence to MKV turns frames into a playable, shareable video.

• Timelapse from camera bursts — Combine hundreds of intervalometer captures into one MKV. At 1/24 second per frame, 1,440 PNGs become a 60-second 24 fps clip; at 1/30 second per frame, the same set runs 48 seconds at 30 fps.
• Render farm output to preview clip — Blender, Cinema 4D, and After Effects often export PNG sequences for lossless intermediates. MKV with H.265 or AV1 keeps quality high while shrinking the preview to a fraction of the source bytes.
• Plex, Jellyfin, and Kodi libraries — MKV is the native container for these media servers and is the only common container that supports lossless audio (FLAC, DTS-HD MA, Dolby TrueHD) and styled ASS / bitmap PGS subtitles. Pair a PNG slideshow with a FLAC audio track for a hi-fi memorial reel.
• Screen-recording frame dumps — Tools like ShareX and OBS can dump frames as numbered PNGs. Stitch them into MKV without re-encoding artifacts you'd get from a lossy intermediate.
• Animation cels and motion graphics — Hand-drawn cels exported as PNG, or Lottie/Rive frame exports, assemble cleanly into MKV at 12, 24, or 30 fps with the alpha channel collapsed against your chosen Background Color.
• Digital signage loops — A handful of PNG ad slates rendered to a single MKV plays reliably on signage players that prefer Matroska's chapter and language-track support.

MKV vs MP4 vs MOV vs WebM for Image-Sequence Output

Sources: Matroska, Library of Congress format registry, Jellyfin codec docs.

Frame Duration to Effective FPS Quick Guide

Frequently Asked Questions

Why pick MKV over MP4 for an image sequence?

If the output will live on a Plex, Jellyfin, or Kodi server, or you want lossless audio (FLAC) or styled subtitles paired with the visuals, MKV is the right choice — those features either aren't supported in MP4 or have limited muxing support. If you need to email the file, embed it on a webpage, or upload to a social platform, MP4 is more universal because every browser, phone, and editor reads it natively. Matroska is open and royalty-free, which is also why open-source players default to it.

How long can my PNG sequence be?

There's no fixed cap from the MKV container itself — Matroska can hold hours of footage. The practical limit is browser memory while the encoder runs. As a rule of thumb, a few thousand 4K PNGs at 30 fps will work on a modern desktop browser; very long sequences (tens of thousands of high-res frames) are better split into chunks or merged later with a tool that streams to disk.

What framerate should I pick for a timelapse?

24 fps gives a cinematic feel, 30 fps looks smooth on phones and modern displays, and 60 fps is best when the underlying motion is fast (clouds, traffic) and you want extra fluidity. Pick the framerate first, then divide your shot count by it to see how long the output runs: 720 PNGs at 24 fps is a 30-second clip; at 60 fps it's 12 seconds.

Will my PNG transparency survive in the MKV?

No. MKV with H.264 / H.265 / VP9 / AV1 outputs uses opaque YUV color (typically yuv420p), so any alpha channel in the source PNG is composited against the Background Color you choose (Black by default). If you need to keep alpha for compositing in a video editor, export ProRes 4444 in MOV or VP9 with alpha in WebM instead.

Why is the H.264 default and when should I switch to H.265 or AV1?

H.264 plays on essentially every device and is the safest default for casual sharing. H.265 (HEVC) typically gives 30–50% smaller files at the same visual quality and is supported by Plex direct-play on most modern hardware. AV1 compresses even better — useful for archival or where decode hardware is recent (2020+ GPUs, modern Apple silicon, recent Android). MJPEG and "copy" are useful for editing intermediates but produce far larger files.

Can I add an audio track to my PNG-to-MKV conversion?

This converter renders MKV with a silent audio track at the chosen audio codec. To add music or narration, do the conversion here, then mux audio into the MKV with a separate tool such as MKVToolNix, or convert your sequence to MP4 and combine with audio in a video editor.

Should I keep the PNG resolution or downscale?

Keep the original PNG resolution if you want maximum fidelity for archival or media-server playback on a 4K screen. Downscale to 1080p (1920×1080) for sharing — file size drops by roughly 75% for the same perceptual quality, and 1080p still looks clean on phones and laptops. Use the Width / Height (Keep aspect ratio) input to scale exactly while preserving the source aspect.

What does Background Color do exactly?

When your PNG aspect ratio doesn't match the chosen output resolution (for example, 4:3 stills going into 16:9 1080p), the converter pads the difference with the Background Color (Black, White, or many named colors). It also fills any padding when Width / Height is set with aspect-ratio lock. If your PNGs already match the output aspect, Background Color has no visible effect.

Can I convert other image formats to MKV the same way?

Yes — the same image-to-MKV pipeline accepts JPG, BMP, WebP, GIF, TIFF, and HEIC sources. See JPG to MKV for camera photos and BMP to MKV for legacy bitmap sequences. To go the other direction (extract a still frame from MKV), use MKV to PNG.