> ## Documentation Index
> Fetch the complete documentation index at: https://vidow.io/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Format Conversion — Convert HLS & DASH Streams to MP4, MKV, MOV

> Convert HLS and DASH streams into standard video containers, or pull out the audio track as MP3 or AAC. All processing happens locally via WebAssembly.

<Info>Format conversion is a **Professional** feature. [Upgrade your plan](/docs/billing/plans) to unlock it.</Info>

Video Downloader Plus can remux HLS (m3u8) and DASH (mpd) streams into standard video containers and extract audio tracks into standalone audio files. Conversion runs entirely inside your browser — nothing is uploaded to a server.

## Video conversion targets

| Target format | Best for                                                                          |
| ------------- | --------------------------------------------------------------------------------- |
| **MP4**       | Broadest device and browser compatibility — the safe default for most use cases   |
| **MKV**       | Archiving with multiple audio tracks, multiple subtitle tracks, and rich metadata |
| **MOV**       | Editing in Final Cut Pro or working within the Apple ecosystem                    |
| **WebM**      | Embedding on web pages and open-format workflows                                  |

## Audio extraction targets

| Target format | Best for                                                                |
| ------------- | ----------------------------------------------------------------------- |
| **MP3**       | Maximum compatibility across every audio player and platform            |
| **AAC**       | Better quality-to-size ratio, especially for Apple devices and services |

## How conversion works

<Steps>
  <Step title="Detect the stream">
    Video Downloader Plus identifies an HLS or DASH stream on the page and surfaces it in the popup.
  </Step>

  <Step title="Choose a target format">
    Select your desired output format from the format picker before starting the download.
  </Step>

  <Step title="Local processing via WebAssembly">
    Video Downloader Plus downloads all segments and passes them through a WebAssembly-based media engine running in your browser. No data leaves your device during this step.
  </Step>

  <Step title="Save the output file">
    The finished file is written to your downloads folder in the format you selected.
  </Step>
</Steps>

## Format comparison

|                           | MP4       | MKV                       | MOV                   | WebM            |
| ------------------------- | --------- | ------------------------- | --------------------- | --------------- |
| **Device compatibility**  | Universal | Good (VLC, most players)  | Apple ecosystem       | Browsers, Linux |
| **Multiple audio tracks** | Limited   | Excellent                 | Good                  | Limited         |
| **Subtitle support**      | Basic     | Excellent (SRT, ASS, PGS) | Good                  | Basic (WebVTT)  |
| **File size**             | Medium    | Medium                    | Medium–Large          | Smaller         |
| **Streaming friendly**    | Excellent | Poor                      | Good                  | Good            |
| **Professional editing**  | Good      | Limited                   | Excellent (Final Cut) | Limited         |
| **Web embedding**         | Good      | Not recommended           | Not recommended       | Excellent       |

### When to use each format

* **MP4** — The right choice for almost everything. Works on every phone, TV, tablet, and browser without configuration.
* **MKV** — When you want to preserve alternate language tracks, multiple subtitle files, or attach metadata for a media server like Plex or Jellyfin.
* **MOV** — When the file is headed into Final Cut Pro or another Apple editing tool that handles MOV natively.
* **WebM** — When file size matters and the destination is a browser or Linux environment. Also the format to reach for when you want VP9 or AV1 output.

### Audio format comparison

|                                     | MP3                            | AAC                              |
| ----------------------------------- | ------------------------------ | -------------------------------- |
| **Compatibility**                   | Universal                      | Excellent on all modern devices  |
| **Quality at low bitrates**         | Adequate                       | Noticeably better                |
| **File size at equivalent quality** | Larger                         | Smaller                          |
| **Best for**                        | Broadest reach, legacy players | Higher fidelity, Apple ecosystem |

## Key details

* **Local-only processing** — The WebAssembly media engine runs entirely in your browser. Your video data stays on your machine.
* **Lossless quality** — Video Downloader Plus remuxes streams into the target container without re-encoding video or audio, so there is no quality degradation for supported codec combinations.
* **Automatic track muxing** — HLS and DASH streams with separate audio and video renditions are merged into a single output file before being saved.
* **DASH SegmentBase passthrough** — When a DASH stream uses SegmentBase (meaning the content is already a standard MP4 with byte-range requests), Video Downloader Plus downloads the file directly and skips the conversion step entirely.