WEBM to ASF Converter

Convert WEBM into Microsoft ASF streaming container

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Settings

The codec to encode the video track. Codec "Without reencoding" copies the video stream from the input file into output without re-encoding if possible.
Set the video quality in a VBR mode. Choose "Custom" if you need to set a fixed bitrate (CBR).
Set an output video resolution by selecting one from the predefined set of the most popular resolutions or manually entering a custom resolution.

webm

WebM is an open, royalty-free multimedia container format developed by Google and launched at the Google I/O conference in May 2010. The format pairs the Matroska container (a subset of MKV) with VP8 or VP9 video codecs and Vorbis or Opus audio codecs, creating a fully open media stack designed specifically for web use. Google released WebM alongside the VP8 codec under permissive BSD-style licensing, removing patent and royalty barriers that hindered the adoption of H.264 for open web video. The WebM container inherits the efficient binary structure of Matroska while restricting it to web-optimized profiles, ensuring fast parsing and lightweight implementation in browsers. WebM with VP9 achieves compression efficiency competitive with H.264 High Profile and approaching HEVC, making it practical for delivering high-quality video at reduced bandwidth. Major web browsers including Chrome, Firefox, Edge, and Opera support WebM playback natively, and YouTube uses VP9 in WebM as a primary delivery format for much of its content. The format supports features such as alpha channel transparency in video, making it valuable for compositing web graphics and overlays. More recently, WebM has been extended to support AV1 video, continuing its evolution as a vehicle for open codec adoption. The combination of competitive compression, zero licensing costs, and universal browser support makes WebM a cornerstone of royalty-free web multimedia delivery.
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asf

ASF (Advanced Systems Format) is a proprietary digital media container developed by Microsoft to support streaming over networks. Introduced in 1996, it was originally called Active Streaming Format and later renamed to Advanced Streaming Format before receiving its current name. ASF serves as the underlying container for Windows Media Audio (WMA) and Windows Media Video (WMV) content, though it can accommodate data from any codec. The format was architected with network delivery in mind, incorporating features such as forward error correction, scalable bit rate support, and the ability to seek within streams without downloading the entire file. ASF files include a header object containing metadata, a data object holding the actual media content, and optional index objects that enable efficient random access. One key advantage is built-in support for digital rights management, which made ASF a popular choice for commercial content distribution during the early days of online media. The container handles multiple synchronized streams, including video, audio, script commands, and metadata markers. While ASF has been largely superseded by more modern containers in many use cases, it remains relevant in legacy Windows media ecosystems and enterprise environments that rely on Windows Media Services infrastructure.
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Microsoft Streaming Native

ASF was built for Windows Media Services. Converting WEBM to ASF makes your content ready for Microsoft-based streaming infrastructure.

Stream-Optimized Settings

Configure bitrate and resolution for optimal streaming performance — produce ASF files tuned for your bandwidth and audience.

Secure File Handling

Uploaded WEBM files are deleted after processing and ASF outputs are purged within 24 hours, keeping your content private.

How to convert WEBM to ASF

1

Select or drag&drop WEBM video to convert it to the ASF format from your computer, iPhone or Android. Moreover, it is possible to choose it from your Google Drive or Dropbox account.

2

Now your video is uploaded and you can start the WEBM to ASF conversion. If it is needed, change the output format to one of the 37 video formats supported. After that, you can add more videos for batch conversion.

3

If you want, you can customize such settings as resolution, quality, aspect ratio and others by clicking the gear icon. Apply them to all the video files if necessary and click the button "Convert" to process.

4

Once your video is converted and edited, you can download it to your Mac, PC or another device. If necessary, save the file to your Dropbox or Google Drive account.

About formats

WebM is an open, royalty-free multimedia container format developed by Google and launched at the Google I/O conference in May 2010. The format pairs the Matroska container (a subset of MKV) with VP8 or VP9 video codecs and Vorbis or Opus audio codecs, creating a fully open media stack designed specifically for web use. Google released WebM alongside the VP8 codec under permissive BSD-style licensing, removing patent and royalty barriers that hindered the adoption of H.264 for open web video. The WebM container inherits the efficient binary structure of Matroska while restricting it to web-optimized profiles, ensuring fast parsing and lightweight implementation in browsers. WebM with VP9 achieves compression efficiency competitive with H.264 High Profile and approaching HEVC, making it practical for delivering high-quality video at reduced bandwidth. Major web browsers including Chrome, Firefox, Edge, and Opera support WebM playback natively, and YouTube uses VP9 in WebM as a primary delivery format for much of its content. The format supports features such as alpha channel transparency in video, making it valuable for compositing web graphics and overlays. More recently, WebM has been extended to support AV1 video, continuing its evolution as a vehicle for open codec adoption. The combination of competitive compression, zero licensing costs, and universal browser support makes WebM a cornerstone of royalty-free web multimedia delivery.
Developer: Google
Initial release: May 19, 2010
ASF (Advanced Systems Format) is a proprietary digital media container developed by Microsoft to support streaming over networks. Introduced in 1996, it was originally called Active Streaming Format and later renamed to Advanced Streaming Format before receiving its current name. ASF serves as the underlying container for Windows Media Audio (WMA) and Windows Media Video (WMV) content, though it can accommodate data from any codec. The format was architected with network delivery in mind, incorporating features such as forward error correction, scalable bit rate support, and the ability to seek within streams without downloading the entire file. ASF files include a header object containing metadata, a data object holding the actual media content, and optional index objects that enable efficient random access. One key advantage is built-in support for digital rights management, which made ASF a popular choice for commercial content distribution during the early days of online media. The container handles multiple synchronized streams, including video, audio, script commands, and metadata markers. While ASF has been largely superseded by more modern containers in many use cases, it remains relevant in legacy Windows media ecosystems and enterprise environments that rely on Windows Media Services infrastructure.
Developer: Microsoft
Initial release: March 12, 1996

Frequently Asked Questions

Why convert WEBM to ASF?

ASF is Microsoft Advanced Systems Format — designed for Windows Media streaming servers. Converting WEBM enables delivery through Microsoft infrastructure.

What plays ASF files?

Windows Media Player, VLC, and Microsoft streaming servers handle ASF natively. It is the native container for Windows Media technologies.

Is ASF the same as WMV?

ASF is the container; WMV is the video codec inside it. Think of ASF as the wrapper and WMV as one possible codec it can carry.

Will streaming quality be good?

ASF supports adaptive streaming with multiple bitrates. Set quality parameters during conversion to match your bandwidth and audience requirements.

Can I convert in bulk?

Upload several WEBM files and convert them all to ASF at once — efficient for populating a Windows Media streaming server.

WEBM to ASF Quality Rating

4.9 (40 votes)
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