MP4 to ASF Converter

Convert MP4 to Advanced Systems Format online

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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.

mp4

MP4 (MPEG-4 Part 14) is the most widely used multimedia container format in the world, standardized by the Moving Picture Experts Group as part of the MPEG-4 specification in 2003. Built on the ISO base media file format (MPEG-4 Part 12), which itself drew from the Apple QuickTime container, MP4 uses a hierarchical atom/box structure that can encapsulate virtually any type of media data. The container most commonly packages H.264 or H.265 video with AAC audio, though it also supports a wide range of alternative codecs including AV1, VP9, MPEG-4 Visual, AC-3, and ALAC. The design supports advanced features such as streaming hints for progressive download and adaptive streaming, chapter markers, multiple audio and subtitle tracks, metadata tags, and embedded thumbnail images. A standardized structure and broad codec support have made MP4 the default choice for online video platforms, mobile devices, digital cameras, and operating system media libraries. HTML5 video with H.264 in MP4 is supported by every major web browser, establishing the combination as the universal baseline for web video delivery. Efficient packaging overhead, combined with the compression capabilities of modern codecs it carries, enables high-quality video distribution at practical file sizes across bandwidth-constrained networks and storage-limited devices.
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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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Streaming Optimized

ASF was built for media streaming. Converting MP4 to ASF gives you files ready for Windows-based streaming servers and networks.

Windows Integration

ASF plays natively in Windows Media Player with no codec packs needed. Perfect for corporate Windows environments.

File Security

Uploaded MP4 files are deleted right after conversion. ASF results are removed from our servers automatically within 24 hours.

How to convert MP4 to ASF

1

Select or drag&drop MP4 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 MP4 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

MP4 (MPEG-4 Part 14) is the most widely used multimedia container format in the world, standardized by the Moving Picture Experts Group as part of the MPEG-4 specification in 2003. Built on the ISO base media file format (MPEG-4 Part 12), which itself drew from the Apple QuickTime container, MP4 uses a hierarchical atom/box structure that can encapsulate virtually any type of media data. The container most commonly packages H.264 or H.265 video with AAC audio, though it also supports a wide range of alternative codecs including AV1, VP9, MPEG-4 Visual, AC-3, and ALAC. The design supports advanced features such as streaming hints for progressive download and adaptive streaming, chapter markers, multiple audio and subtitle tracks, metadata tags, and embedded thumbnail images. A standardized structure and broad codec support have made MP4 the default choice for online video platforms, mobile devices, digital cameras, and operating system media libraries. HTML5 video with H.264 in MP4 is supported by every major web browser, establishing the combination as the universal baseline for web video delivery. Efficient packaging overhead, combined with the compression capabilities of modern codecs it carries, enables high-quality video distribution at practical file sizes across bandwidth-constrained networks and storage-limited devices.
Initial release: 2003
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 MP4 to ASF?

ASF is designed for streaming over Windows networks. Converting is useful for legacy Windows Media Services and corporate intranet media delivery systems.

What opens ASF files?

Windows Media Player handles ASF natively. VLC and PotPlayer also support ASF playback on any platform without extra plugins.

Is ASF the same as WMV?

ASF is the container format — WMV is a specific codec within it. ASF can hold different codecs, making it more flexible as a container.

Can I convert several files?

Upload multiple MP4 videos and convert each to ASF in one batch. Files process in parallel on our servers.

Does ASF support streaming?

ASF was engineered specifically for streaming media delivery. It handles progressive download and live streaming scenarios efficiently.

Will audio be included?

Yes. Both the video and audio streams from your MP4 are packaged into the ASF container during conversion.

MP4 to ASF Quality Rating

4.8 (1,443 votes)
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