ASF to MP4 Converter

Convert ASF to MP4 online, for free.

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Advanced settings (optional)

Video Options

Video Codec

Choose a codec to encode or compress the video stream. To use the most common codec, select "Auto" (recommended). To convert without re-encoding video, choose "Copy" (not recommended).

Video Screen Size

Select a resolution for your video (width x height) in pixels.

Video Aspect Ratio

Change the ratio between width and height, for example, 4:3 or 3:2

Video Frame Rate

Change FPS (frames per second) of video

Rotate Video

Video will be rotated clockwise.

Flip Video

Add Subtitles

Choose a file Browse

Upload a .srt or .ass subtitle file to be burned into your video.

Audio Options

Audio Codec

Choose a codec to encode or compress the audio stream. To use the most common codec, select "Auto" (recommended). To convert without re-encoding audio, choose "Copy" (not recommended).

Adjust Volume

100% represents the original volume. To double the volume, increase it to 200%. To reduce volume by half, select 50%

Fade In Audio

Fade Out Audio

Remove Audio

Trim Settings

Trim Start

Specify the start position of trim (HH:MM:SS). Leave at 00:00:00 to disable.

Trim End

Specify the end position of trim (HH:MM:SS). Leave at 00:00:00 to disable.

What is an ASF (Advanced Systems Format) file?

Advanced Systems Format (ASF) is a proprietary Microsoft product, which serves as a container for Windows multimedia content. Microsoft designed it for streaming and to be independent of systems and protocols. It supports chapters, captions, subtitles, metadata tags, streaming, and hardware players, but does not support menus.

How to open an ASF file?

It is best to use Windows Media Player to open an ASF file. Alternatively, VLC media player is a good choice too. Keep in mind that ASF can contain WMA and WMV files, which might display as the file extension of the ASF file.

Developed by: Microsoft

Initial release: 1995

Useful links:

https://en.wikipedia.org/wiki/Advanced_Systems_Format

https://docs.microsoft.com/en-us/windows/desktop/wmformat/overview-of-the-asf-format

What is an MP4 (MPEG-4) file?

MPEG-4 (MP4) is a container video format that can store multimedia data, usually audio and video. It is compatible with a wide range of devices and operating systems, using a codec to compress file size, resulting in a file that is easy to manage and store. It is also a popular video format for streaming over the Internet, such as on YouTube. Many consider MP4 to be one of the best video formats available today.

How to open an MP4 file?

MP4 files open in the operating system's default video player. Simply double-clicking the file opens it. There is no need for third-party software. On Windows, it opens in Windows Media Player. On Mac, it opens in QuickTime.

On some devices, particularly mobile, opening this file type can be problematic. MP4 is a container that contains various kinds of data, so when there is a problem opening the file, it usually means that data in the container (an audio or video codec) is not compatible with the device’s OS. To resolve this issue, try VLC media player.

Developed by: Moving Picture Experts Group (MPEG)

Standard: ISO/IEC 14496

Initial release: 1999

Useful links:

https://en.wikipedia.org/wiki/MPEG-4

https://mpeg.chiariglione.org/standards/mpeg-4