Avidemux FAQ – Problems with encoded files

When I save a file with Avidemux, my player/file manager does not recognize the filename extension

I encoded a video with Avidemux but I only get black screen when I try to play it back

When I use some filters/subtitles in Avidemux, the saved file is like the original AKA The filters/subtitles aren’t applied to the output video

I encoded a DVD or Video with Avidemux and the picture is blurry. What settings can I change to keep as much details as possible?

 

When I save a file with Avidemux, my player/file manager does not recognize the filename extension

Avidemux does not add filename extensions automatically. When you want to save an AVI file called 「myvideo」, save it as 「myvideo.avi」. If you already saved it as 「myvideo」, just rename it to 「myvideo.avi」 in your file manager. A complete list of the extensions to be used with each output format is available in the Supported output formats section.

I encoded a video with Avidemux but I only get black screen when I try to play it back

Make sure your video player supports the video format. For example, if you’re using Windows Media Player and encoded the video into MPEG-4 (ASP or AVC), a third-party MPEG-4 decoder must be installed on your system, because there is no MPEG-4 decoder included in Microsoft Windows. ffdshow tryouts contains audio and video decoders for the most common modern audio and video formats.

When I use some filters/subtitles in Avidemux, the saved file is like the original AKA The filters/subtitles aren’t applied to the output video

This usually happens when you’ve set the Video to 「Copy」, and is expected behavior. Copy, by definition, copies the video from the input file to the output file without modifying it, so no filters will be applied. When the video dropdown menu is set to 「Copy」, the 「Filters」 button is disabled, and the 「Video > Filters」 menu pops a warning that says 「Video filters cannot be used in copy mode」. You might have thought choosing an encoder other than 「Copy」, adding filters, and setting it back to copy would apply filters without re-encoding … well, that’s not how things work. 😉

To apply some video filters, choose the appropriate encoder in the Video dropdown menu (whatever suits your needs best) and choose the format and file extension accordingly.

NB: Older versions of Avidemux didn’t show the warning via the 「Video > Filters」 menu, and even older versions didn’t disable the 「Filters」 button at all. When Format is set to 「AVI, unpack VOP」 (which is done automatically when you answer yes to a question whether you want to unpack the video), the video is saved in copy mode, too, so filters cannot be applied either.

I encoded a DVD or Video with Avidemux and the picture is blurry. What settings can I change to keep as much details as possible?

First, check that post-processing is turned off for the current session in the 「Video > Post processing …」 menu. You can also turn it off definitely in the 「Tools > Preferences」 menu, in the Video tab. Next, if you added a resize filter, set it to resize using the Lanczos3 method instead of Bilinear or Bicubic. Lanczos3 is the most accurate resizer, or so to say. However, resizing kills details by nature, there’s no way around it. Not resizing might be a better option sharpness-wise depending on what you’re trying to do. Finally, tweak the encoder settings. Discussing the best quality settings for each encoder isn’t the FAQ‘s goal. Encoder-specific guidelines are available in the avidemux forum or on the web.