Very noob when it comes to video. I'm trying to make sense of what I"m finding via Google... but its mostly Greek to me.

I have a bunch of Avi files that won't play in my WD TV Play box. Mediainfo tells me they are xvid. Specs for the box show that should be fine... but digging through forums says its hit-and-miss. So I'd like to try converting them to h264 encoded MKV or mp4 files.

I gather avconv is the tool, but reading the manual just has me really really confused.

I tried the very basic example of:

avconv -i file.avi -c copy file.mp4

it took less than 4 seconds. And it worked... sort of. It "played" in that something came up on the screen... but there was horrible artifacting and scenes would just sort of melt into each other. I want to preserve quality if possible.

I'm not concerned about file size. I'm not terribly concerned with the time it takes either, provided I can do them in a batch.

Can someone familiar with the process please give me a command with the options?

Thank you for your help.

I'm posting the mediainfo in case it helps:

Complete name                            : \\SERVER\Video\Public\test.avi
Format                                   : AVI
Format/Info                              : Audio Video Interleave
File size                                : 189 MiB
Duration                                 : 11mn 18s
Overall bit rate                         : 2 335 Kbps
Writing application                      : Lavf52.32.0

ID                                       : 0
Format                                   : MPEG-4 Visual
Format profile                           : Advanced Simple@L5
Format settings, BVOP                    : 2
Format settings, QPel                    : No
Format settings, GMC                     : No warppoints
Format settings, Matrix                  : Default (H.263)
Muxing mode                              : Packed bitstream
Codec ID                                 : XVID
Codec ID/Hint                            : XviD
Duration                                 : 11mn 18s
Bit rate                                 : 2 129 Kbps
Width                                    : 720 pixels
Height                                   : 480 pixels
Display aspect ratio                     : 16:9
Frame rate                               : 29.970 fps
Standard                                 : NTSC
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Compression mode                         : Lossy
Bits/(Pixel*Frame)                       : 0.206
Stream size                              : 172 MiB (91%)
Writing library                          : XviD 1.2.1 (UTC 2008-12-04)

ID                                       : 1
Format                                   : MPEG Audio
Format version                           : Version 1
Format profile                           : Layer 3
Mode                                     : Joint stereo
Mode extension                           : MS Stereo
Codec ID                                 : 55
Codec ID/Hint                            : MP3
Duration                                 : 11mn 18s
Bit rate mode                            : Constant
Bit rate                                 : 192 Kbps
Channel(s)                               : 2 channels
Sampling rate                            : 48.0 KHz
Compression mode                         : Lossy
Stream size                              : 15.5 MiB (8%)
Alignment                                : Aligned on interleaves
Interleave, duration                     : 24 ms (0.72 video frame)
  • You should consider to not reencode from one lossy codec to another. In the case where your video is in Xvid codec, just remux it into the Matroska container.
    – v010dya
    Nov 10, 2014 at 17:29

6 Answers 6


The standard command from http://manpages.ubuntu.com/manpages/precise/man1/avconv.1.html shows this:

avconv -i test.avi -c:v libx264 -c:a copy outputfile.mp4

This will re-encode your video to h264 (=AVC) and keep your sound unchanged which is mp3 and completely legal to the standard.

A few other options to consider with this commandline are:

  • Tweak the quality of the output video by using the -b parameter (bitrate) or use Constant Rate Factor (CRF) with something like -crf 22
  • Use a libx264 preset such as -preset veryslow for improved video

If you use these the options should be placed after -c:v libx264 option...

You may also look at the GUI programs winff and avidemux which will make things less complicated. (also handbrake is a good one but i never came to terms with it )

  • Ha! I don't know how you look at that gobble-de-gook of a manpage and pull that line out as an obvious "standard command"... but I'm thankful that you did! It worked. I appreciate it.
    – bcsteeve
    Nov 4, 2013 at 14:42
  • Thanks for mentioning Handbrake -- I had it and completely forgot about it. I ended up opening it, searching for my movie folder, slurped all the videos in, enqueued them all, and hit "Encode"! Jul 3, 2015 at 4:37
  • For AAC sound many devices might have a hardware decoder, so keeping it as MP3 is not necessarily better.
    – ccpizza
    Nov 2, 2017 at 0:32

In case you are looking for something graphical, you can consider using mkvtoolnix-gui package. It actually depends on the command line utility, but it will execute the command with all the needed options for you.

mkvmerge gui 1

The first thing that you'll need to do is to add the files containing all the needed streams. You do that (obviously) by pressing add button and selecting the file or by dragging your files into the "Input files" area. You should not use append button, unless your intention is to place the contents of one file after the contents of another (making the final file's duration the sum of all the appended ones).

Since you are saying you are planning to just convert .avi files, then you should simply add one file at the time. Note that the first file that you will add will automatically set the name of the output file, it will match the input name, but the extension will be changed to .mkv. You can of course change that if you wish.

After you add something you will be able to change the parameters of the streams (such as the assigned language, whether the track is "on" by default, and whether a user can chose to disable this stream all together if one wishes.

You can give the title for the stream. I suggest that if you have multi-audio video that you use that together with the language. For example you can have "original" or "single-voice dub" or "director's commentary" for the track names. Many players will show you these when you select the stream to play, and it is very useful. Try not to repeat the information there, however. There is no reason to write "English language" when you can just set the track's language code.

There are also some specific options, which will depend upon which stream you are working on.

mkvmerge gui 2

Sometimes you may wish to add some attachments to your file. If you add an image, many file managers will display this picture as the icon for the final video file. If you are muxing some sort of film, and you happen to have the cover for it, it may be a good choice to put it in as the attachment.

mkvmerge gui 3

Finally in the Global tab you are able to set the metadata for the whole file. The most common thing is to set the title. It will be prefilled by the data taken from the first file that you have added to the "Input files".

You can also add chapter information. Mkvmerge is able to read ogm chapter file as well as xml chapters. It also allows you to edit chapter files, but keep in mind that this tab functions as a separate application, so you won't be editing chapters that are added to your output file, you will need to save them in that tab, and then add them as the input to the file you are now muxing.

The interesting feature of mkvmerge gui is the "Copy to clipboard" which copies the exact terminal command that the application is planning to run. If you intend to mux many files you can set one up, just the way you like it, then copy the command to clipboard and make a bash script that does all the files you want at once.

  • How do you start it?
    – uvasal
    Feb 12, 2015 at 15:50
  • 1
    mmg is the answer
    – uvasal
    Feb 12, 2015 at 15:52

Avidemux is a free video editor designed for simple cutting, filtering and encoding tasks. It supports many file types, including AVI, DVD compatible MPEG files, MP4 and ASF, using a variety of codecs. Tasks can be automated using projects, job queue and powerful scripting capabilities.Avidemux is available for Ubuntu.

sudo apt-get update
sudo apt-get install avidemux

HandBrake (https://handbrake.fr) is pretty versatile tool that you can use, there is a CLI tool also (how to convert avi (xvid) to mkv or mp4 (h264)).


You could also use dmMediaConverter a free FFmpeg GUI. And you can do it without reencoding the video stream (depends on avi codec). Just grab the debs from here: http://dmsimpleapps.blogspot.ro/2014/04/dmmediaconverter.html

enter image description here


I used the following two commands to convert my AVI files to MP4 files that would stream properly from my WD My Cloud Mirror:

ffmpeg -i infile.AVI -strict -2 -profile:v baseline -pix_fmt yuv420p temp.mp4
MP4Box -mpeg4 -brand mp42:0 -add temp.mp4#video:name= -add temp.mp4#audio:name= -new outfile.mp4

ffmpeg converts the AVI file to MP4, changing the video profile and pixel format to conform to widely accepted values. MP4Box repackages the streams into the final MP4 and adds standard metadata.

  • -strict -2 isn't needed to encode AAC audio unless your ffmpeg is very old. You may be able to skip MP4Box if you add the -movflags +faststart output option in ffmpeg.
    – llogan
    May 2, 2018 at 22:21

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