Re: What is the most efficient way to convert a .wmv video?

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Author: Brian Cluff
Date:  
To: Main PLUG discussion list
Subject: Re: What is the most efficient way to convert a .wmv video?
First off, that video is hilarious... but that doesn't help you convert
it to something more useful.

So a quick word on video formats. When you are talling about a video
file you almost always referring to a container format. The popular
container formats are avi, mpg, mp4, mkv, wmv...etc...etc... You can
think of them as just a hard drive with a particular format. Like a
hard drive most container formats can hold just about any kind of
combinations of Video, Audio, Subtitles, and a lot of them can hold
multiple streams of any of those combinations. Container formats are
just ways to keep the video and audio that are separately encoded,
stored in such a way that they can be played back and they don't loose
sync with each other. You can have an MP4 container file that
internally is windows Media Video (wmv) and the audio is windows media
audio (wma), as well as an WMV container that hold h264 video and aac
video which are usually whats inside an MP4 container.

So when I want to put something inside a different container the first
thing I usually do is find out what codecs they were created with. That
can easily be done in VLC by going to the tools pull down menu and
selecting Codec Information.
Often times the container format might not be what I want, but the
internal codecs are already correct, so all I need to do is copy the
video and audio into the new container and I won't suffer any loss in
video/audio quality and it's super fast... and easy.

avconv -i test.wmv -acodec copy -vcodec copy test.mp4

In your case, that won't give you anything usable and actually gives you
and error because of compatibility issues with the container, but it's
worth noting for future reference. What you will need to do is
convert/re-encode the video. You easiest option is probably to get
handbrake. It's usually used for ripping DVDs, but actually does a nice
job of converting videos too, as long as the destination container is
mp4 or mkv, otherwise you'll need to use a different tool like avidemux.
You can get it at: handbrake.fr

Once you have handbrake installed and open, you'll just want to pick one
of the presets from the right side. Choose the "universal" format under
Devices.
The defaults are generally set to give you good quality, but in your
case, the source video isn't in very good quality to start with, so the
defaults will just make the video bigger, so we need to make a few changes.

Click on the Video table and move the slider above "Constant Quality"
till it reads RF:30. Then click on the Audio table, if there are more
than one audio track showing, click on the lower once and then click the
red X to get rid of them. Then select the remaining audio track, make
sure the encoder is set to AAC and then set the bitrate to 96.

Finally click the icon of the diskette in the lower right corner and
save this preset for later use.

When I re-encode your video, I end up with a MP4 file that is 537443.

The suggestion of ffmpeg (actually avconv, since ubuntu doesn't package
ffmpeg anymore) is also a good one, but can add a lot of complexity.
You'll have to have knowledge of what bitrate codecs like and dislike
and what formats can go into what containers. It's probably best to
stick with handbrake, or avidemux or something similar that take a lot
of the complexity out of it, unless you hare having to convert a whole
bunch of videos where a script could take a lot of the pain out of the
process.

Brian Cluff

On 04/05/2013 11:48 PM, wrote:
> What is the most efficient way to convert
> a .wmv video to a mpeg (or other format)
> that most systems/browsers can play?
>
> I have a 21-second video test.wmv -- size 641,131 here:
> - - - http://www.upquick.com/videos/test.wmv - - -
> Firefox apparently cannot play .wmv videos.
>
> So I used Openshot to convert it to test2.mpeg
> (with a resulting size of 6,981,632) here:
> - - - http://www.upquick.com/videos/test2.mpeg - - -
> Firefox plays this fine, but the file size is huge.
>
> Then I used Openshot again to convert it to test3.mpeg
> (with a resulting size of 3,254,272) here:
> - - - http://www.upquick.com/videos/test3.mpeg - - -
> Firefox plays this fine, with less than half the file size.
>
> All of the Openshot settings options shown at this link:
> - - - http://www.upquick.com/videos/openshot.jpg - - -
> are very confusing.
>
> Surely there must be a more efficient (command line)
> method to convert .wmv (and other) video files.
>
> Suggestions?
>
>
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