WHY is a codec?

[ChrisGreaves]

(also, please, a little bit of "what")
I reinstalled Win7 HP last week.
Today I used dear old FastStone (at $20/lifetime, a steal!) to record a screen video; it created a WMV file which wouldn't play in WinAmp or in Windows Media Player.
Short story: http://shark007.net/win7codecs.html" onclick="window.open(this.href);return false;, installed, now can play WMV in Windows Media Player, but not in WinAmp.

I suspect a flaw in my Win7 installation.

In the meantime, Please and Thank You, WHY do I need to d/l and install a codec?
I figured out that a codec is a piece of program code, so in lay terms it's not much different from a DLL or an EXE or a ... - that is, I have installed some program code that makes recorded screen videos visible (in Windows Media Player, if not in WinAmp).

But why did I need to do that?

I'd have thought that Win7 came with all the basic stuff it needed to play WMV files.

(signed) "puzzled again" of Toronto.

[HansV]

Like audio and images, video files would be HUGE if they weren't compressed.

Let's take images as an example. A 640 x 480 full color picture (24-bit color) is 900 KB in size if uncompressed, e.g. in a .bmp file. The same picture could be anything from 20 KB to 200 KB as a .jpg., depending on the quality (the higher the compression, the lower the quality).
The most common image formats (.jpg, .png, .gif) can be viewed on any computer. There are others (such as .tif, .ico, and also some rather obscure ones that may need special software to be viewed).

But with video, the situation is much more complicated. There is a plethora of compression algorithms in use, with lots of variants (even within common formats such as .wmv and .avi). Some are "open", others are proprietary (such as the .bik format of Bink Player), and new versions and variants are being released frequently. For this reason, Microsoft has decided not to try to build support for all possible variants of all possible formats into Windows.

I don't know which compression algorithm FastStone Capture uses, but it is very efficient - it results in quite small files that yet have a very decent quality. I therefore suspect that it is not the "standard" algorithm used for .wmv, and hence the need for a codec.

[ChrisGreaves]

I therefore suspect that it is not the "standard" algorithm used for .wmv, and hence the need for a codec.

Hi Hans, and thanks for the explanation.
So: It's quite possible that at the time I installed FastStone, some 10(?) months ago, it or I installed a Codec and I hadn't realised or remembered it.

That might also explain why, right now, Windows Media Player will play back the WMV I created yesterday, but WinAmp will not (yet!).

[John Gray]

I suspect that this is one of the reasons that people use VLC Media Player, which can handle a large variety of file formats...

[HansV]

Installing VLC Player is a good way of being able to play most audio and video formats if you can live with its quirks and its interface. (I found it rather irritating, but that was some years ago, perhaps it has been improved)
Installing a codec pack is another way; this lets you play most audio and video formats in any media player (for example Windows Media Player).
Neither lets you play QuickTime or Real files without installing additional software, but Real seems to have died out, and I see QuickTime less and less on the Internet...

[ChrisGreaves]

I suspect that this is one of the reasons that people use VLC Media Player, which can handle a large variety of file formats...

Thanks John.
I did a quick download-and-taste of the zip file and can hear my recent video (audio track), but get this cute error-box.
Later today I'll download the self-installing EXE and see if that fares any better.
Interestingly the VLC was able to play a WMV file recorded by FastStone yesterday, so all is not lost!

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