AM Software | AVI editor

A rectangular picture in the computer memory. Each distinct picture element, or pixel, has its own color value, from two levels (black and white) up to 256 levels of intensity per each red, green and blue channel. Thus, bitmaps can have from 1 bit per pixel up to 24 bit per pixel, or from 2 colors to 16,7 millions of colors.
Normally, a bitmap uses no compression and it is stored with .BMP file extension. However AVIedit treats also GIF, JPEG, PCX, PNG and TGA files as bitmaps, transparently. This means that you can use all these file types to build a frame backgrounds, superimpose images using Layer filter and more.

bit rate, bitrate

The speed, in bits per second (bps), at which digital audio and video content should be feed from a source to the player. The source can be for example an Internet server or just a file. 1024 bits per second, or 1 Kbps, means 128 bytes per second. Current avi bitrates about 600 Kbps, or 76 kbytes per second, allows you to store over than 2 hours of SVHS-quality video on a single CD-R. Bit rate is usually set during the encoding process, when you save avi file with compression. The higher the bitrate, the better the quality (but the file gets bigger).

capture card

A hardware device to convert analog video or audio to digital data, which can be stored as a file on a computer. It has an input jack which can be connected to camcorder, webcam, VCR or other live video source. AVIedit supports both legacy VFW and new WDM capture devices.

clip

The audio, video, or still images that used in a video editing software to build a final movie. Often each clip contains its own scene, it makes editing more convenient. AVIedit includes a timeline editor that offers a conventional approach of non-linear video editing, used by most of similar software.

CLSID

Short for Class ID, CLSID is a label in the Windows registry that allows unique identification of a COM objects. Applications that support Microsoft's COM architecture (these are all DirectX based software) often fail to work due to registry misconfiguration, or require you to have some exact version of DirectX installed. This is because they can not perform any [even simplest] action (capture, filtering, editing, saving etc.) until they scanned the registry for an appropriate object by its CLSID (and have found one).

codec

Stands for compressor/decompressor. Hardware chip or software that can compress and de-compress audio or video content. In general, codecs are used to decrease the file size without noticeable loss of quality. With constant frames per second ratio, compression allows to highly reduce the bit rate of a stream. You can see lists of currently installed codecs using AVIedit Options|ICM and Options|ACM menu items.

color correction

The process of adjusting an image to compensate for camera deficiencies or for the characteristics of the output device, or the original film. AVIedit lets you freely manipulate the frame brightness, saturation and contrast. It is possible to assign an arbitrary transfer curve, like the one you probably saw in Adobe Photoshop(tm) Levels plug-in.

contrast

The visual distance between the lightest and darkest areas of a movie frame or a bitmap picture.

cross-fade

A method of smoothly moving from one video clip or photo to another. With a cross-fade transition, the frames in the playing clip fade out as the frames in the new clip fade in. see a tutorial

digital video (DV)

Video and sound stored in a digital format. Also, the compression scheme used in digital video processing. AVIedit can edit DV Type2 avi files, also it includes a tool to convert Type1 DV files to Type2. See File|Tools menu item.

DivX

A compression scheme same as MS MPEG-4 implementation. Allows you to make movies 8 to 12 times smaller with loosing very little quality. In other words, a two hour avi file compressed with DivX will fit onto a standard CD. There are lot of sites around that tell you how to put DVD films on a CD-R for private use. DivX binaries are available for Win32 PC, MAC, BeOS and Linux.
Currently there are three major generations of DivX codecs. First and oldest is DivX 3.11a which is in fact hacked Microsoft MPEG4 V3 codec. Next codec that works is DivX 4.12, its former versions are full of bugs and therefore unusable. Currently DivX 5.02 is available from DivX Networks, but there are no reasons to use it. First of all, it is not fully Video for Windows compliant. That makes some applications crash while compressing videos, and some can not use this codec at all. Secondly, it is not backward compatible - you can not playback DivX 5 encoded videos using either 3 or 4 version of DivX. It still contains a lot of annoying bugs but, instead of fixing them, DivX team constantly adds new whistles and bells to the codec core, so its installer is over 3MB today. The source code of DivX 5 is now closed, of course, so you have no way to fix or workaround their bugs. Finally, now DivX Networks asks your money for DivX 5 Pro, or you must agree to install some spy/adware application. So, better you use plain old DivX 4.12. Anyway, these 1-2% of better video compression that sometimes offers you DivX 5 on some rare avi files, never worth the money you pay for it, and lots of pain you get in return...

file system

Method used to organize and retrieve files from a storage medium like a hard drive. In Windows world most often used are FAT16, FAT32 and NTFS file systems. FAT16, short for 16-bit File Allocation Table, keeps track of the contents of a disk inside the table of a cluster addresses on the drive. Since Win95 OSR2 Microsoft introduced FAT32 that was designed to make FAT16 obsolete, but appears too slow in drive seeking operations. Its the only advantage is that you save few megabytes of space on a gigabyte hard drive. NTFS is a native file system for Windows NT and latter operating systems of this family (Windows 2000, Windows XP...) - incompatible with Windows 95-98, but offers a good performance, large file sizes and extended attributes (security rights etc.)
FAT16 implies a 2GB file size limit; FAT32 allows up to 4GB files, and NTFS virtually does not limit you :)

fourcc

This is a four letter string uniquely identifying the codec and datastream format used in an AVI or ASF file. For example, DivX 3.x codec uses fourcc 'DIV3', and Motion-JPEG codecs use 'MJPG'. To examine/change fourcc label you can use Edit|Info menu item in AVIedit, or use its Direct header access feature, or use our AVIfrate software.

frame rate

The speed at which individual frames change in a movie. The higher the frame rate, the smoother motion appears, but a file requires more storage space.

full-motion video

Video playback at a rate of at least 30 frames per second (fps). Unlike a TV set, on a computer screen video can play various frame speeds depending upon system resources and user requirements. Low frame rates produce a bit jerky video, but high frame rates are much more CPU horse power and HDD space demanding.

gamma

Determines the brightness of midlevel grays (midtones) of an image. Adjusting the gamma lets you change the brightness values of the middle range of gray tones without noticeable changes of shadows and highlights.

header

Short but important part of the avi file that contains information about the codec used to create file, frame rate, picture width and height and some other properties necessary for a player or video editor. In AVIedit, you can edit the header without a rendering the entire file, using File/AVI Header menu item.

IEEE 1394, FireWire, or iLink

Name of the standard for a high-speed connection between PCs, storage devices, digital video cameras etc. In AVIedit, use Options|Preferences dialog box (namely, the Capture tab) to disable legacy VFW support and therefore make AVIedit capture engine WDM-compatible. This way, any new device that uses Windows Driver Model (WDM for short) will work with AVIedit, including DV camcorders connected through a 1394 card.

index

Part of the avi file, mainly located at file end. Includes a list of all video frames in a file and all audio samples. When download of a file is interrupted, a file looses the index, so many software tools can not open it or play it anymore.

key frame

A frame that is stored without subtracting the adjacent frames information. It takes more storage space than delta-frame, but it is independent from other movie frames. Keyframes are used to prevent accumulated compression errors.

Motion-JPEG, MJPG

Very popular compression method, it is similar to one used in JPEG images. Currenly MJPEG is implemented both in hardware and in software, so you can easily edit the avi's compressed using MJPG codec even without a hardware used to obtain the file. Most of modern cameras allow you to take short movies - and they use MJPEG. Compared to Cinepak or Indeo codecs, MotionJPEG is much faster, but offers a bit smaller compression ratios with superior video picture quality.
Many current camera vendors use MJPG compressor to produce a short avi movies (by mistake called 'QuickTime movies') - see FAQ topic.

movie

The same as film, that is, a video stream with audio combined in a single file.

MPEG, MPEG1, MPEG2

A compression algorithm and file format developed by Motion Picture Experts Group. For real life pictures MPEG offers a good compression ratio (say, better than Microsoft RLE and Microsoft Video codecs). However, the keyframe-based (temporal) compression and variable bit rate that make MPEG popular for delivery of final video require significant processing time and introduce visible video quality loss on edits. There are several types of MPEG. The version generally used for Internet and CD-ROM is MPEG-1, which provides picture quality comparable to VHS. MPEG-2 can provide SVHS and DVD picture quality, depending on bitrate. Currently MPEG1 is outdated format and the only reason to use it is the existence of many hardware-based standalone CD and DVD players.
AVIedit can import MPEG1 files by converting them to optionally compressed AVI's.

MPEG4

An advanced compression algorithm developed by Motion Picture Experts Group. Microsoft has created first working codec .DLL and used it in NetShow tools, Windows Media tools, ASF tools and other packages. After it has crippled the codec, so that third-party VCM-compatible video editors couldn't use it anymore, the group of hackers patched the codec and published it under DivX title. Of course, DivX is illegal but it works as like Microsoft MPEG4 codec should be :)
To get the list of all the installed video codecs, use AVIedit's reporting feature: select the Options|ICM menu item.

OpenDML

Avi files use the RIFF file format which is limited to 32 bits size header fields. This is why conventional avi files are limited to 2GB in size. OpenDML specification allows the file to be multi-part (multi-header), thus eliminating the barrier. Some tools are OpenDML compatible, some are not.

overlay

Hardware based video rendering method. The capture card places the video frames directly into the SVGA card memory. This method does not require additional CPU power to support live video display while you capture.

plugin, plug-in

A plug-in is usually a DLL file that you add/install into some other program to increase the functionality of that program. A plug-in cannot be used as a stand-alone application. AVIedit supports plug-ins that are compatible with Adobe de-facto standard. In other words, you can use the same plug-ins that work with Adobe Photoshop (tm), JASC Paint Shop Pro (tm) and other similar software. Of course AVIedit can not support all the possible filters, but most of them will work.

PNG, Portable Network Graphics

The image compression and storage format. It offers nearly the same compression ratio as the PKZIP archiver. Unlike the JPEG, it does not introduce any quality loss. PNG is supported by current web browsers and was meant to replace GIF images worldwide (because the GIFs use patented LZW compression algorithm). AVIedit supports reading of both PNGs and GIFs.

preview

Software based video rendering method. Unlike the overlay, this one requires CPU operation to copy video frame data from a capture card to the display card. The advantage of this method is that any complex image processing, like crop/resize, color balance, denoise etc. can be done at the same time - and in a hardware-independent way. In AVIedit, you can turn it on using Capture/Preview menu item.

RGB, RGB555, RGB24

Method to define pixel colors using Red, Green, and Blue primary colors. The desired color is produced by addition of these red, green and blue color intensities and mainly used for computer monitor displays. Also there is a way to define image color depths. For RGB555 each channel can have 32 levels of intensity, so totally you can define up to 32K different colors at a time (so-called HiColor mode). RGB24 offers you a much better choise of colors - 256 levels (8 bit) per channel, and 24 bit / 16M colors at a time. However, bitmaps that have the same dimensions but different bit depths, RGB555 and RGB24, will differ in file size, too. Better colors require up to 30% more HDD space.

T1

A type of network connection able to transmit at 1.544 megabits per second. T1 and similar lines make up the Internet. Although T1 lines can support video, it is not broadcast TV-quality. However, a video stream being compressed with MPEG-4 algorithm offers at this data rate much better visual quality than S-VHS VCR.

timeline

A method of video editing that focuses on the timing of your clips. In AVIedit, select Edit/Timeline menu item, or click this

button.

transition

The method of smoothly moving from one video clip or photo to another. In AVIedit timeline editor, to add/change transitions, place the mouse pointer into the common area of two overlapped clips and click left mouse button.

Web cam

A small camera (without a tape or moving parts inside) that allows users to view pictures or motion video over the internet. The term webcam is also used to call sites that display images of a people activities through a web page.

.WMV Windows Media Video file

Formerly known as .ASF file format from Microsoft
A .WMV file includes a video stream (compressed using MS MPEG4 or WMV1 codec) combined with WMA encoded audio stream. The file format is proprietary and backward incompatible. Currently, dedicated to slow dialup connections, this media format does not allow even sub-VHS video quality due to blurred picture. WMA audio quality, compared to MPEG Layer3 of the same bitrate, isn't better either.
You may wish to use Windows Media format to create smallest files that are suitable to send by e-mail, however you must keep in mind that .WMV file works like "one way ticket" - once created, it can't be edited anymore, without horrific quality loss. As opposite, AVI files compressed with MPEG4 video codec are still editable and often it is possible to retain source video quality.