What does the digitizer do, what are the common file formats and what does the compression methods means.
The digitizer as I already mentioned is meant to digitize an analogue input. With a digitizer you can connect an ordinary analog camcorder, your TV set and a simple security camera, all of them providing analog data, to the computer and the digitizer (video capture) will make a file out of them. Note that even digital devices such as DVD has analog connection because the TV sets are mostely still analog. As a result this is a good method to ripp of a DVD and make a file out of it, skipping all the defences and making a copy.
Ordinary digitizers does not encode, the software bundled with the package can store the files in AVI (Uncompressed) or to convert it to the compressed format it supports. If no decoding is available then make sure you have plenty of memory available because AVI uncompressed can be 10 times larger then standard DVD Format. If the software support encoding to other formats its fine but the computer will hardly be able to perform any other mission as the encoding will eat most of its resources. If you have a digitizer/encoder the the computer CPU will have to concentrate only on a single mission of storing the compressed data coming out of the Encoder.
The common file formats and compression methods:
1. AVI – full frame update – uncompress formats every single frame contain all the data of each pixel in the maximum details.
2. WMV – Windows media format – belong to the MPEG4 family, highly compressed and the compression is defined by the users to suit a bandwidth as this format was designed for streaming over networks. The bigger the bandwidth you define the higher the quality the bigger the file.
3. MPEG 1 – VCD – this format is meant for Video CDs video size 354×288 high quality – not streaming therefore a file like this when you find it on the internet will be downloaded to your computer completely before it starts playing.
4. MPEG 2 – DVD – this is the native format of the DVD – 704×576 high quality though not the most optimized compression, it provides the best quality but in a quite large file size.
5. FLV – flash video file format also defined in bandwidth/quality, streaming and require a lesser buffering time.Used by all video hosting services. Our video clipmaker will save the files to FLV 360kbps in 320×240.
6. Divx and Xvid – out of the mainstream video compression allows compressing MPEG2 files in 1:3 ratio and still maintain a good quality
Of course there are plenty of variation of each format, but they are neglectale.
Next time: Explaining the concept of video compression
