Perfect Image Video

Understanding Video Codecs

PIV — Tue, 26 Jul 2011 22:47:02 +0000

When you talk about “watching a video,” you’re probably thinking about a combination of one video and one audio stream. They are not two different files, you just have the video file. It could be an AVI file, MP4 file or another kind of video codec. These are just container formats, like a ZIP file that hold multiple kinds of files within it. The container format defines how to store the video and audio streams in a single file.

When you “watch a video,” your video player is doing at least three things at once:

Interpreting the container format to find out which video and audio tracks are available, and how they are stored within the file so that it can find the data it needs to decode next
Decoding the video stream and displaying a series of images on the screen
Decoding the audio stream and sending the sound to your speakers

A video codec is an algorithm by which a video stream is encoded. Your video player decodes the video stream according to the video codec, then displays a series of frames on the screen. Most modern video codecs use all kinds of tricks to minimize the amount of information required to display one frame after the next. Some videos don’t actually change all that much from one frame to the next which allows for high compression rates resulting in a smaller file sizes.

There are lossy and lossless video codecs. Lossless video is much too large to be useful on the internet, so let’s focus on lossy codecs. A lossy video codec means that information is being irretrievably lost during the encoding process. Like copying an audio cassette tape, you’re losing information when encoding the video source, and degrading the quality every time you encode. Instead of the “hiss” of an audio cassette, re-encoding a few times will make the video look blocky, especially during scenes with a lot of motion. (This can happen even if you encode straight from the original source, if you choose a poor video codec or set the wrong parameters.) On the bright side, lossy video codecs can offer amazing compression rates by smoothing over blockiness during playback, to make the loss less noticeable to the human eye.

Duplication vs. Replication

PIV — Tue, 26 Jul 2011 22:44:23 +0000

Perfect Image Video will duplicate your CD or DVD disc when you need them in small quantities of up to 500 copies. On occasion we will do more than 500 disc when your dead line is 2 to 3 days. We duplicate your disc directly from your CD or DVD master and each duplicate copy will be an exact match. Once the duplication process is complete we have several printers to print your image directly on the disc and are capable of printing over 2000 disc per day. If your order requires paper printing we have a full print department to handle any size order. The advantage of the duplication process is you can order any quantity and the turnaround is usually 24 – 48 hours.

CD/DVD replication is done when you order 500 copies or more. Replicated discs are stamped from a glass master that is made from your original CD or DVD. The glass master is used as a mold to create an exact replica of your master disc. The process involves injecting melted high grade plastic onto the master mold to form the disc. We then apply a thin layer of metal to provide a reflection needed for the CD or DVD players to read. The metal layer is coated with lacquer and UV cured for protection. The disc face is now ready to be printed on and packaged to your needs. The advantage of replication is a lower price based on quantity. Most orders are complete in 5 – 7 working days.

Can I Edit From My DVD?

PIV — Tue, 26 Jul 2011 22:01:33 +0000

Here is a question we get all the time.

If your video is available on video tape then it would be a better choice to convert it to a hard drive in either an AVI or Quicktime format. If your only choice is a DVD then ripping software can do the job. Ripping the audio and video files off the DVD will not give you the same quality as digitized video since the DVD is already a compressed format. Once the information is ripped and compressed into an editable format you are ready to go.

The ripping software we recommend is an open source program call Handbrake and can be used on a PC or a Mac. Below I have included the link.

http://handbrake.fr/downloads.php