A closer look at video codecs and containers

A DIGISTOR Professional Video SSD provides a convenient, reliable and high-capacity medium for capturing and storing uncompressed video. When using an SSD for video capture, however, a videographer may often work with a variety of different video formats, so it is key to know the differences between them, and what their implications are for writing to storage.

Videomaker contributing editor Kyle Cassidy pointed out that videographers typically have a large, high-quality digital file that serves as the master copy. From that, they can make a variety of copies suitable for different distribution methods, such as DVD, Blu-ray or online streaming. The original file should be kept at its uncompressed size. Copies may need to be compressed in order to be more readily sharable, but videographers should avoid additional compression that can produce low-resolution images.

"While digital files do not degrade in quality during copying, every time they are compressed with a 'lossy' compression they lose data, so converting your uncompressed DV formatted files even into a high-quality MP4 will result in a loss of quality," explained Cassidy.

Understanding codecs and containers
Video applications have a container that encases the data, as well as a codec that permits the compression and decompression of the file, usually in a lossy way. When creating a file version for a particular medium, videographers may need to consider the aspect ratios, usable bit​ rates and platform-specific support of these containers and codecs.

For example, the popular Audio Video Interleave container does not have a method for specifying an aspect ratio, meaning that videos meant to be seen in 16:9 could show up in 4:3. However, this issue is less prevalent on video players that allow users to select an aspect ratio.

The H.264 codec, which uses the Advanced Video Coding High Definition container, is a standard way for compressing Web video and Blu-ray data, and is notable for its ability to work at both low and high bit​ rates. In the case of Web video, it sends a low resolution stream for quick loading, whereas with a home HD movie it would instead use a high bit​ rate for maximum quality.

In a paper for Media Matters, Texas Instruments' Jeremiah Golston underscored the importance of being comfortable with a wide range of codecs. He characterized modern codecs such as H.264 and WMV9 as offering up to twice the quality of their predecessors, with improved compression ratios.

"The proliferation of multiple standards and proprietary algorithms make it difficult to select one standard especially since hardware decisions are often made far in advance of the product deployment," wrote Golston. "Also t]he growing trend toward networked connectivity means that many products will increasingly have to support more than one standard." 

DIGISTOR's SSD drives ensure that videographers can capture uncompressed video for editing and reproduction. Specifically optimized for Blackmagic hardware, these SSDs are available with up to 480 GB of capacity and can be bought in convenient multi-drive packs.

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