Archive for category Video and motion graphics
Flash video codec issues
Posted by Steve Wylie in Online presentations, Video and motion graphics on March 12, 2006
I have been using FLV (Flash video) to publish short video clips to my blog recently. It’s a really user friendly way for viewers to view short clips without having to download plug-ins, load helper applications, or download files and open them in various applications.
There is, however, a down side.
Flash 7 shipped with support for the Sorenson Spark compression codec, while the newer Flash 8 ships with support for Spark, and a newer, far more efficient codec, ON2 VP6. VP6 produces brilliant images in contrast to Spark, and at lower file size to quality ratios; however it’s not supported in older versions of Flash, which many users will still be using.
I’ve also been puzzled lately as a couple of people who I told to download Flash 8 were still unable to view the file (they could hear the audio but not see the video) even after they’d downloaded the new version of Flash player. I’m not entirely sure why this would be the case. Puzzling at this stage.
Above: Screenshot Flash 7 using Sorenson Spark codec
Above: Screenshot Flash 8 using newer ON2 VP6 codec
Quick guide to anamorphic video
Posted by Steve Wylie in Video and motion graphics on March 10, 2006
What is anamorphic?
Anamorphic video is footage that was recorded at a native wide aspect ratio, but has been vertically stretched to fill a 4:3 resolution format so that it can make best use of the available resolution.
Why use anamorphic?
If you purchase a movie on VHS tape today, you will most likely see black bars above and below the viewable image – this is referred to as letterboxed footage, and is produced to automatically correct the aspect ratio of a video to 4:3.
Of a total of 768×576 pixels available in PAL 4:3 video, letterboxing reduces the actual resolution of the video, and so reduces the final quality and definition of the viewable image. By stretching widescreen video to fit the entire 4:3 resolution, and then compressing the video back down when it’s replayed, you’re able to utilize the full available resolution and still maintain the aspect ratio.
Due to a lack of support for automatically resizing anamorphic video on most tape formats (such as VHS, Betacam SP, and DVCAM), anamorphic distribution on tape is usually only utilized for professional formats which are designed to be used in conjunction with processing equipment that can resize the image as it is played out from a VTR (videotape recorder).
Where can I see anamorphic footage?
The DVD format accommodates anamorphic footage, supporting the automatic resizing (or aspect ratio correction) on DVD players, which can automatically letterbox footage for playback, but allows 16:9 ratio DVDs to utilize the total 720×576 pixels available to DVD recordings.
Why use letterboxed anamorphic?
The 16:9 aspect ratio is an industry standard, along with 4:3. DVD and similar formats – along with much consumer equipment such as widescreen LCD and plasma displays support ARC (aspect ratio conversion) between 4:3 and 16:9 images.
However, many films and artistic video productions rely on an even wider aspect ratio to enhance depth of field and create dramatic and aesthetic effects. The aspect ratios used in film are many and varied and there are no real standards. If consumer and professional equipment was to support any possible resolution it would become expensive and complicated to configure and use – certainly not a feasible option for consumer equipment.
As a result, most films that are recorded in a wider aspect ratio are stretched to the same degree as if the footage was 16:9, and then the rest of the ratio is corrected using letterboxing. It’s a compromise that combines standardisation and the best possible quality on consumer equipment.
In a professional environment, most wide aspect ratio footage is anamorphic to a 16:9 ratio and then letterboxed further to correct as required – even though most professional equipment could cater for resizing to any aspect ratio – mainly out of desire for standards and consistency.