Monday, September 17, 2007

Video aspect ratios

On visionontv we use aproxamations for encoding the video:

for 4x3 video we use 640x480
for 16x9 video we use 800x480

Both are de-interlaced to produce progressive video, in this process we lose around 1/3 of the resolution thus the re-scaling to a smaller size. We also remove the pixal rateo and anamorphic streach in 16x9 video to produce a file that will playback with out distortion on any computer screen. Finerly it is compressed to a standerd H264 MP4 file at around 1600Kps

We could use meay other sizes this is an excert from a good artyical about aspect ratios: Some obvious image sizes in pixels to use to generate square pixel images for digital video are as follows:

NTSC D1 (720 x 486) normal

4:3 square pixels 712 x 534

Full width square pixels 720 x 534

NTSC D1 (720 x 486) widescreen

16:9 square pixels 864 x 486

Full width square pixels 874 x 486

NTSC DV (720 x 480) normal

4:3 square pixels 704 x 528

Full width square pixels 720 x 528

NTSC DV (720 x 480) widescreen

16:9 square pixels 854 x 480

Full width square pixels 874 x 480

PAL (720 x 576) normal

4:3 square pixels 768 x 576

Full width square pixels 788 x 576

PAL (720 x 576) widescreen

16:9 square pixels 1024 x 576

Full width square pixels 1050 x 576

For the full story read the full artical at perrybits