Standards and resolution are both fundamental properties which define a video.
Two associated properties are the geometry and the FPS number.
Standard
Standards are a historic feature which continues today in spite of technological progress.
A rich literature on this subject can be found on the internet.
To simplify things we shall summarize as follows:
- PAL is effective in all the countries where the electricity network is 50 hz (which is the case, for example, for Western European countries)
- NTSC is effective in all the countries where the electricity network is 60 hz (which is the case, for example, for the United States of America)
Geometry
The geometry is the ratio of Width to Height.
- 4:3 corresponds to screens that are almost square
- 16:9 corresponds to screens that are rectangular
- 40:17 corresponds to cinema screens in overall size
Resolution
Unlike with photos, video resolution is not expressed in megapixels but in number of points (pixels) shown by the screen multiplied by the number of lines.
So, 320x240 corresponds to 320 points of width and 240 lines in height
FPS (Frames per second)
Corresponds to the number of images shown every second. You should know that in cinemas, 24 images are shown per second and this figure of 24 images is recognized as corresponding to the maximum number of images which the eye is capable of differentiating:
- More images per second and the eye does not notice it
- Fewer images per second and the film appears jerky
Matrix of combinations managed by ffDiaporama
The following table indicates all the combinations of geometry, standards and resolutions managed by ffDiaporama.
For every combination, it indicates the number of associated FPS:
Name |
Geometry |
PAL |
NTSC |
Remark |
Resolution |
FPS |
Resolution |
FPS |
RIM 240 |
4:3 |
240x180 |
24 FPS |
240x180 |
24 FPS |
Special format used on Blackberry's very small screen |
6:9 |
240x136 |
240x136 |
40:17 |
QVGA |
4:3 |
320x240 |
25 FPS |
320x240 |
29,97 FPS |
Used mainly on the Internet and by first generation smartphones and mobile video players. |
16:9 |
320x180 |
320x180 |
40:17 |
320x136 |
320x136 |
HVGA |
4:3 |
426x320 |
426x320 |
Used mainly on the Internet and by second generation smartphones and mobile video players.
Because this format does not respect the traditional video geometry, black bands appear to fill the screen to 480x320. |
16:9 |
480x270 |
480x270 |
40:17 |
480x204 |
480x204 |
VGA |
4:3 |
640x480 |
640x480 |
Used mainly on the Internet and by some smartphones. |
16:9 |
640x360 |
640x360 |
40:17 |
640x272 |
640x272 |
SD-DVD |
4:3 |
720x576 |
720x480 |
The old television format for cathode ray tubes. Note that this format was specifically created for equipment with oval points: It is the anamorphism of the points that determines the geometry. That is why it is absolutely necessary to avoid this format for anything other than television sets with cathode ray tubes. |
16:9 |
40:17 |
WVGA |
4:3 |
640x480 |
640x480 |
Used mainly on the Internet and by new generation smartphones and mobile video players. This format has become widespread and has replaced the old QVGA, HVGA and VGA format used in the years 2000-2010. Because this format does not respect the traditional video geometries, black bands appear to fill the screen to 800x480. |
16:9 |
800x450 |
800x450 |
40:17 |
800x340 |
800x340 |
XGA |
4:3 |
1024x768 |
1024x768 |
Historically this format was used only by computers (fixed or portable). Now we meet it more and more on tablet computers like the iPad. |
16:9 |
1024x576 |
1024x576 |
40:17 |
1024x436 |
1024x436 |
720p |
4:3 |
960x720 |
960x720 |
23,976 FPS |
Today, this format is widely used on the Internet, in particular by social networking and video-sharing sites. We also find it on certain "home cinema" devices. |
16:9 |
1280x720 |
1280x720 |
40:17 |
1280x544 |
1280x544 |
1080p |
4:3 |
1440x1080 |
1440x1080 |
This is the real "home cinema" format. It is used by the Blue Ray players and the "home cinema" devices. |
16:9 |
1920x1080 |
1920x1080 |
40:17 |
1920x816 |
1920x816 |
Note that many other resolutions exists but which are not used by ffDiaporama.