NTSC and PAL are two types of color coding systems that affect the visual quality of content viewed on analog televisions and, to a much lesser extent, content viewed on high definition televisions. While NTSC provides 30 frames per second (fps) at 720×480 aspect ratio, PAL uses 25 fps and 720×576 aspect ratio. The PAL system offers automatic color correction compared to manual NTSC color correction. NTSC is popular in countries like the USA and Japan, while PAL is more common in countries like the UK, Australia, and Sweden.
There is a third standard called SECAM (Sequential Couleur Avec Memoire or Sequential Color with Memory) that is used in Eastern Europe and France.
Comparison table
NTSC vs PAL Comparison Chart
| NTSC | PAL | |
|---|---|---|
| current rating is 3.57 / 5 (570 evaluations) | current rating 4.05 / 5 (777 estimates) | |
| abbreviation | National Committee on Television System | Phase rotation along the line |
| Video bandwidth | 4.2 MHz | 5.0 MHz |
| Sound carrier | 4.5 MHz | 5.5 MHz |
| Bandwidth | 6 MHz | 7 to 8 MHz |
| Vertical frequency | 60 Hz | 50 Hz |
| Horizontal frequency | 15.734 kHz | 15.625 kHz |
| Color subcarrier frequency | 3.579545 MHz | 4.433618 MHz |
| Lines / Field | 525/60 | 625/50 |
Countries using NTSC versus PAL
NTSC systems are mainly limited to North America, parts of South America, Japan, Taiwan, the Philippines, and South Korea. PAL systems are much more common throughout the world and can be found in Australia, most of Western Europe, China, parts of Africa, India, and elsewhere. The third system, known as SECAM, is located in France, Russia, and parts of Africa.
Differences in PAL and NTSC color coding
PAL manages color automatically using the phase rotation of the color signal, which eliminates tint errors. In addition, chroma phase errors have been eliminated in PAL systems. NTSC receivers have manual hue control for color correction, so if colors are not clear, the higher saturation of NTSC systems makes them more visible and adjustments need to be made.
Another technical aspect is that interleaved color information – Hanover stripes – can lead to graininess in the image if there are extreme phase errors. This can happen even in PAL systems, especially if the decoder circuits are not properly aligned, or with earlier generation decoders. However, such extreme phase shifts are more commonly seen in ultra-high frequency (UHF) signals (less robust than VHF) or in areas where terrain or infrastructure restricts transmission paths and affects signal strength.
A PAL decoder can be thought of as a pair of NTSC decoders:
- PAL can be decoded with two NTSC decoders.
- By switching between two NTSC decoders every other line, PAL can be decoded without a phase delay line or two phase-locked loops (PLLs).
- This works because one decoder receives a phase-inverted color subcarrier with respect to the other decoder. It then cancels the phase of that subcarrier during decoding. This results in the elimination of smaller phase errors. However, a PAL decoder with a delay line gives excellent performance. Some Japanese TVs originally used the dual NTSC method to avoid paying Telefunken royalties.
- PAL and NTSC have slightly different color spaces, but differences in color decoders are ignored here.
- PAL supports SMPTE 498.3 and NTSC complies with EBU Recommendation 14.
- This technical explanation ignores the issue of frame rates and color subcarriers. These technical details do not play a direct role (apart from subsystems and physical parameters) for signal decoding.
Image quality in NTSC versus PAL
PAL lines come out at 50 fields per second (since Europe uses a 50 Hz power supply), that is, 25 variable lines. PAL TVs display 25 frames per second, which makes motion display faster. PAL can have fewer frames per second, but it also has more lines than NTSC. PAL television broadcasts have a resolution of 625 lines, compared to 525 lines for NTSC. The more lines, the more visual information, which means better image quality and resolution.
Conversion from NTSC to PAL and vice versa
If a PAL movie is being converted to NTSC tape, add 5 additional frames per second, otherwise, the action may appear choppy. The opposite is true for the NTSC movie converted to PAL. You need to shoot five frames per second or the action may seem unnaturally slow.
PAL and NTSC on HDTVs
There is still a wide analog system for television, so while digital and high definition (HD) signals are becoming a universal standard, variations remain. The main visual difference between NTSC and PAL systems for high definition televisions (HDTVs) is the refresh rate. NTSC refreshes the screen 30 times per second, while PAL systems refreshes 25 times per second. For some types of content, especially high-resolution images (such as those created with 3D animation), HDTVs using the PAL system may show a slight tendency to “flicker”. However, the picture quality is the same as NTSC and most people won’t notice any problem.
