PAL to NTSC Conversion Services
The movie tape that you bought in a foreign land, most likely will not play in your VCR and also, you will not be able to watch it on your TV.
It is also true the other way round.
Video standards differ from country to country.
There are three types of video standards that are being used in the world and these are, PAL, NTSC and SECAM.
PAL standard is used in Western Europe, South America, Australia, New Zealand, India, and China.
South America uses the derivatives of the PAL system, PAL-M, PAL-N, PAL with the Unites States using National Television Standards Committee (NTSC).
SECAM is being the standard in France and some other neighbouring countries of France, which were once under the French colonial rule.
Every part of the world uses a mixture of these standards and as a result, video tapes from one part of the country are found to be incompatible with the standard prevalent in the other.
It is interesting to note as to why this difference in standards were first created.
In order to work, TV receivers need to have a source for its field timing reference signals.
The timing signals enable the TV to receive the next frame in a synchronised manner, that is, these signals tells the TV to be ready to receive the next picture in the stream of images.
At the beginning of early design consideration, TV designers decided to use the mains power frequency as a source to generate the synchronisation signals.
The decision to do so had two very good reasons.
In old designs of power supply, you would get the rolling hums in the TV picture tubes, which happened because of the mismatch of the TV power supply frequency with that of the main power supply.
The TV cameras in those days would have much flicker which created enormous problem when shooting programs.
There are two main power frequency standards that are being used in the world - 50Hz and 60Hz.
This immediately divided the world into different TV standards, with one having 25 frames per second (50Hz) and the other, 30 frames per second (60Hz).
At a later time, the 60Hz standard frequency was adjusted to 59.
94Hz in order to accommodate colour signals.
The issue relating to field frequency remained with the design, even after the original technical reasons had gone.
The biggest problem regarding TV standards remain related to the field rate and it is hard to find a solution.
Besides the difference between the standards using 50Hz and 60Hz, further division appeared since the time the colour broadcasting came in.
The majority of the 60Hz countries started to use a technology called NTSC standard, developed in the United States by a committee called the National Television Standards Committee.
With NTSC a video or closed circuit environment works perfectly, while a broadcasting environment displays a hue of different colours with this standard.
Most of the countries using 50Hz as their main power frequency have adopted the PAL standard.
It is not that the PAL system is the only colour system standard using the 50Hz main power frequency, the French developed their own SECAM (SEquential Couleur Avec Memoire) standard.
This they did for some political reasons, mainly to protect the interest of their own TV manufacturers.
SECAM has been also adopted by most of the East European countries, in order to be different with its western counterparts.
PAL Technology PAL technology was developed in Germany by Walter Bruch, and was first introduced in the year 1967.
It is an analog video format used in television transmission and is widely used in Europe, Australia and some Asian, African, and South American countries.
Within Europe - France, Bulgaria, Russia, Yugoslavia, and some other countries in Eastern Europe mainly uses SECAM technology.
PAL system uses 625 lines per frame, with the refresh rate at 25 frames per second, inter-laced.
This interlacing feature improves the picture quality without consuming any extra bandwidth.
In PAL system, each frame consists of two fields, which is termed as half-a-frame.
In each of these two fields, the first one displays all the even lines and the other one displays the odd, within these 625 lines.
These two fields are displayed in succession and there are 50 fields per second, corroborating with the 50Hz mains power frequency.
There are variants in PAL.
PAL-M is a combination of PAL and NTSC, using 525 lines per frame at 60Hz.
This standard is used in Brazil, while PAL-N is another derivative of PAL, using narrow bandwidth and the standard is used in Argentina, Paraguay, and Uruguay.
United Kingdom uses the other variant of PAL, PAL-I, with other European countries using PAL-B/G.
PAL60 is similar to NTSC and uses 59.
94 fields per second.
It is used mainly for displaying NTSC video or DVD on a PAL TV set.
NTSC Technology The video standard in the United States have been set by the National Television Standards Committee, which is called NTSC in short.
This standard has been adopted in other countries as well, such as, Japan.
NTSC standard has 29.
97 interlaced frames of video a second, often specified as 30 frames per second, with 525 lines per frame.
Out of these 525 lines, 480 lines are used for vertical resolution and the rest are used for synchronisation, vertical retrace, and other data such as captioning.
The scan lines in NTSC are interlaced, with two fields containing the odd scanned lines and the even ones respectively.
This provides a near flicker free image utilising 59.
94Hz refresh rate, which comes to 60 cycles at 1.
001 seconds.
This is close to 60Hz alternating current power used in the United States.
In trying to convert NTSC to PAL or SECAM, the most difficult part is the mismatch of the frame rate between the three.
In the process of this conversion, the equipment used is made to guess the contents of the intermediate frames which introduce artifacts.
This is quite detectable by trained eyes.
A frame consists of a packet of composite image information and the 525 lines per frame in the NTSC standard may contain up to 16 million colours.
A composite signal would mean a video signal which contains all the colours, such as, red, blue, and green signals and may also consist of audio signals.
Radio interferences is known to disturb NTSC transmission, therefore by the time the picture gets transmitted on to your TV screen, the picture often loses its colour balance.
This necessitates the inclusion of a "tone" or "hue" control on NTSC sets, which is not necessary in PAL and SECAM TV sets.
Further more, some observers find that with NTSC, the 525 line resolution of NTSC results in a lower quality image than the hardware is capable of.
SECAM Technology SECAM is the short form of Sequentiel Couleur avec Mémoire, French for "sequential color with memory".
This is an analog system which uses Frequency Modulation (FM) for encoding the chrominance information.
SECAM technology stores the lines of colour information in a memory.
This does not produce the colour artifacts that are found in the NTSC systems.
SECAM was developed with PAL as the basic design.
Contrary to PAL, it transmits Red-Yellow and Blue-Yellow information in alternate lines and they are combined by storing the video lines.
SECAM was introduced in France in the year 1967 and it is still being used.
It is also being used in the countries which were French colonies before, as well as parts of Eastern Europe, like, Bulgaria, Hungary, and former Soviet Union.
It is observed that this had a political motive, mainly with the former Soviet Union restricting their broadcasts along with its member East European countries, within its own people, making it impossible for most Eastern Europeans to view television which was broadcasted from outside the Iron Curtain which were mostly using PAL.
The Conversion - PAL to NTSC The heart of conversion is the converter itself.
There are many converters available in the market in different qualities.
There are service providers who would convert your tapes to the appropriate standard against a charge.
In converting a PAL standard to NTSC, the most difficult part is the different numbers of lines and different frequencies of fields/frames in video pictures that exist in the two standards.
Considering that that PAL has is 625 lines at 50 fields per second and with NTSC, having 525 lines at 60 fields per second, it is quite difficult to convert one to the other.
Further, generating 60 fields per second from a format with 50 fields per second is quite a challenging task.
In doing so, every second new 10 fields need to be generated out of nothing.
The converter has to create new image at the output from the PAL input signals and that too in real time.
Therefore, converting an incoming 50 frames per second PAL signal to 60 frames per second NTSC signal requires much skill, so as to use the existing information to provide a quality conversion.
If a video image can be taken as a series of individual picture elements or pixels, arranged across the screen as a grid, the number of rows can be taken as the number of lines in the displayed image.
In order to interpolate the number of lines at the output in relation to that of the input, some mathematical process is involved in placing the pixel on the output line along with the hue and luminance for each pixel.
The interpolation algorithm enables a pixel to be picked up from the video that is the input side, and placing it appropriately on the output buffer side.
Conversion interpolation methods used in converters are much the same, except that the process have a three dimensional relationship and these are, the horizontal and vertical dimensions plus the added dimension of time to account for motion between fields.
This complicates the earlier thought-out method, as we are now thinking of 3 grids to match three dimensional arrays.
The third dimension is related to time which represents motion from one field to the other.
Therefore, the relationship between the input and the output becomes complicated.
In processing a motion effectively, you need to detect the motion and its direction at the first place.
There are various kinds of converters dealing with this motion and the direction of it, in various ways.
The cheapest kind never bothers with it.
The next grade of converters is those which track the motion over two fields, while the professional grade tracks up to 6 fields.
The greater numbers of field tracked, provides more accurate predictions of motion.
In converting a PAL system to NTSC, having 625 lines @ 25 frames per second and 525 lines at 30 frames per second respectively, it can be observed that every second 100 lines needs to be dropped in the process of conversion.
With dropping 100 lines, an additional 5 frames need to be created.
In the inexpensive converters, the 100 lines are just dropped to create 525 lines out of PAL 625 equally spaced through frames.
In order to create 5 new frames, it just repeats a single frame 5 times, thus effectively adding 5 frames.
It works fine as along as the image is not moving or is in motion.
Video is a dynamic medium and with the kind of conversion just discussed, the effect is highly undesirable.
The more sophisticated converters measure the nature of motion within the video and then employing a more complex algorithm dynamically produce a corrected and well compensated output.
The mid-range converters deploy inter-field interpolation, which create new frame not by just repeating one frame but by averaging adjacent fields.
In converting PAL to NTSC, there are two method used by these converters, one being the 2-line, where the converter creates a new line by comparing adjacent two lines and the 4-line ones, creating the 5th line comparing 4 adjacent lines.
As the averaging of the adjacent lines goes up, the greater is the picture smear.
There needs to be a compromise.
As the complexity increases, the price tag of the converter goes up.
There are various other kinds of quite complex converters, which produce better and better converted output as the price of the converter goes up.
There are many service providers offering PAL to NTSC conversion with price ranging fro $20 to $40 for a 120 minute to 6 and 8 hours of play time.
When you buy a video tape in a foreign land, in a country which uses PAL, you can drop the tape with one of these service providers who would give you a converted tape on NTSC for your viewing, with some of them providing volume discount.
The prices are generally exclusive of delivery charges.
It is also true the other way round.
Video standards differ from country to country.
There are three types of video standards that are being used in the world and these are, PAL, NTSC and SECAM.
PAL standard is used in Western Europe, South America, Australia, New Zealand, India, and China.
South America uses the derivatives of the PAL system, PAL-M, PAL-N, PAL with the Unites States using National Television Standards Committee (NTSC).
SECAM is being the standard in France and some other neighbouring countries of France, which were once under the French colonial rule.
Every part of the world uses a mixture of these standards and as a result, video tapes from one part of the country are found to be incompatible with the standard prevalent in the other.
It is interesting to note as to why this difference in standards were first created.
In order to work, TV receivers need to have a source for its field timing reference signals.
The timing signals enable the TV to receive the next frame in a synchronised manner, that is, these signals tells the TV to be ready to receive the next picture in the stream of images.
At the beginning of early design consideration, TV designers decided to use the mains power frequency as a source to generate the synchronisation signals.
The decision to do so had two very good reasons.
In old designs of power supply, you would get the rolling hums in the TV picture tubes, which happened because of the mismatch of the TV power supply frequency with that of the main power supply.
The TV cameras in those days would have much flicker which created enormous problem when shooting programs.
There are two main power frequency standards that are being used in the world - 50Hz and 60Hz.
This immediately divided the world into different TV standards, with one having 25 frames per second (50Hz) and the other, 30 frames per second (60Hz).
At a later time, the 60Hz standard frequency was adjusted to 59.
94Hz in order to accommodate colour signals.
The issue relating to field frequency remained with the design, even after the original technical reasons had gone.
The biggest problem regarding TV standards remain related to the field rate and it is hard to find a solution.
Besides the difference between the standards using 50Hz and 60Hz, further division appeared since the time the colour broadcasting came in.
The majority of the 60Hz countries started to use a technology called NTSC standard, developed in the United States by a committee called the National Television Standards Committee.
With NTSC a video or closed circuit environment works perfectly, while a broadcasting environment displays a hue of different colours with this standard.
Most of the countries using 50Hz as their main power frequency have adopted the PAL standard.
It is not that the PAL system is the only colour system standard using the 50Hz main power frequency, the French developed their own SECAM (SEquential Couleur Avec Memoire) standard.
This they did for some political reasons, mainly to protect the interest of their own TV manufacturers.
SECAM has been also adopted by most of the East European countries, in order to be different with its western counterparts.
PAL Technology PAL technology was developed in Germany by Walter Bruch, and was first introduced in the year 1967.
It is an analog video format used in television transmission and is widely used in Europe, Australia and some Asian, African, and South American countries.
Within Europe - France, Bulgaria, Russia, Yugoslavia, and some other countries in Eastern Europe mainly uses SECAM technology.
PAL system uses 625 lines per frame, with the refresh rate at 25 frames per second, inter-laced.
This interlacing feature improves the picture quality without consuming any extra bandwidth.
In PAL system, each frame consists of two fields, which is termed as half-a-frame.
In each of these two fields, the first one displays all the even lines and the other one displays the odd, within these 625 lines.
These two fields are displayed in succession and there are 50 fields per second, corroborating with the 50Hz mains power frequency.
There are variants in PAL.
PAL-M is a combination of PAL and NTSC, using 525 lines per frame at 60Hz.
This standard is used in Brazil, while PAL-N is another derivative of PAL, using narrow bandwidth and the standard is used in Argentina, Paraguay, and Uruguay.
United Kingdom uses the other variant of PAL, PAL-I, with other European countries using PAL-B/G.
PAL60 is similar to NTSC and uses 59.
94 fields per second.
It is used mainly for displaying NTSC video or DVD on a PAL TV set.
NTSC Technology The video standard in the United States have been set by the National Television Standards Committee, which is called NTSC in short.
This standard has been adopted in other countries as well, such as, Japan.
NTSC standard has 29.
97 interlaced frames of video a second, often specified as 30 frames per second, with 525 lines per frame.
Out of these 525 lines, 480 lines are used for vertical resolution and the rest are used for synchronisation, vertical retrace, and other data such as captioning.
The scan lines in NTSC are interlaced, with two fields containing the odd scanned lines and the even ones respectively.
This provides a near flicker free image utilising 59.
94Hz refresh rate, which comes to 60 cycles at 1.
001 seconds.
This is close to 60Hz alternating current power used in the United States.
In trying to convert NTSC to PAL or SECAM, the most difficult part is the mismatch of the frame rate between the three.
In the process of this conversion, the equipment used is made to guess the contents of the intermediate frames which introduce artifacts.
This is quite detectable by trained eyes.
A frame consists of a packet of composite image information and the 525 lines per frame in the NTSC standard may contain up to 16 million colours.
A composite signal would mean a video signal which contains all the colours, such as, red, blue, and green signals and may also consist of audio signals.
Radio interferences is known to disturb NTSC transmission, therefore by the time the picture gets transmitted on to your TV screen, the picture often loses its colour balance.
This necessitates the inclusion of a "tone" or "hue" control on NTSC sets, which is not necessary in PAL and SECAM TV sets.
Further more, some observers find that with NTSC, the 525 line resolution of NTSC results in a lower quality image than the hardware is capable of.
SECAM Technology SECAM is the short form of Sequentiel Couleur avec Mémoire, French for "sequential color with memory".
This is an analog system which uses Frequency Modulation (FM) for encoding the chrominance information.
SECAM technology stores the lines of colour information in a memory.
This does not produce the colour artifacts that are found in the NTSC systems.
SECAM was developed with PAL as the basic design.
Contrary to PAL, it transmits Red-Yellow and Blue-Yellow information in alternate lines and they are combined by storing the video lines.
SECAM was introduced in France in the year 1967 and it is still being used.
It is also being used in the countries which were French colonies before, as well as parts of Eastern Europe, like, Bulgaria, Hungary, and former Soviet Union.
It is observed that this had a political motive, mainly with the former Soviet Union restricting their broadcasts along with its member East European countries, within its own people, making it impossible for most Eastern Europeans to view television which was broadcasted from outside the Iron Curtain which were mostly using PAL.
The Conversion - PAL to NTSC The heart of conversion is the converter itself.
There are many converters available in the market in different qualities.
There are service providers who would convert your tapes to the appropriate standard against a charge.
In converting a PAL standard to NTSC, the most difficult part is the different numbers of lines and different frequencies of fields/frames in video pictures that exist in the two standards.
Considering that that PAL has is 625 lines at 50 fields per second and with NTSC, having 525 lines at 60 fields per second, it is quite difficult to convert one to the other.
Further, generating 60 fields per second from a format with 50 fields per second is quite a challenging task.
In doing so, every second new 10 fields need to be generated out of nothing.
The converter has to create new image at the output from the PAL input signals and that too in real time.
Therefore, converting an incoming 50 frames per second PAL signal to 60 frames per second NTSC signal requires much skill, so as to use the existing information to provide a quality conversion.
If a video image can be taken as a series of individual picture elements or pixels, arranged across the screen as a grid, the number of rows can be taken as the number of lines in the displayed image.
In order to interpolate the number of lines at the output in relation to that of the input, some mathematical process is involved in placing the pixel on the output line along with the hue and luminance for each pixel.
The interpolation algorithm enables a pixel to be picked up from the video that is the input side, and placing it appropriately on the output buffer side.
Conversion interpolation methods used in converters are much the same, except that the process have a three dimensional relationship and these are, the horizontal and vertical dimensions plus the added dimension of time to account for motion between fields.
This complicates the earlier thought-out method, as we are now thinking of 3 grids to match three dimensional arrays.
The third dimension is related to time which represents motion from one field to the other.
Therefore, the relationship between the input and the output becomes complicated.
In processing a motion effectively, you need to detect the motion and its direction at the first place.
There are various kinds of converters dealing with this motion and the direction of it, in various ways.
The cheapest kind never bothers with it.
The next grade of converters is those which track the motion over two fields, while the professional grade tracks up to 6 fields.
The greater numbers of field tracked, provides more accurate predictions of motion.
In converting a PAL system to NTSC, having 625 lines @ 25 frames per second and 525 lines at 30 frames per second respectively, it can be observed that every second 100 lines needs to be dropped in the process of conversion.
With dropping 100 lines, an additional 5 frames need to be created.
In the inexpensive converters, the 100 lines are just dropped to create 525 lines out of PAL 625 equally spaced through frames.
In order to create 5 new frames, it just repeats a single frame 5 times, thus effectively adding 5 frames.
It works fine as along as the image is not moving or is in motion.
Video is a dynamic medium and with the kind of conversion just discussed, the effect is highly undesirable.
The more sophisticated converters measure the nature of motion within the video and then employing a more complex algorithm dynamically produce a corrected and well compensated output.
The mid-range converters deploy inter-field interpolation, which create new frame not by just repeating one frame but by averaging adjacent fields.
In converting PAL to NTSC, there are two method used by these converters, one being the 2-line, where the converter creates a new line by comparing adjacent two lines and the 4-line ones, creating the 5th line comparing 4 adjacent lines.
As the averaging of the adjacent lines goes up, the greater is the picture smear.
There needs to be a compromise.
As the complexity increases, the price tag of the converter goes up.
There are various other kinds of quite complex converters, which produce better and better converted output as the price of the converter goes up.
There are many service providers offering PAL to NTSC conversion with price ranging fro $20 to $40 for a 120 minute to 6 and 8 hours of play time.
When you buy a video tape in a foreign land, in a country which uses PAL, you can drop the tape with one of these service providers who would give you a converted tape on NTSC for your viewing, with some of them providing volume discount.
The prices are generally exclusive of delivery charges.
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