The different formats of the converted video in the video format determine the performance of the signal in terms of brightness, chromaticity, contrast, sharpness, sharpness, and maximum resolution.
From the analysis of various video formats, we can know that the level of video high-definition quality can be roughly sorted as right (from high to low): among them, the highest level of DVI digital video signals are currently selected, but there are only short distances. Disadvantages of transmission (effective distance is about 5 meters), SDI digital video has the advantage of being editable and longer-distance transmission. RGBHV and VGA are actually unified signals, but there are two kinds of names due to different components of the signal, S- Video has a significant improvement in brightness utilization compared to Video (short for composite video) and effectively eliminates color creep. The RF format is the lowest level signal and is only used in the range of surveillance and public television.
Engineering applications often face many conversion processes for signal formats. Which of these different formats of signal conversion need to follow?
What effect will it ultimately have?
Generally considered:
The low-level format has a significant quality improvement to the high-level format conversion, such as the early multi-frequency scanner or quadruple-frequency scanner, and the current popular intelligent video regulator, which is Video-RGBHV (composite video-component video) The conversion process has a significant improvement in improving the quality of the signal. Because these products use multi-bit digital technology, signal quality (sharpness, brightness, signal-to-noise ratio) can be highly restored.
DVI digital video is usually converted to SDI or RGBHV, and the resolution of the original signal is lost after conversion, but the DVI signal is transmitted over long distances;
The actual effect of converting VGA signals into RGBHVs has not been improved because they are equivalent, but solve the problem of synchronous universal matching of VGA signals and enable longer distance transmission.
The process of converting high-level formats to low-level formats (such as VGA to Video) can cause serious damage to any aspect of the original signal, including brightness, chrominance, color, contrast, sharpness, sharpness, and maximum resolution. This conversion does not make any sense, but it has a certain value in the early days, such as: converting the computer's VGA signal into Video for tape recording, TV TV wall display, or for "grabbing" transmission in video conferencing.
High-level conversion to low-level video formats
The inherent scan jitter standard video signal consists of a set of scan lines, not all of which are visible. In the NTSC system, there are 483 visible lines, and 576 in the PAL and SECAM formats. TV video images with a small number of lines are limited in displaying very small text or other complicated details. In contrast, the number of scan lines of a computer display device can range from low resolution (≤ 480 bars) to high resolution (≥ 1280 bars).
Many new computer graphics cards now allow users to choose between several different display resolutions. Obviously the higher the resolution, the better the details of the text and images. The television signal is interlaced, meaning that each screen "picture" is actually composed of two fields, that is, two fields consisting of odd and even lines, respectively. First, the odd lines are scanned and then blanked, and then the even lines are scanned between the original odd lines. The odd and even fields that are displayed in turn and then hidden make the image with a certain shape susceptible to significant jitter, especially those thin horizontal lines.
In contrast, computer signals are generated using non-interlaced signals, also known as "progressive" methods. All scan lines are swept in order from top to bottom and left to right, regardless of parity. This eliminates the image jitter problem caused by interlaced scanning in television systems.
Signal Format Compatibility NTSC, PAL, and SECAM are several common standard TV video signal formats that specify the number of lines of the displayed image, the definition of the color information, and the speed of the scan line (ie, the refresh rate).
There are also many different formats for these formats, such as composite video, S-Video, and D1 (digital) video, but all of these formats have a lot in common. For example, they are all interlaced, with a scan line number of 483 (NTSC) or 576 (PAL and SECAM), all with a fixed refresh rate. The two interlaced fields of NTSC form one frame, appearing 30 times per second (30 Hz), and for PAL and SECAM systems, 25 times per second (25 Hz).
Unlike TV video, computer video signals do not have a single standard that must be adhered to. The range of resolution and refresh rate is wide, and the refresh rate is generally between 60 Hz and 85 Hz. Although computers do not display images in interlaced mode, some graphics cards provide interlaced display capabilities.
In any case, the computer video signal delivers chroma and luminance information to the monitor in the same way. All VGA, SVGA, and Mac computer video formats pass red, green, and blue information as separate signals (components). Thus, this allows the computer to display a wide range of colors without distortion, while the most common television video format combines red, green, and blue information into a single signal (chroma) that is passed to the monitor.
The process of converting a high-level format to a low-level format is generally implemented by a scan converter. This technical concept sounds very simple. Even if people agree with the design concept, there are still many technical factors to consider:
The computer input compatibility of the scan converter is compatible with the maximum resolution of the computer. How much does it require "genlock" - the color sampling rate of the scan converter. The quality of the encoder of the scan converter. How does the output of the video signal have a built-in? Test pattern
Anyone familiar with computer resolution knows that the number of video lines does not meet the standard resolution. Therefore, when the above signals are input to a projector or a display device, there is an incompatibility problem, which is expressed as follows:
The pixel of the picture is missing. Most of the details cannot be reproduced. The image is stretched or distorted, and only the information can be reproduced.
The projector or display device enforces compatible processing of the input image. This additional processing often degrades the image quality (human factors, similar to the ladder correction function).
Another limitation is the vertical refresh rate generated by the scan converter. The vertical refresh rate of the output signal from the scan converter is up to 60Hz or 50Hz, depending on whether the output signal is NTSC or PAL/SECAM, and many projectors can be input. And display a higher refresh rate to provide a better image quality. When using a scan converter, the image displayed by the projector at a lower refresh rate is limited.
Loss of the projector's native resolution LCD and DLP projectors or PDP display devices are often used with scan converters or video conditioners. These devices use pixels to display images. The number of pixels is called intrinsic resolution. rate. Although many projectors can display images with lower resolution than the native resolution, the quality of the displayed image is highest at the native resolution. For example, a projector with an inherent resolution of 1024×768 can display a picture with a resolution of 800×600, but its effect is better than displaying an image with a resolution of 1024×768, because the resolution is 1024×768 for each of the images. point corresponds to the native resolution of each pixel of the projector 1024 × 768, so that the display color is very clear, as no resolution of 800 × 600 display an image that needs to be compensated color video decreased sharpness of the image caused by The different formats of the formatted converted video determine the performance of the signal in terms of brightness, chromaticity, contrast, sharpness, sharpness, and maximum resolution.
From the analysis of various video formats, we can know that the level of video high-definition quality can be roughly sorted as right (from high to low): among them, the highest level of DVI digital video signals are currently selected, but there are only short distances. Disadvantages of transmission (effective distance is about 5 meters), SDI digital video has the advantage of being editable and longer-distance transmission. RGBHV and VGA are actually unified signals, but there are two kinds of names due to different components of the signal, S- Video has a significant improvement in brightness utilization compared to Video (short for composite video) and effectively eliminates color creep. The RF format is the lowest level signal and is only used in the range of surveillance and public television.
Engineering applications often face many conversion processes for signal formats. Which of these different formats of signal conversion need to follow?
What effect will it ultimately have?
Generally considered:
The low-level format has a significant quality improvement to the high-level format conversion, such as the early multi-frequency scanner or quadruple-frequency scanner, and the current popular intelligent video regulator, which is Video-RGBHV (composite video-component video) The conversion process has a significant improvement in improving the quality of the signal. Because these products use multi-bit digital technology, signal quality (sharpness, brightness, signal-to-noise ratio) can be highly restored.
DVI digital video is usually converted to SDI or RGBHV, and the resolution of the original signal is lost after conversion, but the DVI signal is transmitted over long distances;
The actual effect of converting VGA signals into RGBHVs has not been improved because they are equivalent, but solve the problem of synchronous universal matching of VGA signals and enable longer distance transmission.
The process of converting high-level formats to low-level formats (such as VGA to Video) can cause serious damage to any aspect of the original signal, including brightness, chrominance, color, contrast, sharpness, sharpness, and maximum resolution. This conversion does not make any sense, but it has a certain value in the early days, such as: converting the computer's VGA signal into Video for tape recording, TV TV wall display, or for "grabbing" transmission in video conferencing.
High-level conversion to low-level video formats
The inherent scan jitter standard video signal consists of a set of scan lines, not all of which are visible. In the NTSC system, there are 483 visible lines, and 576 in the PAL and SECAM formats. TV video images with a small number of lines are limited in displaying very small text or other complicated details. In contrast, the number of scan lines of a computer display device can range from low resolution (≤ 480 bars) to high resolution (≥ 1280 bars).
Many new computer graphics cards now allow users to choose between several different display resolutions. Obviously the higher the resolution, the better the details of the text and images. The television signal is interlaced, meaning that each screen "picture" is actually composed of two fields, that is, two fields consisting of odd and even lines, respectively. First, the odd lines are scanned and then blanked, and then the even lines are scanned between the original odd lines. The odd and even fields that are displayed in turn and then hidden make the image with a certain shape susceptible to significant jitter, especially those thin horizontal lines.
In contrast, computer signals are generated using non-interlaced signals, also known as "progressive" methods. All scan lines are swept in order from top to bottom and left to right, regardless of parity. This eliminates the image jitter problem caused by interlaced scanning in television systems.
Signal Format Compatibility NTSC, PAL, and SECAM are several common standard TV video signal formats that specify the number of lines of the displayed image, the definition of the color information, and the speed of the scan line (ie, the refresh rate).
There are also many different formats for these formats, such as composite video, S-Video, and D1 (digital) video, but all of these formats have a lot in common. For example, they are all interlaced, with a scan line number of 483 (NTSC) or 576 (PAL and SECAM), all with a fixed refresh rate. The two interlaced fields of NTSC form one frame, appearing 30 times per second (30 Hz), and for PAL and SECAM systems, 25 times per second (25 Hz).
Unlike TV video, computer video signals do not have a single standard that must be adhered to. The range of resolution and refresh rate is wide, and the refresh rate is generally between 60 Hz and 85 Hz. Although computers do not display images in interlaced mode, some graphics cards provide interlaced display capabilities.
In any case, the computer video signal delivers chroma and luminance information to the monitor in the same way. All VGA, SVGA, and Mac computer video formats pass red, green, and blue information as separate signals (components). Thus, this allows the computer to display a wide range of colors without distortion, while the most common television video format combines red, green, and blue information into a single signal (chroma) that is passed to the monitor.
The process of converting a high-level format to a low-level format is generally implemented by a scan converter. This technical concept sounds very simple. Even if people agree with the design concept, there are still many technical factors to consider:
The computer input compatibility of the scan converter is compatible with the maximum resolution of the computer. How much does it require "genlock" - the color sampling rate of the scan converter. The quality of the encoder of the scan converter. How does the output of the video signal have a built-in? Test pattern
Anyone familiar with computer resolution knows that the number of video lines does not meet the standard resolution. Therefore, when the above signals are input to a projector or a display device, there is an incompatibility problem, which is expressed as follows:
The pixel of the picture is missing. Most of the details cannot be reproduced. The image is stretched or distorted, and only the information can be reproduced.
The projector or display device enforces compatible processing of the input image. This additional processing often degrades the image quality (human factors, similar to the ladder correction function).
Another limitation is the vertical refresh rate generated by the scan converter. The vertical refresh rate of the output signal from the scan converter is up to 60Hz or 50Hz, depending on whether the output signal is NTSC or PAL/SECAM, and many projectors can be input. And display a higher refresh rate to provide a better image quality. When using a scan converter, the image displayed by the projector at a lower refresh rate is limited.
Loss of the projector's native resolution LCD and DLP projectors or PDP display devices are often used with scan converters or video conditioners. These devices use pixels to display images. The number of pixels is called intrinsic resolution. rate. Although many projectors can display images with lower resolution than the native resolution, the quality of the displayed image is highest at the native resolution. For example, a projector with an inherent resolution of 1024×768 can display a picture with a resolution of 800×600, but its effect is better than displaying an image with a resolution of 1024×768, because the resolution is 1024×768 for each of the images. point corresponds to the native resolution of each pixel of the projector 1024 × 768, so that the display color is very clear, as no resolution of 800 × 600 display an image that needs to be compensated color video decreased sharpness of the image caused by The different formats of the formatted converted video determine the performance of the signal in terms of brightness, chromaticity, contrast, sharpness, sharpness, and maximum resolution.
From the analysis of various video formats, we can know that the level of video high-definition quality can be roughly sorted as right (from high to low): among them, the highest level of DVI digital video signals are currently selected, but there are only short distances. Disadvantages of transmission (effective distance is about 5 meters), SDI digital video has the advantage of being editable and longer-distance transmission. RGBHV and VGA are actually unified signals, but there are two kinds of names due to different components of the signal, S- Video has a significant improvement in brightness utilization compared to Video (short for composite video) and effectively eliminates color creep. The RF format is the lowest level signal and is only used in the range of surveillance and public television.
Engineering applications often face many conversion processes for signal formats. Which of these different formats of signal conversion need to follow?
What effect will it ultimately have?
Generally considered:
The low-level format has a significant quality improvement to the high-level format conversion, such as the early multi-frequency scanner or quadruple-frequency scanner, and the current popular intelligent video regulator, which is Video-RGBHV (composite video-component video) The conversion process has a significant improvement in improving the quality of the signal. Because these products use multi-bit digital technology, signal quality (sharpness, brightness, signal-to-noise ratio) can be highly restored.
DVI digital video is usually converted to SDI or RGBHV, and the resolution of the original signal is lost after conversion, but the DVI signal is transmitted over long distances;
The actual effect of converting VGA signals into RGBHVs has not been improved because they are equivalent, but solve the problem of synchronous universal matching of VGA signals and enable longer distance transmission.
The process of converting high-level formats to low-level formats (such as VGA to Video) can cause serious damage to any aspect of the original signal, including brightness, chrominance, color, contrast, sharpness, sharpness, and maximum resolution. This conversion does not make any sense, but it has a certain value in the early days, such as: converting the computer's VGA signal into Video for tape recording, TV TV wall display, or for "grabbing" transmission in video conferencing.
High-level conversion to low-level video formats
The inherent scan jitter standard video signal consists of a set of scan lines, not all of which are visible. In the NTSC system, there are 483 visible lines, and 576 in the PAL and SECAM formats. TV video images with a small number of lines are limited in displaying very small text or other complicated details. In contrast, the number of scan lines of a computer display device can range from low resolution (≤ 480 bars) to high resolution (≥ 1280 bars).
Many new computer graphics cards now allow users to choose between several different display resolutions. Obviously the higher the resolution, the better the details of the text and images. The television signal is interlaced, meaning that each screen "picture" is actually composed of two fields, that is, two fields consisting of odd and even lines, respectively. First, the odd lines are scanned and then blanked, and then the even lines are scanned between the original odd lines. The odd and even fields that are displayed in turn and then hidden make the image with a certain shape susceptible to significant jitter, especially those thin horizontal lines.
In contrast, computer signals are generated using non-interlaced signals, also known as "progressive" methods. All scan lines are swept in order from top to bottom and left to right, regardless of parity. This eliminates the image jitter problem caused by interlaced scanning in television systems.
Signal Format Compatibility NTSC, PAL, and SECAM are several common standard TV video signal formats that specify the number of lines of the displayed image, the definition of the color information, and the speed of the scan line (ie, the refresh rate).
There are also many different formats for these formats, such as composite video, S-Video, and D1 (digital) video, but all of these formats have a lot in common. For example, they are all interlaced, with a scan line number of 483 (NTSC) or 576 (PAL and SECAM), all with a fixed refresh rate. The two interlaced fields of NTSC form one frame, appearing 30 times per second (30 Hz), and for PAL and SECAM systems, 25 times per second (25 Hz).
Unlike TV video, computer video signals do not have a single standard that must be adhered to. The range of resolution and refresh rate is wide, and the refresh rate is generally between 60 Hz and 85 Hz. Although computers do not display images in interlaced mode, some graphics cards provide interlaced display capabilities.
In any case, the computer video signal delivers chroma and luminance information to the monitor in the same way. All VGA, SVGA, and Mac computer video formats pass red, green, and blue information as separate signals (components). Thus, this allows the computer to display a wide range of colors without distortion, while the most common television video format combines red, green, and blue information into a single signal (chroma) that is passed to the monitor.
The process of converting a high-level format to a low-level format is generally implemented by a scan converter. This technical concept sounds very simple. Even if people agree with the design concept, there are still many technical factors to consider:
The computer input compatibility of the scan converter is compatible with the maximum resolution of the computer. How much does it require "genlock" - the color sampling rate of the scan converter. The quality of the encoder of the scan converter. How does the output of the video signal have a built-in? Test pattern
Anyone familiar with computer resolution knows that the number of video lines does not meet the standard resolution. Therefore, when the above signals are input to a projector or a display device, there is an incompatibility problem, which is expressed as follows:
The pixel of the picture is missing. Most of the details cannot be reproduced. The image is stretched or distorted, and only the information can be reproduced.
The projector or display device enforces compatible processing of the input image. This additional processing often degrades the image quality (human factors, similar to the ladder correction function).
Another limitation is the vertical refresh rate generated by the scan converter. The vertical refresh rate of the output signal from the scan converter is up to 60Hz or 50Hz, depending on whether the output signal is NTSC or PAL/SECAM, and many projectors can be input. And display a higher refresh rate to provide a better image quality. When using a scan converter, the image displayed by the projector at a lower refresh rate is limited.
Loss of the projector's native resolution LCD and DLP projectors or PDP display devices are often used with scan converters or video conditioners. These devices use pixels to display images. The number of pixels is called intrinsic resolution. rate. Although many projectors can display images with lower resolution than the native resolution, the quality of the displayed image is highest at the native resolution. For example, a projector with an inherent resolution of 1024×768 can display a picture with a resolution of 800×600, but its effect is better than displaying an image with a resolution of 1024×768, because the resolution is 1024×768 for each of the images. The dots correspond to each pixel of the projector with an inherent resolution of 1024×768, so that the display of the color is very clear, and there is no need for color compensation like the image with a resolution of 800×600, resulting in a decrease in image sharpness.
From the analysis of various video formats, we can know that the level of video high-definition quality can be roughly sorted as right (from high to low): among them, the highest level of DVI digital video signals are currently selected, but there are only short distances. Disadvantages of transmission (effective distance is about 5 meters), SDI digital video has the advantage of being editable and longer-distance transmission. RGBHV and VGA are actually unified signals, but there are two kinds of names due to different components of the signal, S- Video has a significant improvement in brightness utilization compared to Video (short for composite video) and effectively eliminates color creep. The RF format is the lowest level signal and is only used in the range of surveillance and public television.
Engineering applications often face many conversion processes for signal formats. Which of these different formats of signal conversion need to follow?
What effect will it ultimately have?
Generally considered:
The low-level format has a significant quality improvement to the high-level format conversion, such as the early multi-frequency scanner or quadruple-frequency scanner, and the current popular intelligent video regulator, which is Video-RGBHV (composite video-component video) The conversion process has a significant improvement in improving the quality of the signal. Because these products use multi-bit digital technology, signal quality (sharpness, brightness, signal-to-noise ratio) can be highly restored.
DVI digital video is usually converted to SDI or RGBHV, and the resolution of the original signal is lost after conversion, but the DVI signal is transmitted over long distances;
The actual effect of converting VGA signals into RGBHVs has not been improved because they are equivalent, but solve the problem of synchronous universal matching of VGA signals and enable longer distance transmission.
The process of converting high-level formats to low-level formats (such as VGA to Video) can cause serious damage to any aspect of the original signal, including brightness, chrominance, color, contrast, sharpness, sharpness, and maximum resolution. This conversion does not make any sense, but it has a certain value in the early days, such as: converting the computer's VGA signal into Video for tape recording, TV TV wall display, or for "grabbing" transmission in video conferencing.
High-level conversion to low-level video formats
The inherent scan jitter standard video signal consists of a set of scan lines, not all of which are visible. In the NTSC system, there are 483 visible lines, and 576 in the PAL and SECAM formats. TV video images with a small number of lines are limited in displaying very small text or other complicated details. In contrast, the number of scan lines of a computer display device can range from low resolution (≤ 480 bars) to high resolution (≥ 1280 bars).
Many new computer graphics cards now allow users to choose between several different display resolutions. Obviously the higher the resolution, the better the details of the text and images. The television signal is interlaced, meaning that each screen "picture" is actually composed of two fields, that is, two fields consisting of odd and even lines, respectively. First, the odd lines are scanned and then blanked, and then the even lines are scanned between the original odd lines. The odd and even fields that are displayed in turn and then hidden make the image with a certain shape susceptible to significant jitter, especially those thin horizontal lines.
In contrast, computer signals are generated using non-interlaced signals, also known as "progressive" methods. All scan lines are swept in order from top to bottom and left to right, regardless of parity. This eliminates the image jitter problem caused by interlaced scanning in television systems.
Signal Format Compatibility NTSC, PAL, and SECAM are several common standard TV video signal formats that specify the number of lines of the displayed image, the definition of the color information, and the speed of the scan line (ie, the refresh rate).
There are also many different formats for these formats, such as composite video, S-Video, and D1 (digital) video, but all of these formats have a lot in common. For example, they are all interlaced, with a scan line number of 483 (NTSC) or 576 (PAL and SECAM), all with a fixed refresh rate. The two interlaced fields of NTSC form one frame, appearing 30 times per second (30 Hz), and for PAL and SECAM systems, 25 times per second (25 Hz).
Unlike TV video, computer video signals do not have a single standard that must be adhered to. The range of resolution and refresh rate is wide, and the refresh rate is generally between 60 Hz and 85 Hz. Although computers do not display images in interlaced mode, some graphics cards provide interlaced display capabilities.
In any case, the computer video signal delivers chroma and luminance information to the monitor in the same way. All VGA, SVGA, and Mac computer video formats pass red, green, and blue information as separate signals (components). Thus, this allows the computer to display a wide range of colors without distortion, while the most common television video format combines red, green, and blue information into a single signal (chroma) that is passed to the monitor.
The process of converting a high-level format to a low-level format is generally implemented by a scan converter. This technical concept sounds very simple. Even if people agree with the design concept, there are still many technical factors to consider:
The computer input compatibility of the scan converter is compatible with the maximum resolution of the computer. How much does it require "genlock" - the color sampling rate of the scan converter. The quality of the encoder of the scan converter. How does the output of the video signal have a built-in? Test pattern
Anyone familiar with computer resolution knows that the number of video lines does not meet the standard resolution. Therefore, when the above signals are input to a projector or a display device, there is an incompatibility problem, which is expressed as follows:
The pixel of the picture is missing. Most of the details cannot be reproduced. The image is stretched or distorted, and only the information can be reproduced.
The projector or display device enforces compatible processing of the input image. This additional processing often degrades the image quality (human factors, similar to the ladder correction function).
Another limitation is the vertical refresh rate generated by the scan converter. The vertical refresh rate of the output signal from the scan converter is up to 60Hz or 50Hz, depending on whether the output signal is NTSC or PAL/SECAM, and many projectors can be input. And display a higher refresh rate to provide a better image quality. When using a scan converter, the image displayed by the projector at a lower refresh rate is limited.
Loss of the projector's native resolution LCD and DLP projectors or PDP display devices are often used with scan converters or video conditioners. These devices use pixels to display images. The number of pixels is called intrinsic resolution. rate. Although many projectors can display images with lower resolution than the native resolution, the quality of the displayed image is highest at the native resolution. For example, a projector with an inherent resolution of 1024×768 can display a picture with a resolution of 800×600, but its effect is better than displaying an image with a resolution of 1024×768, because the resolution is 1024×768 for each of the images. point corresponds to the native resolution of each pixel of the projector 1024 × 768, so that the display color is very clear, as no resolution of 800 × 600 display an image that needs to be compensated color video decreased sharpness of the image caused by The different formats of the formatted converted video determine the performance of the signal in terms of brightness, chromaticity, contrast, sharpness, sharpness, and maximum resolution.
From the analysis of various video formats, we can know that the level of video high-definition quality can be roughly sorted as right (from high to low): among them, the highest level of DVI digital video signals are currently selected, but there are only short distances. Disadvantages of transmission (effective distance is about 5 meters), SDI digital video has the advantage of being editable and longer-distance transmission. RGBHV and VGA are actually unified signals, but there are two kinds of names due to different components of the signal, S- Video has a significant improvement in brightness utilization compared to Video (short for composite video) and effectively eliminates color creep. The RF format is the lowest level signal and is only used in the range of surveillance and public television.
Engineering applications often face many conversion processes for signal formats. Which of these different formats of signal conversion need to follow?
What effect will it ultimately have?
Generally considered:
The low-level format has a significant quality improvement to the high-level format conversion, such as the early multi-frequency scanner or quadruple-frequency scanner, and the current popular intelligent video regulator, which is Video-RGBHV (composite video-component video) The conversion process has a significant improvement in improving the quality of the signal. Because these products use multi-bit digital technology, signal quality (sharpness, brightness, signal-to-noise ratio) can be highly restored.
DVI digital video is usually converted to SDI or RGBHV, and the resolution of the original signal is lost after conversion, but the DVI signal is transmitted over long distances;
The actual effect of converting VGA signals into RGBHVs has not been improved because they are equivalent, but solve the problem of synchronous universal matching of VGA signals and enable longer distance transmission.
The process of converting high-level formats to low-level formats (such as VGA to Video) can cause serious damage to any aspect of the original signal, including brightness, chrominance, color, contrast, sharpness, sharpness, and maximum resolution. This conversion does not make any sense, but it has a certain value in the early days, such as: converting the computer's VGA signal into Video for tape recording, TV TV wall display, or for "grabbing" transmission in video conferencing.
High-level conversion to low-level video formats
The inherent scan jitter standard video signal consists of a set of scan lines, not all of which are visible. In the NTSC system, there are 483 visible lines, and 576 in the PAL and SECAM formats. TV video images with a small number of lines are limited in displaying very small text or other complicated details. In contrast, the number of scan lines of a computer display device can range from low resolution (≤ 480 bars) to high resolution (≥ 1280 bars).
Many new computer graphics cards now allow users to choose between several different display resolutions. Obviously the higher the resolution, the better the details of the text and images. The television signal is interlaced, meaning that each screen "picture" is actually composed of two fields, that is, two fields consisting of odd and even lines, respectively. First, the odd lines are scanned and then blanked, and then the even lines are scanned between the original odd lines. The odd and even fields that are displayed in turn and then hidden make the image with a certain shape susceptible to significant jitter, especially those thin horizontal lines.
In contrast, computer signals are generated using non-interlaced signals, also known as "progressive" methods. All scan lines are swept in order from top to bottom and left to right, regardless of parity. This eliminates the image jitter problem caused by interlaced scanning in television systems.
Signal Format Compatibility NTSC, PAL, and SECAM are several common standard TV video signal formats that specify the number of lines of the displayed image, the definition of the color information, and the speed of the scan line (ie, the refresh rate).
There are also many different formats for these formats, such as composite video, S-Video, and D1 (digital) video, but all of these formats have a lot in common. For example, they are all interlaced, with a scan line number of 483 (NTSC) or 576 (PAL and SECAM), all with a fixed refresh rate. The two interlaced fields of NTSC form one frame, appearing 30 times per second (30 Hz), and for PAL and SECAM systems, 25 times per second (25 Hz).
Unlike TV video, computer video signals do not have a single standard that must be adhered to. The range of resolution and refresh rate is wide, and the refresh rate is generally between 60 Hz and 85 Hz. Although computers do not display images in interlaced mode, some graphics cards provide interlaced display capabilities.
In any case, the computer video signal delivers chroma and luminance information to the monitor in the same way. All VGA, SVGA, and Mac computer video formats pass red, green, and blue information as separate signals (components). Thus, this allows the computer to display a wide range of colors without distortion, while the most common television video format combines red, green, and blue information into a single signal (chroma) that is passed to the monitor.
The process of converting a high-level format to a low-level format is generally implemented by a scan converter. This technical concept sounds very simple. Even if people agree with the design concept, there are still many technical factors to consider:
The computer input compatibility of the scan converter is compatible with the maximum resolution of the computer. How much does it require "genlock" - the color sampling rate of the scan converter. The quality of the encoder of the scan converter. How does the output of the video signal have a built-in? Test pattern
Anyone familiar with computer resolution knows that the number of video lines does not meet the standard resolution. Therefore, when the above signals are input to a projector or a display device, there is an incompatibility problem, which is expressed as follows:
The pixel of the picture is missing. Most of the details cannot be reproduced. The image is stretched or distorted, and only the information can be reproduced.
The projector or display device enforces compatible processing of the input image. This additional processing often degrades the image quality (human factors, similar to the ladder correction function).
Another limitation is the vertical refresh rate generated by the scan converter. The vertical refresh rate of the output signal from the scan converter is up to 60Hz or 50Hz, depending on whether the output signal is NTSC or PAL/SECAM, and many projectors can be input. And display a higher refresh rate to provide a better image quality. When using a scan converter, the image displayed by the projector at a lower refresh rate is limited.
Loss of the projector's native resolution LCD and DLP projectors or PDP display devices are often used with scan converters or video conditioners. These devices use pixels to display images. The number of pixels is called intrinsic resolution. rate. Although many projectors can display images with lower resolution than the native resolution, the quality of the displayed image is highest at the native resolution. For example, a projector with an inherent resolution of 1024×768 can display a picture with a resolution of 800×600, but its effect is better than displaying an image with a resolution of 1024×768, because the resolution is 1024×768 for each of the images. point corresponds to the native resolution of each pixel of the projector 1024 × 768, so that the display color is very clear, as no resolution of 800 × 600 display an image that needs to be compensated color video decreased sharpness of the image caused by The different formats of the formatted converted video determine the performance of the signal in terms of brightness, chromaticity, contrast, sharpness, sharpness, and maximum resolution.
From the analysis of various video formats, we can know that the level of video high-definition quality can be roughly sorted as right (from high to low): among them, the highest level of DVI digital video signals are currently selected, but there are only short distances. Disadvantages of transmission (effective distance is about 5 meters), SDI digital video has the advantage of being editable and longer-distance transmission. RGBHV and VGA are actually unified signals, but there are two kinds of names due to different components of the signal, S- Video has a significant improvement in brightness utilization compared to Video (short for composite video) and effectively eliminates color creep. The RF format is the lowest level signal and is only used in the range of surveillance and public television.
Engineering applications often face many conversion processes for signal formats. Which of these different formats of signal conversion need to follow?
What effect will it ultimately have?
Generally considered:
The low-level format has a significant quality improvement to the high-level format conversion, such as the early multi-frequency scanner or quadruple-frequency scanner, and the current popular intelligent video regulator, which is Video-RGBHV (composite video-component video) The conversion process has a significant improvement in improving the quality of the signal. Because these products use multi-bit digital technology, signal quality (sharpness, brightness, signal-to-noise ratio) can be highly restored.
DVI digital video is usually converted to SDI or RGBHV, and the resolution of the original signal is lost after conversion, but the DVI signal is transmitted over long distances;
The actual effect of converting VGA signals into RGBHVs has not been improved because they are equivalent, but solve the problem of synchronous universal matching of VGA signals and enable longer distance transmission.
The process of converting high-level formats to low-level formats (such as VGA to Video) can cause serious damage to any aspect of the original signal, including brightness, chrominance, color, contrast, sharpness, sharpness, and maximum resolution. This conversion does not make any sense, but it has a certain value in the early days, such as: converting the computer's VGA signal into Video for tape recording, TV TV wall display, or for "grabbing" transmission in video conferencing.
High-level conversion to low-level video formats
The inherent scan jitter standard video signal consists of a set of scan lines, not all of which are visible. In the NTSC system, there are 483 visible lines, and 576 in the PAL and SECAM formats. TV video images with a small number of lines are limited in displaying very small text or other complicated details. In contrast, the number of scan lines of a computer display device can range from low resolution (≤ 480 bars) to high resolution (≥ 1280 bars).
Many new computer graphics cards now allow users to choose between several different display resolutions. Obviously the higher the resolution, the better the details of the text and images. The television signal is interlaced, meaning that each screen "picture" is actually composed of two fields, that is, two fields consisting of odd and even lines, respectively. First, the odd lines are scanned and then blanked, and then the even lines are scanned between the original odd lines. The odd and even fields that are displayed in turn and then hidden make the image with a certain shape susceptible to significant jitter, especially those thin horizontal lines.
In contrast, computer signals are generated using non-interlaced signals, also known as "progressive" methods. All scan lines are swept in order from top to bottom and left to right, regardless of parity. This eliminates the image jitter problem caused by interlaced scanning in television systems.
Signal Format Compatibility NTSC, PAL, and SECAM are several common standard TV video signal formats that specify the number of lines of the displayed image, the definition of the color information, and the speed of the scan line (ie, the refresh rate).
There are also many different formats for these formats, such as composite video, S-Video, and D1 (digital) video, but all of these formats have a lot in common. For example, they are all interlaced, with a scan line number of 483 (NTSC) or 576 (PAL and SECAM), all with a fixed refresh rate. The two interlaced fields of NTSC form one frame, appearing 30 times per second (30 Hz), and for PAL and SECAM systems, 25 times per second (25 Hz).
Unlike TV video, computer video signals do not have a single standard that must be adhered to. The range of resolution and refresh rate is wide, and the refresh rate is generally between 60 Hz and 85 Hz. Although computers do not display images in interlaced mode, some graphics cards provide interlaced display capabilities.
In any case, the computer video signal delivers chroma and luminance information to the monitor in the same way. All VGA, SVGA, and Mac computer video formats pass red, green, and blue information as separate signals (components). Thus, this allows the computer to display a wide range of colors without distortion, while the most common television video format combines red, green, and blue information into a single signal (chroma) that is passed to the monitor.
The process of converting a high-level format to a low-level format is generally implemented by a scan converter. This technical concept sounds very simple. Even if people agree with the design concept, there are still many technical factors to consider:
The computer input compatibility of the scan converter is compatible with the maximum resolution of the computer. How much does it require "genlock" - the color sampling rate of the scan converter. The quality of the encoder of the scan converter. How does the output of the video signal have a built-in? Test pattern
Anyone familiar with computer resolution knows that the number of video lines does not meet the standard resolution. Therefore, when the above signals are input to a projector or a display device, there is an incompatibility problem, which is expressed as follows:
The pixel of the picture is missing. Most of the details cannot be reproduced. The image is stretched or distorted, and only the information can be reproduced.
The projector or display device enforces compatible processing of the input image. This additional processing often degrades the image quality (human factors, similar to the ladder correction function).
Another limitation is the vertical refresh rate generated by the scan converter. The vertical refresh rate of the output signal from the scan converter is up to 60Hz or 50Hz, depending on whether the output signal is NTSC or PAL/SECAM, and many projectors can be input. And display a higher refresh rate to provide a better image quality. When using a scan converter, the image displayed by the projector at a lower refresh rate is limited.
Loss of the projector's native resolution LCD and DLP projectors or PDP display devices are often used with scan converters or video conditioners. These devices use pixels to display images. The number of pixels is called intrinsic resolution. rate. Although many projectors can display images with lower resolution than the native resolution, the quality of the displayed image is highest at the native resolution. For example, a projector with an inherent resolution of 1024×768 can display a picture with a resolution of 800×600, but its effect is better than displaying an image with a resolution of 1024×768, because the resolution is 1024×768 for each of the images. The dots correspond to each pixel of the projector with an inherent resolution of 1024×768, so that the display of the color is very clear, and there is no need for color compensation like the image with a resolution of 800×600, resulting in a decrease in image sharpness.
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