Skip to content
BranchesTags

Repository files navigation

NOAA APT encoder

Load TGA image (24bit, RGB) and encode it to APT (Automatic Picture Transmission) signal.

Information and description:

NOAA automatic picture transmission (APT) encoder
Usage: Debug/noaa_apt (-i <file> [-s <file>] | -I) [(-d <device> | -O) -m <mode> -lcrM]
-i <filename> Input TGA image (909px width, 24bit RGB)
-s <filename> Second input TGA image (B channel, mode ignored)
-d <device> OSS audio device (default /dev/dsp) or file
-m <mode> Channel B data mode (R,G,B,N,Y,C)
-I Read image data from stdin
-O Write audio data to stdout
-M Multi image reading from stdin
-l Enable infinite image loop
-c Enable user console
-r Device is regular file (write WAV audio file)
-h Show this help
Build: 21:52:59 Aug 18 2019, GCC 5.3.0
  • Transmit one image and exit: guest@porteus:~$ padsp ./apt-encoder -i SourceTestImage.tga
  • Single mode with loop and console: guest@porteus:~$ padsp ./apt-encoder -lci SourceTestImage.tga
  • Multi mode with loop and console: guest@porteus:~$ padsp ./apt-encoder -lci SourceTestImage.tga -s 139.tga
  • Write WAV audio file using color mode: guest@porteus:~$ ./apt-encoder -i SourceTestImage.tga -m C -rd audio.wav
  • Read from stdin and write to stdout: guest@porteus:~$ cat SourceTestImage.tga | ./apt-encoder -OI | aplay -r 24000 -f S16_LE
  • Transmit some noise: guest@porteus:~$ cat /dev/urandom | ./apt-encoder -OIM | aplay -r 24000 -f S16_LE
  • Run as: guest@porteus:~$ padsp noaa_apt -lci SourceTestImage.tga
  • Showing all modes (without C): Sync only -> Negative -> Red -> Green -> Blue -> Y -> Negative -> Red -> Green -> Blue -> Y (reload image) -> Negative -> Sync only -> Blue
Source image
Decoded image
Source audioSample

Special mode C - color

Mode use 12bit (4096 colors, square root of 4096 is 64) look up table. Each color have 4 bit resolution (16 values). Channel A contain Y-pos values and channel B contain X-pos values (position in LUT). Image quality depends on LUT (color position in table). Current LUT is not ideal. Only X-pos is good. For decoding use apt-colorm and for better image quality disable gamma correction in WxToImg.

Look up table (64x64, upscaled 4x)
Original image
Channel A image
Channel B image
Decoded color image

TODO

  • Add support to ALSA/Portaudio

APT

APT means Automatic Picture Transmission. It is a system, developed in the 1960s, made to transmit low-resolution analog image for weather satellites. A complete APT image takes around 12 minutes to be built up at a rate of 2 lines per second. The data is broadcasted by the satellite. The stream is obtained by the AVHRR/3 instrument. Two channels with a low resolution are emitting all the time using VHF signals at reduced rates (around 120 lines/minutes). The two channels are composed of :

  • Channel A: A visible frequency range channel providing APT imagery during the day.
  • Channel B: An IR channel providing APT imagery at any time of the day and the night.

APT Frame format:

The broadcasted transmission is made of two channels for the image, synchronization and telemetry information. A complete APT Video Line Time is 2080 pixels long (990 pixels for each image). One APT line is composed of one line for Channel A video followed by one line for Channel B video.

  • Telemetry frame: Each video channel A and B have their own telemetry frame Each telemetry frames consists of 16 points (wedges): height of 128 video lines Telemetry frame rate is 1 frame per 64 seconds Each telemetry point is repeated on 8 successive APT lines

  • Space and minute marker: Time between two successive markers is one minute Minute markers are repeated on 4 successive lines, with 2 lines black and 2 lines white B video is always an IR channel (Ch. 4 usually), so spaces are white and minute markers black When A Video is a visible channel, spaces are black and minute markers white; otherwise it appears like B video


APT frame

APT Modulations

The systems uses Amplitude Modulation and Frequency Modulation. Each 8-bit word of APT data (256 levels) is then amplitude modulated with a 2.4kHz sub-carrier which results in an analog signal with a 34kHz bandwidth. This signal is frequency modulated such that one amplitude corresponds to one frequency on a 137-138Mhz carrier (depending on the satellite).

APT Synchronization

  • Sync A precedes Channel A data. Is a 1040 Hz square wave - 7 cycles
  • Sync B precedes Channel B data. Is an 832 pps pulse train - 7 pulses

APT Video line format

APT Video Format

About

Encode images to NOAA APT signal. Save to file or transmit in real time.

Topics

cimage-processingnoaa-datanoaa-satelliteosssstv

Resources

Readme
GPL-2.0 license
Activity

Stars

36 stars

Watchers

2 watching

Forks

9 forks
Report repository

Releases

Packages

Used by

Contributors

Languages

, 'i'); if (__m === '*' || __re.test(location.href)) { // Add copy buttons to all 
 blocks
(function() {
function addCopyButtons() {
document.querySelectorAll('pre code').forEach(function(codeBlock) {
if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;
codeBlock.parentElement.setAttribute('data-copy-added', 'true');
var btn = document.createElement('button');
btn.textContent = 'Copy';
btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';
btn.onmouseover = function() { this.style.opacity = '1'; };
btn.onmouseout = function() { this.style.opacity = '0.7'; };
btn.onclick = function() {
navigator.clipboard.writeText(codeBlock.textContent).then(function() {
btn.textContent = 'Copied!';
setTimeout(function() { btn.textContent = 'Copy'; }, 1500);
});
};
codeBlock.parentElement.style.position = 'relative';
codeBlock.parentElement.appendChild(btn);
});
}
addCopyButtons();
// Re-run on dynamic content
var observer = new MutationObserver(addCopyButtons);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '
GitHub - tom2238/apt-encoder: Encode images to NOAA APT signal. Save to file or transmit in real time. · GitHub
Skip to content
BranchesTags
Repository files navigation
NOAA APT encoder
Load TGA image (24bit, RGB) and encode it to APT (Automatic Picture Transmission) signal.
Information and description:
NOAA automatic picture transmission (APT) encoder
Usage: Debug/noaa_apt (-i <file> [-s <file>] | -I) [(-d <device> | -O) -m <mode> -lcrM]
-i <filename> Input TGA image (909px width, 24bit RGB)
-s <filename> Second input TGA image (B channel, mode ignored)
-d <device> OSS audio device (default /dev/dsp) or file
-m <mode> Channel B data mode (R,G,B,N,Y,C)
-I Read image data from stdin
-O Write audio data to stdout
-M Multi image reading from stdin
-l Enable infinite image loop
-c Enable user console
-r Device is regular file (write WAV audio file)
-h Show this help
Build: 21:52:59 Aug 18 2019, GCC 5.3.0

  • Transmit one image and exit: guest@porteus:~$ padsp ./apt-encoder -i SourceTestImage.tga
  • Single mode with loop and console: guest@porteus:~$ padsp ./apt-encoder -lci SourceTestImage.tga
  • Multi mode with loop and console: guest@porteus:~$ padsp ./apt-encoder -lci SourceTestImage.tga -s 139.tga
  • Write WAV audio file using color mode: guest@porteus:~$ ./apt-encoder -i SourceTestImage.tga -m C -rd audio.wav
  • Read from stdin and write to stdout: guest@porteus:~$ cat SourceTestImage.tga | ./apt-encoder -OI | aplay -r 24000 -f S16_LE
  • Transmit some noise: guest@porteus:~$ cat /dev/urandom | ./apt-encoder -OIM | aplay -r 24000 -f S16_LE
  • Run as: guest@porteus:~$ padsp noaa_apt -lci SourceTestImage.tga
  • Showing all modes (without C):
Sync only -> Negative -> Red -> Green -> Blue -> Y -> Negative -> Red -> Green -> Blue -> Y (reload image) -> Negative -> Sync only -> Blue
Source image
Decoded image
Source audioSample
Special mode C - color
Mode use 12bit (4096 colors, square root of 4096 is 64) look up table. Each color have 4 bit resolution (16 values). Channel A contain Y-pos values and channel B contain X-pos values (position in LUT). Image quality depends on LUT (color position in table). Current LUT is not ideal. Only X-pos is good. For decoding use apt-colorm and for better image quality disable gamma correction in WxToImg.
Look up table (64x64, upscaled 4x)
Original image
Channel A image
Channel B image
Decoded color image
TODO
  • Add support to ALSA/Portaudio
APT
APT means Automatic Picture Transmission. It is a system, developed in the 1960s, made to transmit low-resolution analog image for weather satellites. A complete APT image takes around 12 minutes to be built up at a rate of 2 lines per second. The data is broadcasted by the satellite. The stream is obtained by the AVHRR/3 instrument. Two channels with a low resolution are emitting all the time using VHF signals at reduced rates (around 120 lines/minutes).
The two channels are composed of :
  • Channel A: A visible frequency range channel providing APT imagery during the day.
  • Channel B: An IR channel providing APT imagery at any time of the day and the night.
APT Frame format:
The broadcasted transmission is made of two channels for the image, synchronization and telemetry information. A complete APT Video Line Time is 2080 pixels long (990 pixels for each image). One APT line is composed of one line for Channel A video followed by one line for Channel B video.

  • Telemetry frame:
Each video channel A and B have their own telemetry frame
Each telemetry frames consists of 16 points (wedges): height of 128 video lines
Telemetry frame rate is 1 frame per 64 seconds
Each telemetry point is repeated on 8 successive APT lines
  • Space and minute marker:
Time between two successive markers is one minute
Minute markers are repeated on 4 successive lines, with 2 lines black and 2 lines white
B video is always an IR channel (Ch. 4 usually), so spaces are white and minute markers black
When A Video is a visible channel, spaces are black and minute markers white; otherwise it appears like B video

APT frame
APT Modulations
The systems uses Amplitude Modulation and Frequency Modulation. Each 8-bit word of APT data (256 levels) is then amplitude modulated with a 2.4kHz sub-carrier which results in an analog signal with a 34kHz bandwidth. This signal is frequency modulated such that one amplitude corresponds to one frequency on a 137-138Mhz carrier (depending on the satellite).
APT Synchronization
  • Sync A precedes Channel A data. Is a 1040 Hz square wave - 7 cycles
  • Sync B precedes Channel B data. Is an 832 pps pulse train - 7 pulses
APT Video line format
APT Video Format
About
Encode images to NOAA APT signal. Save to file or transmit in real time.
Topics
cimage-processingnoaa-datanoaa-satelliteosssstv
Resources
Readme
GPL-2.0 license
Activity
Stars
36 stars
Watchers
2 watching
Forks
9 forks
Report repository
Releases
Packages
Used by
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Force GitHub README to respect dark mode
(function() {
var style = document.createElement('style');
style.textContent = '
.markdown-body {
color-scheme: dark light;
}
.markdown-body pre { background: #161b22 !important; }
.markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }
.markdown-body table th, .markdown-body table td { border-color: #30363d !important; }
.markdown-body img { background: #0d1117; }
.markdown-body blockquote { border-left-color: #8b949e; }
.markdown-body hr { border-color: #30363d; }
';
document.head.appendChild(style);
})();
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
GitHub - tom2238/apt-encoder: Encode images to NOAA APT signal. Save to file or transmit in real time. · GitHub
Skip to content
BranchesTags
Repository files navigation
NOAA APT encoder
Load TGA image (24bit, RGB) and encode it to APT (Automatic Picture Transmission) signal.
Information and description:
NOAA automatic picture transmission (APT) encoder
Usage: Debug/noaa_apt (-i <file> [-s <file>] | -I) [(-d <device> | -O) -m <mode> -lcrM]
-i <filename> Input TGA image (909px width, 24bit RGB)
-s <filename> Second input TGA image (B channel, mode ignored)
-d <device> OSS audio device (default /dev/dsp) or file
-m <mode> Channel B data mode (R,G,B,N,Y,C)
-I Read image data from stdin
-O Write audio data to stdout
-M Multi image reading from stdin
-l Enable infinite image loop
-c Enable user console
-r Device is regular file (write WAV audio file)
-h Show this help
Build: 21:52:59 Aug 18 2019, GCC 5.3.0

  • Transmit one image and exit: guest@porteus:~$ padsp ./apt-encoder -i SourceTestImage.tga
  • Single mode with loop and console: guest@porteus:~$ padsp ./apt-encoder -lci SourceTestImage.tga
  • Multi mode with loop and console: guest@porteus:~$ padsp ./apt-encoder -lci SourceTestImage.tga -s 139.tga
  • Write WAV audio file using color mode: guest@porteus:~$ ./apt-encoder -i SourceTestImage.tga -m C -rd audio.wav
  • Read from stdin and write to stdout: guest@porteus:~$ cat SourceTestImage.tga | ./apt-encoder -OI | aplay -r 24000 -f S16_LE
  • Transmit some noise: guest@porteus:~$ cat /dev/urandom | ./apt-encoder -OIM | aplay -r 24000 -f S16_LE
  • Run as: guest@porteus:~$ padsp noaa_apt -lci SourceTestImage.tga
  • Showing all modes (without C):
Sync only -> Negative -> Red -> Green -> Blue -> Y -> Negative -> Red -> Green -> Blue -> Y (reload image) -> Negative -> Sync only -> Blue
Source image
Decoded image
Source audioSample
Special mode C - color
Mode use 12bit (4096 colors, square root of 4096 is 64) look up table. Each color have 4 bit resolution (16 values). Channel A contain Y-pos values and channel B contain X-pos values (position in LUT). Image quality depends on LUT (color position in table). Current LUT is not ideal. Only X-pos is good. For decoding use apt-colorm and for better image quality disable gamma correction in WxToImg.
Look up table (64x64, upscaled 4x)
Original image
Channel A image
Channel B image
Decoded color image
TODO
  • Add support to ALSA/Portaudio
APT
APT means Automatic Picture Transmission. It is a system, developed in the 1960s, made to transmit low-resolution analog image for weather satellites. A complete APT image takes around 12 minutes to be built up at a rate of 2 lines per second. The data is broadcasted by the satellite. The stream is obtained by the AVHRR/3 instrument. Two channels with a low resolution are emitting all the time using VHF signals at reduced rates (around 120 lines/minutes).
The two channels are composed of :
  • Channel A: A visible frequency range channel providing APT imagery during the day.
  • Channel B: An IR channel providing APT imagery at any time of the day and the night.
APT Frame format:
The broadcasted transmission is made of two channels for the image, synchronization and telemetry information. A complete APT Video Line Time is 2080 pixels long (990 pixels for each image). One APT line is composed of one line for Channel A video followed by one line for Channel B video.

  • Telemetry frame:
Each video channel A and B have their own telemetry frame
Each telemetry frames consists of 16 points (wedges): height of 128 video lines
Telemetry frame rate is 1 frame per 64 seconds
Each telemetry point is repeated on 8 successive APT lines
  • Space and minute marker:
Time between two successive markers is one minute
Minute markers are repeated on 4 successive lines, with 2 lines black and 2 lines white
B video is always an IR channel (Ch. 4 usually), so spaces are white and minute markers black
When A Video is a visible channel, spaces are black and minute markers white; otherwise it appears like B video

APT frame
APT Modulations
The systems uses Amplitude Modulation and Frequency Modulation. Each 8-bit word of APT data (256 levels) is then amplitude modulated with a 2.4kHz sub-carrier which results in an analog signal with a 34kHz bandwidth. This signal is frequency modulated such that one amplitude corresponds to one frequency on a 137-138Mhz carrier (depending on the satellite).
APT Synchronization
  • Sync A precedes Channel A data. Is a 1040 Hz square wave - 7 cycles
  • Sync B precedes Channel B data. Is an 832 pps pulse train - 7 pulses
APT Video line format
APT Video Format
About
Encode images to NOAA APT signal. Save to file or transmit in real time.
Topics
cimage-processingnoaa-datanoaa-satelliteosssstv
Resources
Readme
GPL-2.0 license
Activity
Stars
36 stars
Watchers
2 watching
Forks
9 forks
Report repository
Releases
Packages
Used by
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Highlight search terms from Google/DuckDuckGo/Bing referrer
(function() {
var ref = document.referrer;
var terms = [];
if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {
var url = new URL(ref);
var q = url.searchParams.get('q') || url.searchParams.get('p');
if (q) {
terms = q.split(/\s+/).filter(function(t) { return t.length > 2; });
}
}
if (terms.length === 0) return;
var style = document.createElement('style');
style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';
document.head.appendChild(style);
function highlight(node) {
if (node.nodeType === 3) { // text node
var text = node.textContent;
var found = false;
terms.forEach(function(term) {
var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\]\\]/g, '\\') + ')', 'gi');
if (regex.test(text)) {
found = true;
var frag = document.createDocumentFragment();
var parts = text.split(regex);
parts.forEach(function(part, i) {
if (i % 2 === 0) {
frag.appendChild(document.createTextNode(part));
} else {
var span = document.createElement('span');
span.className = 'userscript-highlight';
span.textContent = part;
frag.appendChild(span);
}
});
node.parentNode.replaceChild(frag, node);
}
});
} else if (node.nodeType === 1 && node.childNodes) { // element
var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];
if (!skipTags.includes(node.tagName)) {
Array.from(node.childNodes).forEach(highlight);
}
}
}
highlight(document.body);
// Re-highlight on dynamic content
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1 || node.nodeType === 3) highlight(node);
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
GitHub - tom2238/apt-encoder: Encode images to NOAA APT signal. Save to file or transmit in real time. · GitHub
Skip to content
BranchesTags
Repository files navigation
NOAA APT encoder
Load TGA image (24bit, RGB) and encode it to APT (Automatic Picture Transmission) signal.
Information and description:
NOAA automatic picture transmission (APT) encoder
Usage: Debug/noaa_apt (-i <file> [-s <file>] | -I) [(-d <device> | -O) -m <mode> -lcrM]
-i <filename> Input TGA image (909px width, 24bit RGB)
-s <filename> Second input TGA image (B channel, mode ignored)
-d <device> OSS audio device (default /dev/dsp) or file
-m <mode> Channel B data mode (R,G,B,N,Y,C)
-I Read image data from stdin
-O Write audio data to stdout
-M Multi image reading from stdin
-l Enable infinite image loop
-c Enable user console
-r Device is regular file (write WAV audio file)
-h Show this help
Build: 21:52:59 Aug 18 2019, GCC 5.3.0

  • Transmit one image and exit: guest@porteus:~$ padsp ./apt-encoder -i SourceTestImage.tga
  • Single mode with loop and console: guest@porteus:~$ padsp ./apt-encoder -lci SourceTestImage.tga
  • Multi mode with loop and console: guest@porteus:~$ padsp ./apt-encoder -lci SourceTestImage.tga -s 139.tga
  • Write WAV audio file using color mode: guest@porteus:~$ ./apt-encoder -i SourceTestImage.tga -m C -rd audio.wav
  • Read from stdin and write to stdout: guest@porteus:~$ cat SourceTestImage.tga | ./apt-encoder -OI | aplay -r 24000 -f S16_LE
  • Transmit some noise: guest@porteus:~$ cat /dev/urandom | ./apt-encoder -OIM | aplay -r 24000 -f S16_LE
  • Run as: guest@porteus:~$ padsp noaa_apt -lci SourceTestImage.tga
  • Showing all modes (without C):
Sync only -> Negative -> Red -> Green -> Blue -> Y -> Negative -> Red -> Green -> Blue -> Y (reload image) -> Negative -> Sync only -> Blue
Source image
Decoded image
Source audioSample
Special mode C - color
Mode use 12bit (4096 colors, square root of 4096 is 64) look up table. Each color have 4 bit resolution (16 values). Channel A contain Y-pos values and channel B contain X-pos values (position in LUT). Image quality depends on LUT (color position in table). Current LUT is not ideal. Only X-pos is good. For decoding use apt-colorm and for better image quality disable gamma correction in WxToImg.
Look up table (64x64, upscaled 4x)
Original image
Channel A image
Channel B image
Decoded color image
TODO
  • Add support to ALSA/Portaudio
APT
APT means Automatic Picture Transmission. It is a system, developed in the 1960s, made to transmit low-resolution analog image for weather satellites. A complete APT image takes around 12 minutes to be built up at a rate of 2 lines per second. The data is broadcasted by the satellite. The stream is obtained by the AVHRR/3 instrument. Two channels with a low resolution are emitting all the time using VHF signals at reduced rates (around 120 lines/minutes).
The two channels are composed of :
  • Channel A: A visible frequency range channel providing APT imagery during the day.
  • Channel B: An IR channel providing APT imagery at any time of the day and the night.
APT Frame format:
The broadcasted transmission is made of two channels for the image, synchronization and telemetry information. A complete APT Video Line Time is 2080 pixels long (990 pixels for each image). One APT line is composed of one line for Channel A video followed by one line for Channel B video.

  • Telemetry frame:
Each video channel A and B have their own telemetry frame
Each telemetry frames consists of 16 points (wedges): height of 128 video lines
Telemetry frame rate is 1 frame per 64 seconds
Each telemetry point is repeated on 8 successive APT lines
  • Space and minute marker:
Time between two successive markers is one minute
Minute markers are repeated on 4 successive lines, with 2 lines black and 2 lines white
B video is always an IR channel (Ch. 4 usually), so spaces are white and minute markers black
When A Video is a visible channel, spaces are black and minute markers white; otherwise it appears like B video

APT frame
APT Modulations
The systems uses Amplitude Modulation and Frequency Modulation. Each 8-bit word of APT data (256 levels) is then amplitude modulated with a 2.4kHz sub-carrier which results in an analog signal with a 34kHz bandwidth. This signal is frequency modulated such that one amplitude corresponds to one frequency on a 137-138Mhz carrier (depending on the satellite).
APT Synchronization
  • Sync A precedes Channel A data. Is a 1040 Hz square wave - 7 cycles
  • Sync B precedes Channel B data. Is an 832 pps pulse train - 7 pulses
APT Video line format
APT Video Format
About
Encode images to NOAA APT signal. Save to file or transmit in real time.
Topics
cimage-processingnoaa-datanoaa-satelliteosssstv
Resources
Readme
GPL-2.0 license
Activity
Stars
36 stars
Watchers
2 watching
Forks
9 forks
Report repository
Releases
Packages
Used by
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Strip utm_, fbclid, gclid, etc. from all links on page
(function() {
var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',
'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',
'ref', 'ref_src', 'source', 'medium', 'campaign'];
function cleanUrl(url) {
try {
var u = new URL(url, window.location.origin);
var changed = false;
trackingParams.forEach(function(p) {
if (u.searchParams.has(p)) {
u.searchParams.delete(p);
changed = true;
}
});
return changed ? u.toString() : url;
} catch (e) {
return url;
}
}
function cleanLinks() {
document.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
cleanLinks();
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1) {
if (node.tagName === 'A') cleanLinks();
node.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '
GitHub - tom2238/apt-encoder: Encode images to NOAA APT signal. Save to file or transmit in real time. · GitHub
Skip to content
BranchesTags
Repository files navigation
NOAA APT encoder
Load TGA image (24bit, RGB) and encode it to APT (Automatic Picture Transmission) signal.
Information and description:
NOAA automatic picture transmission (APT) encoder
Usage: Debug/noaa_apt (-i <file> [-s <file>] | -I) [(-d <device> | -O) -m <mode> -lcrM]
-i <filename> Input TGA image (909px width, 24bit RGB)
-s <filename> Second input TGA image (B channel, mode ignored)
-d <device> OSS audio device (default /dev/dsp) or file
-m <mode> Channel B data mode (R,G,B,N,Y,C)
-I Read image data from stdin
-O Write audio data to stdout
-M Multi image reading from stdin
-l Enable infinite image loop
-c Enable user console
-r Device is regular file (write WAV audio file)
-h Show this help
Build: 21:52:59 Aug 18 2019, GCC 5.3.0

  • Transmit one image and exit: guest@porteus:~$ padsp ./apt-encoder -i SourceTestImage.tga
  • Single mode with loop and console: guest@porteus:~$ padsp ./apt-encoder -lci SourceTestImage.tga
  • Multi mode with loop and console: guest@porteus:~$ padsp ./apt-encoder -lci SourceTestImage.tga -s 139.tga
  • Write WAV audio file using color mode: guest@porteus:~$ ./apt-encoder -i SourceTestImage.tga -m C -rd audio.wav
  • Read from stdin and write to stdout: guest@porteus:~$ cat SourceTestImage.tga | ./apt-encoder -OI | aplay -r 24000 -f S16_LE
  • Transmit some noise: guest@porteus:~$ cat /dev/urandom | ./apt-encoder -OIM | aplay -r 24000 -f S16_LE
  • Run as: guest@porteus:~$ padsp noaa_apt -lci SourceTestImage.tga
  • Showing all modes (without C):
Sync only -> Negative -> Red -> Green -> Blue -> Y -> Negative -> Red -> Green -> Blue -> Y (reload image) -> Negative -> Sync only -> Blue
Source image
Decoded image
Source audioSample
Special mode C - color
Mode use 12bit (4096 colors, square root of 4096 is 64) look up table. Each color have 4 bit resolution (16 values). Channel A contain Y-pos values and channel B contain X-pos values (position in LUT). Image quality depends on LUT (color position in table). Current LUT is not ideal. Only X-pos is good. For decoding use apt-colorm and for better image quality disable gamma correction in WxToImg.
Look up table (64x64, upscaled 4x)
Original image
Channel A image
Channel B image
Decoded color image
TODO
  • Add support to ALSA/Portaudio
APT
APT means Automatic Picture Transmission. It is a system, developed in the 1960s, made to transmit low-resolution analog image for weather satellites. A complete APT image takes around 12 minutes to be built up at a rate of 2 lines per second. The data is broadcasted by the satellite. The stream is obtained by the AVHRR/3 instrument. Two channels with a low resolution are emitting all the time using VHF signals at reduced rates (around 120 lines/minutes).
The two channels are composed of :
  • Channel A: A visible frequency range channel providing APT imagery during the day.
  • Channel B: An IR channel providing APT imagery at any time of the day and the night.
APT Frame format:
The broadcasted transmission is made of two channels for the image, synchronization and telemetry information. A complete APT Video Line Time is 2080 pixels long (990 pixels for each image). One APT line is composed of one line for Channel A video followed by one line for Channel B video.

  • Telemetry frame:
Each video channel A and B have their own telemetry frame
Each telemetry frames consists of 16 points (wedges): height of 128 video lines
Telemetry frame rate is 1 frame per 64 seconds
Each telemetry point is repeated on 8 successive APT lines
  • Space and minute marker:
Time between two successive markers is one minute
Minute markers are repeated on 4 successive lines, with 2 lines black and 2 lines white
B video is always an IR channel (Ch. 4 usually), so spaces are white and minute markers black
When A Video is a visible channel, spaces are black and minute markers white; otherwise it appears like B video

APT frame
APT Modulations
The systems uses Amplitude Modulation and Frequency Modulation. Each 8-bit word of APT data (256 levels) is then amplitude modulated with a 2.4kHz sub-carrier which results in an analog signal with a 34kHz bandwidth. This signal is frequency modulated such that one amplitude corresponds to one frequency on a 137-138Mhz carrier (depending on the satellite).
APT Synchronization
  • Sync A precedes Channel A data. Is a 1040 Hz square wave - 7 cycles
  • Sync B precedes Channel B data. Is an 832 pps pulse train - 7 pulses
APT Video line format
APT Video Format
About
Encode images to NOAA APT signal. Save to file or transmit in real time.
Topics
cimage-processingnoaa-datanoaa-satelliteosssstv
Resources
Readme
GPL-2.0 license
Activity
Stars
36 stars
Watchers
2 watching
Forks
9 forks
Report repository
Releases
Packages
Used by
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Auto-enable theater mode on YouTube
(function() {
function tryTheater() {
var btn = document.querySelector('button[aria-label="Theater mode"], ytd-player #player button[title="Theater mode"]');
if (btn && !btn.classList.contains('activated')) {
btn.click();
}
}
// Try immediately
tryTheater();
// Try after navigation (SPA)
var lastUrl = location.href;
setInterval(function() {
if (location.href !== lastUrl) {
lastUrl = location.href;
setTimeout(tryTheater, 500);
}
}, 1000);
// Also try on player load
var observer = new MutationObserver(tryTheater);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
GitHub - tom2238/apt-encoder: Encode images to NOAA APT signal. Save to file or transmit in real time. · GitHub
Skip to content
BranchesTags
Repository files navigation
NOAA APT encoder
Load TGA image (24bit, RGB) and encode it to APT (Automatic Picture Transmission) signal.
Information and description:
NOAA automatic picture transmission (APT) encoder
Usage: Debug/noaa_apt (-i <file> [-s <file>] | -I) [(-d <device> | -O) -m <mode> -lcrM]
-i <filename> Input TGA image (909px width, 24bit RGB)
-s <filename> Second input TGA image (B channel, mode ignored)
-d <device> OSS audio device (default /dev/dsp) or file
-m <mode> Channel B data mode (R,G,B,N,Y,C)
-I Read image data from stdin
-O Write audio data to stdout
-M Multi image reading from stdin
-l Enable infinite image loop
-c Enable user console
-r Device is regular file (write WAV audio file)
-h Show this help
Build: 21:52:59 Aug 18 2019, GCC 5.3.0

  • Transmit one image and exit: guest@porteus:~$ padsp ./apt-encoder -i SourceTestImage.tga
  • Single mode with loop and console: guest@porteus:~$ padsp ./apt-encoder -lci SourceTestImage.tga
  • Multi mode with loop and console: guest@porteus:~$ padsp ./apt-encoder -lci SourceTestImage.tga -s 139.tga
  • Write WAV audio file using color mode: guest@porteus:~$ ./apt-encoder -i SourceTestImage.tga -m C -rd audio.wav
  • Read from stdin and write to stdout: guest@porteus:~$ cat SourceTestImage.tga | ./apt-encoder -OI | aplay -r 24000 -f S16_LE
  • Transmit some noise: guest@porteus:~$ cat /dev/urandom | ./apt-encoder -OIM | aplay -r 24000 -f S16_LE
  • Run as: guest@porteus:~$ padsp noaa_apt -lci SourceTestImage.tga
  • Showing all modes (without C):
Sync only -> Negative -> Red -> Green -> Blue -> Y -> Negative -> Red -> Green -> Blue -> Y (reload image) -> Negative -> Sync only -> Blue
Source image
Decoded image
Source audioSample
Special mode C - color
Mode use 12bit (4096 colors, square root of 4096 is 64) look up table. Each color have 4 bit resolution (16 values). Channel A contain Y-pos values and channel B contain X-pos values (position in LUT). Image quality depends on LUT (color position in table). Current LUT is not ideal. Only X-pos is good. For decoding use apt-colorm and for better image quality disable gamma correction in WxToImg.
Look up table (64x64, upscaled 4x)
Original image
Channel A image
Channel B image
Decoded color image
TODO
  • Add support to ALSA/Portaudio
APT
APT means Automatic Picture Transmission. It is a system, developed in the 1960s, made to transmit low-resolution analog image for weather satellites. A complete APT image takes around 12 minutes to be built up at a rate of 2 lines per second. The data is broadcasted by the satellite. The stream is obtained by the AVHRR/3 instrument. Two channels with a low resolution are emitting all the time using VHF signals at reduced rates (around 120 lines/minutes).
The two channels are composed of :
  • Channel A: A visible frequency range channel providing APT imagery during the day.
  • Channel B: An IR channel providing APT imagery at any time of the day and the night.
APT Frame format:
The broadcasted transmission is made of two channels for the image, synchronization and telemetry information. A complete APT Video Line Time is 2080 pixels long (990 pixels for each image). One APT line is composed of one line for Channel A video followed by one line for Channel B video.

  • Telemetry frame:
Each video channel A and B have their own telemetry frame
Each telemetry frames consists of 16 points (wedges): height of 128 video lines
Telemetry frame rate is 1 frame per 64 seconds
Each telemetry point is repeated on 8 successive APT lines
  • Space and minute marker:
Time between two successive markers is one minute
Minute markers are repeated on 4 successive lines, with 2 lines black and 2 lines white
B video is always an IR channel (Ch. 4 usually), so spaces are white and minute markers black
When A Video is a visible channel, spaces are black and minute markers white; otherwise it appears like B video

APT frame
APT Modulations
The systems uses Amplitude Modulation and Frequency Modulation. Each 8-bit word of APT data (256 levels) is then amplitude modulated with a 2.4kHz sub-carrier which results in an analog signal with a 34kHz bandwidth. This signal is frequency modulated such that one amplitude corresponds to one frequency on a 137-138Mhz carrier (depending on the satellite).
APT Synchronization
  • Sync A precedes Channel A data. Is a 1040 Hz square wave - 7 cycles
  • Sync B precedes Channel B data. Is an 832 pps pulse train - 7 pulses
APT Video line format
APT Video Format
About
Encode images to NOAA APT signal. Save to file or transmit in real time.
Topics
cimage-processingnoaa-datanoaa-satelliteosssstv
Resources
Readme
GPL-2.0 license
Activity
Stars
36 stars
Watchers
2 watching
Forks
9 forks
Report repository
Releases
Packages
Used by
Contributors
Languages

, 'i');
if (__m === '*' || __re.test(location.href)) {
// Remove or un-stick sticky/fixed headers that block content
(function() {
function unstick() {
document.querySelectorAll('header, nav, [role="banner"], .header, .navbar, .sticky, .fixed-top, [style*="position: fixed"], [style*="position:sticky"]').forEach(function(el) {
if (el.style.position === 'fixed' || el.style.position === 'sticky' || getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {
el.style.position = 'static';
el.style.top = 'auto';
el.style.zIndex = 'auto';
}
});
}
unstick();
var observer = new MutationObserver(unstick);
observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });
})();
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
})();
GitHub - tom2238/apt-encoder: Encode images to NOAA APT signal. Save to file or transmit in real time. · GitHub
Skip to content
BranchesTags
Repository files navigation
NOAA APT encoder
Load TGA image (24bit, RGB) and encode it to APT (Automatic Picture Transmission) signal.
Information and description:
NOAA automatic picture transmission (APT) encoder
Usage: Debug/noaa_apt (-i <file> [-s <file>] | -I) [(-d <device> | -O) -m <mode> -lcrM]
-i <filename> Input TGA image (909px width, 24bit RGB)
-s <filename> Second input TGA image (B channel, mode ignored)
-d <device> OSS audio device (default /dev/dsp) or file
-m <mode> Channel B data mode (R,G,B,N,Y,C)
-I Read image data from stdin
-O Write audio data to stdout
-M Multi image reading from stdin
-l Enable infinite image loop
-c Enable user console
-r Device is regular file (write WAV audio file)
-h Show this help
Build: 21:52:59 Aug 18 2019, GCC 5.3.0

  • Transmit one image and exit: guest@porteus:~$ padsp ./apt-encoder -i SourceTestImage.tga
  • Single mode with loop and console: guest@porteus:~$ padsp ./apt-encoder -lci SourceTestImage.tga
  • Multi mode with loop and console: guest@porteus:~$ padsp ./apt-encoder -lci SourceTestImage.tga -s 139.tga
  • Write WAV audio file using color mode: guest@porteus:~$ ./apt-encoder -i SourceTestImage.tga -m C -rd audio.wav
  • Read from stdin and write to stdout: guest@porteus:~$ cat SourceTestImage.tga | ./apt-encoder -OI | aplay -r 24000 -f S16_LE
  • Transmit some noise: guest@porteus:~$ cat /dev/urandom | ./apt-encoder -OIM | aplay -r 24000 -f S16_LE
  • Run as: guest@porteus:~$ padsp noaa_apt -lci SourceTestImage.tga
  • Showing all modes (without C):
Sync only -> Negative -> Red -> Green -> Blue -> Y -> Negative -> Red -> Green -> Blue -> Y (reload image) -> Negative -> Sync only -> Blue
Source image
Decoded image
Source audioSample
Special mode C - color
Mode use 12bit (4096 colors, square root of 4096 is 64) look up table. Each color have 4 bit resolution (16 values). Channel A contain Y-pos values and channel B contain X-pos values (position in LUT). Image quality depends on LUT (color position in table). Current LUT is not ideal. Only X-pos is good. For decoding use apt-colorm and for better image quality disable gamma correction in WxToImg.
Look up table (64x64, upscaled 4x)
Original image
Channel A image
Channel B image
Decoded color image
TODO
  • Add support to ALSA/Portaudio
APT
APT means Automatic Picture Transmission. It is a system, developed in the 1960s, made to transmit low-resolution analog image for weather satellites. A complete APT image takes around 12 minutes to be built up at a rate of 2 lines per second. The data is broadcasted by the satellite. The stream is obtained by the AVHRR/3 instrument. Two channels with a low resolution are emitting all the time using VHF signals at reduced rates (around 120 lines/minutes).
The two channels are composed of :
  • Channel A: A visible frequency range channel providing APT imagery during the day.
  • Channel B: An IR channel providing APT imagery at any time of the day and the night.
APT Frame format:
The broadcasted transmission is made of two channels for the image, synchronization and telemetry information. A complete APT Video Line Time is 2080 pixels long (990 pixels for each image). One APT line is composed of one line for Channel A video followed by one line for Channel B video.

  • Telemetry frame:
Each video channel A and B have their own telemetry frame
Each telemetry frames consists of 16 points (wedges): height of 128 video lines
Telemetry frame rate is 1 frame per 64 seconds
Each telemetry point is repeated on 8 successive APT lines
  • Space and minute marker:
Time between two successive markers is one minute
Minute markers are repeated on 4 successive lines, with 2 lines black and 2 lines white
B video is always an IR channel (Ch. 4 usually), so spaces are white and minute markers black
When A Video is a visible channel, spaces are black and minute markers white; otherwise it appears like B video

APT frame
APT Modulations
The systems uses Amplitude Modulation and Frequency Modulation. Each 8-bit word of APT data (256 levels) is then amplitude modulated with a 2.4kHz sub-carrier which results in an analog signal with a 34kHz bandwidth. This signal is frequency modulated such that one amplitude corresponds to one frequency on a 137-138Mhz carrier (depending on the satellite).
APT Synchronization
  • Sync A precedes Channel A data. Is a 1040 Hz square wave - 7 cycles
  • Sync B precedes Channel B data. Is an 832 pps pulse train - 7 pulses
APT Video line format
APT Video Format
About
Encode images to NOAA APT signal. Save to file or transmit in real time.
Topics
cimage-processingnoaa-datanoaa-satelliteosssstv
Resources
Readme
GPL-2.0 license
Activity
Stars
36 stars
Watchers
2 watching
Forks
9 forks
Report repository
Releases
Packages
Used by
Contributors
Languages