Re: signed 8 bit to sign and magnitude handler needed [PART ONE]
this is part two
I found the below PHP code online that seemed appropriate and tried to
convert it to Livecode but it didn't return useful values.
(not sure if I needed [$num = bindec($bin);] - turns number into string?)
/*
-- original PHP version found online and not tested in PHP
function _bin8dec($bin) {
// function to convert 8bit binary numbers to integers using two's
complement
$num = bindec($bin);
if($num 0xFF) { return false; }
if($num = 0x80) {
return -(($num ^ 0xFF)+1);
} else {
return $num;
}
} ?
*/
function bin8dec pBinary
// does not crash, but returns useless values
// function to convert 8bit binary numbers to integers using two's
complement
-- [ $num = bindec($bin); ] not needed - php for convert to
string ?
if pBinary 0xFF then return false
if pBinary = 0x80
then
return -(( pBinary ^ 0xFF)+1);
else
return pBinary
end if
end bin8dec
thanks in advance for any help..
sqb
On 17 March 2011 12:00, stephen barncard stephenrevoluti...@barncard.comwrote:
This isn't that long a message but it appears I've pushed the limit.
THis is part one.
Stephen Barncard
San Francisco Ca. USA
more about sqb http://www.google.com/profiles/sbarncar
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RE: signed 8 bit to sign and magnitude handler needed [PART ONE]
From: stephen barncard Continuing on the exporting aiff files from audioclips quest, I discovered that 'some' (about 10%) of the exported files data would not play correctly. They sounded distorted and loud at full scale. Digging in further, I discovered that 8 bit AIFF files are not signed (due to their history), but instead are ( I think ) sign and magnitude 8 bit. So I need to convert the data for just the 8 bit files. I know this is dumb ass simple, but I've been staring at these numbers for too ling and need some fresh eyes. I am *seeking a handler in Livecode* to convert numbers between 0-255 (what I think is) two's compliment 8 bit to (what I think is) sign and magnitude numbers between 0-255. that is, I need to convert a number series that looks like below (word wrap is inevitable.) 80 7F 7F 7F 7E 7E 7E 7D 7D 7C 7C 7B 7B 7B 7A 7A 0010 79 79 78 78 78 78 78 77 77 77 77 77 77 77 77 77 0020 77 78 78 78 78 79 7A 7A 7B 7B 7C 7D 7D 7E 7F 80 0030 81 81 83 83 84 85 86 87 88 89 8A 8B 8C 8C 8C 8E 0040 8E 8F 90 90 90 91 91 91 92 91 91 91 92 91 91 90 0050 90 90 8E 8E 8D 8C 8B 8A 89 88 87 85 84 83 81 80 0060 7F 7D 7B 7A 79 77 76 75 73 72 71 6F 6F 6D 6C 6B (this is the same sine wave going above and below center in both lists) to be converted to numbers that look like this: 00 FF FF FF FE FE FE FD FD FC FC FB FB FB FA FA 0010 F9 F9 F8 F8 F8 F8 F8 F7 F7 F7 F7 F7 F7 F7 F7 F7 0020 F7 F8 F8 F8 F8 F9 FA FA FB FB FC FD FD FE FF 00 0030 01 01 03 03 04 05 06 07 08 09 0A 0B 0C 0C 0C 0E 0040 0E 0F 10 10 10 11 11 11 12 11 11 11 12 11 11 10 0050 10 10 0E 0E 0D 0C 0B 0A 09 08 07 05 04 03 01 00 0060 FF FD FB FA F9 F7 F6 F5 F3 F2 F1 EF EF ED EC EB (this is a SSND chunk dump from an audio file that plays correctly.) (part two will show the PHP code I tried to convert but failed) Looks like offset binary to me, so x - 128 is the two's complement version. If you need to represent the latter as unsigned bytes, the easiest way is probably (x + 128) bitAnd 255. -- Ciao, Paul D. DeRocco Paulmailto:pdero...@ix.netcom.com ___ use-livecode mailing list use-livecode@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode
Re: signed 8 bit to sign and magnitude handler needed [PART ONE]
That's the magic formula. Looks like it could be fast too. Thanks, Paul... function bin8decU pBinary return (pBinary+ 0x80) bitAnd 0xFF end bin8decU function convertBlock pBlock repeat for each character tCH in pBlock put bin8decU(tCH) after tOut end repeat return tOut end convertBlock sqb On 17 March 2011 12:15, Paul D. DeRocco pdero...@ix.netcom.com wrote: From: stephen barncard Continuing on the exporting aiff files from audioclips quest, I discovered that 'some' (about 10%) of the exported files data would not play correctly. They sounded distorted and loud at full scale. Digging in further, I discovered that 8 bit AIFF files are not signed (due to their history), but instead are ( I think ) sign and magnitude 8 bit. So I need to convert the data for just the 8 bit files. I know this is dumb ass simple, but I've been staring at these numbers for too ling and need some fresh eyes. I am *seeking a handler in Livecode* to convert numbers between 0-255 (what I think is) two's compliment 8 bit to (what I think is) sign and magnitude numbers between 0-255. that is, I need to convert a number series that looks like below (word wrap is inevitable.) 80 7F 7F 7F 7E 7E 7E 7D 7D 7C 7C 7B 7B 7B 7A 7A 0010 79 79 78 78 78 78 78 77 77 77 77 77 77 77 77 77 0020 77 78 78 78 78 79 7A 7A 7B 7B 7C 7D 7D 7E 7F 80 0030 81 81 83 83 84 85 86 87 88 89 8A 8B 8C 8C 8C 8E 0040 8E 8F 90 90 90 91 91 91 92 91 91 91 92 91 91 90 0050 90 90 8E 8E 8D 8C 8B 8A 89 88 87 85 84 83 81 80 0060 7F 7D 7B 7A 79 77 76 75 73 72 71 6F 6F 6D 6C 6B (this is the same sine wave going above and below center in both lists) to be converted to numbers that look like this: 00 FF FF FF FE FE FE FD FD FC FC FB FB FB FA FA 0010 F9 F9 F8 F8 F8 F8 F8 F7 F7 F7 F7 F7 F7 F7 F7 F7 0020 F7 F8 F8 F8 F8 F9 FA FA FB FB FC FD FD FE FF 00 0030 01 01 03 03 04 05 06 07 08 09 0A 0B 0C 0C 0C 0E 0040 0E 0F 10 10 10 11 11 11 12 11 11 11 12 11 11 10 0050 10 10 0E 0E 0D 0C 0B 0A 09 08 07 05 04 03 01 00 0060 FF FD FB FA F9 F7 F6 F5 F3 F2 F1 EF EF ED EC EB (this is a SSND chunk dump from an audio file that plays correctly.) (part two will show the PHP code I tried to convert but failed) Looks like offset binary to me, so x - 128 is the two's complement version. If you need to represent the latter as unsigned bytes, the easiest way is probably (x + 128) bitAnd 255. -- Ciao, Paul D. DeRocco Paulmailto:pdero...@ix.netcom.com ___ use-livecode mailing list use-livecode@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode -- Stephen Barncard San Francisco Ca. USA more about sqb http://www.google.com/profiles/sbarncar ___ use-livecode mailing list use-livecode@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode
