Changeset 4825 for extensions/AMetaData
- Timestamp:
- Feb 2, 2010, 12:12:58 AM (14 years ago)
- File:
-
- 1 edited
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extensions/AMetaData/JpegMetaData/Readers/IfdReader.class.php
r4824 r4825 451 451 case 0x9201: // ShutterSpeedValue, tag0x9201 452 452 if($values[1]==0) $values[1]=1; 453 $returned=ConvertData::toExposureTime(1/round(pow(2, $values[0]/$values[1]),0)); 453 /* 454 * the formula to compute the shutter speed value is 1/pow(2, x) 455 * 456 * Because of rounding errors, the result obtained using this formula 457 * is sometimes incorrect. 458 * 459 * We consider that if the result is greater than the second, the 460 * result is rounded to 2 hundredths of a second (to avoid something 461 * like 3.0000124500015s) 462 * 463 * in other case (result is less than 1 second) there is no rules 464 * result can be strange, but for now I don't know how to resolve this 465 * problem 466 * 467 */ 468 469 $value=1/pow(2, $values[0]/$values[1]); 470 if($value>1) 471 { 472 $value=round($value,2); 473 } 474 $returned=ConvertData::toExposureTime($value); 454 475 break; 455 476 case 0x9202: // ApertureValue, tag0x9202
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