function MPEGaudioHeaderValid($rawarray, $echoerrors = false, $allowBitrate15 = false)
{
if (($rawarray['synch'] & 0xffe) != 0xffe) {
return false;
}
static $MPEGaudioVersionLookup;
static $MPEGaudioLayerLookup;
static $MPEGaudioBitrateLookup;
static $MPEGaudioFrequencyLookup;
static $MPEGaudioChannelModeLookup;
static $MPEGaudioModeExtensionLookup;
static $MPEGaudioEmphasisLookup;
if (empty($MPEGaudioVersionLookup)) {
$MPEGaudioVersionLookup = getid3_mp3::MPEGaudioVersionArray();
$MPEGaudioLayerLookup = getid3_mp3::MPEGaudioLayerArray();
$MPEGaudioBitrateLookup = getid3_mp3::MPEGaudioBitrateArray();
$MPEGaudioFrequencyLookup = getid3_mp3::MPEGaudioFrequencyArray();
$MPEGaudioChannelModeLookup = getid3_mp3::MPEGaudioChannelModeArray();
$MPEGaudioModeExtensionLookup = getid3_mp3::MPEGaudioModeExtensionArray();
$MPEGaudioEmphasisLookup = getid3_mp3::MPEGaudioEmphasisArray();
}
if (isset($MPEGaudioVersionLookup[$rawarray['version']])) {
$decodedVersion = $MPEGaudioVersionLookup[$rawarray['version']];
} else {
echo $echoerrors ? "\n" . 'invalid Version (' . $rawarray['version'] . ')' : '';
return false;
}
if (isset($MPEGaudioLayerLookup[$rawarray['layer']])) {
$decodedLayer = $MPEGaudioLayerLookup[$rawarray['layer']];
} else {
echo $echoerrors ? "\n" . 'invalid Layer (' . $rawarray['layer'] . ')' : '';
return false;
}
if (!isset($MPEGaudioBitrateLookup[$decodedVersion][$decodedLayer][$rawarray['bitrate']])) {
echo $echoerrors ? "\n" . 'invalid Bitrate (' . $rawarray['bitrate'] . ')' : '';
if ($rawarray['bitrate'] == 15) {
// known issue in LAME 3.90 - 3.93.1 where free-format has bitrate ID of 15 instead of 0
// let it go through here otherwise file will not be identified
if (!$allowBitrate15) {
return false;
}
} else {
return false;
}
}
if (!isset($MPEGaudioFrequencyLookup[$decodedVersion][$rawarray['sample_rate']])) {
echo $echoerrors ? "\n" . 'invalid Frequency (' . $rawarray['sample_rate'] . ')' : '';
return false;
}
if (!isset($MPEGaudioChannelModeLookup[$rawarray['channelmode']])) {
echo $echoerrors ? "\n" . 'invalid ChannelMode (' . $rawarray['channelmode'] . ')' : '';
return false;
}
if (!isset($MPEGaudioModeExtensionLookup[$decodedLayer][$rawarray['modeextension']])) {
echo $echoerrors ? "\n" . 'invalid Mode Extension (' . $rawarray['modeextension'] . ')' : '';
return false;
}
if (!isset($MPEGaudioEmphasisLookup[$rawarray['emphasis']])) {
echo $echoerrors ? "\n" . 'invalid Emphasis (' . $rawarray['emphasis'] . ')' : '';
return false;
}
// These are just either set or not set, you can't mess that up :)
// $rawarray['protection'];
// $rawarray['padding'];
// $rawarray['private'];
// $rawarray['copyright'];
// $rawarray['original'];
return true;
}