While already have the code/script needed to just combine .wav files into a single output file/track, it concatenates them, end-to-end:
//function to handle joining/merging
function joinWavs($wavs){
$fields = join('/',array( 'H8ChunkID', 'VChunkSize', 'H8Format',
'H8Subchunk1ID', 'VSubchunk1Size',
'vAudioFormat', 'vNumChannels', 'VSampleRate',
'VByteRate', 'vBlockAlign', 'vBitsPerSample' ));
$data = '';
foreach($wavs as $wav){
$fp = fopen($wav,'rb');
$header = fread($fp,36);
$info = unpack($fields,$header);
// read optional extra stuff
if($info['Subchunk1Size'] > 16){
$header .= fread($fp,($info['Subchunk1Size']-16));
}
// read SubChunk2ID
$header .= fread($fp,4);
// read Subchunk2Size
$size = unpack('vsize',fread($fp, 4));
$size = $size['size'];
// read data
$data .= fread($fp,$size);
}
return $header.pack('V',strlen($data)).$data;
}//end of joinWavs function
//and here's code to pass an array of file names to the above function, and spit out resulting file
$outgoing = joinWavs($arFiles);
header("Content-Type: audio/x-wav");
header("Content-Disposition: attachment; filename=dynamic.wav");
header('Content-Transfer-Encoding: binary');
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Pragma: public');
header('Content-Length: ' . strlen( $outgoing));
echo $outgoing;
Do also have some other code to handle something similar with .MP3 files, but, it's a bit longer/too big to post in a message here, but, either way, issue is would want to specifically mix/combine multiple files into 1 output stream/file, but would need/want to set possibly overlapping start times for the input chunks/tracks in the output track, if that makes sense?
Now, aside from trying to do this with something like a call to a command line command on different operating systems - that idea seems to get mentioned quite a bit on the 'net, am just thinking that something like this should be relatively doable/possible using binary streams/data from the source files, etc. - or am I wrong here?
Stay well
Jacob Kruger
Blind Biker
Skype: BlindZA
'...fate had broken his body, but not his spirit...'
