Merge two mp3 php

Question

Do you know a class to merge two MP3 files using PHP?

I've found nothing on Google.

Answer 1

If by merging, you mean placing one audio over the other, then please disregard this answer.

If you dont want to re-encode the MP3s, you can probably just append them. I know this worked for MPEG movies, so I guess it could work for MP3s too. Another option would be to add the audo files to a Zip Archive with no compression and then rename the extension to .mp3.

I did a quick test and this

file_put_contents('combined.mp3',
    file_get_contents('file1.mp3') .
    file_get_contents('file2.mp3'));

worked fine. The ID3 tags will be wrong, but the resulting file contains both audio files. For some other possible gotchas, see the link in Pekka's answer.

Also, some quick googling resulted in

• http://www.sourcerally.net/Scripts/20-PHP-MP3-Class
• http://codingforums.com/showthread.php?t=169069

and some discussion

• http://ask.metafilter.com/21381/Merge-mp3s-with-PHP

Answer 2

This is not possible. There is no implementation of the MP3 codec in PHP. You will need to use an external command-line tool to do this. (Which, depending on your server configuration, you can execute from within PHP as @ceejayoz says.)

See these questions for solutions:

• Merging MP3 files in Linux Debian using PHP

• What is the best way to merge mp3 files?

Answer 3

If the .mp3 files are just MPEG-1 or MPEG-2 Layer III audio, then the files can just be concatenated. There is no real concept of a header for the whole file. Each frame has a header followed by data, and the file is just comprised of a sequence of frames, which is called the bitstream. The bitrate, stereo mode, etc, do not necessarily have to be the same within a bitstream, so you can concatenate dissimilar files. The Wikipedia article explains this, but I think the spec actually is easier to understand.

ID3 tags, or an other data, within the file (which technically renders it a non-compliant bitstream) may muck things up on the decoder end.

The spec for MPEG-1 and MPEG-2 audio is actually pretty simple. Writing a parser to chunk a file into frames, and then interpreting the headers is not that much work. The last time I did this, it only took an hour or two.

The ID3 spec isn't that complicated either, so I suspect writing some code to strip out the tags before concatenation should be easy, but I have never done this.

The getID3() library (http://getid3.sourceforge.net/) may provide some guidance, too. It has been a while since I have used it, but it may also support opening MP3s and stripping out the ID3 tags already.

HTH

Answer 4

For anyone interested in doing the same thing now, you can use the following library: https://github.com/falahati/PHP-MP3

composer require falahati/php-mp3

Merge two MP3 file:

$audio1 = \falahati\PHPMP3\MpegAudio::fromFile("1.mp3");
$audio2 = \falahati\PHPMP3\MpegAudio::fromFile("2.mp3");
$audio1->append($audio2)->saveFile("3.mp3");

Answer 5

Important things to remember:

• The bit rates must match. It's also a good idea to ensure the rate (Hz) and stereo/mono are matched (I used Audacity).
• The Content-length header be the length of both files.

Here's a sample from my text-to-speech project. I needed to add a 1 second silence at the end of MP3 audio that was generated dynamically:

$output_audio = textToMP3("Hello World");               // Original audio
$silent_audio = file_get_contents("silence.mp3");       // 1 second silence
$content_length = strlen($output_audio) + strlen($silent_audio);

// Output the audio stream
header('Content-type: audio/mpeg');
header('Content-length: ' . $content_length);
header('Cache-Control: no-cache');
header("Pragma: no-cache");
header("Expires: 0");
echo $audio . $silent_audio;