PHP-FFMpeg: How to properly concatenate two videos? - php

Question

THE SITUATION:
I need it to concatenate multiple videos into one single video.
I am using the library PHP-FFMpeg.
But I don't manage to make it working.
THE VIDEOS:
The videos are recordings made with the MediaRecorder Web API.
The video format is: video/webm;codecs=h264
The audio format is opus.
recorder = new MediaRecorder(this.stream, {
mimeType: 'video/webm;codecs=h264'
})
CONCAT USING PHP-FFMPEG (using saveFromSameCodecs):
This is how I try to concat them using saveFromSameCodecs:
(I have checked the paths and are correct)
$video = $ffmpeg->open( $path1 );
$video
->concat([$path1, $path2])
->saveFromSameCodecs($path_output, TRUE);
But it failed with the following error message:
ffmpeg failed to execute command '/usr/local/bin/ffmpeg' '-f' 'concat' '-safe' '0' '-i' '/private/var/folders/dw/919v2nds7s78pz_qhp7z9rcm0000gn/T/ffmpeg-concath1kHiX' '-c' 'copy' '/Users/francescomussi/Desktop/Apps/cameraProject/back-end/camera-laravel/storage/app/public/videos/output.mp4'
CONCAT USING FFMPEG COMMAND LINE:
On suggestion on #RolandStarke and #LordNeckbeard I have tried using the ffmpeg command line to get a better insight on what is going on.
If I use the following command line:
ffmpeg -f concat -safe 0 -i mylist.txt -c copy output.mp4
I get the following error, related to the audio opus codec.
If I use the following command line, converting the audio coded to acc:
ffmpeg -f concat -safe 0 -i mylist.txt -c:v copy -c:a aac output.mp4
The final video is properly created, as a concatenation of the other videos.
CONCAT USING PHP-FFMPEG: (using saveFromDifferentCodecs)
It seems the problem is ONLY related to the codec.
So I have tried using saveFromDifferentCodecs:
$format = new FFMpeg\Format\Video\X264('libfdk_aac', 'libx264');
$result = $video1
->concat([$path1, $path2])
->saveFromDifferentCodecs($format, $output_path);
But I still get an error:
ffmpeg failed to execute command '/usr/local/bin/ffmpeg' '-i' '/Users/francescomussi/Desktop/Apps/cameraProject/back-end/camera-laravel/storage/app/public/videos/test1.mp4' '-i' '/Users/francescomussi/Desktop/Apps/cameraProject/back-end/camera-laravel/storage/app/public/videos/test2.mp4' '-filter_complex' '[0:v:0] [0:a:0] [1:v:0] [1:a:0] concat=n=2:v=1:a=1 [v] [a]' '-map' '[v]' '-map' '[a]' '-b:a' '128k' '/Users/francescomussi/Desktop/Apps/cameraProject/back-end/camera-laravel/storage/app/public/videos/output.mp4'
CONCAT USING PHPFFMPEG (but with different videos):
If the problem is only related to the codec, then using two different videos with video codec: h264 and audio codec aac, it should work, but it doesn't:
ffmpeg failed to execute command '/usr/local/bin/ffmpeg' '-f' 'concat' '-safe' '0' '-i' '/private/var/folders/dw/919v2nds7s78pz_qhp7z9rcm0000gn/T/ffmpeg-concatoJGhLt' '-c' 'copy' '/Users/francescomussi/Desktop/Apps/cameraProject/back-end/camera-laravel/storage/app/public/videos/output.mp4'
But using the command line it works smoothly: ffmpeg -f concat -safe 0 -i mylist.txt -c copy output.mp4
CONCAT USING shell_exec:
I have tried using shell_exec, with the first two videos (opus codec):
echo shell_exec("/usr/local/bin/ffmpeg -f concat -safe 0 -i /Users/francescomussi/Desktop/Apps/cameraProject/back-end/camera-laravel/mylist.txt -c:v copy -c:a aac /Users/francescomussi/Desktop/Apps/cameraProject/back-end/camera-laravel/output.mp4 2>&1");
And it works smoothly.
The final output is created, and with the acc audio codec.
TESTING THE LIBRARY:
To see if php-mpeg was actually working, I test it by making a basic resize of a video and it worked correctly.
RESUME:
Using ffmpeg command lines everything works fine
Using shell_exec everything works fine
Using php-ffmpeg I always get the error ffmpeg failed to execute command
QUESTION:
How can I concat videos using php-ffmpeg?
Is the issue caused by wrong encoding?
Thanks!

Answer 1

When encountering issues with php-ffmpeg the best approach is to copy the command from the error message and paste it in terminal. This will give you a better error message.
In your case the the error is
ffmpeg failed to execute command '/usr/local/bin/ffmpeg' '-f' 'concat' '-safe' '0' '-i' '/private/var/folders/dw/919v2nds7s78pz_qhp7z9rcm0000gn/T/ffmpeg-concath1kHiX' '-c' 'copy' '/Users/francescomussi/Desktop/Apps/cameraProject/back-end/camera-laravel/storage/app/public/videos/output.mp4
Debugging this is a bit harder as the temp file /private/var/[...]/ffmpeg-concath1kHiX is deleted when you try to execute the ffmpeg command in the terminal. To test it you can create the temp file yourself like:
$vidoes = [__DIR__ . '/small.mp4', __DIR__ . '/small.mp4'];
file_put_contents('videolist.txt', implode("\n", array_map(function ($path) {
return 'file ' . addslashes($path);
}, $vidoes)));
Now you can run the ffmpeg command in the terminal
ffmpeg -f concat -safe 0 -i videolist.txt -c copy /Users/[...]/videos/output.mp4
#[...]
#File '/Users/[...]/videos/output.mp4' already exists. Overwrite ? [y/N]
#Not overwriting - exiting
So you your case the error is that the output file already existed. The solution is to use an other non-existing output file or delete it before concatenating your videos.
Here an example how to concatenate files (small.mp4 taken from http://techslides.com/sample-webm-ogg-and-mp4-video-files-for-html5)
<?php
require 'vendor/autoload.php';
$ffmpeg = FFMpeg\FFMpeg::create();
$video = $ffmpeg->open(__DIR__ . '/small.mp4');
$video
->concat([__DIR__ . '/small.mp4', __DIR__ . '/small.mp4'])
->saveFromSameCodecs(__DIR__ . '/out-'. time() . '.mp4', true);

Answer 2

The correct answer is the one from #RolandStarke.
Here I just want to put together a list of suggestions that may be useful to debug other similar problems in dealing with ffmpeg:
Make a reinstall of ffmpeg. It may be a missing option or a missing codec. Here is how to install (for mac), including all possible options (september 2018). It took me 30minutes so be patient.
brew install ffmpeg --with-chromaprint --with-fdk-aac --with-fontconfig --with-freetype --with-frei0r --with-game-music-emu --with-libass --with-libbluray --with-libbs2b --with-libcaca --with-libgsm --with-libmodplug --with-librsvg --with-libsoxr --with-libssh --with-libvidstab --with-libvorbis --with-libvpx --with-opencore-amr --with-openh264 --with-openjpeg --with-openssl --with-opus --with-rtmpdump --with-rubberband --with-sdl2 --with-snappy --with-speex --with-srt --with-tesseract --with-theora --with-tools --with-two-lame --with-wavpack --with-webp --with-x265 --with-xz --with-zeromqlibzeromq --with-zimg
To have the updated options list you can run: brew options ffmpeg or just google it.
Try to do the same thing you are trying to do, but using the ffmpeg command line only. It will more insight and a better error reporting. For example for concat:
ffmpeg -f concat -safe 0 -i mylist.txt -c copy output.mp4
Check that PHP-FFMpeg is properly working. Concat it's a bit more difficult operation. You can try with a simpler one and see if it's working and if the library is properly installed. For example you can try a simple conversion:
FFMpeg::fromDisk('local')
->open('public/videos/test.mp4')
->export()
->toDisk('local')
->inFormat(new FFMpeg\Format\Video\X264('libmp3lame', 'libx264'))
->save('public/videos/converted_test.mp4');
Double check every path. And in the case of concat, make sure the output file doesn't already exists.
It may be an encoding problem. Try other types of files with different codecs to see if that's actually the issue. In case you can convert beforehand to the proper codec.
Add line breaks in the source code. In my case I was getting the generic error: Unable to save concatenated video. Here is the source code:
try {
$this->driver->command($commands);
} catch (ExecutionFailureException $e) {
$this->cleanupTemporaryFile($outputPathfile);
$this->cleanupTemporaryFile($sourcesFile);
throw new RuntimeException('Unable to save concatenated video', $e->getCode(), $e);
}
But if I dump the execution and then die it, right before that block:
dd($this->driver->command($commands));
It was giving me a more detailed error message.
You can also dump the commands array: dd($commands);
Finally here is a list of similar issue with PHP-FFMpeg that you can check to see if the solution has already been given: https://github.com/pascalbaljetmedia/laravel-ffmpeg/wiki/FFmpeg-failed-to-execute-command
If you have other suggestions feel free to comment or edit the answer.