Log says to view log file but there is no log file

[rnveach]

Describe Your Environment

• 1.38.3 release
• PPA
• LUbuntu 22.04.5 LTS
• LibreWolf 151 (version of Firefox)

Describe the bug

I attempted to download a video of multiple events using the montage review and I got an internal server error.

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I went to the console log and saw messages like:

7/6/26, 8:38:29 PM EDT	web_php	62421	ERR	Unable to generate video, check /var/cache/zoneminder/events/1/2026-07-06/2914117/ffmpeg.log for details	/usr/share/zoneminder/www/includes/Event.php	841
7/6/26, 8:38:28 PM EDT	web_php	62421	INF	Creating video file Event-2914117.mp4 for event 2914117	/usr/share/zoneminder/www/includes/Event.php	803

However, when I went look at the ffmpeg log, it did not exist. As far as I know this was the first error, and all the events that were part of the timeframe all produced the same error with no log files where it was specified to be.

I had enough diskspace for the video, as my first screenshot showed, however I think the issue might be that ZM is trying to generate the videos in the same folder as my events and that location didn't have enough space. The place it wanted to store the individual video is a different drive then where it said the full zip file would be, and I usually keep the drive my events are on maxed with the images. The storage view in ZM shows it is 80% full, but from my experience that is usually around the max because of space needed for the file pathing and names.

Is there an option to change where the videos are created?

To Reproduce
Steps to reproduce the behavior:

1. Go the montage review and queue up an hour.
2. Click on download video.
3. Click on Generate download and then watch it fail a short bit later.

Expected behavior

I was expecting to either download a video, or get a clear error message on why it failed in the logs. If the log file couldn't be created, I would expect the web view logs to show the error for why the file couldn't be created.

Debug Logs

N/A

[IgorA100]

However, when I went look at the ffmpeg log

Have you looked at this file /var/cache/zoneminder/events/1/2026-07-06/2914117/ffmpeg.log?
What format are your recorded events stored in (mkv, mp4)?

[IgorA100]

I can't test 1.38.3, but try changing the following in the \includes\download_functions.php file:
if (!$event->DefaultVideo()) $event->GenerateVideo();
to
if (!$event->DefaultVideo() || $event->DefaultVideo() === 'index.m3u8') $event->GenerateVideo();

[rnveach]

Have you looked at this file /var/cache/zoneminder/events/1/2026-07-06/2914117/ffmpeg.log?

In my original post I said, However, when I went look at the ffmpeg log, it did not exist. . Hence the title of this issue.

What format are your recorded events stored in (mkv, mp4)?

The export format is set to zip. I assume the video format is still the default for ZM as I don't modify the options usually. This is the value for the only relevant option I saw in the options page. If you need another options, let me know which one you want me to provide.

Images
FFMPEG_FORMATS: mpg mpeg wmv asf avi* mov swf 3gp**

try changing the following in the \includes\download_functions.php file:

I will try this later and let you know.

[rnveach]

try changing the following in the \includes\download_functions.php file:

No change. Still same issue.

[rnveach]

Unable to generate video, check

I found the code creating this error inside includes/Event.php (at /usr/share/zoneminder/www).

Unable to generate video, check /var/cache/zoneminder/events/1/2026-07-07/2915565/ffmpeg.log for details

This is the command created:
/usr/bin/ffmpeg -y -r 6.39 -i /var/cache/zoneminder/events/1/2026-07-07/2915565/�d-capture.jpg -vf -s 320x240 -r 25 '/var/cache/zoneminder/events/1/2026-07-07/2915565/Event-2915565.mp4' > /var/cache/zoneminder/events/1/2026-07-07/2915565/ffmpeg.log 2>&1

I don't know why there is that weird character between 2915565/ and d-capture.jpg but thats what I get from copying from the system log. It may have something to do with '%0'.ZM_EVENT_IMAGE_DIGITS .'d-capture.jpg' in the code. My EVENT_IMAGE_DIGITS is set to 5.

I ran this inside /var/cache/zoneminder/events/1/2026-07-07/2915565 and this created the ffmpeg.log file and this was its contents:

ffmpeg version 4.4.2-0ubuntu0.22.04.1 Copyright (c) 2000-2021 the FFmpeg developers
  built with gcc 11 (Ubuntu 11.2.0-19ubuntu1)
  configuration: --prefix=/usr --extra-version=0ubuntu0.22.04.1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libdav1d --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librabbitmq --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzimg --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-pocketsphinx --enable-librsvg --enable-libmfx --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
  libavutil      56. 70.100 / 56. 70.100
  libavcodec     58.134.100 / 58.134.100
  libavformat    58. 76.100 / 58. 76.100
  libavdevice    58. 13.100 / 58. 13.100
  libavfilter     7.110.100 /  7.110.100
  libswscale      5.  9.100 /  5.  9.100
  libswresample   3.  9.100 /  3.  9.100
  libpostproc    55.  9.100 / 55.  9.100
/var/cache/zoneminder/events/1/2026-07-07/2915565/d-capture.jpg: No such file or directory

I don't know why running manually created the log file, but the PHP fails to do so.

It is looking like the issue is related to '%0'.ZM_EVENT_IMAGE_DIGITS .'d-capture.jpg'.

zoneminder/web/includes/Event.php

Line 868 in 9218653

.' -i ' . $event_path.'/'.( $this->DefaultVideo() ? $this->DefaultVideo() : '%0'.ZM_EVENT_IMAGE_DIGITS .'d-capture.jpg' )

Edit:

I sent this to AI to get its thoughts, and it says the usage of escapeshellcmd is an issue for the entire command.
https://www.php.net/manual/en/function.escapeshellcmd.php
According to the official documentation, it will escape > that is trying to be used here to output the file. I created a simple test example php, and this is what it says will be the full escaped command:
/usr/bin/ffmpeg -y -r 6.39 -i /var/cache/zoneminder/events/1/2026-07-07/2915565/%05d-capture.jpg -vf -s 320x240 -r 25 '/var/cache/zoneminder/events/1/2026-07-07/2915565/Event-2915565.mp4' \> /var/cache/zoneminder/events/1/2026-07-07/2915565/ffmpeg.log 2\>\&1

You can see other commands in this file which are properly escaped.

[rnveach]

I believe I have a fix for the command. It is now creating the log file, but the ffmpeg is failing with a new error.

It now creates all the video files on the server, but the server call still fails with a 500. There is no error in the system console and I can see it creating all the videos as they are info logs.

[rnveach]

It looks like this is the next error in trying to export a video:
#4975 (comment)

Line with error:

zoneminder/web/includes/download_functions.php

Line 108 in 9218653

$filePath = findVideoEventFile($event, "mp4");

Function is defined at:

zoneminder/web/includes/functions.php

Line 2533 in 9218653

function findVideoEventFile ($Event, $ext="*") {

Edit: I tried adding a require_once('functions.php'); but it still generated the same error.