melt-7 "Application provided invalid, non monotonically increasing dts to muxer in stream 1: 51200 >= 51200" on any input

[timohahaa]

Describe the bug
I try to run a simple

melt video.mp4 in=0 out=25  -consumer avformat:highlights.mp4 vcodec=libx264

On a video-only file and get an almost imidiate error:

4
No LADSPA plugins were found!
Check your LADSPA_PATH environment variable.
Failed to load "info"
[swscaler @ 0x55d8dc9935c0] Warning: data is not aligned! This can lead to a speed loss
Failed to load "info"
+-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+                                                                               |1=-10| |2= -5| |3= -2| |4= -1| |5=  0| |6=  1| |7=  2| |8=  5| |9= 10|                                                                               +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+ +-----+
+---------------------------------------------------------------------+
|               H = back 1 minute,  L = forward 1 minute              |
|                 h = previous frame,  l = next frame                 |
|           g = start of clip, j = next clip, k = previous clip       |
|                0 = restart, q = quit, space = play                  |
+---------------------------------------------------------------------+
[mp4 @ 0x7f9d6c000d00] Timestamps are unset in a packet for stream 1. This is deprecated and will stop working in the future. Fix your code to set the timestamps properly
[mp4 @ 0x7f9d6c000d00] Encoder did not produce proper pts, making some up.
[mp4 @ 0x7f9d6c000d00] Application provided invalid, non monotonically increasing dts to muxer in stream 1: 51200 >= 51200
Current Position:         25

It seems like no matter what file I take, I get this error. Some files are regular YT videos downloaded with yt-dlp, some are other stuff, that works with ffmpeg just fine. Maybe my command is wrong?

Desktop

• OS: Linux my-host-name1 5.15.0-136-generic #147-Ubuntu SMP Sat Mar 15 15:53:30 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux
• MLT/melt version: 7.4.0

Context:

My goal is to take a big video and trim some parts from it (basically a CLI video-editor).
Something like this:

melt \
    video.mp4 in=0 out=25 \
    video.mp4 in=45 out=70 \
    video.mpap in=100 out=150  \
     -consumer avformat:edited_file.mp4

So take clips from 0 to 25 secs, from 45 to 70, etc. And combine them in a resulting video.
I am very new to melt, need help!

[ddennedy]

Ignore the messages, they are harmless. Now, what is wrong?

[timohahaa]

Ignore the messages, they are harmless. Now, what is wrong?

The messages appear in red, same as if an ffmpeg command with -xerror was called on a video with real non-mon-dts problems. I expect video to be 25 seconds in length for the first command, but only get 1.088000 seconds in return

For the last command with 3 inputs I get only 2.176000 seconds, when I expect 100

[ddennedy]

Bare numeric values for in and out are in frames, not seconds, and you are using a very old version of melt (nearly 4 years). The message reported in subject no longer occurs. If you want to specify time values in seconds, you need to learn that from mltframework.org.

[timohahaa]

I build 7.32.0 from source and the error message disappeared, thanks. About docs - I look through producer section but cant seem to find any docs about in/out values. Seems like melt-cli is not currently documented?

[ddennedy]

Documentation link at the top of the web site: https://mltframework.org/docs/
Second item: https://mltframework.org/docs/melt/
Under Miscellaneous section is link Time Values

Otherwise, yeah, the documentation is not great. AI might be helpful but will also lead you astray. Still, it can provide some hints and push you to uncover things, some of which requires digging into examples and source code. MLT is primarily for developers, and melt is not really intended to be used directly by non-developers, although you are certainly welcome to try. Just don't expect a whole lot of help because the people making this are busy making Shotcut and Kdenlive where we prefer to provide a more plush end user UI.