How do I resolve ffmpeg concat command error "unknown keyword..."?

Question

I am trying to concatenate two video files using ffmpeg, and I am receiving an error.

To eliminate compatibility issues between the two videos, I have been concatenating the same video with itself, and the same error persists.

ffmpeg \
  -f concat \
  -safe 0 \
  -i intro_prepped.avi intro_prepped.avi \
  -c copy \
  concat.avi  

And the error output I receive is....

[concat @ 0x220d420] Line 1: unknown keyword 'RIFFf�?' intro_prepped.avi: Invalid data found when processing input

I have tried various combinations of concat flags and have not been able to get it to work. Has anyone seen this error before?

Flanker

Answer 1

Docs for several ways of concatenating files: https://trac.ffmpeg.org/wiki/Concatenate

Here's a command I use to concatenate videos:

ffmpeg \
  -i "concat:input1.avi|input2.avi|input3.avi" \
  -c:a copy \
  -c:v copy \
  output.avi

Nickell

I tried: ` ffmpeg -i "concat:media3.mp4|media4.mp4|media5.mp4" -c:a copy -c:v copy output.mp4` And it just produced a copy of media3.mp4, without any concatenation. However, this version from your link worked: ` ffmpeg -f concat -safe 0 -i mylist.txt -c copy output.mp4` worked, where mylist.txt was: ` # this is a comment file 'media3.mp4' file 'media4.mp4' file 'media5.mp4'` Any idea what the difference is here? – Culicid

the difference is the word file. Look at my answer below – Reputed

This file-level copy method only work for some formats (MPEG-1, MPEG-2 PS, DV) , but not for mp4. – Bolme

Answer 2

This is a bit late for the original post, but I was just searching for answers to the same problem so I think it's still relevant and I haven't found any more recent posts answering the same problem.

I found that my .txt file was encoded wrong. I opened the file in Notepad and did a 'Save As...' I changed the encoding to UTF-8 and the ffmpeg concat command worked.

Surfboarding

This was the issue for me too. Thank you. For those using Notepad++, the same can be done there with the 'Encoding' tab on the main title bar. – Mannes

Click on current encoding name on right side of status bar or press Ctrl+Shift+P - and type "Change File Encoding" to achieve this in VSCode. – Cicala

And this is the issue when you create a file with echo in powershell. – Balm

Exactly what I needed. In VSCODE, you can click the current encoding in the lower-right of the app tray (near Ln, Col, Spaces and line-endings), pick UTF-8, then "Save with new encoding". – Aquiline

Answer 3

I tried all of the aforementioned and it didn't work.

It looks like that the file names in the list have to be specially formatted to look like:

file '/path/to/file1.wav'

with a word file included. I spend a lot of time trying to guess why ffmpeg encountered an error trying to read the file names. It didn't matter if they were in the list or in the command line. So only after I utilized a command

for f in *.wav; do echo "file '$f'" >> mylist.txt; done

to make list from ffmpeg's manual I had success. The only difference was an additional word file.

Here you can read it yourself: https://trac.ffmpeg.org/wiki/Concatenate#demuxer

Reputed

Answer 4

Your text file is likely encoded in UTF-16.

Fix: (Windows 10)

• Open text file
• Select 'Save as'
• Look by the save button, you get to pick encoding with a drop down box, select UTF-8.
• Save and run ffmpeg again.

I used the Powershell code on ffmpegs webpage to make a text file with filenames, and Powershell seems to save text files as some variant of UTF-16, so I chose the safer UTF-8.

Urethrectomy

Answer 5

I struggled with all these instructions above on my Mac (M1, Ventura, ffmpeg version N-109530-g4a80db5fc2-tessus). None of them worked for me - but a combination of all did the trick!

This is how I got it running:

• place all input files the same folder
• create input.txt in this folder - content looks like this:

  file 'input1.mp4'
  file 'input2.mp4'
  file 'input3.mp4'
  file 'input4.mp4'
  

  • Note:
    • file encoding must be UTF-8
    • file keyword must be present
    • filename must not be fully qualified (I got exceptions using '/path/to/input1.mp4')
    • filename must be enclosed by '
• navigate to this folder in the terminal
• execute ffmpeg -f concat -i input.txt -c copy ffmpegOUT.mp4

Baudelaire

Answer 6

The input file should be a text file, not an avi. The text file lists the files to concatenate.

See the concat demuxer documentation and FFmpeg Wiki: Concat.

Upperclassman

Is there a way to concatenate two files on the command line? I am doing it from a bash script and do not know the file names ahead of time. – Flanker

Sure. See the other examples in that link. – Upperclassman

Answer 7

Nobody had a full, working, concat text file batch file anywhere. So I am posting it

md ts
for %%x in (input\*.m4a) do (ffmpeg -i "%%x" -c copy -bsf:v h264_mp4toannexb ts\%%~nx.ts)
for %%c in ("ts\*ts") do (echo file '%%c')>>list.txt
for %%f in (input\*.m4a) do (set fn=%%~nf)
ffmpeg -f concat -safe 0 -i "list.txt" -c copy "%cd%\%fn%".m4a

Flea

Answer 8

Latest:

Using windows 10

1. gather files using this with sort according to date modification:

   foreach ($i in Get-ChildItem -Path .\*.mp4 | Sort-Object -Property LastWriteTime) {echo "file '$i'" >> mylist.txt}
   

2. save as the mylist as UTF-8

3. combine them by running this at powershell:

   ffmpeg -f concat -safe 0 -i mylist.txt -vcodec copy output.mp4
   

4. ffmpeg must be installed to use directly.

5. if you want to just directly use ffmpeg exe without installation then use:

    ./ffmpeg -f concat -safe 0 -i mylist.txt -vcodec copy output.mp4
   

   given that ffmpeg.exe is in the same directory and powershell is at that directrory

Marcellusmarcelo

Answer 9

for me it worked by disabling BOM on the UTF-8 format. So the file was UTF-8 and noBOM.

e.g. the contents of the text file:

file 'video1.mp4'
file 'video2.mp4'
file 'video3.mp4'

and use:

ffmpeg -f concat -i input_videos.txt -c copy ffmpeg_out.mp4

Pouched