I want to merge videos in batch size of twenty (20) each. I'm running a Linux machine. The videos are in mp4 format and moderate quality. Some even have the audio stream missing. So far I've tried ffmpeg, mencoder, cvlc/vlc and MP4Box. I want to write a command line script to achieve this, since I'm doing batch processing.

The main issue is that some of the solutions I tried work well for two videos, some work well for videos with audio stream and yet others work well for some other subset of my video set. However, I have not been able to find a comprehensive solution for this task.

  • 2
    Please don't ask same question in multi SE sites: superuser.com/questions/928548/… – Maythux Jun 16 '15 at 10:25
  • Could you post specifically what you've tried so far? – ohaal Jun 16 '15 at 14:18
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    @ohaal I tried using various concatenation methods given in ffmpeg, including filters and file protocols. I also tried using the concat feature of cvlc/vlc. I also tried the concat feature of mencoder. All of these worked partially. This finally helped me solve the matter. – Dhruv Singal Jun 18 '15 at 4:25
  • Yes, you already mentioned the tools, what I meant was the actual commands you ran. Also it would be great if you could include the command that ended up solving it for you (in your answer), for future visitors. – ohaal Jun 18 '15 at 7:18
  • Aah, I see your point. Unfortunately, I can't list the commands due to the sheer number. The command which solved my problem was this melt {input-sequence} -consumer avformat:{output-name} acodec=libmp3lame vcodec=libx264 – Dhruv Singal Jun 19 '15 at 7:14

10 Answers 10


I am using mkvmerge to join multiple MP4 files into single one:

mkvmerge -o outfile.mkv infile_01.mp4 \+ infile_02.mp4 \+ infile_03.mp4
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  • 3
    It is better to use the extension .mkv for the output file, as it is a Matroska container irrespective of what extension you give. – haridsv Sep 17 '17 at 7:27
  • Here's how to install mkvmerge: tipsonubuntu.com – Morgoth Jan 31 '18 at 9:54
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    Only this command mkvmerge works. All ffmpeg ones fail with shifted audio at least. – 42n4 Sep 22 '19 at 11:39

You can do it using ffmpeg:

ffmpeg -i concat:"input1.mp4|input2.mp4" output.mp4

reference and more info

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    I tried doing that. The issue with this is that it doesn't give a proper out. 1. The audio tracks are muddled. 2. There is some disturbance in the video track. – Dhruv Singal Jun 16 '15 at 11:26
  • I used it for more than sample, the result is high quality, maybe your source video quality is the problem? – Maythux Jun 17 '15 at 5:58
  • You are probably right. This solved the issue: askubuntu.com/a/637179/420614 – Dhruv Singal Jun 18 '15 at 4:18
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    Don't use the concat protocol to concatenate MP4. It only works with certain formats that most general users don't encounter. Use concat demuxer or concat filter instead. – llogan Nov 17 '17 at 18:11
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    Use with formats that support file level concatenation (MPEG-1, MPEG-2 PS, DV). Do not use with MP4. Source: stackoverflow.com/questions/7333232/… – SemperPeritus Feb 19 '19 at 13:53

Create a file files.txt with all the files you want to have concatenated in the following form (lines starting with a # are ignored):

# this is a comment
file 'file1.mp4'
file '/path/to/file2.mp4'
file 'file3.mp4'

Note that these can be either relative or absolute paths. Then you can stream copy or re-encode your files:

ffmpeg -f concat -safe 0 -i files.txt -c copy output.mp4
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This solved the matter: https://stackoverflow.com/a/22324018/5014767

melt is a great command line utility for this. Here is the page

Edit from comments: The command which solved my problem was this melt {input-sequence} -consumer avformat:{output-name} acodec=libmp3lame vcodec=libx264

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I wrote a little shell script to concat MP4s without transcoding using ffmpeg.

for f in $(ls *.MP4); do
    ffmpeg -i $f -c copy -bsf:v h264_mp4toannexb -f mpegts $f.ts

CONCAT=$(echo $(ls *.ts) | sed -e "s/ /|/g")

ffmpeg -i "concat:$CONCAT" -c copy -bsf:a aac_adtstoasc output.mp4

rm *.ts

This creates intermediate files in an MPEG container and then concatenates them into an MP4.

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  • 1
    It's important to note that this script will fail if any of the filenames contain spaces or, in some cases, special characters. For the loop, it's significantly better to use just for f in *.MP4 without using ls. (You should always avoid using ls in scripts for a couple of important reasons; there are better options.) Also, use quotes for variables unless you are certain that there are no spaces or other special characters, so "${f}" (or just "$f") instead of unquoted $f. – Paddy Landau Jun 14 '18 at 14:11
  • CONCAT=$(echo $(ls *.ts) | sed -e "s/ /|/g") doesn't work well with file names that are 1, 2, 3... 10... 20. It ends up parsing them as 1, 10... 2, 20... etc. I suggest CONCAT=$(echo $(ls -v *.ts) | sed -e "s/ /|/g") this will ensure order. – tisaconundrum Nov 16 '18 at 8:05

My script, purely in bash and ffmpeg. Re-encodes files given on a command line into one.

Requires the files to be of the same resolution. Accepts different metadata rotation, which ffmpeg concat: doesn't.

rm ffmpeg-concat-output.mkv

for FNAME in $@; do
    echo "Processing ${FNAME}"

    if [ -z "${FILTER}" ]; then
        FILTER="[$INDEX:v:0] [$INDEX:a:0]"
        FILTER="${FILTER} [$INDEX:v:0] [$INDEX:a:0]"
    let INDEX+=1

COMMAND="ffmpeg ${INPUTS} \
    -filter_complex '${FILTER} \
        concat=n=${INDEX}:v=1:a=1 [v] [a]' \
    -map '[v]' -map '[a]' \

#   -af 'volume=15dB' # won't work with -filter_complex

bash -c "${COMMAND}"
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I created a Python script that, using moviepy, can concatenate also subsegments (useful if you want for example remove some parts from a video).

Use it with:

vcat -i inputfile1,inputfile2[start-end],... -o <outputfile>
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LossLessCut works very well for this. Fast and painless.

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I wrote a wrapper around ffmpeg called vidmerger 🎞, which makes it very easy to merge multiple videos inside a folder, for instance to merge all mp4 files inside the current directory, just run:

vidmerger .
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In addition to Maythux's answer, from :

A few multimedia containers (MPEG-1, MPEG-2 PS, DV) allow one to concatenate video by merely concatenating the files containing them.

I.e. the videos to be concatenated use one of the abovementioned video containers (to which I'll add MPEG-4 Part 14 for personal experience), you could simply:

cat video1.ext video2.ext video3.ext > video4.ext
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    I tried this but it only returns the first video as the output. I read somewhere that it doesn't work, though I don't remember the rationale behind this. – Dhruv Singal Jun 16 '15 at 11:28
  • @DhruvSingal Yes, I can confirm this, I've tried this on two MP4 videos with the exact same video / audio encoding and as you I could only browse through the first video. Which seems reasonable, however I'm pretty sure that I've done this before once with a couple of MP4 videos. Perhaps the memory isn't serving well here, or there are other requirements for this to work. I want to research on this since I'm interested also, if I find something I'll update the answer and drop you a comment – kos Jun 16 '15 at 11:45
  • We somehow need to change the metadata at the start of the first video to encompass the entire length of the combined movie, and other stuff probably. Only a few mpeg4 files let me see the metadata.. – Ken Mollerup Oct 22 '15 at 14:55
  • This can't work. – vy32 Feb 29 at 22:08

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