Joining webm videos under Linux

Question

How can I concatenate several .webm files (e.g. downloaded from youtube) into a single file? I've tried a simple cat followed by "mencoder -forceidx -oac copy -ovc copy ..." - didn't work. I'm using Linux.

score 13 · Accepted Answer · answered May 20 '12 at 19:55

13

As Lou mentioned, try mkvmerge like this (from command line):

mkvmerge -o output.webm -w file1.webm + file2.webm

answered May 20 '12 at 19:55

Laurent S

336

score 3 · Answer 2 · answered May 07 '12 at 18:42

Remember that the WebM container format is a strict subset of Matroska, so Matroska tools will work on WebM files. Try mkvmerge (which ships with mkvtoolnix) to re-mux files without re-encoding. The result may or may not be satisfactory for your purposes, but mkvtoolnix is mature and GPLv2-licensed, and well worth a try. There's even a mkvmerge GUI.

score 0 · Answer 3 · answered Jan 11 '19 at 05:50

If you use the mkvmerge GUI, you right-click in the "input file" section, then choose "Add Files" and select the first file from wherever you stored it.

Now, you right-click on the first file in the "input file" section and select "append files".

If, instead of choosing "append files", you chose "add files as additional parts", it won't work. This option is for combining files where the second/third/etc files don't have video headers (like if you used the Unix split command to just cut a file into chunks). If you chose that option with two WebM files, you wouldn't get any errors, but only the first video file will be present in the resulting MKV.

Joining webm videos under Linux

3 Answers3