Append one file to another using FFMPEG

Question

All the FFMPEG examples show how to take file1 + file2 and write result to the file3.

Is FFMPEG just able to open file1, seek to the end and then append file2, without creating the third, intermediate, file?

I would like to make a Windows Explorer context menu item. Each run of this item will append the clicked file to a file with specific name.

Answer 1

We may use pipe: as output, and >> shell operator for appending.

Example for appending input2.ts to the end of input1.ts:

ffmpeg -i input2.ts -c copy -f mpegts pipe: >> input1.ts