Concatenate TS files with correct timestamps

Question

I'm trying to merge multiple ts chunk files to one single file, without any loss of quality or reencoding. The files are taken from a live stream, however I'm trying to merge them in a diffrent order and not the order they were streamed.

Example of files:

0000000033.ts
0000000034.ts
0000000039.ts
0000000044.ts

I tried:

cat 0000000033.ts 0000000034.ts 0000000039.ts 0000000044.ts >combined.ts

and

ffmpeg -i "concat:0000000033.ts|concat:0000000034.ts|concat:0000000039.ts|concat:0000000044.ts" -c copy -bsf:a aac_adtstoasc output.mp4

This kinda works, however I instead of beeing 4 seconds long it's around 15. It plays this way:

[first 2 clips]
[5 secs pause]
[39.ts]
[5 secs pause]
[44.ts]
[done]

This happens to both the cat and ffmpeg combined version. So it seems the ts chunks contain timestamps from the stream that are beeing used.

How can I fix that to make it one continous clip?

The chunks here are more of an example, the chunks will be dynamically selected.

Solution 1

If you have a long list of TS files, you can create a playlist, a file containing a list of the TS files in this line format:

    file 'seg-37-a.ts'

These commands produce such a file, with the TS files sorted numerically.

    delimiterBeforeFileNumber="-"
    ls |egrep '[.]ts$' \
        |sort "-t$delimiterBeforeFileNumber" -k2,2n \
        |sed -r "s/(.*)/file '\1'/" >ts.files.txt

Then the creation of the single file can read the playlist using the -f concat modifier of ffmpeg's -i option.

    ffmpeg -f concat -i ts.files.txt -c copy tsw.014.ts.mp4

Solution 2

Haven't checked whether this works with the concat protocol, but you need to generate a new set of timestamps.

ffmpeg -i "concat:0000000033.ts|0000000034.ts|0000000039.ts|0000000044.ts" \
       -c copy -bsf:a aac_adtstoasc -fflags +genpts output.mp4