Concat Demuxer doesn't work, Concat Protocol does, but too many files!

[EJacobs]

Hi!

Using FFmpeg N-80892-g2a8dadb, 32 bit

I have to join many video segments.

Concat demuxer doesn't work. First segment (0.mp4) contains header information that rest of segments don't contain (1.mp4 2.mp4 etc.).

Concat demuxer returns error:

[mov,mp4,m4a,3gp,3g2,mj2 @ 03965900] could not find corresponding trex
[mov,mp4,m4a,3gp,3g2,mj2 @ 03965900] error reading header
[concat @ 003e2320] Impossible to open '1.mp4'

Concat protocol works without errors.

However the string size limitation prevents entering the whole command string with all of the video segments. Need to use Concat Protocol, but with a text file so I can specify all segments.

Issue 4860 requested this; it was closed with "Won't fix" and "Use demuxer."

But demuxer doesn't work in this case!

To reproduce:

Attached 5 segments to this ticket, including first 0.mp4 and video.txt file.

Run Demuxer:

ffmpeg.exe -f concat -i "video.txt" -c copy "video.mp4"

Get above error.

Run Protocol:

ffmpeg -i "concat:0.mp4|1.mp4|2.mp4|3.mp4|4.mp4" -c copy video.mp4

Works.

Limited by command string size.

:(

[Elon Musk]

Use cat.