[FFmpeg-trac] #5686(ffmpeg:new): Concat Demuxer doesn't work, Concat Protocol does, but too many files!

[FFmpeg]

#5686: Concat Demuxer doesn't work, Concat Protocol does, but too many files!
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             Reporter:  EJacobs      |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:  ffmpeg       |                  Version:
             Keywords:  concat       |  unspecified
  protocol                           |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
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 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.

 :(

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Ticket URL: <https://trac.ffmpeg.org/ticket/5686>
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