[FFmpeg-user] Mjpeg mp4 concat issue

[balasubramanya]

Hi All,

  I am new to this forum but old user of ffmpeg. 

I am using ffmpeg to convert/merge video files(in mp4 format) without
re-encoding. I have few mjpeg files which I would like to merge. I am using
following command to do my task.

*scenario 1: using concat*

ffmpeg.exe -i "concat:1.mp4|2.mp4" -c copy -f mp4 out.mp4
I am getting following log and the output contains data of only 1 video
file. [mjpeg @ 024e2f80] overread 8 error is also observed.



[mjpeg @ 024e2f80] overread 8
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'concat:1.mp4|2.mp4':
  Metadata:
    compatible_brands: qt  isom
    major_brand     : qt
    minor_version   : 0
    creation_time   : 2013-09-10 04:36:27
  Duration: 00:00:24.70, start: 0.000000, bitrate: 4021 kb/s
    Stream #0:0(eng): Video: mjpeg (jpeg / 0x6765706A), yuvj420p, 800x600
[SAR 1:1 DAR 4:3], 1715 kb/s, 10 fps, 10 tbr, 600 tbn, 600 tbc
    Metadata:
      creation_time   : 2013-09-10 04:29:50
      handler_name    : Alias Handler
    Stream #0:1(eng): Video: mjpeg (jpeg / 0x6765706A), yuvj420p, 800x600
[SAR 1:1 DAR 4:3], 1699 kb/s, 10 fps, 10 tbr, 600 tbn, 600 tbc
    Metadata:
      creation_time   : 2013-09-10 04:36:27
      handler_name    : Alias Handler
Output #0, mp4, to 'out.mp4':
  Metadata:
    compatible_brands: qt  isom
    major_brand     : qt
    minor_version   : 0
    encoder         : Lavf54.59.106
    Stream #0:0(eng): Video: mjpeg (l[0][0][0] / 0x006C), yuvj420p, 800x600
[SAR 1:1 DAR 4:3], q=2-31, 1715 kb/s, 10 fps, 19200 tbn, 600 tbc

    Metadata:
      creation_time   : 2013-09-10 04:29:50
      handler_name    : Alias Handler
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
Press [q] to stop, [?] for help
frame=  334 fps=0.0 q=-1.0 Lsize=    6996kB time=00:00:33.30
bitrate=1721.1kbits/s
video:6994kB audio:0kB subtitle:0 global headers:0kB muxing overhead
0.030340%


*scenario 2: using file convert and concat*

a. ffmpeg.exe -i 1.mp4 -c copy -f avi 1.avi

b. ffmpeg.exe -i 2.mp4 -c copy -f avi 2.avi

c. ffmpeg.exe -i "concat:1.avi|2.avi" -c copy -f mp4 out.mp4


Input #0, avi, from 'concat:1.avi|2.avi':
  Metadata:
    encoder         : Lavf54.59.106
  Duration: 00:00:33.35, start: 0.000000, bitrate: 3068 kb/s
    Stream #0:0: Video: mjpeg (jpeg / 0x6765706A), yuvj420p, 800x600 [SAR
1:1 DAR 4:3], 20 tbr, 20 tbn, 20 tbc
File 'out.mp4' already exists. Overwrite ? [y/N] y
Output #0, mp4, to 'out.mp4':
  Metadata:
    encoder         : Lavf54.59.106
    Stream #0:0: Video: mjpeg (l[0][0][0] / 0x006C), yuvj420p, 800x600 [SAR
1:1 DAR 4:3], q=2-31, 10240 tbn, 20 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
Press [q] to stop, [?] for help
frame=  581 fps=0.0 q=-1.0 Lsize=   12122kB time=00:12:51.35 bitrate=
128.7kbits/s
video:12119kB audio:0kB subtitle:0 global headers:0kB muxing overhead
0.026149%


In this scenario the resultant file after (c) contains both file data but
the frame rate changes to 

[mov,mp4,m4a,3gp,3g2,mj2 @ 01f87a60] max_analyze_duration 5000000 reached at
5310499
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'out.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2mp41
    encoder         : Lavf54.59.106
  Duration: 00:12:51.35, start: 0.000000, bitrate: 128 kb/s
    Stream #0:0(und): Video: mjpeg (mp4v / 0x7634706D), yuvj420p, 800x600
[SAR 1:1 DAR 4:3], 128 kb/s, 0.75 fps, 10 tbr, 10240 tbn, 10240 tb
c
    Metadata:
      handler_name    : VideoHandler
At least one output file must be specified



where as original input details are 


Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '1.mp4':
  Metadata:
    major_brand     : qt
    minor_version   : 0
    compatible_brands: qt  isom
    creation_time   : 2013-09-10 04:29:50
  Duration: 00:00:33.40, start: 0.000000, bitrate: 1716 kb/s
    Stream #0:0(eng): Video: mjpeg (jpeg / 0x6765706A), yuvj420p, 800x600
[SAR 1:1 DAR 4:3], 1715 kb/s, 10 fps, 10 tbr, 600 tbn, 600 tbc
    Metadata:
      creation_time   : 2013-09-10 04:29:50
      handler_name    : Alias Handler
At least one output file must be specified

and 

Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '2.mp4':
  Metadata:
    major_brand     : qt
    minor_version   : 0
    compatible_brands: qt  isom
    creation_time   : 2013-09-10 04:36:27
  Duration: 00:00:24.70, start: 0.000000, bitrate: 1700 kb/s
    Stream #0:0(eng): Video: mjpeg (jpeg / 0x6765706A), yuvj420p, 800x600
[SAR 1:1 DAR 4:3], 1699 kb/s, 10 fps, 10 tbr, 600 tbn, 600 tbc
    Metadata:
      creation_time   : 2013-09-10 04:36:27
      handler_name    : Alias Handler
At least one output file must be specified



I am using ffmpeg 1.1.3 version. Can some one help me to fix this issue. I
can provide test contents if required.

Regards,
Bala




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