Cannot open (in Avidemux) an MPEG created by Avidemux

[wiven57]

Hello all,

Pretty new to video editing, and thank you in advance for your help. I saw a thread with a similar error for trying to open HD ts files, but I haven't seen this particular problem yet so here goes--

I created a bunch of shortened videos from MPEG files with Avidemux, using the "copy" options for video and audio and the "video only" option for output, since I didn't need the audio. All seemed to be good, videos open up fine in Windows Media Player and other programs. Then I wanted to edit the videos further, but when I go to open the cut videos in Avidemux, I get the "Cannot find demuxer for..."/"Cannot open file" errors. I don't see any options to change for reading files, and I think this is the relevant part of the log file...?

[HandleAction] ************ OPEN_VIDEO **************
[TS Demuxer] Probing...
[checkMarker] [Ts Demuxer] Sync ok :18 Sync ko :3911
[checkMarker] [Ts Demuxer] Sync ok :18 Sync ko :3904
[detectTs] [TS Demuxer] Not a TS file
[TS Demuxer] Not a ts file
[flvHeader] Cannot open that
[mkvHeader] Cannot open that
[MP4] Cannot open that...
[mxfHeader] Cannot open that (b3010000)
[openDML] Cannot open that
[picHeader] Cannot open that
[asfHeader] Cannot open that
match :0 / 455 (probeSize:1048576)
[PS Demuxer] Not a ps file
[HandleAction] ************ OPEN_APP_LOG **************

I am running Window 7. Any suggestions on what I'm doing wrong? I'm really hoping it wasn't a major error in how I saved the files from the first cut because going back and editing the original files again would be quite laborious...

Thanks for your help!

[AQUAR]

Probe the video with Mediainfo (free program!) and post the info.

[wiven57]

This info?

General
CompleteName                     : C:\Users\Tina\Dropbox\Shared projects\Peromyscus videos-spring 2014\practice videos-Feb 25\oft-102.mpg
Format                           : MPEG Video
Format_Version                   : Version 2
FileSize/String                  : 135 MiB
Duration/String                  : 5mn 0s
OverallBitRate/String            : 3 773 Kbps

Video
Format                           : MPEG Video
Format_Version                   : Version 2
Format_Profile                   : Main@Main
Format_Settings_BVOP/String      : Yes
Format_Settings_Matrix/String    : Default
Format_Settings_GOP              : M=3, N=15
Duration/String                  : 5mn 0s
BitRate/String                   : 3 766 Kbps
Width/String                     : 720 pixels
Height/String                    : 480 pixels
DisplayAspectRatio/String        : 4:3
FrameRate/String                 : 29.970 fps
Standard                         : NTSC
ColorSpace                       : YUV
ChromaSubsampling                : 4:2:0
BitDepth/String                  : 8 bits
ScanType/String                  : Progressive
Compression_Mode/String          : Lossy
Bits-(Pixel*Frame)               : 0.364
TimeCode_FirstFrame              : 00:00:08:13
StreamSize/String                : 135 MiB (100%)

[AQUAR]

I think avidemux is looking for a video stream in the .mpg file of the MPEG TS/PS format and not finding any.
Maybe you gave it the wrong file extension or more likely you probably just saved an elementary mpeg video stream without putting it into a media container (.m2v file?).
I would try to put the video stream into an MKV container and then load it into avidemux.
Try MKVToolnix - just load the .mpg file and hit remux - this new .MKV file will/should be recognisable by avidemux.
No recoding involved here so no loss of detail.

[snork]

[ââ,¬Â¦] or more likely you probably just saved an elementary mpeg video stream without putting it into a container (.m2v file?).

In this case (.m2v file) You can use avidemux 2.5.6, that one will open .m2v files fine. It does not even matter, if those files are named *.m2v (correctly) or *.whatever instead.

For me (also windows user) avidemux 2.6.7 does just not open those, with the same complaints in the log as wiven found them.

[AQUAR]

Yes, the 2.5.6 branch is more complete for these older codecs.
It has no problem opening these video only mpeg containers.

But if you wan't to use the 2.6 branch you have to place the video stream into a media container it knows how to demux.
Hopefully mean will add "m2v" functionality in due course.

[AQUAR]

Just one other point I came across whilst playing with 2.6 for this issue:
Using avidemux_r9034_win32, encoding to mpeg2(ff) into the video only muxer option, the 'saving progress window' is unresponsive .
That is the progress/feedback fields remain empty eventhough the encoding is being performed.
I'll check to see if that is still the case on my other PC for win64. 

[wiven57]

Thanks so much for the responses. Interestingly, when I tried to open the video in MKVToolnix, I get the following error--

Error: Found B frame without second reference in a non closed GOP. Fix the MPEG2 video stream before attempting to multiplex it.

Thoughts?

I also don't see an option for a Windows download of 2.5.6? I tried downloading and extracting the tar.gz file (with 7-Zip) but couldn't seem to get it working...

Thanks again for your help!

[AQUAR]

You can find avidemux v2.5.6 on sourceforce.
http://avidemux.sourceforge.net/download.html

Just a layman's attempt to make sense of that MKVToolnix error (as always!):
I guess being a B frame, it's not finding the frames its referencing.
It needs data from these referenced frames for reconstructing the picture in its own frame.
As the MPEG was encoded with open GOP, these GOP's are not independant.
Hence those referenced frames may be in another GOP (previous GOP?) and thats not so good for editing.
And it seems not so good when remuxing either because of these 'orphan' B frames.
That's just my thought and maybe way inaccurate.

If anyone here knows about this MKVToolnix error it would be interesting to share.

Anyway: try Avidemux 2.5.6 to mux and/or edit the elementary mpeg stream.
It may well just index the mpeg file and drop/ignore those unresolved B frames.