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Timecode discontinuity

2013-04-12
2013-04-12
  • CUT Productions

    CUT Productions - 2013-04-12

    Hi Philip,

    I thought it was all working with bmxtranswrap but I can only transcode the picture alone.

    I have prepared a sequence in Avid, starting at 09:58:00:00, with programme start at 10:00:00:00. All tracks are mixdowns with the same timecode: video and 4 24bit 48Khz tracks. Exported from Avid via AAF as Avid mxf and renamed as video and audio1-4.

    I am getting "ERROR: Timecode discontinuity between sequence track segments" if I use "bmxtranswrap.exe -p -t as11op1a --ps-avcihead -o example.mxf video.mxf audio1.mxf audio2.mxf audio3.mxf audio4.mxf".

    Any suggestions as to what is causing this?

    Regards,

    Steve

     
  • Philip de Nier

    Philip de Nier - 2013-04-12

    bmxtranswrap assumes the MXF files are a sequence if they don't belong to the same clip. This allows joining clips spanned across multiple P2/XDCAM cards. It checks that the timecode is continuous and that is why you get the timecode discontinuity error.

    Use the --group option to force bmxtranswrap to treat the MXF files as a group (/clip).

    Philip

     
  • CUT Productions

    CUT Productions - 2013-04-12

    Hi Please disregard this I think I have solved it with "--group".

    Regards,

    Steve

     
  • CUT Productions

    CUT Productions - 2013-04-12

    Hi Philip I discovered your answer by my own trail and error and cross paths with you on replying to this thread.

     
  • CUT Productions

    CUT Productions - 2013-04-12

    Sorry Philip, one more thing. The sequence now defaults to 00:00:00:00 and fails in the DPP metadata tool on material start.

    I assume I need to add "-y 09:58:00:00"? But the help says: -y <hh:mm:sscff> Override input start timecode. Is drop frame when c is not ':'. which is unclear. c = drop frame and : = non-drop frame?</hh:mm:sscff>

    Thanks,

    Steve

     
  • Philip de Nier

    Philip de Nier - 2013-04-12

    Yes, use -y to override the timecode read from the input files. Do the input files not have a material timecode set (run mxf2raw.exe -i <filename> to see it)?</filename>

    The format is hh:mm:sscff, and so if the character 'c' is a ':' then the timecode is non-drop frame; otherwise it is interpreted as a drop frame timecode. E.g. 09:58:00:00 non-drop, 09:58:00;00 or 09:58:00x00 drop. ';' sometimes has special meaning in commandline and so another character can be used instead.

    Philip

     
  • CUT Productions

    CUT Productions - 2013-04-12

    Ok thanks,

    The --group command seems to wipe out the timecode and reset it to 00:00:00:00 for the sequence. I have successfully transcoded an output DPP AS11 file now with a sidecar XML. I tried both 'c' and ':' (both worked) but I did assume ':' would be the correct non-drop.

    The correct working command-line now is:

    "bmxtranswrap.exe -p -t as11op1a --ps-avcihead -y 9:58:00:00 --group -o example.mxf video.mxf audio1.mxf audio2.mxf audio3.mxf audio4.mxf"

    Steve

    p.s I would make that help line for -y clearer.

     
  • Philip de Nier

    Philip de Nier - 2013-04-12

    Good to hear that it works.

    The --group option shouldn't wipe out the timecode if all the input files have the same material timecode. My guess would be that either they don't have a material timecode (maybe only a source or physical timecode) or they are different. Running mxf2raw.exe would have confirmed it.

    Yes, you should use ':' in the timecode string. A timecode using 'c' works in your case because it is ignored for 25fps which can't have drop frame timecode.

    Philip

     
  • CUT Productions

    CUT Productions - 2013-04-12

    The answer must be in the former as I can vouch they are all, video and audio tracks, 09:58:00:00.

    What is the command line to check them in mxf2raw.

    Many thanks,

    Steve

     
  • Philip de Nier

    Philip de Nier - 2013-04-12

    Command to get info is: "mxf2raw.exe -i filename.mxf". Look for "Material start timecode" and "File src start timecode" in the output.

    If you want Avid info as well then add "--avid" option. If you want AS-11 info then add "--as11".

    Philip

     
  • CUT Productions

    CUT Productions - 2013-04-12

    Many thanks Philip, I'll report back.

    BTW the reason for my interest in AAF send to before is that AAF is the only way to get this kind of essence out of pre Media Composer 6.5. You can of course just copy (or work directly from) the original Avid .mxf media but it is more cumbersome and risky.

    Regards,

    Steve

     
  • CUT Productions

    CUT Productions - 2013-04-12

    Yes you are quite right, whilst the video.mxf has a material start TC of 09:58:00:00, the audio tracks have only a physical src start timecode of 09:58:00:00.

    It's not a major problem now that the command-line takes care of it, but do you have any idea what might have caused that?

    Regards,

    Steve

     
  • Philip de Nier

    Philip de Nier - 2013-04-12

    OK, thanks. I'm not really familiar with the workings of Avid and so don't know what could have caused the difference. Maybe it is related to the fact that the video and audio are in different clips, and that the timecode is being applied to only one of the clips, i.e. the video clip.

    Philip

     
  • CUT Productions

    CUT Productions - 2013-04-12

    Yes I think you could be right. The only option to get the sequence out properly via AAF was to do a video mixdown and a consolidate of the audio (there was no mixdown option for audio) So I suspect there is a distinction in the way Avid addresses the metadata for the two methods?

    Do you have any suggestion for creating a .DPT template for the DPP Metadata app?

    Many thanks,

    Steve

     
  • CUT Productions

    CUT Productions - 2013-04-12

    It's OK Philip,

    I discovered I can save any sidecar with a .DPT extention as a template.

    Thanks very much for all your help,

    Steve

     
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