Basic NTS file editor


Well-Known Member
I have been using ffmpeg to remux edited recordings, and the sidecar package to create new NTS files. I have observed some odd behaviour with H.264 video. If you rewind back to the start of a recording. The on screen time marker jumps to the end of the progress bar and stays there. You can still rewind and fast forward but if you stop playback it will not resume from the same place again, though at least doing this allows the marker to return to normal. This problem is related to the played time value (timebar display) corresponding to the variable at 0x18 for the first frame in the NTS file (see the file format document in the wiki). The value for the first frame (=0) is fine but the corresponding values for the next 2 to 6 frames (it varies) get set to a high number that is longer than the recording duration.
Using a hex editor and manually setting the above rogue values to zero fixes the problem. However, I am trying to automate the process as much as possible using a shell script. Ideally I would like to be able to use a command line NTS file editor to patch the files so this could be incorporated into the script. The editor would be similar to the existing HMT tool, but is simpler, only requiring the patch commands. af123 - at your convenience, would you be amenable to making such a tool available?
Wouldn't it be better to fix the sidecar package, or isn't it a sidecar problem?
I don't know why this happens with ffmpeg-remuxed H.264 video, but I think it is sidecar related. There are other problems with sidecar, in that it generates non-monotonically increasing timestamps. A fix for sidecar would be great, but raydon has not posted for more than six months.