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pirateprentice

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Posts posted by pirateprentice


  1. Without a firmware upgrade to fix the bogus file export, then probably not. I don't see that happening on these old boxes now.

    So the 'simplest' option for PC or Mac is likely to be a Python script that uses multiple steps of a command-line program such as ffmpeg.
    I don't really have the time to do that at the moment.

    If you had, say, a couple of important AVI files (with audio!) that you needed fixing, and you don't mind sending them to me via something like Dropbox, I could fix them with my custom software and send them back to you.
    That would count as 'simple' but obviously I wouldn't be able to offer this as a routine service.

    Paul


  2. I finally managed to solve this (if anybody still interested) but it involved a bit of programming.

    The problem is that the file header declares 25Hz (or whatever the unit is set to) but the actual frame rate is 8Hz, 13.5Hz or other random number, so it plays incorrectly.

    If exported as AVI file, however, the audio is declared correctly, so the correct duration is known, and then dividing that by the number of frames gives the actual frame rate, which can then be overwritten back in the file. I wrote a bit of software to do this, but its for linux. Anyone who'd like to do a windows/mac version is welcome to the source code.

    The output is a file that plays with correct frame rate (13.5Hz or whatever) and with the audio intact. I then use ffmpeg to resample the video to a standard rate like 30Hz, again preserving audio.

    Has this problem been fixed on newer Swann units?

     


  3. I've had this same problem with my NVR-7300. I had not realised that it only applies at night (which is when my wildlife footage happens). I guess either the cameras or the DVR cannot apply 'night' processing at the speed needed for 25fps. However, the files exported still have 25 in the header as the frame rate. This means that the quote from Swan that RacingSnake got in a post above is misleading:

     

    For the playback speed, this is due to the player assuming the frame rate rather than reading the header. The native player plays at normal speed. To improve the night vision quality the camera has a dynamic frame rate while in night mode to ensure the best image. You can turn this off and force full frames but it can result in reduced night image quality.

     

    Do we know what the "turn this off and force full frames" setting actually is, anybody?

     

    The problem is that the files say FR=25 even when it is slower (around 12fps I usually find, although it seems to vary). So any playback software plays it at 25fps, which is then speeded up. It makes no difference if the files are exported raw (.264) or in AVI mode - thats just about the file wrapper.

     

    Partial solution: I use the software ffmpeg (https://ffmpeg.org) to change the frame rate, using the command:

    > ffmpeg -r 12 -i output_file.mp4

    - where 12 is the guessed frame rate. I have to trial and error until the output file plays at the right speed.

    But, this does not keep the audio. I think the only solution to that is to record off the audio output of the unit itself and then combine with the corrected video. Ugh! Any other ideas for audio?

     

    I also tried Swannview Link on android, using playback and then the 'record video to phone' function. But those files were the same - they say 25fps but are lower.

     

    One thing I need to try is to set the camera to run at (say) 10fps and see if that produces correct speed files. Will report...

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