VideoHelp Forum

Our website is made possible by displaying online advertisements to our visitors. Consider supporting us by disable your adblocker or Try ConvertXtoDVD and convert all your movies to DVD. Free trial ! :)
+ Reply to Thread
Results 1 to 12 of 12
Thread
  1. I have a bit of a unique problem. In order to do some video analysis, I need to be able to capture a DisplayPort input at full resolution in a RAW recording (YUY2 is fine in this case). I just got in the Datapath VisionSC-DP2, and it actually works great in VirtualDub capture mode (with some extremely fast storage, of course).

    However, I am looking for a scriptable capture method, and the archaic VirtualDub scripting language does not allow for access to capture mode. We are currently using the Dual-Link DVI Version of the Datapath card for capture at 2560x1440 60hz with some cobbled together directshow graphs and that works fine, but as soon as we go to 4K, we start to drop frames and hit a bottleneck somewhere.

    Obviously next to no one is doing this sort of RAW capture, but does anyone have suggestions as to what software might be able to handle this? I've tried FFMPEG with little success. DirectShow is the only interface to this card.

    Thanks!
    Quote Quote  
  2. Banned
    Join Date
    Oct 2014
    Location
    Northern California
    Search PM
    That's gonna cost you top dollar!

    Cinedeck ZX 45 can do what you want but you better open your wallet!

    Quote Quote  
  3. Disk I/O is probably your problem. Current hard drives max out around 150 MB/s sustained. If your computer is fast enough use a lossless codec to reduce the drive I/O rate. Or use a RAID array.
    Quote Quote  
  4. Originally Posted by jagabo View Post
    Disk I/O is probably your problem. Current hard drives max out around 150 MB/s sustained. If your computer is fast enough use a lossless codec to reduce the drive I/O rate. Or use a RAID array.

    Disk I/O is not a problem, I'm using a PCIe SSD capable of 2GB/s. When I record with VirtualDub at 60hz I get no dropped or inserted frames. I'm just looking for an automated way to do the same thing, instead of having to use the VDub capture interface
    Quote Quote  
  5. Try using the dump filter for your graph output (no container, you can remux later if necessary).

    AVI for example keeps a keyframe index. It preextends the file, writes the index, then goes back to where it was to write data. When the data catches up to the index it preextends the file again, writes the index, then goes back to write data. You get long pauses each time it pre extends. Using the dump filter will just write raw data to the file with no container overhead.
    Quote Quote  
  6. I'm currently using the Capture Card -> AVI Mux -> File Writer.

    I can't find a dump filter in graph edit, is it a third party filter I have to import?
    Quote Quote  
  7. I think dump.ax came withMS GraphEdit 9. Search the forums here for dump.ax or dump.zip and you'll find copies.
    Quote Quote  
  8. I managed to create and run a graphfile to record the raw output using the dump filter, and it seems to have worked okay.

    Any recommendations on how to mux it into an AVI?
    Quote Quote  
  9. AviSynth's RawSource() should be able to handle it.

    Code:
    RawSource("YUY2.RAW", 1920, 1080, "YUYV")  # a 1920x1080 YUY2 video
    Change the file name and dimensions to suit. Open the AVS script in VirtualDub and save as AVI. Or you can open the AVS script in GraphStudio and write to an AVI file.
    Quote Quote  
  10. Originally Posted by kenaddison View Post
    I've tried FFMPEG with little success. DirectShow is the only interface to this card.

    Thanks!
    works for me
    Code:
    @ffmpeg -video_size 640x480 -f dshow -i video="USB Video Device" -c:v mjpeg -q:v 8 -dc 8 -vf format='pix_fmts=yuv422p' -y camera.avi
    dshow device query:
    Code:
    ffmpeg -list_devices true -f dshow -i dummy
    @pause
    Quote Quote  
  11. Originally Posted by pandy View Post
    Originally Posted by kenaddison View Post
    I've tried FFMPEG with little success. DirectShow is the only interface to this card.

    Thanks!
    works for me
    Code:
    @ffmpeg -video_size 640x480 -f dshow -i video="USB Video Device" -c:v mjpeg -q:v 8 -dc 8 -vf format='pix_fmts=yuv422p' -y camera.avi
    dshow device query:
    Code:
    ffmpeg -list_devices true -f dshow -i dummy
    @pause
    You can't set the ffmpeg rtbuffer large enough for 4k frame sizes, it just keeps dropping frames at that datarate.
    Quote Quote  
  12. Originally Posted by kenaddison View Post
    You can't set the ffmpeg rtbuffer large enough for 4k frame sizes, it just keeps dropping frames at that datarate.
    IMHO you can - AFAIR i've set buffer over 512MB...
    Quote Quote  



Similar Threads