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Keep dropping frames

Discussion in 'Video capturing from analog sources' started by Nilis, Jun 3, 2004.

  1. Nilis

    Nilis Member

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    Ok I here is my situation: I have a lot of old vhs tapes that need to be saved ;) I just bought 2 Hitachi 160GB SATA drives and made a RAID 0 setup so you probably think that the writing to disk should be fast enough. I captured like 28min of video in full pal resolution using the lossless Huffyuv codec but I still seem to have dropped 48 frames. How is this possible CPU usage never came above 25%.

    BTW how to check the framerate of my vhs tapes?

    Ok it seems that vdub ads and removes frames to keep the video and audio clock synchronized. That still leaves my 2nd question last question. And here is an aditional one. When I view the source video and put it full screen there are no bleck bars but when I capture at 720x576 there are blackbars on the both sides of the screen when the captured video is played full screen. Do I need to capture at a different resolution?
     
    Last edited: Jun 3, 2004
  2. Minion

    Minion Senior member

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    Yes..Virtual-Dub Dropps and adds Frames so it can keep sync with the Audio being Captured...But the thing with this is when it adds Frames and Dropps Frames to keep sync this Changes the Frame rate slightly so when you encode the File to Mpeg2 for DVD it will go out of Sync because the file is being encoded to a Slightly different Frame rate....
    This method of Keeping sync is only effective if leaving the File in AVI format but not if you have to encode the File to mpeg....
    You should be useing a Capture program that compensates for the Time lag between the Audio and Video by dynamicly resampleing the audio so it keeps sync with the Video.....
    Some programs that do this are Virtual_VCR and IU_VCR or even useing the "MainConcept Encoder" to capture as it has the Proper Syncing Feature ,but to enable the Proper Syncing feature you have to set the "Video" Stream as the "Master" Stream....

    When you Wiew the Source Video in Full screen the Video Gets stretched so it Fulls up the Screen but it also is being displayed in an Incorrect resolution...But when you Preview the Captured file in Full screen it doesn"t get stretched so Black bars get added so it fills up the Screen...The Black bars aren"t Part of the File ,They are added by the Media Player so it can Play in Full screen without distorting the Resolution or Aspect ratio.....
    So if you are Captureing at 720+576-Pal then that is the Correct resolution for Captureing to Pal for DVD....

    You didn"t need to get a SATA Raid array to Capture video...I have a 160gb ATA/133 drive and it captures Uncompressed AVI at Full resolution (1.2gb/Per Min) without dropping frames....But I"m sure that haveing a raide array can come in handy at times.....

    well good luck.....Cheers
     
  3. Nilis

    Nilis Member

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    Thanx for the info. But it basically comes down to not capture the vhs tapes with vdub if I want to make an dvd, but I should use one of the program you suggested?

    Yesterday I tried burning a svcd, as I do not have my dvd-burner yet, and I played it on my dvd but somehow it looked a jumpy :S
     
  4. Minion

    Minion Senior member

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    If your SVCD Looked Jumpy while Playing back then it is probably because of Interlaceing...
    It can cause a jumpy effect in Scenes with a Lot of Motion, this is usually caused because the Field order is Reverced but even when the field order is set correctly you can still get a Jumpy effect...To stop this you need to de-interlace your File when encodeing it to mpeg2/SVCD...
    What encoder do you use to Create your SVCD Files???
    Tmpgenc has a Good De-interlace Filter actually it has a Choice of 16 different filters but Tmpgenc is a Fairly slow Encoder, If you want to use a faster encoder then the MainConcept encoder is Good, It can also capture Video to both Mpeg1/2 and AVI formats but you get better quality captureing to AVI then encodeing it to Mpeg2/SVCD or DVD....
    Virtual-Dub isn"t the best to capture with if you want to eventually make a VCD/SVCD/DVD because it only has one way of keeping sync...You can use Virtual_VCR or any program that has a Syncing feature were you can set the Master Stream to Audio or Video..
    If you choose the Audio as the Master stream it will Change the Frame rate to keep sync with the audio like Virtual-Dub does but if you choose the "Video" as the Master stream then it dynamicly changes the Audio sample rate so the audio keeps sync with the Video....
    But sometimes that feature doesn"t allways keep perfect sync especially in long movies and depending on the program so at the end of Capture the Audio can still be out of sync with the Video because the audio and Video lengths are different but this can usually be fixed by useing an audio editor like Goldwave to Stretch/Shrink the audio in the avi file to the length of the Video and that usually Re-Syncs the audio and Video and it is easy to do.....
    well good Luck...Cheers


    PS: If your VHS Tapes are Pal VHS Tapes then there Frame Rate is 25fps....
     
  5. Nilis

    Nilis Member

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    Aah I thought I did not need to deinterlace as I was going to watch it on a tv. I captured the vhs, mtb stuff with lots of high speed motion, tape to avi with virtualdub and after that I made the svcd using WinDVD Creator Platinum as i have a legal version of that one. It showed no options it was just like import the file add some menu and transition effects and burn it. I'll have a look around to see if it has deinterlace options. I also have a legal versionof Powerdirector Pro 2.55 and offcourse tmpegenc but that is a 30day trail. Encoding speed is not really important.

    About the framerate. I allways thought it would be PAL but I hade fraps on sometime and it showed 30fps. But somehow I cannot get it to show FPS again on video.
     
  6. Minion

    Minion Senior member

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    You should not be useing Programs Like "WinDVD Creator" and "PowerDirector" to convert your Files to Mpeg format because they use Low Quality Mpeg encoders so you will Never get the best results useing one of those Types of Programs to encode your Captured AVI files....
    You should be useing a High Quality Standalone Mpeg encoder Like the MainConcept Encoder or Tmpgenc to encode your AVI files to Mpeg format ....
    These encoders have the Option to de-interlace while encodeing to Mpeg and they will Produce MUCH better Quality than the Programs you have been useing and then can produce the Better quality useing a Lower Bitrate so you can fit more video on a CD/DVD and with better Quality....


    All though it is Theoreticly true that you shouldn"t see Interlace Lines while watching on an Interlaced TV that doesn"t take into account that your Field Order could be Reverced or that your Field order can be getting reverced back and Forth a few times durring the Capture which there is No way of fixing unless you deinterlace and these types of Problems pop up all the Time when recording Old Footage....

    If you Truely Live in a Pal country and your VHS Tapes are Truely Pal VHS Tapes then the Frame Rate MUST be 25fps because Pal doesn"t use any other Framerate....
    NTSC usees Framerates of 23.976/24fps and 29.976/30fps....

    Cheers
     
  7. Nilis

    Nilis Member

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    Ok I'll use tmpgenc for encoding to mpeg and only use those silly programs to author and burn. thanx again for the advice.
     

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