Newbie Question - Do I have to encode twice?

Discussion in 'Amateur Video Production' started by Eric, Apr 1, 2004.

  1. Eric

    Eric Guest

    Very new to this DVD burning stuff... I dump my digital video camera
    to AVI files about 4gig for 1 hour. Then in ULead VideoStudio I
    convert them down to MPEG-1 which is fine quality for what I need. I
    would like to fit a few hours on one DVD. The conversion takes a
    while (maybe 2 hours) on my AMD Athlon 1600+. Now I have a file
    200mb.

    All is fine up to this point. Now I want to get these MPEG-1 files on
    a DVD. When I run them through a DVD creator like Roxio or ULead, it
    takes about 10 hours of 'encoding'. Can I just COPY them to a blank
    DVD? Would they play? Is there anyway to copy them and create a
    menu? Something like that blue default menu with bars of track info.
    I REALLY don't need/want any fancy menus.
     
    Eric, Apr 1, 2004
    #1
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  2. Eric

    Eric Guest

    Like I said... New to this stuff...

    I converted them from AVI to MPEG-1 thinking that they would be a lot
    smaller and I can fit that many more clips on one DVD. For example, 6
    hours of TV shows. The same way a stand-alone DVD recorder can record
    6 hours or so at it's worst quality. Is this not the correct way to
    do it?

    Do I want to just use some program to convert my AVI to VOB and then
    just copy the VOB's to the video_ts directory on a blank disc? Can I
    do that?

    Eric
     
    Eric, Apr 2, 2004
    #2
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  3. Eric

    Will Dormann Guest

    If you want 6 hours on a single DVD, then you're going to want to use
    1/4 D1 resolution and somewhere around a 1500 kbit average bitrate. I
    don't think it'll look too nice, though. Going from AVI to MPEG1 to
    MPEG2 is obviously one step too many. Have a look at www.dvdrhelp.com

    No. But authoring programs like DVD-Lab will take your DVD-ready MPEG2
    files and just remultiplex them into VOB files. (Without needing to
    re-encode).


    -WD
     
    Will Dormann, Apr 2, 2004
    #3
  4. Eric

    Bariloche Guest

    That's how I encoded myself, so far, when trying to pack as much as
    possible within a DVD. But now I'm doing it (1/4 D1) with CQ 65%. It
    may mean a higher bitrate than 1500 when needed -but then, it's
    needed. CQ, whenever possible, gives you the best benefits from VBR,
    while using 1-pass encoding (faster). There's a drawback, indeed: you
    cannot calculate the final size precisely. But better leave it to
    chance wether you pack 4 hours or 7 on disc.
     
    Bariloche, Apr 3, 2004
    #4
  5. Eric

    Mike T Guest

    Using the CQ mode in TMPGenc is by far the best mpeg encoding, but you are
    right that the final file size is difficult to control. If you can access
    this group- which is a discussion group, no files
    posted, then they have a method using AVISynth to creat a script that will
    encode 5 seconds of every minute of the entire video file using the CQ
    setting in TMPGenc. This way you have a pretty good sample of the full
    video and can quickly adjust the CQ setting to get the desired final file
    size. This site http://www.svcd.cc has the info, but it costs $20/year and
    is worth it. If you post a question to the above group, you will usually
    get help and a link to the info on using the CQ mode.

    Mike T
     
    Mike T, Apr 3, 2004
    #5
  6. Eric

    Bariloche Guest

    Unfortunately, my ISP doesn't follow it, neither can it be found on
    Google.
    It should be easy to write a program that would read the AVI header,
    to find out the framecount, then writes down a script

    V=AviSource("TheClip.avi")

    V1=V.Trim(0, 150)
    V2=V.Trim(1800, 1950)
    V3=V.Trim(3600, 3750)
    ....

    Return V1+V2+V3...

    Is this what they are doing?

    I'm thinking of programming a tool that shall do that, and a few other
    things as well. Let's see if I can find some time in the near future.
     
    Bariloche, Apr 5, 2004
    #6
  7. Eric

    erratic Guest

    I saw an avisynth script like that for CCE's 1-pass VBR mode and it used
    the SelectRangeEvery command.

    For example:
    SelectRangeEvery(250,25) returns the first 25 frames (1 PAL second) out
    of every 250 frames (10 seconds). You could encode 10% of your file that
    way and then multiply the filesize by ten to get a rough idea of how big
    the completely enoded file would get (in CQ mode).
     
    erratic, Apr 5, 2004
    #7
  8. Eric

    erratic Guest

    I just remembered that for best results you should use your MPEG-2 GOP
    size as the second number, so if you use a GOP size of 12 the command
    would be SelectRangeEvery(120,12) to encode 10% of your avi file or
    SelectRangeEvery(1200,12) to encode only 1% of your avi file, etc.
     
    erratic, Apr 5, 2004
    #8
  9. Eric

    Mike T Guest

    Well, then it is time you need a better usenet provider. Below is one that
    has free service, I believed it has limited downloads, but for text groups
    this should not be a problem. http://www.teranews.com/
    I don't remember the details, just that the script allows for encoding 5
    seconds of each minute of the video to get a good representation of the
    action scenes to find the CQ setting that would give the final file size
    desired.

    Mike T
     
    Mike T, Apr 5, 2004
    #9
  10. Eric

    Ken Maltby Guest

    I also prefer a RT "CQ" VBR approach, but then I have a HW
    encoder and capture software that works best in that fashion.

    On the rare occasion that my captured DVD compliant MPEG2
    Half D1 file is too large to fit the DVD or CD I want to put it on;
    I just Author it then run it through DVD Shrink. Since with my
    normal settings the files usually fit, when they don't it is by a small
    amount and they suffer little in DVD Shrink.

    Luck;
    Ken
     
    Ken Maltby, Apr 6, 2004
    #10
  11. Eric

    Bariloche Guest

    Yes, SelectRangeEvery would be easier. But, why using 1-pass VBR mode?
    I thought the idea was encoding in CQ, then extrapolating the results
    to forecast the final file size.
     
    Bariloche, Apr 6, 2004
    #11
  12. Eric

    Bariloche Guest

    It allows you to capture CQ instead of CBR? How fine -even if I would
    not, generally speaking, use it for VHS tapes that need further
    processing (cropping, filtering) before the final mpeg encoding.
     
    Bariloche, Apr 6, 2004
    #12
  13. Eric

    erratic Guest

    One-pass VBR in CCE is similar to CQ in TMPGEnc. In TMPGEnc you select
    a quality value, in CCE a quantizer value, but the result is an
    unpredictable filesize.
     
    erratic, Apr 6, 2004
    #13
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