newbie Q direct editing mpg streams

Discussion in 'Professional Video Production' started by anern, Oct 1, 2008.

  1. anern

    anern Guest

    Hi,
    I'm currently using Vegas to edit TV programs captured from a DVB-T
    card, to trim start, end and remove ads. Is there a way of doing this
    without decompressing/recompressing, IE just cut out the bits I don't want
    and create a new file in the origonal format. I also want to do this with
    other file formats.

    Cheers,

    Bruce.
     
    anern, Oct 1, 2008
    #1
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  2. anern

    Netmask Guest

    ProjectX http://www.oozoon.de/main_en.html is the best to do this as it
    fixes a lot of transmission errors as it demuxes and you can do simple
    edits. However you then have to mux the audio and video back together and
    it's interface is a bit toxic until you find your way around. but a program
    that is worth having. It is the only program to demux all streams audio,
    video and subtitles (specify page number) from DVB-T transmissions

    By far the easiest non re-encoding program for DVB-T derived files to MPEG2
    is MPEGStreamclip http://www.squared5.com/ it has a good interface, is MAC
    and PC compatible and you can convert to Quicktime and a few other formats
    (it will re-encode in this case). This program is quite popular in the
    Topfield http://www.topfield-australia.com.au/ and Beyonwiz
    http://www.beyonwiz.com.au/DP_P1_overview.asp community
     
    Netmask, Oct 2, 2008
    #2
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  3. anern

    Netmask Guest

    follow up you could take a look at Womble it does stream copy mode on DVB-T
    MPEG2 files - a simplified (extremely) Vegas with 4 time lines for video
    with or with out sound, Title track, and 2 audio tracks and will read TS,
    Topfield Rec files etc..
     
    Netmask, Oct 2, 2008
    #3
  4. anern

    anern Guest

    Hi,
    Thanks, I'll go try them. I was kind of suprised the mainstream editors
    did'nt offer this sort of thing, Maybe I'm just being pickey about
    degredation as a result of the decode/recode process.
     
    anern, Oct 2, 2008
    #4
  5. anern

    Netmask Guest

    Womble is very quick in streamcopy mode - a couple of minutes for a 1 hour
    program
     
    Netmask, Oct 2, 2008
    #5
  6. "anern" wrote ...
    The "mainstream editors" were mostly made for professional or
    semi-pro use. Professionals tend to use the traditional file formats
    (such as DV-AVI) which are much less compressed, and are
    designed for editing.

    OTOH, MPEG was designed as a release format (because its
    strong suit is serious compression to achive maximum distrbution
    efficiency). MPEG and other temporally-compressed codecs
    were not orignally intended to be edited. They were designed
    as one-way, release-only encoding schemes.

    But in recent years, many end-user consumers (such as yourself)
    have wanted to edit (mostly just trim out commercial breaks, etc.)
    MPEG that they recorded off the air Since this is not exactly a
    "professional" application, the "mainstream editors" aren't exactly
    the place to find such functionality. That is why a new breed of
    consumer apps (Womble, etc.) have appeared which were
    explicitly designed to edit MPEG and similar temporally-
    compressed codecs.

    Unless you are doing simple cuts editing exactly on an I-frame,
    the editing application has to decode the intermediate frame(s)
    content, and apply your editing changes, then re-encode back
    to MPEG. While this is efficient in terms of file size and
    distribution/storage size, it produces visible artifacts as a result
    of the decoding and re-encoding. But then MPEG was not
    origially intended as a production format for this very reason.
    http://en.wikipedia.org/wiki/MPEG-2
     
    Richard Crowley, Oct 2, 2008
    #6
  7. anern

    Netmask Guest


    The OP was not wanting a lecture in the history of editing or file types as
    he clearly stated what his intentions were ie simple top and tailing of
    DVB-T files

    ......"Hi,
    I'm currently using Vegas to edit TV programs captured from a DVB-T
    card, to trim start, end and remove ads. Is there a way of doing this
    without decompressing/recompressing, IE just cut out the bits I don't want
    and create a new file in the original format. I also want to do this with
    other file formats.

    Cheers,

    Bruce. ............"

    So simple programs like VideRedo or Womble as mpeg editors are good enough
    for this application and probably quicker and easier to use...
     
    Netmask, Oct 4, 2008
    #7
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